must be noted that the EM38 and the DUALEM data were measured at different times with different
field soil water status. Poor relationships between MVG shape parameters and ECa datasets were
observed (0.052Ks and FF of first Archie's law and the negative relation between Ks and S_e of second
Archie's law have achieved with different sensor at various DOE.

**Conclusion**

It can be concluded that the saturated hydraulic conductivity *Ks* can be estimated by using different equations of various ECa sensors such as EM38 and DUALEM. Poor relationships between MVG shape parameters and ECa data were observed. Therefore the prediction of MVG shape parameters from an ECa dataset is highly uncertain. The negative relationship between *logKs* and S<sub>e</sub> of different sensors were obtained.
# Quantifying the uncertainties in the estimation of multilayered soil hydraulic properties at a catchment scale.

S. KRISHNAN KUTTY<fnref n="1" />, S. BUIS<fnref n="1" />, M. GUERIF<fnref n="1" />, S. MUDDU<fnref n="2" />, L. RUIZ<fnref n="3" />,<fnref n="4" />

Estimation of soil hydraulic parameters (SHP) is critical for modeling the coupled surface-subsurface processes at various scales, but the spatial variability of the parameters and insufficient data sets restricted its applicability at the catchment scale (Vereecken *et al.* 2008). Although extensive soil data is becoming more and more available at various scales in the form of digital soil maps, there is still a large gap between this available information and the input parameters needed for hydrological models. Inverse approaches using hydrological and crop model brought substantial improvement in the estimation of SHP from remote sensing observations, but this problem is still challenging. In particular, the soil layers and order/sequence of vertical heterogeneity of soil textures affect the uncertainty of parameter estimation due to complex nature of soil water in the layered soil profile (Shin et al., 2012). Several studies attempted estimating multilayered SHP by inversion of SVAT/crop model using LAI and evapotranspiration (ET) alone or in addition to SSM in model inversions (Sreelash et al., 2012; Shin et al., 2012). Though inversions with crop models provided better estimates of root zone SHP at plot scale, the large data requirements of crop model creates additional uncertainty in the estimated SHP via the uncertainty in the input data (non-estimated parameters) when applied at a catchment scale. To address this issue it is necessary to quantify the uncertainty associated with each of the input (non-estimated) parameters like agricultural practices, climate, soil parameters and vegetation parameters of a crop/SVAT model and their impact on groundwater refill.

The objective of this study is to perform such an analysis using remote sensing observations (LAI and surface soil moisture) and crop model inversion with different levels of precision to estimate the SHP and its uncertainty at a spatial scale in an agricultural catchment. The case study is provided by the Berambadi catchment (South India, www.ambhas.com), which is associated with the RBV network of Observatories of France (http://rbv.ipgp.fr/). The Stics crop model (http://www6.paca.inra.fr/stics_eng/) was calibrated for the main species cropped in the area. We consider three levels of uncertainty associated to the spatialization of the non-estimated parameters, according to the sources of data used: 1) a low level, by considering data obtained in field experiments; 2) a high level by considering the full range of values encountered on the site through a farmer survey for agricultural practices characterization and existing, poorly precise, maps and different pedotransfer functions for soil parameters definition; 3) an intermediate level by considering a smart use of field data, farmer survey, climate and soil data, in order to derive decision rules on agricultural practices. The applicability of remote sensing data for the estimation of SHP was tested by using LAI and surface soil moisture retrieved from RADARSAT-2 data. LAI was estimated from radar vegetation index (RVI) and surface soil moisture using the Water Cloud Model (Sreelash, 2014). The uncertainty associated to SHP estimates is therefore propagated to drainage fluxes estimates and allow to quantify the gain obtained from a better knowledge of crop management options in the watershed and adapted pedotransfer functions.

## References:

Shin Y., Mohanty, B. and Ines, A, 2013, Estimating Effective Soil Hydraulic Properties Using Spatially Distributed Soil Moisture and Evapotranspiration Vadose Zone Journal Volume: 12 Issue: 3.

K. Sreelash. Estimation of root zone soil hydraulic properties by inversion of STICS crop model using ground or microwave remote sensing observations. PhD Thesis, Submitted to Dept of Civil Engg. Indian Institute of Science, Bangalore, Jan-2014.

<footnote n="1">¹INRA, AVIGNON, France</footnote>

<footnote n="2">²INDIAN INSTITUTE OF SCIENCE, BANGALORE, India</footnote>

<footnote n="3">³INDO-FRENCH CELL FOR WATER SCIENCES, BANGALORE, France</footnote>

<footnote n="4">⁴INRA, RENNES, France</footnote>
K. Sreelash, M. Sekhar, L. Ruiz, Sat Kumar, M. Guerif, S. Buis, P. Durand and C. Gascuel-Odoux.
Parameter estimation of a two-horizon soil profile is improved by combining crop canopy and surface
soil moisture observations using inverse modelling and GLUE approach. Journal of Hydrology (2012).

Vereecken, H., Huisman, J.A., Bogena, H., Vanderborght, J., Vrugt, J.A. and Hopmans, J.W. (2008).
"On the value of soil moisture measurements in vadose zone hydrology: a review". Water Resources
Research 44.
# Soil moisture and water potential vertical profiles information about the rootzone: from the plot to the catchment scale.

S. Ferraris¹

¹University of Torino, DIST, Torino, Italy

Since 1997 an experimental field with intensive soil moisture TDR measurements has been set. The site is sandy permanent meadow in a plain topography area, down to 2 meters depth. It is a midlatitude north-west Italy area.

During the first years also water potential was measured and the retention and conductivity curves have been estimated.

Several short time monitoring exercises in areas with similar climate but complex topography has been performed.

The link between time structure of rainfall and soil moisture dynamics has been studied. It was meaningful for upscaling the soil moisture in the other experiments, up to the catchment scale.
# Reconstruction of former lake levels of groundwater-fed lakes in northeastern Germany using RapidEye archive data

I. Heine¹, E. Dietze², S. Itzerott¹

¹GFZ German Research Centre For Geosciences, 1.4 Remote Sensing, Potsdam, Germany
²GFZ German Research Centre For Geosciences, 5.2 Climate Dynamics and Landscape Evolution, Potsdam, Germany

Groundwater-fed lakes in northeastern Germany revealed massive fluctuations in their lake levels during the last decades. However, precise lake level measurements were only recorded for a small numbers of lakes. In this study we evaluate the use of multi-spectral images (RapidEye) to extract former water-land-boundaries and estimate the corresponding former lake levels. The main test area for the evaluation is lake Großer Fürstenseer See near Neustrelitz.

Lake Großer Fürstenseer See is characterized by a significant increase of its lake level since 2010. Its shore is heterogeneous with different topography and a variety of vegetation. The evaluation is based on selected subsets of the shoreline with different characteristics. After the pre-processing of the RapidEye images from 2009 to 2014, we extracted the water-land-boundary using a normalized difference water index (NDWI). The corresponding lake levels were estimated by merging the water-land-boundary with a high-resolution digital elevation model showing the terrain and the underwater topography of the lake. The evaluation of the data used and the methodology are based on DGPS measurements and in situ lake level records.

RapidEye images enable the monitoring of seasonal and annual variations of lake level changes of lake Großer Fürstenseer See. The extracted water-land-boundary showed a higher accuracy at shoreline subsets with shallow slopes and little vegetation than at steep and vegetated shorelines. As the accuracy of the estimated lake levels strongly depends on the accuracy of the extracted water-land-boundary, shallow and not vegetated shorelines are best suitable for the estimation of the lake level.
Multi-decadal lake-level dynamics in north-eastern Germany as derived by a
combination of gauging, proxy-data and modelling

K. Kaiser<fnref n="1" />, I. Heine<fnref n="1" />, I. Heinrich<fnref n="1" />, M. Natkhin<fnref n="2" />, R. Dannowski<fnref n="3" />, G. Lischeid<fnref n="3" />, T. Schneider<fnref n="4" />, J. Henkel<fnref n="4" />, M. Küster<fnref n="5" />, K.-U. Heußner<fnref n="6" />, O. Bens<fnref n="1" />, A. Brauer<fnref n="1" />, J. Chmieleski<fnref n="4" />

In the glacially formed, lake-rich territory of north-eastern Germany pronounced hydrological changes were detected in the last decades, leading to the general question how lake levels and related groundwater levels perform in a longer perspective, i.e. during the last century. But long-term gauging records are rare; most observations do not start before the late 20th century. Therefore the potential of historic hydrological data, comprising drowned trees (as a geo-/bioarchive) and aerial as well as map imagery (as a document archive) was tested in order to derive discrete-time lake-level stands. These data are contrasted with retrograde lake-level modelling, obtaining a record with continuous-time character.

Two small glacial lakes without surficial drainage (i.e. closed/endorheic lakes) were investigated in the Schorfheide area, c. 70 km north of Berlin. Both are dominantly fed by groundwater but differ in their hydrogeological and catchment characteristics. For one lake a c. 40 year-long gauging record is available, showing high lake levels in the 1980s followed by a lowering of c. 3 m till the mid-2000s. In both lakes submerged in situ tree remains were discovered and dated by dendrochronology, revealing low lake levels during the first half of the 20th century. One lake basin has been almost completely dry till c. 1960. Aerial photos provided data on lake levels since the 1930s which are corroborated by evidence of topographic mapping. Combining the empiric data with retrograde lake-level modelling, a well-proven lake-level record can be established for one lake that covers the last c. 90 years. The same general lake-level dynamics could be reconstructed by means of proxy data for the other lake. In both cases climate dominantly drives the lake level. Comparison with other multi-decadal lake-level records from the region shows that these differ, depending on the hydrological lake type which modifies water feeding and water level.

<footnote n="1">¹GFZ German Research Centre for Geosciences, Potsdam, Germany</footnote>

<footnote n="2">²Thünen-Institute of Forest Ecosystems, Eberswalde, Germany</footnote>

<footnote n="3">³Leibniz Centre for Agricultural Landscape Research (ZALF), Institute of Landscape Hydrology, Müncheberg, Germany</footnote>

<footnote n="4">⁴Eberswalde University for Sustainable Development, Faculty of Landscape Management and Nature Conservation, Eberswalde, Germany</footnote>

<footnote n="5">⁵University of Greifswald, Institute of Geography and Geology, Greifswald, Germany</footnote>

<footnote n="6">⁶German Archaeological Institute (DAI), Berlin, Germany</footnote>
# Linking diatom deposition in Lake Tiefer See (NE Germany) with the spring temperature gradient

U. Kienel<fnref n="1" />,<fnref n="2" />, B. Brademann<fnref n="2" />, N. Dräger<fnref n="2" />, P. Dulski<fnref n="2" />, F. Ott<fnref n="2" />, B. Plessen<fnref n="2" />, A. Brauer<fnref n="2" />

The currently strongest link of instrumental and past time scales at Lake Tiefer See (NE Germany) is an inverse relation of the deposition of siliceous phytoplankton (diatoms) with the rapidity of spring warming.

The now fully implemented monitoring of weather and lake conditions and sediment deposition showed a much larger diatom deposition following the late ice breakup and rapid spring warming in April 2013 compared to that after the mild winter and gradual spring warming in 2012. Crucial for this response is the timing of nutrient supply (deep mixing) and light availability (stratification). The exemplified inverse relation of diatom deposition with the duration of spring warming (0 - 10°C) is verified for the annually averaged diatom Si in the recent varved sediment record (AD 1924 - 2010) using the Schwerin temperature series. We find 49% explained variability in a linear regression. This percentage increases when the period of intensive manuring and drainage in the catchment (1975 - 1995) is removed from the dataset.

This transfer function can be used to reconstruct the spring temperature development from the diatom Si permitted by the range of values covered in the recent period and measured in the long sediment core of Lake Tiefer See.

This study is a contribution to the Virtual Institute of Integrated Climate and Landscape Evolution Analysis -ICLEA- of the Helmholtz Association and uses TERENO infrastructure.

<footnote n="1">¹University of Greifswald, Institute for Geography and Geology, Greifswald, Germany</footnote>

<footnote n="2">²German Research Centre for Geosciences GFZ, 5.2 Climate Dynamics and Landscape Evolution, Potsdam, Germany</footnote>
# Process-based modeling of daily growth as a function of environmental forcing in mixed temperate forests

S. Simard¹, G. Gea-Izquierdo², J. Guiot², I. Heinrich¹, G. Helle¹

¹GFZ, 5.2 Climate Dynamics and Landscape Evolution, Potsdam, Germany

²CEREGE UMR7330, Aix-en-Provence cedex 4, France

In spring 2012, an extensive monitoring site for tree growth and water relations was established within the framework of the Virtual Institute for Integrated Climate and Landscape Evolution Analyses (ICLEA) project using TERENO infrastructures in the lowlands of NE-Germany (Müritz National Park). Dendrometers and sap flow sensors were installed in mixed stands of mature pine, beech and oak growing along soil hydrological transects nearby a lake shore. This set up searches to evaluate the response of the species to changing climate and varying water availability. The climate at the study site is characterized by annual precipitation varying between 550 and 650 mm/year which has remained stable in the region over the last 115 years. In contrast, an increase in air temperature since the late 80s has been observed.

Process-based models are useful tools to properly investigate the impact that climate and environmental variability will have on forest growth dynamics. To this end, we will implement a process-based model to understand cambial activity at a daily time scale. We will analyze how carbon is allocated to the stem in relation to environmental variability from the monitoring data. The model aims to serve as a basis to link past climatic variability and tree growth to be used for predictive purposes.
Climate reconstructions from tree-ring widths for the last 850 years and the need for
new tree-ring proxies in northern Poland

I. Heinrich<fnref n="1" />, A. Knorr<fnref n="1" />, A. Bieber<fnref n="1" />, K.- U. Heußner<fnref n="2" />, T. Ważny<fnref n="3" />, M. Slowinski<fnref n="1" />, G. Helle<fnref n="1" />, S. Simard<fnref n="1" />, T. Scharnweber<fnref n="4" />, A. Brauer<fnref n="1" />

Tree-ring based temperature reconstructions form the scientific backbone of the current debate over global change, and they are the major part of the palaeo data base used for the IPCC report. However, long temperature reconstructions derived from temperate lowland trees growing well within their distributional limits in central Europe are not part of the IPCC report, which is an essential gap in the international data base. It appears that dendroclimatological analysis at temperate lowland sites was so far difficult to perform mainly for three reasons: diffuse climate-growth relationships, the lack of long chronologies due to absence of sufficient numbers of long-living trees and the potential loss of low-frequency signals due to the short length of the sample segments.

We present two robust multi-centennial reconstructions of winter temperatures and summer precipitation based on pine and oak tree-ring widths chronologies from northern Poland, where so far no long tree-ring based reconstructions were available. We compared the new records with global, hemispherical and regional reconstructions, and found good agreement with some of them. In comparison, the winter temperature of our reconstruction, however, did not indicate any modern warming nor did the summer precipitation reconstruction suggest any modern 20th century changes.

Then again, due to the short segment lengths of our individual series the resulting multi-centennial reconstructions suffered from the segment length curse inhibiting the preservation of low-frequency signals. Therefore, in a second step, we measured cell structures within the tree rings and developed chronologies of parameters such as cell wall thickness and cell lumen area for a period of several decades. We used our new method (Liang et al. 2013a,b) applying confocal laser scanning microscopy to increment core surfaces for efficient histometric analyses. We focused on samples covering the last century because meteorological data necessary for calibration studies were available for direct comparisons. It was demonstrated that the correlations with climate were strong and different from those found for tree-ring widths (e.g., N-Poland oak-vessel-lumen-area-chronology with previous September-to-December mean temperature r = 0,61 and N-Poland pine-tracheid-lumen-area-chronology with mean Feb-to-June temperature r = -0,66). Since the cell structure data did not contain age trends, there was no reason for detrending, thus we were able to use raw values. By using raw values low-frequency signals could be sustained in the chronologies. Currently, long chronologies of cell structure measurements are being developed to finally produce robust reconstructions for the temperate lowlands of Europe, which contain not only high- but also low-frequency climate information for the last Millennium.

<footnote n="1">¹GFZ Potsdam, Section 5.2, Potsdam, Germany</footnote>

<footnote n="2">²German Archaeological Institute, Berlin, Germany</footnote>

<footnote n="3">³University of Arizona, Tree-Ring Laboratory, Tucson, Poland</footnote>

<footnote n="4">⁴University of Greifswald, Landscape Ecology, Greifswald, Germany</footnote>
# Evaluating the water fluxes from vegetation ecosystems along precipitation gradient in the dry Mediterranean region

E. Rotenberg¹, S. Rohatyn¹, E. Ramati¹, A. David¹, U. Deckin¹, D. Yakir¹

¹The Weizmann Inst., EPS, Rehovot, Israel

Quantifying evepotranspiration fluxes from vegetative surfaces in dry regions is critical to assess future plant survival and its effect on local hydrology and agriculture, as well as for large scale modeling efforts. This requires knowledge of the main flux components, of evaporation (E), interception (I), transpiration (T), runoff (R) and recharge. Dry lands ecosystems, especially Mediterranean ecosystems types, are characterized by a mosaic of a range of small and different vegetation types having different water uses strategies, resulting in different flux patterns. Large inter-annual variations in rainfall in dry regions further add complexity to the partitioning of the water fluxes in the soil-plant-atmosphere system to its components over a given region. Finally, traditional observation systems rely on sparse permanent flux tower sites, which further increase the difficulties in studying complex systems. To address the challenges noted above we developed a new measurement approach relying on a mobile observing system to quantify changes in water fluxes along a sharp south-north aridity gradient in Israel, and in both forests and nearby non-forested ecosystems in each case (Figure 1).

Our newly developed mobile observing system composed of three main core elements: First, it is a completely mobile and fast deployment unit fitted to rough terrains and independent of line power for extended periods. Second, it permits the traditional eddy covariance (EC) flux measurements, including radiations, in canopies ranging from grasslands to forests (using extendable mast up to 30 m). Third, it offers appropriate laboratory conditions for the deployment of any analytical instrumentation, for additional tracers and auxiliary measurements. This study extends the long-term study in the permanent FLUXNET site in Yatir, which indicate that the semi-arid forest ecosystem evapotranspiration (ET) is about 95% the annual precipitation, while tree transpiration is about 60% of ET, interception is ~11%, runoff is virtually zero, and the recharge to depth is 0-5% (Raz Yaseef et al., 2009). Both rain amount and rainfall distribution during the wet season have considerable effects on the water fluxes and carbon uptake by the forest ecosystem, and while the forest prevents soil erosion, over the non-forested area large rainfall episodes bring significant floods and erosions. These studies have shown that afforestation activities in the semi-arid zones could have significant effects on mitigating carbon raises in the atmosphere (Rotenberg&Yakir, 2010).

Measurements with the mobile system are on a campaign basis of about two weeks per site, repeated at different seasons, and include in addition to EC fluxes trees sap-flow and catchment runoff measurements. Four measurement sites were used from the Yatir area in the south, having long-term aridity index of 0.18, two intermediate sites in central Israel, and a wet site in Northern Israel with aridity index of 0.6 (Figure 1). At each location, measurements were made in a pine (Aleppo pine) forest site, and in a nearby un-forested ecosystem site (total of eight measurement sites). The system's quality of measurements was confirmed against a permanent EC site at the Yatir forest and was recently used for the first time to combine conventional and quantum cascade laser flux measurements (Asaf et al., 2013). Variations in fluxes between sites and between ecosystems at the same site where large and changed in magnitude over the seasons. For example, during winter, daily transpiration (and carbon uptake) patterns were similar at all pine sites (equivalent to about 50% of net radiation; Rn), but T become insignificant and constant during day at dry site (Yatir) during summer time (equivalent to 10% of Rn). At the wetter sites, winter activity patterns were sustained also throughout summer (with T equivalent to ~30% of Rn). This nonlinear response across the climatic gradient and across sites indicated that a single permanent observation site could not be used to predict the activities in the complex system. The water use by plant types, indicated by T/E ratio, were lower at the non-forested sites, which was reflected also in the reduced net carbon uptake by the non-forested ecosystems.
References

Asaf D, Rotenberg E, Tatarinov F, Dicken U, Montzka S A, Yakir D (2013) Ecosystem photosynthesis inferred from measurements of carbonyl sulphide flux. *Nature Geoscience*, **6**, 186-190.

Raz-Yaseef, N., Yakir, D., Rotenberg, E., Schiller, G. & Cohen, S. Ecohydrology of a semi-arid forest: partitioning among water balance components and its implications for predicted precipitation changes. *Ecohydrology*, 143-154 (2009).

Rotenberg, E. & Yakir, D. Contribution of Semi-Arid Forests to the Climate System. *Science* **327**, 451-454, doi:10.1126/science.1179998 (2010).

Wilson, K., et al., 2002. Energy balance closure at FLUXNET sites, *Agricultural and Forest Meteorology*. 113, pp. 223-243.
Evaporation measurements at the Dead Sea

J. Metzger¹

¹Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, Karlsruhe, Germany

The Dead Sea area is a unique environment of great ecological and economic importance. The region is faced to various problems, especially the strong variability in water availability and the impact of climate change. Therefore, the understanding of the water cycle and the quantification of the water budget components of the Dead Sea are of great importance. Evaporation is a central component in this region, because it contributes directly to the water budget, but also indirectly by triggering precipitation. Models estimate the current evaporation at around 1200 - 1300 mm/year, but haven't been evaluated with measurements. Therefore a one-year field experiment was designed and energy balance stations were installed in spring 2014 in the framework of the HGF Virtual Institute DESERVE (DEad Sea Research VEnue).

At three characteristic sites (within vegetation, over bare soil, and directly at the coastline) eddy covariance measurements are performed to quantify evaporation. For westerly wind directions the wind is blowing from the land to the water and the bare-soil and coastline station measure the evaporation from the soil. So we have two comparable measurements of soil evaporation over a short distance. For northerly to southerly wind directions, the wind is blowing from the water to the land and the air over the water is advected to the energy balance station at the coastline. Thereby the instruments measure the actual evaporation from the water and the other energy balance station further inland still measures the evaporation from the soil. Due to predominant local wind systems, such as land and sea breeze, sufficient cases with wind directions from the water are guaranteed. Furthermore it is possible to investigate correlations and dependencies of the evaporation on various meteorological variables, such as wind speed, air temperature or radiation.

This measurements enable the calibration of models, which calculate the Dead Sea water budget, so that the accuracy of the results can be improved and future scenarios of water availability can be calculated to provide a basis for water resource management in this region.
# Data collection and visualization of water services: Applications for nexus governance in Africa

T. Mannschatz¹, M. Kurian¹, S. Hülsmann¹

¹UNU-FLORES, Dresden, Germany

Africa receives the third largest amount of global annual precipitation, which builds up the African water resources. Still, at the continental level, Africa's renewable water resources only represent around 9 per cent of the world's total freshwater resources, making it the second-driest continent. Moreover, in Africa the water resources are spatially-unequally distributed. In combination with varying population density, this results in wide differences in water availability and poses challenges for water supplies. (Semi-arid regions have to deal with droughts, poor water quality, soil salinity, low agricultural production and limited water supply. Successfully coping with water-related problems and handling future water demands depend on effective water resource management. The management needs data about the actual and future state of the environment (including water resources) and socio-economics. The data assessment and management requires an integrated approach where spatial data is key for further system analysis and water management. However, the results of data assessment, complex system analysis and predictions need to be visualized making it understandable and useful for both, decision makers and the public. As an example of new data collection approaches for data-poor environments we introduce the water Point mapping system (WPMS) which is currently implemented in Tanzania as one of the Geo-information and communication technology tools for the management and presentation of information in a spatial context. It aims at enabling planners, decision makers and other key partners to identify the geographic areas and communities in which to focus their efforts for maximum impact. UNU-FLORES is working with the Ministry of Water, Republic of Tanzania on a WPMS project based on a request to build capacity for evidence based decision making that advances the nexus approach. In addition to rural water supply, applications of WPMS in other sectors such as irrigation and livestock management are being explored in collaboration with governments elsewhere in Africa.
Intermediate Scale Soil Moisture Surveys in TERENO with the Cosmic Neutron Rover

M. Schrön¹, I. Schröter¹, H. Paasche¹, L. Samaniego¹, S. Zacharias¹

¹UFZ, MET, CHS, Leipzig, Germany

Monitoring soil moisture with Cosmic Ray Neutron Sensors (CRS) is an emerging field of research, because the mesoscale footprint (~0.3 km² and 50cm depth, [1]) is of great interest for land surface models that usually work at resolutions ranging between point measurements (e.g. TDR) and remote sensing data. More than 20 stationary probes are already maintained all over the TERENO observatory.

We equipped a Land Rover vehicle with multiple CRS detectors that allow environmental neutron sensing with high temporal resolution on-the-fly. The so-called *Cosmic Neutron Rover* can be used to quickly capture large spatial patterns of soil moisture, biomass and snow in a whole catchment on demand. The measurements can be calibrated and compared with the high number of various soil moisture networks in the TERENO observatory, like stationary CRS, wireless point-sensor networks (SoilNet), TDR campaigns or remote-sensing/air-borne data. Since the latter method is lacking validation data sets at its large scale, the *Cosmic Neutron Rover* can be a unique and promising tool to provide soil moisture data at a comparable spatial scale.

The talk will give an overview about recent and upcoming studies with the new measurement technique in TERENO and TERENO-MED.

[1] M. Zreda et al. 2012, "COSMOS: the COsmic-ray Soil Moisture Observing System.", HESS 16(11), doi:10.5194/hess-16-4079-2012
# Cosmic-ray neutron intensities at a forest site - determination of soil moisture, biomass and canopy interception

M. Andreasen¹, K. H. Jensen¹, M. C. Looms¹, T. O. Sonnenborg², H. Bogena³, M. Zreda⁴, D. Desilets⁵

¹University of Copenhagen, Geosciences and Natural Resource Management, Copenhagen, Denmark

²Geological Survey of Denmark and Greenland, Denmark, Copenhagen, Denmark

³Forschungszentrum Juelich GmbH, Agrosphere IBG-3, Juelich, Germany

⁴University of Arizona, Department of Hydrology and Water Resources, Tucson, United States

⁵Hydroinnova LLC, Albuquerque, United States

The water pooled above-ground (e.g. in snow, biomass, canopy interception) and in the shallow subsurface (soil and litter moisture) are controlling the exchange of water and energy between the land surface and the atmosphere. Therefore, measurements of the water stored within the interface of the shallow subsurface and the atmosphere are critical for the prediction of evapotranspiration and groundwater recharge. The scale of measurements is due to considerable spatial and temporal variability important to consider. At present soil moisture within the Ahlergaarde subcatchment (1055 km²) of the Skjern River watershed (2500 km²) (Danish Hydrologic Observatory - HOBE) are collected at point scale using Decagon ECH2O 5TE capacitance sensors (30 stations with sensors installed in three depths) and at larger scale (44*44 km) by SMOS satellite retrievals. Canopy interception is estimated from measurements of precipitation at a forest clearing and throughfall at three stations within the forest, each covering an area of approx. 3 m³. However, calibration and validation of a hydrological model with a regular grid of e.g. 500 meter requires measurements at a corresponding scale. Upscaling of point measurements are possible but associated with uncertainties as a substantial amount of points were to be sensed to represent the heterogeneity of the area.

A cosmic-ray neutron probe continuously detects the cosmic-ray neutron intensity within a footprint of approximately 300 m at sea level and depths of 10-70 cm. The neutron intensity is inversely correlated to the hydrogen stored in the soil, biomass, litter layer, snow and/or canopy interception. Soil moisture constitutes in most cases the largest pool of hydrogen and it has in several studies been shown that the cosmic-ray neutron probe provides reliable estimates of soil moisture.

Lately, more attention has been given to use the cosmic-ray neutron probe for measuring other variables than soil moisture. At sites with extensive or considerable annual variation in vegetation cover, the signal is affected by the change in the biomass-water content of a cropped field (from sprout to harvest) as well as the canopy interception of a forested site.

Continuous cosmic-ray neutron intensity measurements are carried out at three land cover types to estimate intermediate scale soil moisture. Further, the potential of using the cosmic-ray neutron method to determine the water content of the biomass and the canopy interception are tested using multiple height measurements at a forest site and by neutron transport modeling using the extended version of the Monte Carlo N-Particle Transport Code (MCNPX).

Through 2013 and 2014 six cosmic-ray neutron probes were installed in the Ahlergaarde catchment at sites representing the three major land covers, i.e. agriculture (61 %), forest (17 %) and heath (14 %). Probes were at all three sites installed at 1.5 m above the ground surface. At the forest site probe installations were additionally conducted at the canopy surface at 27.6 m above the ground surface and probes detecting neutron intensity of lower energies were added to both detection heights. The probes at the ground surface were used for soil moisture detection. The difference in the count rates at the different energy levels and heights above the surface were detected to investigate the potential of using cosmic-ray neutron intensity measurements to estimate biomass-water and the canopy interception fluxes.

Modelling was conducted to simulate the response of different amounts of biomass, soil moisture and canopy interception on the neutron intensities and to test whether these responses could be seen in
the measurements. However, as both probes are contaminated by neutrons of either too high or too low energies additional field experiments were performed. Adding cadmium foil to the probes the neutrons of unwanted energies were shielded out leaving more distinct ranges to be detected, enabling the comparison of model results with measurements.
# Estimation of recharge using cross-borehole electrical resistivity tomography from long-term monitoring of saline tracer

E. Haarder¹, M. C. Looms¹, A. Binley², L. Nielsen¹, K. H. Jensen¹

¹University of Copenhagen, Department of Geosciences and Natural Resource Management, Copenhagen, Denmark

²Lancaster University, Lancaster Environment Centre, Lancaster, United Kingdom

Recharge is one of the main components of the hydrological cycle. The direct measurement of recharge is difficult and it is, therefore, usually approximated based on the measurement of other water fluxes and mass balance considerations. Here we present results of a field experiment in which we estimate recharge using geophysical methods. The experiment was conducted at the agricultural field site, Voulund, within the Danish hydrological observatory in the Skjern river catchment, HOBE. At the field site a variety of instrumentation was installed to assist in estimating water fluxes and state variables, for example, eddy flux evaporation, potential evapotranspiration, precipitation, lysimeter recharge, soil moisture using TDR, Decagon 5TE probes, cosmic-ray intensity, and cross-borehole geophysics. In September 2011, a saline tracer was added across a 12 m by 12 m area at the surface within the field site, at an application rate mimicking natural infiltration. The movement of the saline tracer front was monitored using cross-borehole electrical resistivity tomography (ERT); data were collected on a daily to weekly basis and continued for one year after tracer application. The ERT data was subsequently inverted and corrected for temperature changes in the subsurface. Spatial moment analysis was used to calculate the tracer mass, center of mass and thereby recharge. The recovered mass was underestimated by the ERT data by up to 50% during the entire period. Such mass balance errors are widely recognized and are a result of variable measurement sensitivity and smoothing implicit in the regularization scheme of the applied inversion routine. Furthermore, it was not possible to calculate the center of mass after 7.5 months of measurements due to tracer mass loss through the bottom of the measurement domain, i.e. at the groundwater table. The results were nonetheless in very good agreement with porewater samples collected and analyzed from five cores extracted within the tracer application area. Recharge during the 7.5 months from September 2011 to the end of April 2012 was estimated to 585 mm using the ERT data. This value is in good accordance with recharge estimates made using buried lysimeters located only meters away from the cross-borehole ERT array.
Combined satellite and proximal soil sensing approach for improved catchment
characterization

C. von Hebel¹, S. Rudolph², L. Weihermüller¹, J. A. Huisman¹, A. Mester¹, H. Vereecken¹, J. van der Kruk¹

¹Forschungszentrum Jülich, Institute for Bio- and Geoscience - Agrospehere (IBG3) , Jülich, Germany

²British Geological Survey, Environmental Science Centre, Keyworth, United Kingdom

Recent developments in proximal soil sensing techniques offer unique opportunities to characterize the vadose zone across spatial scales, especially when combining these techniques with remote sensing approaches. Here, we link RapidEye satellite imagery and multi-depth-sensing electromagnetic induction (EMI) measurements of 20 ha arable land around Selhausen (Germany) and investigate one specific 1.1 ha plot using geophysical and conventional soil sampling methods. For the area, large-scale leaf area index (LAI) was estimated from the satellite images and compared to the lateral and vertical apparent electrical conductivity (ECa) distributions that were recorded using the multi-configuration EMI system. Increasing and decreasing ECa values with depth separated the area into the lower terrace (LT) and the upper terrace (UT), respectively. At the mainly gravelly UT, distinct LAI patterns coincided with higher ECa values that were measured with the deepest sensing EMI coil configuration. Soil analysis revealed higher subsoil clay content, related to higher water holding capacity, which enabled better crop performance under drought conditions. To extract depth information, we performed detailed investigations at the selected plot that showed UT sediments in the eastern part and LT sediments (loamy silt) toward the west. Here, we developed a dedicated quantitative EMI inversion scheme to obtain a three-dimensional (3-D) layered subsurface electrical conductivity model using multi-configuration EMI data. The smoothly changing lateral and vertical electrical conductivities were validated with grain size distribution maps and two previously measured 120 m long electrical resistivity tomography (ERT) transects. Overall, the 3-D subsurface model obtained with EMI inversions and the independent ERT inversions showed very similar subsurface structures. Small differences in absolute electrical conductivity values within certain layers were attributed to varying soil moisture states at different dates. Consequently, the combined sensor and data processing approach opens up new perspectives for an improved characterization of relatively large areas up to the km²-scale and provided subsoil information that can improve models that aim at improved descriptions of catchment processes.
# Controls for multi-scale temporal variation in ecosystem methane exchange during the growing season of a permanently inundated fen

F. Koebsch<fnref n="1" />, G. Jurasinski<fnref n="2" />, M. Koch<fnref n="2" />, J. Hofmann<fnref n="2" />, S. Glatzel<fnref n="3" />

Wetlands are the largest natural sources for atmospheric methane (CH₄). In wetlands with permanent shallow inundation, the seasonal variation of CH₄ exchange is mainly controlled by temperature and phenology. In addition, ecosystem CH₄ exchange varies considerably on smaller temporal scales such as days or weeks. Several single processes that control CH₄ emissions on the local soil-plant-atmosphere continuum are well investigated, but their interaction on ecosystem level is not well understood yet. We applied wavelet analysis to a quasi-continuous Eddy Covariance CH₄ flux time series to describe the temporal variation of ecosystem CH₄ exchange within the growing season of a permanently inundated temperate fen. Moreover, we addressed time scale-specific controls and investigated whether their impact changes during the course of the growing season. Water and-/soil temperature correlated with ecosystem CH₄ exchange at time scales of 6-11 and 22 days which exceeds the time scales that are typically associated with the passage of weather fronts. The low response time might be due to the high heat capacity of the water column. On a daily scale, shear-induced turbulence (expressed by friction velocity) and plant activity (expressed by canopy photosynthesis) caused a diurnal variation of ecosystem CH₄ exchange with peak time around noon. However, this pattern was apparent only at the beginning of the growing season (April/May). In the following, the daily cycle of convective mixing within the water column (expressed by the water temperature gradient) gradually gained importance and caused high night-time CH₄ emissions, thereby levelling off the diurnal CH₄ emission pattern. Our study highlights the need for multi-scale approaches that consider the non-stationarity of the underlying processes to adequately describe the complexity of ecosystem CH₄ exchange.

<footnote n="1">¹Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Inorganic and Isotope Geochemistry, Potsdam, Germany</footnote>

<footnote n="2">²University of Rostock, Landscape Ecology and Site Evaluation, Rostock, Austria</footnote>

<footnote n="3">³University of Vienna, Geography and Regional Research, Vienna, Austria</footnote>
# Meso-scale eddies contribute to near-surface turbulent exchange: evidence from field measurements

F. Eder¹,², M. Schmidt³, T. Damian⁴, K. Träumner⁴, M. Mauder¹,⁵

¹Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), Garmisch-Partenkirchen, Germany

²Karlsruhe Institute of Technology (KIT), IMK-IFU, Garmisch-Partenkirchen, Germany

³Jülich Research Centre, Agrosphere (IBG-3), Jülich, Germany

⁴Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research, Troposphere Research (IMK-TRO), Karlsruhe, Germany

⁵Karlsruhe Institute of Technology (KIT), Institute of Geography and Geoecology (IfGG), Karlsruhe, Germany

The eddy-covariance technique tends to underestimate the turbulent heat fluxes, which results in the non-closure of the surface energy balance. In this study, we show experimental evidence that meso-scale turbulent organized structures, which are inherently not captured by the standard eddy-covariance technique, penetrate down into the Prandtl layer and contribute to near-surface exchange. Using a combined setup of three Doppler wind lidars above a cropland-dominated area in the Eifel/Lower Rhine Valley Observatory of the TERENO program, we were able to detect convective coherent structures in the surface layer down to a few meters above ground. In order to assess whether these structures affect the eddy-covariance measurements, we analyzed data from two micrometeorological stations in the study area with respect to energy balance closure. In accordance with several studies before, our data confirm a strong dependence of the energy balance residual on friction velocity. In addition, we also found the energy balance residual to be positively correlated with the vertical moisture gradient in the lower atmospheric boundary-layer, but not with the temperature gradient. This indicates that meso-scale transport probably contributes more to the exchange of latent heat than of sensible heat, since we assume that the organized structures are the dominant transport mechanism between the surface layer and the outer layer. Moreover, we show that flow distortion due to tower mountings and measurement devices affects the energy balance closure considerably for certain wind directions and that a neglect of canopy heat storage can cause large residuals during the morning hours.
# Modelling of hourly evapotranspiration and soil water contents at the grass-covered boundary-layer field site Falkenberg, Germany

M. Wegehenkel¹, F. Beyrich¹

¹Leibniz Centre for Agricultural Landscape Research (ZALF), Institute of Landscape Systems Analysis, Muencheberg, Germany

## 1 Question

Real evapotranspiration (ETr) is a key variable for hydrology, agronomy and meteorology. In addition to atmospheric conditions, in particular global radiation, temperature, wind speed or air humidity, ETr is also influenced by vegetation type, phenology and soil water storage. Modelling of root water uptake by vegetation cover is an essential part of hydrological models and a prerequisite for an accurate simulation of ETr. In deterministic hydrological models, root water uptake is normally calculated by a sink term in the Richards equation with various parameterizations as functions of water stress. In the last years, new so called compensatory root water uptake models were developed for a more adequate description of soil water extraction by plant roots. Compensatory means that reduced root water uptake in upper stressed parts of the soil part is compensated by an increased uptake in deeper unstressed soil layers. However, only a few studies using experimental field data for the validation of such root water uptake models are published until now. Therefore, a further verification of such compensatory root water uptake approaches using field experiments with a higher measurement frequency and longer investigation periods was recommended in these studies.

## 2 Methods

In our study, we analysed a two-years period from 2003-2004 with hourly rates of ETr derived from Eddy-Covariance (EC)-measurements and soil water contents monitored by Time Domain Reflectometry (TDR)-probes at the grass-covered boundary layer field site Falkenberg of the Lindenberg Meteorological Observatory-Richard-Aßmann-Observatory, operated by the German Meteorological Service (DWD). These ETr-rates and soil water contents were compared with the results of a modelling approach consisting of the Penman-Monteith equation and of the soil water balance model Hydrus-1D using an uncompensatory and a compensatory root water uptake model. One objective of our study was an analysis of the impact of the application of these two different root water uptake approaches on the model outputs to give a further experimental verification of root water uptake models. In contrast to experimental data with a daily time step, hourly measured data enable a more detailed analysis of the temporal dynamics of ETr and soil water contents near the soil surface, and, therefore, a more rigorous test of hydrological models.

## 3 Results

The comparison of soil water contents and ETr-rates simulated by our modelling approach with the measured ones suggested in general a satisfactory model performance. The calibration of soil hydraulic parameters and the estimation of an appropriate rooting depth of grass cover showed the highest impact on the simulation quality. In comparison with the results obtained from the other simulations, the application of compensatory root water uptake with a critical root water uptake index $ω_c=0.25$ led to a decrease in the model performance for the total investigation period. However, in the dry summer 2003, we found contradictory results in the model performance for ETr and for soil water contents. Corresponding soil water contents simulated by using compensatory root water uptake with $ω_c=0.25$ showed a better agreement with the measured ones than the other model applications in this period, whilst corresponding ETr calculated by this approach ranged significantly below those measured by the EC-system.

## 4 Conclusions
The recommendation of a possible model based triggering between the use of compensatory root water uptake in dry periods and the application of uncompensatory root water uptake in wetter periods was indicated by the comparison of simulated and measured soil water contents, but not by the comparison of calculated with observed ETr. Therefore, in the case of the application of such compensatory root water uptake models, the resulting impact on ETr-rates in dry periods should be analysed to identify unrealistic model outputs and to define an appropriate value of the critical root water uptake index ωc.

In our study, simulated ETr-rates were typically higher with a mean of 20% than those measured by the EC-System. These differences might be related to the frequently reported inability of EC measurements to close the local energy budget.

We should finally remark that the investigation period 2003-2004 showed annual rates of precipitation below the longterm mean. Therefore, an application of compensatory and uncompensatory root water uptake models using experimental data obtained from years with higher precipitation at the GM Falkenberg should be the subject of a separate study.
# Integrated Climate and Hydrology Modelling - catchment scale coupling of a regional climate model and a hydrological Model

M. A. D. Larsen¹, M. Drews¹, J. C. Refsgaard², K. H. Jensen³, M. Butts⁴, J. H. Christensen⁵,
O. B. Christensen⁵

¹Technical University of Denmark, Copenhagen, Denmark

²Geological Survey of Denmark and Greenland, Copenhagen, Denmark

³University of Copenhagen, Department of Geosciences and Natural Resource Management,
Copenhagen, Denmark

⁴DHI, Hoersholm, Denmark

⁵Danish Meteorological Institute, Copenhagen, Denmark

## Introduction

Observations and climate projections provide evidence that water resources are vulnerable and subject to a high potential impact by climate change with wide implications for human societies and ecosystems. An improved understanding of the hydrological feedback and interaction mechanisms between the atmosphere, the land-surface and the subsurface is therefore crucial. Previous modelling efforts primarily used each model in sequential steps whereas recent years have seen the emergence of studies coupling climate and hydrology models with the aim of directly including the atmosphere/land-surface/subsurface interaction. On the domain shared by the two models, the coupled system thereby utilize the higher temporal and geographical detail inherent in the hydrology land-surface scheme as well as the wider range of processes at the land- and sub-surface.

In the present study we investigate a dynamically coupled version of a comprehensive distributed hydrological modelling system, MIKE SHE, nested inside the DMI-HIRHAM regional climate model (RCM). A particular challenge in coupling a climate model to a hydrological model resides in the vastly different philosophies expressed by such codes. While RCM's generally implement primary physical equations, hydrological models are often greatly calibrated. Likewise, temporal and spatial resolutions are often quite different. Also, present versions of MIKE SHE are native only to the Microsoft Windows operating system, necessitating the development of a novel cross-platform model interface based on open-source OpenMI technology. The setup has proven stable and has been used for simulations of several years.

## Method

The coupled model has been evaluated for a groundwater-dominated catchment in the western part of Denmark, Skjern River (2500 km² - 500 m grids), embedded within an RCM domain (4000 x 2800 km - 11 km grids). A two-way interaction between the atmosphere, land-surface and subsurface is enabled through and energy based (Shuttleworth-Wallace) land-surface model (SWET) within the shared domain. In this manner the simple land-surface model embedded in DMI-HIRHAM is effectively replaced by the superior land-surface component of the combined MIKE SHE/SWET model, which includes a wider range of processes at the land-surface and 3D distributed subsurface flows as well as higher temporal and spatial resolution. Outside the shared domain DMI-HIRHAM utilizes its own embedded land-surface model; however, the model nesting enables the detection of possible feedbacks (e.g. soil moisture and precipitation) from the improved surface/subsurface hydrology to the atmosphere even outside the shared domain. Simulations were performed for two different periods with differing aims: (i) 26 simulations were performed for a one-year period (1 May 2009 to 30 Apr 2010) to investigate the influence of the inter-model data transfer interval (varied from 12 to 120 min) as well as the influence DMI-HIRHAM coupled and uncoupled model variability. (ii) 8 simulations (ongoing and therefore subject to increase) were performed in selected periods from 2000-2010 having good observation data, evaluating the coupled model performance, as opposed to uncoupled, with regard to more severe events of drought, high precipitation and warm/cold periods.

## Results
HIRHAM coupled output was assessed against distributed data sets of precipitation, air temperature, wind speed, relative humidity, global radiation and surface pressure. For the first batch of runs (i) the former four of these variables showed a statistically significant improvement in the coupled run root mean square error (RMSE) levels with a more frequent inter-model data transfer interval whereas the latter two variables were largely unaffected. In the current configuration, which is limited by transferring actual data files between the models due to security constrains, as opposed to memory transfer, an optimal transfer rate is seen in the order of 30 min. with regard to computation time vs. performance. Also, a significant regional variability is seen for precipitation for the coupled setup. In general however, the coupled performance is poorer compared to the uncoupled. The second batch of coupled simulations (ii) investigate the influence of including the more detailed land-surface scheme from MIKE SHE/SWET on the coupled performance in cases of more severe weather. In this manner we explore a possible reduction of the well-known climate model bias, e.g. for higher temperatures and high precipitation.

## Conclusions

Presented here are the results from two full studies employing a fully dynamic coupling performed on several years with a sub-diurnal data exchange rate between the HIRHAM RCM and the MIKE SHE/SWET including full 3D subsurface flow, river flow and an energy based evapotranspiration scheme. The poorer results of the coupled setup, compared to uncoupled, is explained by the rigorous calibration and refinement of both models over a number of years, or even decades, to reproduce observations. These refinements however, are completely disregarded by imposing a new model over the shared domain which inevitably results in model deterioration. Therefore, an important issue for future studies is to pursue a strategy for calibrating the coupled model setup as a whole to overcome the danger of having the model calibration compensate for biases in other model. Further experiments should also include running on a larger shared domain and employing the setup for other regions. However, in the present study we emphasize the overall feasibility of the coupling tool and suggest that modelling studies of the future climate are likely to benefit from the coupled model setup.
# Investigation of connections between water budget components and soil water content distribution on a forested site

C. Drüe<fnref n="1" />, A. Graf<fnref n="2" />, H. Bogena<fnref n="2" />, H. Hardelauf<fnref n="2" />, T. Pütz<fnref n="2" />, G. Heinemann<fnref n="1" />, H. Vereecken<fnref n="2" />

The Wüstebach site represents a small catchment located in a low mountain range in the west of Germany that is entirely forested with spruce trees. All major water budget components are observed: precipitation, potential and actual evapotranspiration, as well as runoff. Evapotranspiration is determined from eddy covariance measurements made on at 40-m mast towering above the trees. The soil water content was monitored site-wide by a sensor network of 109 positions with sensors at three depths each. Precipitation is measured at various positions on and near the site and runoff is recorded by a gauge at the site outflow. Comparison of the individual energy balance contributions suggests an energy flux closure of about 80%. The catchment water budget was found to be dominantly energy-limited, with the evaporation amounting to approximately 90 % of its potential value, but less than half of precipitation. Precipitation, evapotranspiration and runoff close the water budget with a residual of 2 % of annual precipitation. On the daily timescale, the residual of the water budget was larger and could be explained to a moderate extent by the ambient temperature.

The typical time scale of these processes was about 4 days and less. They were presumably dominated by unaccounted fast-turnover storage terms such as interception, as a major source of uncertainty. At weekly resolution, soil water content explained more than half (R<fnref n="2" /> = 0.62) of the water budget residual. In the spatial domain, two slightly different spatial patterns of soil water content could be identified that were associated with mean soil water contents values below and above 0.35 cm³/cm³, respectively.

<footnote n="1">¹Universität Trier, Umweltmeteorologie, Trier, Germany</footnote>

<footnote n="2">²Forschungszentrum Jülich, Agrosphere, Jülich, Germany</footnote>
# Land surface energy partitioning explained by maximum convective power: evaluating the effects of vegetation and weather conditions at three eddy covariance sites in Germany

M. Renner<fnref n="1" />, C. Bernhofer<fnref n="2" />, U. Moderow<fnref n="2" />, U. Spank<fnref n="2" />, A. Kleidon<fnref n="1" />

Absorbed solar radiation heats the surface while the emission of thermal radiation and the convective heat exchange with the atmosphere both cool the surface. Considering that convective exchange can be regarded as a Carnot heat engine which transforms heat into convective mass exchange, the radiative-turbulent partitioning can be predicted by assuming that the atmospheric heat exchange operates at a limit of maximum power (Kleidon and Renner, 2013). This state corresponds to strong surface-atmosphere interactions and predicts that 50% of the absorbed solar radiation $R_{sn}$ is used by convective fluxes. Further, we indirectly infer heat storage fluxes from the requirement that a certain part of the heat absorbed during daytime is released by radiative loss during nighttime. Hence the heat storage considerations directly affect the net long wave radiative exchange at the diurnal time scale.

This simple model provides a testable Null hypothesis which we evaluate for locally driven summer conditions. Specifically we explore alternative hypotheses on turbulent-radiative partitioning which include effects of land use and weather conditions for three neighboring Eddy-Covariance sites of TU Dresden between 2007-12.

Generally the simple partitioning predicts both, the net longwave $R_{ln}$ and the total convective fluxes $J = H+LE$ very well for the grass ($R_{ln}: r^2 = 74\%$, mean error ME = -1 W m$^{-2}$; $J: r^2 = 88\%$, ME = 9 W m$^{-2}$) and the crop site ($R_{ln}: r^2 = 69\%$, ME = 4 W m$^{-2}$; $J: r^2 = 85\%$, ME = 10 W m$^{-2}$). However, at the forest site the observed convective partitioning $J/R_{sn} = 0.6$ is much larger than derived by our simple model which biases our predictions ($R_{ln}: r^2 = 73\%$, ME = 27 W m$^{-2}$; $J: r^2 = 78\%$, ME = -50 W m$^{-2}$). This significant difference in energy partitioning of tall vegetation highlights an important biophysical mechanism which is, however, not represented in our simple model and may be linked to canopy effects which increase land-atmospheric interaction.

With respect to weather conditions, the strongest effect was found to be related to atmospheric moisture conditions, with reduced convective cooling and increased radiative exchange during and after rainfall as well as low vapor pressure deficit. It appears that these mostly large scale driven moist conditions strongly reduce the vertical temperature difference which can be thought of the driving heat gradient of the convective heat engine.

We conclude that strong surface-atmosphere interactions shape the energy partitioning at the land surface and that thermodynamic limits provide useful constraints on convective exchange. Our top-down approach highlights that tall vegetation effectively increases the convective exchange and that the inclusion of atmospheric moisture in the simple energy balance framework will further improve predictions.

Kleidon, A. and Renner, M.: Thermodynamic limits of hydrologic cycling within the Earth system: concepts, estimates and implications, Hydrol. Earth Syst. Sci., 17, 2873-2892, doi:10.5194/hess-17-2873-2013, 2013

<footnote n="1">¹Max-Planck-Institute for Biogeochemistry, Biospheric Theory and Modelling Group, Jena, Germany</footnote>

<footnote n="2">²TU Dresden, Meteorology, Dresden, Germany</footnote>
# Leaf area and soil controls of boreal forest water, energy and carbon fluxes - a modeling study over a stand rotation

S. Launiainen¹, G. G. Katul², A. Lauren¹

¹Finnish Forest Research Institute, Joensuu, Finland

²Duke University, Nicholas School of Environment, Durham, United States

Boreal coniferous forests in Northern Europe are extensively managed for timber, fibre and to greater extent for bioenergy production. Depending on site fertility, climatic conditions and production goals a typical stand rotation period ranges from 60 to 120 years, during which one to three commercial thinnings are performed before final clear-felling and subsequent planting of a new stand. During rotation, forest structure and species composition are modified by natural succession and forestry practices, which in turn affect within-canopy microclimate and leaf- and stand scale mass and energy exchange. To understand dynamics of stand-scale water (H2O), energy and carbon (C) fluxes and their partitioning over rotation period, a multi-layer soil-plant-atmosphere model APES is used in combination with eddy-covariance (EC) fluxes from Fennoscandic coniferous forests.

The APES couples canopy microclimate and leaf-scale, field layer and soil H₂O, C, and energy exchange using biophysical theory. Here the model is first parameterized for a boreal coniferous forest using literature values and field measurements from a Scots pine stand at Hyytiälä SMEAR II -station in Southern Finland. Then, it is used to upscale component processes to a stand scale, and shown to well reproduce i) above and sub-canopy EC fluxes, ii) forest floor C and H₂O exchange and iii) soil heat and water balances. The changes of leaf-area density and shape, species composition and field layer properties over a stand rotation are derived from a statistical forest growth model, incorporated into the multi-layer model and the structural and physiological controls on growing-season H₂O, C and energy fluxes and their partitioning are considered. Finally, coupling of leaf-scale and forest floor processes with stand water budget enables assessing how the stand scale fluxes and their partitioning are mediated by site properties and water availability.
Modeling soil CO₂ production and transport to investigate the intra-day variability of surface efflux and soil CO₂ concentration measurements in a Scots Pine Forest (Pinus Sylvestris, L.)

S. Goffin<fnref n="1" />, C. Wylock<fnref n="2" />, B. Haut<fnref n="2" />, M. Maier<fnref n="3" />, M. Aubinet<fnref n="1" />, B. Longdoz<fnref n="4" />

Soil CO₂ efflux (Fₛ) is one of the most important components of the C cycle to elucidate because of its impact on the atmospheric CO₂ loading. Fₛ results from two main processes: the CO₂ production and its transport within the soil. Both processes should be considered to improve the mechanistic understanding of Fₛ, especially its temporal variation at short-time scales. In this study, a measurement campaign of Fₛ and vertical soil CO₂ concentration [CO₂] profiles was conducted in a Scots Pine Forest soil in Hartheim (Germany) and used to investigate, through modeling, which process among the CO₂ production and its transport is responsible for observed intraday variation of both variables. A reference model taking into account a purely diffusive CO₂ transport and a temperature-dependent CO₂ production is compared to models with more complex description of either the CO₂ production or CO₂ transport. For the transport, the introduction of the advection and the dispersion is investigated. For the production, the emergent hypothesis of the phloem pressure concentration wave influence is tested. We conclude that the intra-day variation of Fs and [CO₂] are better represented when the more complex CO₂ production expression is taken into account compared to the more detail description of CO₂ transport.

<footnote n="1">¹Université de Liège–Gembloux Agro-Bio Tech, Unit of Biosystem Physics, Gembloux, Belgium</footnote>

<footnote n="2">²Université Libre de Bruxelles (ULB), Transfers, Interfaces and Processes (TIPs), Brussels, Belgium</footnote>

<footnote n="3">³University of Freiburg, Chair of Soil Ecology, Freiburg im Breisgau, Germany</footnote>

<footnote n="4">⁴INRA, UMR Forest Ecology & Ecophysiology, Champenoux, France</footnote>
# Quantifying the effect of model scales with the inclusion of groundwater on simulated surface-energy fluxes

P. Shrestha¹, M. Sulis¹, S. Kollet², C. Simmer¹

¹Bonn University, Meteorological Institute, Bonn, Germany

²Research Centre Jülich, Institute for Bio- and Geosciences, Agrosphere (IBG-3), Jülich, Germany

Non-linear interactions between landcover and soil moisture affects the partitioning of surface energy fluxes. On the other hand, spatial-temporal variability of soil moisture is dependent on: 1) Variability of meteorological conditions and precipitation events, and 2) Spatial heterogeneity of landcover, geology and topography. For numerical models, heterogeneity is a deterministic source of variability related to model scales (grid cell size) of the numerical domain. Modeling scales becomes important as one moves from column models (related to modeling vertical fluxes) to physically based models with integrated surface-groundwater flows, adding a new dimension of spatial complexity. This study tries to examine how the model scales effect the soil moisture variability and surface-energy fluxes with the inclusion of a ground water model. We use the hydrological component of the newly developed Terrestrial System Modeling Platform (TerrSysMP) over a subcatchment of Rur in Germany. The hydrological component of TerrSysMP (TerrSysMP-Hydro) consists of NCAR Community Land Model (CLM) coupled with 3D variably saturated ground water model ParFlow. Results are presented based on the yearly simulations at multiple modeling scales (960m, 480m, 240m, 120m and 90m).
# Sensitivity of soil moisture initialization for decadal predictions under different regional climatic conditions in Europe

S. Khodayar¹, A. Sehlinger¹, H. Feldmann¹, C. Kottmeier¹

¹Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

The impact of soil initialization is investigated through perturbation simulations with the regional climate model COSMO-CLM. The focus of the investigation is to assess the sensitivity of simulated extreme periods, dry and wet, to soil moisture initialization in different climatic regions over Europe and to establish the necessary spin up time within the framework of decadal predictions for these regions.

Sensitivity experiments consisted of a reference simulation from 1968 to 1999 and 5 simulations from 1972 to 1983. The Effective Drought Index (EDI) is used to select and quantify drought status in the reference run to establish the simulation time period for the sensitivity experiments. Different soil initialization procedures are investigated. The sensitivity of the decadal predictions to soil moisture initial conditions is investigated through the analysis of water cycle components' (WCC) variability. In an episodic time scale the local effects of soil moisture on the boundary-layer and the propagated effects on the large-scale dynamics are analysed.

The results show: (a) COSMO-CLM reproduces the observed features of the drought index. (b) Soil moisture initialization exerts a relevant impact on WCC, e.g., precipitation distribution and intensity. (c) Regional characteristics strongly impact the response of the WCC. Precipitation and evapotranspiration deviations are larger for humid regions. (d) The initial soil conditions (wet/dry), the regional characteristics (humid/dry) and the annual period (wet/dry) play a key role in the time that soil needs to restore quasi-equilibrium and the impact on the atmospheric conditions. Humid areas, and for all regions, a humid initialization, exhibit shorter spin up times, also soil reacts more sensitive when initialised during dry periods. (e) The initial soil perturbation may markedly modify atmospheric pressure field, wind circulation systems and atmospheric water vapour distribution affecting atmospheric stability conditions, thus modifying precipitation intensity and distribution even several years after the initialization.
How best to optimize a global process-based carbon land surface model?

N. MacBean¹, P. Peylin¹, C. Bacour², S. Leonard¹, F. Maignan¹, P. Ciais¹, P. Cadule¹, F. Chevallier¹, T. Thum³, D. Santaren¹

¹LSCE, Gif sur Yvette, France

²Noveltis, Toulouse, France

³Finish Meteorological Institut, Helsinki, Finland

Global process-based land surface models are used to predict the response of the Earth's ecosystems to environmental changes. However, the estimated water and carbon fluxes remain subject to large uncertainties, partly because of unknown or poorly calibrated parameters. Assimilation of *in situ* data, remote sensing products, and/or atmospheric trace gas concentrations into these models is a promising approach to optimize key parameters, providing that all major processes are well represented. So far, most of the studies have focused on using one single data stream, either remotely sensed estimates of the vegetation activity (fAPAR or NDVI) to constrain the modeled plant phenology, *in situ* measurements of net CO₂ and latent heat fluxes (NEE, LE at FluxNet sites), in situ above ground forest biomass data, or atmospheric CO₂ concentrations (through the use of a transport model) to provide constraint on the net carbon fluxes at hourly to inter-annual time-scales. However, the combination of these data streams is expected to provide a much larger constraint on ecosystem carbon, water and energy dynamics.

At LSCE we have constructed a global Carbon Cycle Multi-Data Assimilation System (CCDAS) to assimilate i) MODIS-NDVI observations (selected points), ii) *in situ* NEE and LE fluxes at around 70 FluxNet sites, iii) specific forest biomass data (total or yearly increment) and iv) atmospheric CO₂ measurements at more than 80 sites. We used different methods of data assimilation (including a 4D-Var approach), depending on the number and type of data streams that are considered, in order to optimize the main parameters of the global vegetation model ORCHIDEE (around 15-20 parameters per PFT).

Using such a CCDAS, we investigated several questions: What is the additional information brought by the measurements of above ground biomass data on the top of eddy covariance fluxes to constrain the C allocation within ORCHIDEE? What is the level of constraint brought by the global atmospheric CO₂ data compared to FluxNet NEE/LE and satellite-derived NDVI data? What is the impact of the multi-data stream assimilation on the projected global land carbon balance at the horizon 2100 using future climate scenarios?

In order to answer these questions we have conducted several studies over a 3-year period with the assimilation of i) each data stream separately and ii) several combinations of them in both a step-wise and simultaneous mode. The estimated parameters from each experiment will be compared together and the corresponding land carbon fluxes/stocks (and to a lesser extend the land water fluxes) will be analyzed in terms of seasonal and inter-annual variations at site level or continental scale. These estimates will be compared against independent datasets/approaches in order to highlight the benefit of Carbon Cycle Data Assimilation Systems.

Keywords: data assimilation, carbon, CCDAS
# Assimilation of four-dimensional soil moisture response to assess the saturated hydraulic conductivity at the Landscape Evolution Observatory: a sensor failure analysis

D. Pasetto¹, G.- Y. Niu²,³, L. Pangle², C. Paniconi⁴, M. Putti¹, P. A. Troch²,³

¹University of Padova, Department of Mathematics, Padova, Italy

²University of Arizona, Biosphere 2, Tucson, United States

³University of Arizona, Department of Hydrology and Water Resources, Tucson, United States

⁴Institut National de la Recherche Scientifique, Centre Eau Terre Environnement (INRS-ETE), Quebec City, Canada

The Landscape Evolution Observatory (LEO) at Biosphere 2 (University of Arizona) consists of three identical, sloping, 333 m² convergent landscapes inside a 5,000 m² environmentally controlled facility. The one-meter depth soil that covers each of these engineered landscapes is equipped with a dense sensor network measuring the spatial distribution of soil moisture, energy, and carbon states and fluxes. The water mass balance on the hillslope is completely controlled by measuring the changes in system mass (thanks to ten load cells embedded into the structure), the water outflows at the lower boundary of the hillslope, and the imposed rainfall evaporation rates at the landscape surface. This real-scale landscape allows for data collection at spatial and temporal scales that are impossible in natural field settings. For this reason the experiments at LEO are perfect benchmarks to validate hydrological models and, eventually, data assimilation techniques. In particular, in this presentation the water dynamics is simulated with the physically-based hydrological model CATHY, that couples surface and subsurface water flows. The data collected during the first LEO experiment (22 h of rainfall at ~12 mm h⁻¹) show that, although carefully put in place and compacted, the soil at the first landscape is characterized by heterogeneous hydraulic properties. Thus, assimilation of the measurements of the whole sensor network is necessary to calibrate the numerical model and characterize the spatial distribution of the soil hydraulic properties. An ensemble Kalman filter with state augmentation technique is employed for the estimation of the soil saturated hydraulic conductivity assimilating the soil moisture content at 496 5-TM Decagon sensors distributed over 5 different depths. To assess the reliability of the assimilation procedure in CATHY, we consider a synthetic scenario reproducing the first experiment. We explore the sensitivity of the parameter estimation under scenarios of heterogeneity (different correlation lengths of the prior distribution) and varying degrees of sensor failure.
# Estimating Vegetation Transpiration and Soil Evaporation Sequences with a Dual Source Variational Data Assimilation Scheme

T. Xu¹, S. M. Bateni², L. Song¹

¹Beijing Normal University, School of Geography, Beijing, China

²University of Hawaii at Manoa, Department of Civil and Environmental Engineering, Honolulu, United States

Recently, a number of studies have focused on estimating surface turbulent heat fluxes via assimilation of sequences of land surface temperature (LST) observations into variational data assimilation (VDA) schemes. Using the full heat diffusion equation as a constraint, the surface energy balance equation can be solved via assimilation of sequences of LST within a VDA framework. However, the VDA methods have been tested only with total evapotranspiration (ET). The estimated vegetation transpiration (ETc) and soil evaporation (ETs) are not validated with real data. Hence, in this study, dual-source (DS) VDA schemes are tested at Daman site located in middle reach of Heihe River Basin (HRB). The ground-measured meteorology data are used as model forcing data. The DS-VDA estimated ET is validated with observation derived from eddy covariance (EC) instrument. Moreover, the ETs and ETc are measured by stable isotope instrument, and the data used to validate model estimates. The DS-VDA scheme is compared with two source surface energy balance model (TSEB) proposed by Normal et al., [1995]. The results indicate that the DS-VDA outperforms TSEB at Daman site.
# Future scenarios of soil water availability at managed grassland ecosystems in the Austrian Alps

A. Hammerle<fnref n="1" />, P. Calanca<fnref n="2" />, M. Themeßl<fnref n="3" />, A. Gobiet<fnref n="3" />, G. Wohlfahrt<fnref n="1" />

Available soil water is a major constraint for numerous ecosystem functions and is likely to be considerably affected by projected shifts in temperature and precipitation. Quantifying likely future changes in soil water content is therefore essential for assessing impacts of climate change on ecosystem functions.

We present a data fusion approach addressing changes in soil water content of temperate grasslands in the Austrian Alps under future climate scenarios. We use a simple soil bucket model, characterized by an efficient structure and minimal requirements regarding meteorological inputs (solar radiation, precipitation and air temperature). The model is therefore suitable for the analysis of a wide range of ecological datasets. Model parameter were constrained by up to three different datasets (soil water content, evapotranspiration and snow water equivalent) using a Bayesian inversion scheme.

Given a repository of data collected at ten sites in the Eastern Alps as well as a set of downscaled and error corrected (quantile mapping) regional climate scenarios, developed for the years 1961 - 2050 with 5 different regional/global climate models (CNRMRM, AITCCLM, KNMIRACMO, DMIHIRHAM, ETHZCLM) we simulated soil water content conditions under these future climate scenarios.

Despite the simple model structure calibrated model runs do show a very good performance at the majority of investigated sites. Results show that if any trend can be found, the investigated ecosystems tend to higher soil water contents on average, associated with a distinct decrease in snow cover duration under future climate conditions. Regardless of these average trends some climate models cause an increasing frequency and a longer duration of extreme dry soil water conditions under future climate scenarios.

<footnote n="1">¹University of Innsbruck, Institute of Ecology, Innsbruck, Austria</footnote>

<footnote n="2">²Forschungsanstalt Agroscope Reckenholz-Tänikon ART, Zürich, Switzerland</footnote>

<footnote n="3">³University of Graz, Wegener Zentrum für Klima und Globalen Wandel, Graz, Austria</footnote>
# MODIS Land Surface Temperature Assimilation and Verification at Rur Catchment

X. Han¹, H.-J. Hendricks Franssen¹, H. Bogena¹, H. Vereecken¹

¹Forschungszentrum Jülich, IBG3, Jülich, Germany

The 1 km remote sensing products of Land Surface Temperature (LST) are available operationally from MODIS (Moderate-resolution Imaging Spectroradiometer). There are four measurements per day from MODIS Terra/Aqua sensors with low measurement error (around 1 K). In this study, MODIS LST products were assimilated into the Community Land Model (CLM) to improve the soil moisture, soil temperature, latent and sensible fluxes estimation. Remote sensing of soil moisture has severe limitations for the Rur catchment given the spatially highly variable landuse distribution and coarse resolution of passive microwave remote sensing; LST assimilation could be an alternative for the improvement of soil moisture simulation given the coupled water and energy balances at the land surface. In this study the assimilation algorithm Local Ensemble Transform Kalman Filter (LETKF) with the state augmentation method is used. Vegetation and soil properties are also updated in some simulation scenarios. Besides soil temperature, also soil moisture is explicitly updated by LETKF on the basis of the LST-measurements. The atmospheric forcing data, vegetation properties (leaf area index, etc.) and soil properties (sand and clay fraction, etc.) are randomized to represent the model uncertainties. The assimilation results were evaluated against measured soil moisture, soil temperature and latent and sensible heat fluxes obtained for the Eifel/Lower Rhine Valley Observatory of TERENO.
Advanced microwave forward operator for the Noah-MP land surface model

C.- H. Park<sup>1,2</sup>, A. Behrendt<sup>1</sup>, M. Pause<sup>3</sup>, G. Sebastian<sup>3</sup>, V. Wulfmeyer<sup>1</sup>

<sup>1</sup>University of Hohenheim, Stuttgart, Germany

<sup>2</sup>University of Tübingen, Tübingen, Germany

<sup>3</sup>Water & Earth System Science (WESS), Tübingen, Germany

From local to global scales, microwave remote-sensing techniques can provide temporally and spatially highly resolved observations of land surface properties including soil moisture and temperature as well as the state of vegetation. These variables are critical for agricultural productivity and water resource management. Furthermore, having accurate information of these variables allows us to improve the performances of numerical weather forecasts and climate prediction models. However, it is challenging to translate a measured brightness temperature into the multiple land surface properties because of the inherent inversion problem. In this study, we introduce a novel model forward observation operator for microwave remote sensing to resolve this inversion problem and to close the gap between land surface modeling and observations. It is composed of the Noah-MP land surface model [1] as well as new models for the dielectric mixing [2] and the radiative transfer.

For developing a realistic forward operator, the land surface model must simulate soil and vegetation processes properly. The Noah-MP land surface model provides an excellent starting point because it contains already a sophisticated soil texture and land cover data set. Soil moisture transport is derived using the Richards equation in combination with a set of soil hydraulic parameters. Vegetation properties are considered using several photosynthesis models with different complexity. The energy balance is closed for the top soil and the vegetation layers, respectively. The energy flux becomes more realistic due to including not only the volumetric ratio of land surface properties but also their surface fraction as sub-grid scale information (semitile approach). Radiative transport is calculated for the bare soil and the vegetated components of the grid box using a two-stream radiative transport model. These model characteristics provide all relevant information needed for a simulation of the microwave emission from the land surface with unprecedented realism.

A case study will be provided to investigate how well the simulation of the observation operator matches to the real world. L-band microwave remote-sensing measurement over the Schäfertal region in Germany have been used for this case study. Furthermore, we discuss the future extension of this operator for thermal infrared radiation (TIR).

The novel observation operator integrated into Noah-MP will be able to simulate an anisotropic scale brightness temperature measurement with isotropic computation of the effective dielectric constant. In other words, in the data assimilation scheme the measured brightness temperature can then be ingested into the subgrid scale model properties of Noah-MP. Finally, this operator can be implemented in a consistent land-surface-atmosphere data assimilation system, e.g., Noah-MP can be coupled with the Weather Research and Forecasting (WRF) model system.

References

[1] G. Y. Niu, Z. L. Yang, K. E. Mitchell, F. Chen, M. B. Ek, M. Barlage, et al., "The community Noah land surface model with multiparameterization options (Noah-MP): 1. Model description and evaluation with local-scale measurements," Journal of Geophysical Research: Atmospheres (1984-
# Evaluation of plants effect on the mobility of heavy metals in a phytoremediation action of the ancient zinc mine the Avinières (St Laurent le Minier, France)

A. Navel¹,²,³, J. M. F. Martins¹,²,³, L. Spadini¹,²,³, J. Schneider¹,²,³, E. Vince¹,²,³, S. Sebastianutti¹,²,³, J. P. Gaudet¹,²,³

¹CNRS-LTHE UMR 5564, INSU, Grenoble, France

²IRD, Grenoble, France

³Université de Grenoble, Grenoble, France

This study was conducted in the frame of the SYMETAL project (ANR CESA) and aimed at evaluating the mobility and retention of three heavy metals, Zinc, lead and Cadmium, in ore residues stabilized with metallicolous plants. An experimental approach combining laboratory columns and field lysimeters leaching was developed. Ore residues of the ancient zinc mine "The Avinières" (St-Laurent-le-minier, France), stored in tailing ponds, were collected and homogenised before filling the columns and lysimeters. These setups were unplanted (controls) or vegetated with three plant species: Anthyllis Vulneraria (metallicolous plant), Festuca arvernensis and Koeleria vallesiana, alone or mixed. A. Vulneraria was mycorhized with Mesorhizobium metallidurans in order to improve its growth through nitrogen fixation. Rain simulations were performed every month or 6 months on the columns and lysimeters, respectively. Water balance was controlled to be equivalent in both situations. Physical and geochemical factors were monitored all along the period and especially during the leaching experiments (water flux, pH, heavy metal content, ionic mass balance...). These factors were shown to be quite constant during each leaching experiment but evolved significantly with time and also between the different vegetation conditions. Plant growth was shown to highly modify water infiltration and metal concentrations in the leachates. The temporal increase of water flux observed in the columns and lysimeters along the infiltration experiments was attributed to the rhizosphere development, which is supposed to modify the spatial structure of the ore residue, thus improving water infiltration. In columns and lysimeters vegetated with A. vulneraria only, high nitrate contents were measured in the leachates, in relation with nitrogen fixation. On the contrary when A. vulneraria was associated with F. arvernensis alone or with K. vallesiana, nitrate was directly consumed by the latter two plants and further undetected in the leachates, demonstrating the advantage of plant associations for phytoremediation actions. Furthermore compared to unplanted columns or lysimeters, the leaching of cadmium and zinc in vegetated ore residues was significantly and variably decreased depending on the number of plant species. On the contrary, lead mobilization from the ore residues was very low in relation with its low water solubility, and seemed unaffected by plants introduction. Our results showed that plant species introduction modifies both the physical properties of the ore residue and also its geochemistry, with strong benefits in terms of plant growth and heavy metal retention. Modelling of these results with a combined hydro-geochemical approach is ongoing and will help better understanding the processes involved in metal transfer limitation. These results thus demonstrate the benefit of mixing grass and metallicolous plants to stabilize ore residues from mining activities.
# ClimAgro- understanding the anthropogenic and natural drivers of water balance in changing alpine grasslands using a network of small-scale lysimeters

G. Frenck<fnref n="1" />, G. Leitinger<fnref n="1" />, N. Obojes<fnref n="2" />, U. Tappeiner<fnref n="1" />,<fnref n="2" />, E. Tasser<fnref n="2" />

Technological and social development, land-use strategies and environmental changes strongly affect the degree of utilisation in alpine agro-ecosystems. Equally, the functioning of these systems and the services they provide are also subject to the same set of drivers. Patterns of biodiversity, productivity, nutrient and water cycling vary distinctively along the gradients of agricultural intensity and environmental characteristics. Hence, defining the interplay of the anthropogenic and natural drivers which influence the different components of the water balance in alpine ecosystems is essential for informing long-term projections concerning the provision of freshwater from mountain regions. Employing a network of small-scale lysimeters, the ClimAgro project seeks to investigate how management intensity and environmental change may affect the ecological components of water cycling in grasslands of two contrasting regional alpine climates. The data gathered within ClimAgro, comprising also manipulations of temperature, precipitation and agricultural intensity, will characterise changes in the individual players of ecological water cycling and allow decomposing the hydrological coupling of the soil-plant-atmosphere system. The combination of *in situ* manipulation and transplantation of vegetation monoliths will further allow outlining methodological differences in the two major approaches used to investigate climate change effects on vegetation properties. Here, we present the details of the ClimAgro project with respect to experimental design, sampling strategy and research infrastructure. A comprehensive summary of the small-scale lysimeter approach, field site characteristics and measurements scheme as well as preliminary results will visualise how ClimAgro seeks to investigate the eco-hydrology of alpine grassland ecosystems under climate and management change.

<footnote n="1">¹University of Innsbruck, Institute for Ecology, Innsbruck, Austria</footnote>

<footnote n="2">²EURAC, Institute for Alpine Environment, Bolzano, Italy</footnote>
# Impacts of climate change on carbon and nitrogen cycling of (pre-) alpine grassland ecosystems under intensive and extensive management - a climate sequence lysimeter study

R. Kiese¹, J. Fu¹, H. Lu¹, E. Diaz-Pinez¹, R. Gasche¹, M. Dannenmann¹, K. Butterbach-Bahl¹

¹KIT, IMK-IFU, Garmisch-Partenkirchen, Germany

Due to cool and moist climatic conditions alpine grassland soils of moderate elevation are rich in soil organic carbon and associated nitrogen. In the framework of an in-situ climate change experiment we test the hypothesis that soil organic carbon and nitrogen are either volatilized (GHG emissions) or leached with seepage water due to increase in temperature. Field investigations are carried out in the (Pre-) Alpine TERENO Observatory covering several research sites in South-Bavaria, Germany. IMK-IFU has installed 36 lysimeters with undisturbed intact grassland soil cores (diameter 1m, depth 1.4m) and is operating them at three sites differing in altitude (Graswang 850m, Rottenbuch 750m, Fendt 600m). Lysimeters were partly translocated from higher elevation to sites at lower elevation and other soil cores still staying at the sites as controls. Along the altitudinal gradient maximum mean annual temperature differences are δ 2.5°C (850-600m) and slightly lower mean annual rainfall with decreasing altitude. In addition to the space for time in-situ climate change approach the total of 36 lysimeters are split into treatments of intensive (up to 5 cuts and manure applications) and extensive (2 cuts and 1 manure application) grassland management.

The different components of the water balance i.e. precipitation, evapotranspiration and groundwater recharge of each lysimeter are measured by precision weighting of the lysimeters and a separate container for collection of seepage water at the lower boundary condition (1.4m). Soil moisture and temperature are measured in 10, 30, 50, 140 cm soil depth. Soil water in 10, 30, 50 and 140 cm soil depth is sampled by under pressurized suction cups. Water samples are collected regularly every 2 weeks and at higher frequency (e.g. 3 times a week) after fertilization and cutting events, and analyzed for concentration of DOC, DON, $NH_4^+$ and $NO_3^-$. Greenhouse Gas (GHG) emissions ($CO_2$, $N_2O$ and $CH_4$) were measured by the static chamber technique mostly with automatic chambers with a new developed robot systems and QCL laser analytics in high temporal resolution. In addition to water, nutrient and GHG fluxes measurements also focused on plant biomass, $N_2$-emissions, nitrogen turnover processes and dynamics and activity of soil microorganisms.

Climate change, generally stimulated plant growth and soil C and N turnover leading to increased soil $CO_2$ emissions and an increased uptake of atmospheric $CH_4$. Increases of DOC losses were only of minor importance. $N_2O$ emission were generally low and slightly increased in spring, summer and autumn but significantly decreased during the winter period under global change conditions, the latter due to lower intensity and frequency of frost-thaw events. The main gaseous nitrogen component emitted from the (pre-) alpine grassland ecosystems was $N_2$ which also showed a much stronger increase with climate change than $N_2O$. Furthermore, climate change lead to a significant increase in nitrate leaching, whereas leaching of ammonium and DON remained unaffected. Climate induced changes in the GHG balance of (pre-) alpine grassland ecosystems are mainly triggered by increased $CO_2$ emissions since magnitude of $CH_4$ and $N_2O$ exchange, even regarding their much higher global warming potential (GWP) are only of minor importance. Overall, impacts of climate change on ecosystem C and N losses seem to be more severe under extensive management.
# Nitrate leaching and soil N₂O emissions and their responses to different nitrogen management options in a rainfed wheat-maize rotation system, Southwest China

M. Zhou<fnref n="1" />, B. Zhu<fnref n="2" />, N. Brüggemann<fnref n="3" />, R. Kiese<fnref n="1" />, K. Butterbach-Bahl<fnref n="1" />

Overuse of nitrogen fertilizer is severely impacting the regional and global environment due to unintended losses of reactive nitrogen to surface and groundwater bodies and the atmosphere. However, studies quantifying gaseous and hydrological nitrogen loss pathways are scarce. In this study we provide results from a multi-year field lysimeter experiment in southwest China, where we simultaneously quantified NO₃⁻ leaching and soil N₂O emissions from a rain-fed wheat-maize rotation. NO₃⁻ leaching losses were the main N loss pathway in our study region, though leaching events only occurred during the summer maize growing season. The seasonal NO₃⁻ leaching losses ranged from 28.0 to 53.3 kg N ha⁻<fnref n="1" /> (mean: 32.8 kg N ha⁻<fnref n="1" />), which corresponds to 12.7% to 35.5% (mean: 21.9%) of applied N in maize growing seasons. Annual N₂O fluxes from the N fertilized treatments ranged from 1.9 to 6.7 kg N ha⁻<fnref n="1" /> yr⁻<fnref n="1" /> (N₂O emission factor: 0.12-1.06%; mean: 0.61%). A significantly exponential decaying relationship between NO₃⁻ leaching loss and soil N₂O emissions was found, indicating that the tradeoff between NO₃⁻ leaching and N₂O emission exist in the investigated wheat-maize rotation system. Thus, our findings suggest that developing agricultural N management practices towards reductions of reactive nitrogen losses needs to carefully consider the tradeoff between NO₃⁻ leaching and N₂O emissions.

To meet the challenges of guaranteeing crop yields while reducing environmental impacts of nitrogen use due to associated losses of nitrate leaching and N₂O emissions, we conducted another field experiments on rainfed wheat-maize rotation by using large-scale field lysimeters (each size: 8 × 4 m<fnref n="2" />) at the same study site. One control and three same total rate of N application (280 kg N ha⁻<fnref n="1" /> yr⁻<fnref n="1" />) were included: control; synthetic N fertilizer (NPK); synthetic N fertilizer plus pig manure (OMNPK) and synthetic N fertilizer plus crop residue (RSDNPK). Crop grain yields, NO₃⁻ leaching and greenhouse gas (GHG, CH₄ and N₂O) were simultaneously measured for one year. As compared to NPK treatment, the treatments of OMNPK and RSDNPK tended to reduce NO₃⁻ leaching by 36% and 22%, respectively. The N₂O emissions from RSDNPK treatments were significantly lower than those for NPK and OMNPK treatments. Linking crop grain yields with NO₃⁻ leaching and GHG emissions, either the OMNPK or RSDNPK treatments tended to decrease both yield-scaled NO₃⁻ leaching and yield- scaled GWP as compared to NPK treatment. Our study shows that it is possible to reduce the negative environmental impacts of NO₃⁻ leaching and N₂O emissions without compromising crop productivity through minimal adjustments of fertilization practice options.

<footnote n="1">¹Institute of Meteorology and Climate Research-Atmospheric Environmental Research (IMK-IFU),
Karlsruhe Institute of Technology, Garmisch-Partenkirchen, Germany</footnote>

<footnote n="2">²Institute of Mountain Hazards and Environment, CAS, Chengdu, China</footnote>

<footnote n="3">³Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Jülich, Germany</footnote>
# The Hydrosphere section of the Helmholtz Alliance on Remote Sensing and Earth System Dynamics: Enhancing the understanding of hydrological processes by remote sensing

C. Montzka<fnref n="1" />, J. Bendix<fnref n="2" />, T. Blume<fnref n="3" />, H. Bogena<fnref n="1" />, V. Brancato<fnref n="4" />, P. Dietrich<fnref n="5" />, S. Eiermann<fnref n="2" />, T. Grau<fnref n="5" />, A. Güntner<fnref n="3" />, I. Hajnsek<fnref n="4" />,<fnref n="6" />, I. Heidbüchel<fnref n="3" />, H.-J. Hendricks-Franssen<fnref n="1" />, S. Itzerott<fnref n="7" />, T. Jagdhuber<fnref n="6" />, F. Jonard<fnref n="1" />, H. Kunstmann<fnref n="8" />, W. Kurtz<fnref n="1" />, A. Lehmann<fnref n="9" />, C. Lorenz<fnref n="8" />, P. Marzahn<fnref n="10" />, L. Samaniego<fnref n="11" />, I. Schröter<fnref n="5" />, D. Spengler<fnref n="7" />, D. Spieler<fnref n="11" />, S. Suchandt<fnref n="12" />, B. Thies<fnref n="2" />, H. Vereecken<fnref n="1" />, S. Vey<fnref n="3" />, J. Wickert<fnref n="13" />, U. Wollschläger<fnref n="5" />, S. Zwieback<fnref n="4" />

The Earth system comprises a multitude of geophysical processes that are intimately meshed through complex interactions. In times of accelerated global change, the understanding and quantification of these processes is of primary importance. Spaceborne remote sensing sensors are predestined to produce geophysical data products at the global scale. The Helmholtz Alliance will therefore complement the high degree of innovation in radar remote sensing technology, which has been successfully implemented with TanDEM-X, and will establish a unique chain from satellite technology, mission operation to information extraction and integration into local, regional and global models.

The overall goal of the hydrosphere-related Alliance activities is to enhance the understanding of hydrological processes by optimally exploiting the observations of current (e.g., SMOS, TerraSAR-X) and planned (e.g., SMAP, Tandem-L) satellite missions. Therefore, we are developing and improving remote sensing derived data products, such as soil moisture from active and passive microwave sensors, the combination of radar and hyperspectral sensors, and the determination of sea surface currents velocity by SAR along-track interferometry. Moreover, we are establishing algorithms for validation and building up ground based observation infrastructures for the accuracy assessment of remotely sensed data products. Methods with larger footprints such as GNSS reflectometry, cosmic-ray neutron probes and geophysical measurement techniques serve as an improved reference for spaceborne observations compared to point-scale measurements. Satellite-based as well as in-situ observations are integrated in numerical models by data assimilation methods to allow for a quantitative understanding of dynamic processes in the hydrosphere.

Scientific questions that are addressed in this research consortium include:

* Does the assimilation of soil moisture and freeze/thaw states help to minimize parameter uncertainty of hydrological models?

<footnote n="1">¹Forschungszentrum Jülich, Institute of Bio- and Geosciences: Agrosphere (IBG 3), Juelich, Germany</footnote>

<footnote n="2">²Phillipps University Marburg, Department of Geography, Marburg, Germany</footnote>

<footnote n="3">³Helmholtz Centre Potsdam, Hydrology, Potsdam, Germany</footnote>

<footnote n="4">⁴ETH Zürich, Institute of Environmental Engineering, Zürich, Switzerland</footnote>

<footnote n="5">⁵Helmholtz Centre for Environmental Research (UFZ), Department Monitoring & Exploration Technologies, Leipzig, Germany</footnote>

<footnote n="6">⁶German Aerospace Center (DLR), Microwaves and Radar Institute, Oberpfaffenhofen, Germany</footnote>

<footnote n="7">⁷Helmholtz Centre Potsdam, Remote Sensing, Potsdam, Germany</footnote>

<footnote n="8">⁸Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, Garmisch-Partenkirchen, Germany</footnote>

<footnote n="9">⁹Helmholtz Centre for Ocean Research (GEOMAR), Ocean Circulation and Climate Dynamics Theory and Modelling, Kiel, Germany</footnote>

<footnote n="10">¹⁰Ludwig-Maximilian University, Department of Geography, Physical Geography and Environmental Modeling, Munich, Germany</footnote>

<footnote n="11">¹¹Helmholtz Centre for Environmental Research (UFZ), Department Computational Hydrosystems, Leipzig, Germany</footnote>

<footnote n="12">¹²German Aerospace Center (DLR), Remote Sensing Technology Institute, Oberpfaffenhofen, Germany</footnote>

<footnote n="13">¹³Helmholtz Centre Potsdam, GPS/Galileo Earth Observation, Potsdam, Germany</footnote>
* To what extent does the assimilation of subgrid-scale (e.g. 50-500 m) variability of state variables contribute to the derivation of effective parameters at larger scales (e.g. 1-5 km) in order to characterize hydrological processes?

* Does the assimilation of high-resolution synchronized observations of soil moisture and snow water equivalent help to reduce the predictive uncertainty of hydrologic models?

* Is Tandem-L with the high spatial resolution of the soil moisture product able to improve the regionalization of land surface models?

* Can the global operational geodetic GNSS ground network contribute to a global soil moisture monitoring and validation system in conjunction with remote sensing products?

* Can the improved land surface model enhance our understanding about soil-vegetation - atmosphere water fluxes and coupled plant water/carbon dynamics?
Radar altimetry backscattering signatures at Ka-band over West Africa

F. Frappart<fnref n="1" />, E. Mougin<fnref n="1" />, C. Fatras<fnref n="1" />, M. Grippa<fnref n="1" />, P. Borderies<fnref n="2" />, I. Guiro<fnref n="3" />, B. Sambou<fnref n="3" />

This study presents an analysis of radar signatures acquired over West-Africa at Ka band using the first one year and a half of Saral nadir-looking altimeter data. The backscattering coefficients time series are generated over regional transects and local sites. Meridian transects from the wet tropics to the arid regions of the Sahara desert point out the spatial and temporal changes of the radar response at Ka-band over the West-African bioclimatic gradient in terms of surface roughness, land cover and soil wetness. Comparisons with radar responses at Ku- and C- bands using nadir-looking altimeters (35-day orbital period ENVISAT RA-2 over 2003-2010 on the same orbit as Saral and 10-day orbital period Jason-2 since mid-2008) will be presented. Comparisons with time-variations of in situ soil moisture measurements will also be presented for a study site located in Senegal.

<footnote n="1">¹Observatoire Midi-Pyrénées, Toulouse, France</footnote>

<footnote n="2">²ONERA, Toulouse, France</footnote>

<footnote n="3">³Université de Dakar, Institut des Sciences de l'Environnement, Dakar, Senegal</footnote>
# Evaluation of standard pre-processing techniques for X-Bandradar using hydrologic modeling

S. Thober¹, P. Kilian¹,², L. Samaniego¹, D. Spieler¹, B. Pospichal²

¹Helmholtz Centre for Environmental Research, Computational Hydrosystems, Leipzig, Germany

²University of Leipzig, Institute of Meteorology, Leipzig, Germany

Precipitation is the key driver of hydrological processes on the land surface; like runoff, infiltration, and evaporation. A standard device for measuring precipitation are rain gauges which exhibit a relatively good measurement accuracy but only provide point measurements. The estimation of areal precipitation by interpolating rain gauge data is a big challenge because of the high spatial variability and intermittency of precipitation. Weather radar data provide a promising addition to rain gauge measurements for the estimation of areal rainfall. They are able to better resolve the spatial variability of precipitation at the expense of measurement accuracy.

In this study, the impact of different precipitation products obtained separately by rain gauge and radar data on hydrologic fluxes like runoff is going to be assessed. The study domain covers the Selke river catchment located in the TERENO Harz observatory. The study period encompasses the calendar year 2013. Hourly rain gauge data is made available by the German Weather Service (DWD), which is interpolated using external drift kriging. The radar data is obtained from the TERENO rain scanner located within the observatory. Raw reflectivity data from this X-Band radar is corrected for ground clutter and attenuation as well as transformed to precipitation rates using standard procedures available from the literature. Both precipitation products are then used to force the mesoscale hydrologic model (mHM) to produce river discharge.

It is expected that the precipitation products will generate different streamflow discharges. Preliminary comparisons of the two precipitation products highlight that the discharge produced by the rain gauge interpolation show a closer match than the one obtained from the radar to the observed one. This study provides the first insights on the potential utility of assimilating discharge data to improve radar based precipitation estimates.
# Installation and operation of sensors for automated optical measurements at two eddy covariance sites

M. Lange¹, B. Dechant¹

¹Helmholtz Centre for Environmental Research - UFZ, Computational Landscape Ecology, Leipzig, Germany

We installed multispectral 4-channel and hyperspectral sensors at eddy-flux measurement sites monitoring two different vegetation types, grasland and deciduous forest. Spectral measurements are taken with dual-field-of-view systems continuously and automatically. Radiances and irradiances are measured in order to derive diurnal and seasonal reflectance dynamics. These measurements are compared with airborne hyperspectral data from a flight campaign, ground measurements with a field spectrometer, a RGB-camera to observe changes in phenology and the micrometeorologicaland ecophysiologicaldatameasured at the eddy-covariance sites.

Our main goals are:

(1) the retrieval of fluorescence and calculation of vegetation indices to estimate GPP from eddy-flux-measurements

(2) the retrieval of other biophysical parameters, such as phenology, LAI and chlorophyll content to validate of satellite products, especially for SENTINEL-2.

Here we present our measurement concept and technical set-up as well as first results.
# Spatio-temporal Dynamics of Land-use and Land-cover in the Mu Us Sandy Land, China, using the Change Vector Analysis Technique

A. Karnieli¹

¹Ben Gurion University, The Remote Sensing Laboratory, Sede Boker Campus, Israel

Sandification refers to land degradation in sandy areas. Considerable attention has been given to sandification processes in China since vast areas of sandy deserts are located in the north of the country within arid and semi-arid climatic zones. The current paper is aimed at assessing the land-use/land-cover spatial and temporal dynamics of the Mu Us Sandy Land, China, via change detection methodology based on spaceborne images. Two biophysical variables, NDVI, positively correlated with vegetation cover, and albedo, positively correlated with cover of exposed sands, were computed from a time series of merged NOAA-AVHRR and MODIS images (1981 to 2010). Generally, throughout the study period, NDVI increased and albedo decreased. Improved understanding of spatial and temporal dynamics of these environmental processes was achieved by using the Change Vector Analysis (CVA) technique applied to NDVI and albedo data extracted from four sets of consecutive Landsat images, several years apart. Changes were detected for each time step as well as over the entire period (1978 to 2007). CVA created four categories of land-cover change - vegetation, exposed sands, water bodies, and wetlands. The CVA's direction and magnitude result in pixel-based maps of the change rather than broad qualitative classes, such as slight-, moderate-, or severe land degradation that previously presented for this region. Each of the four categories has a biophysical meaning that was validated in selected hot-spots, employing very high spatial resolution images (e.g., IKONOS). Careful selection of images, taking into account inter and intra annual variability of rainfall, enables differentiating between short-term conservancies (e.g., drought) and long-term alterations. NDVI and albedo, although comparable to tasseled cap's brightness and greenness indices, have the advantage of being computed using reflectance values extracted from various Landsat platforms since the early 1970s. It is shown that, over the entire study period, the majority of the Mu Us Sandy Land area remained unchanged. Part of the area (6%), mainly in the east, was under human-induced rehabilitation processes, in terms of increasing vegetation cover. In other areas (5.1%), bare sands were found to expand to the central-north and the southwest of the area.
# Multitemporal soil pattern analysis with multispectral remote sensing data at field
Borrentin in testsite Demmin, TERENO Northeast Germany

G. Blasch¹, C. Hohmann¹, D. Spengler¹

¹German Research Centre for Geosciences Potsdam (GFZ), Remote Sensing, Potsdam, Germany

For (1) general issues of policy-making, land resource management and environment-monitoring as well as for (2) more precise applications in precision agriculture, hydrological modelling and soil landscape studies soil maps should provide qualitative and quantitative soil information at different scales (landscape-, field-level). In the early 1990´s evolved the philosophy of "site-specific (crop) management" (SSM) in precision agriculture. Nucleus is the identification of (crop) management zones as relatively homogenous sub-units of farm fields, considering temporal-spatial variability of soil and crop characteristics at scales finer than soil mapping units. Because of large coverage as well as detailed spatial and spectral information multispectral imagery offers excellent capability for detection of homogenous surficial soil patterns due to existing relationships between soil (colour/brightness) reflectance and specific soil properties (e.g. organic content, texture, CaCO₃, soil moisture). This implies a great potential for identifying management zones at low costs. Because of different land use and vegetation conditions, monotemporal analysis with one single remote sensing dataset always contains heterogeneous spatial reflectance pattern without any temporal dimension. Regarding agricultural land use, static soil pattern persist beside temporal pattern characterized by crop type, vegetation phenology and land management practices. To eliminate the disturbing influence of temporal pattern a multitemporal approach is needed. This also allows evaluating the stability of soil reflectance pattern and categorizing them into static and temporal pattern. As (additional) spatial-precise basic soil information identified static soil pattern can be used for delineating management zones and mapping functional soil property units in several SSM-models of application maps generation.

We present a model for functional soil mapping at field scale for precision farming based on multitemporal remote sensing data analysis and GIS spatial data modelling. The objective is (i) to demonstrate the potential of multitemporal soil pattern analysis in comparison to monotemporal analysis and (ii) to generate functional soil maps based on identified static homogenous soil pattern and related soil property. The most important step in soil pattern analysis is the separation between static pattern and temporal reflectance pattern, influenced by (vital and senescent) vegetation and land management practices. By using the high spatial and temporal resolution of multispectral RapidEye satellite imagery in standardized principal component and per-Pixel-analysis static spatial soil pattern could be derived and allowed to produce a highly significant functional soil map respective to organic matter for field Borrentin, Northeast Germany. Due to existence of archive data and data availability, this model might be more rapid, less time-consuming and at lower costs than proximal sensing techniques.
# Remote Sensing of Forest 3-D Structure by Means of Synthetic Aperture Radar Systems: Status, Potentials and Challenges

M. Pardini¹, F. Kugler¹, M. Tello-Alonso¹, A. Torano-Caicoya¹, K. Papathanassiou¹

¹German Aerospace Center, Microwave and Radar Institute, Wessling, Germany

The next generation of spaceborne Synthetic Aperture Radar (SAR) remote sensing missions will enable systematic monitoring of dynamic processes on the Earth surface with high quality and resolution providing a unique data source to significantly advance our understanding of the Earth system and its dynamics. At the same time, the development of a new generation of SAR techniques combined with the evolution of radar technology and the implementation of innovative SAR measurement configurations have the potential to change the way forest monitoring, management and modelling is addressed today. Indeed, today it is already possible to accurately estimate critical (horizontal and vertical) forest structure parameters such as forest height and vertical forest layering with a high spatial resolution. At the same time, the next generation of spaceborne SAR configurations will be able to measure these parameters with a high temporal resolution (on a weekly to monthly basis) opening the door to estimate natural and anthropogenic changes of these parameters and provide a better understanding of their causes and effects.

In this presentation, we critically review the current state-of-the-art in forest parameter estimation by means of SAR, specifically forest height, forest structure and forest biomass. We identify potential forest products and the challenges associated with their integration into the existing framework of forest ecosystem research and management. These issues are being investigated within the Biosphere Topic in the "Alliance on Remote Sensing and Earth System Dynamics" established by the Helmholtz Association, Germany's largest scientific research organization.

Regarding forest height and forest structure estimation, radar remote sensing applications have been developed in the last decades. Indeed, the polarimetric-interferometric (PolInSAR) combination of multiple SAR images acquired in spatial diversity (i.e. multi-baseline) was a decisive step in order to estimate forest height and structure with high resolution and large coverage. PolInSAR forest height estimation matured and developed from a pre-operational to an operational PolInSAR product that has been validated in a series of airborne and spaceborne experiments over a variety of natural and managed temperate, boreal, and tropical test sites characterized by different stand and terrain conditions. The overall obtained estimation accuracy is on the order of 10% or better. In addition to forest height, the availability of multiple PolInSAR interferograms at a low electromagnetic frequency (e.g. L-band) makes it possible to determine not only forest height, but also a full profile of the backscattered power (reflectivity) along the vertical dimension for each spatial resolution cell, which depends on the horizontal and vertical structure of the vegetation. Contrarily to forest height inversion, the use of the 3D radar reflectivity for forestry applications is still in a very early stage.

An underdeveloped element is the physical interpretation of the vertical radar reflectivity profiles. Efforts are still to be provided to clearly assess how and how accurately structure-related SAR observables can be translated into geophysical information of interest. Also, the benefits of shifting from 2-D to 3-D observation capabilities have to be evaluated and new forest products that could result from this have to be identified. The aim of the research activities currently being carried out in the Alliance Biosphere framework is to bridge this gap. In the scope of this presentation, progresses in two specific applications will be shown. The first one concerns forest classification and characterization of the forest stages from the 3D structure information derived from SAR after mapping this information in a space of quantitative horizontal and vertical structure descriptors. The second one concerns biomass estimation. It will be shown that more accurate biomass distribution maps can be obtained from SAR, not only considering forest height estimation, but also accounting for the vertical structure information derived from the reflectivity profiles. Preliminary validation is performed through comparison with available terrestrial data.
# Spatio-temporal downscaling of passive microwave soil moisture product using active microwave

S. K. Tomer<fnref n="1" />, A. Al Bitar<fnref n="1" />, S. Muddu<fnref n="2" />, S. Corgne<fnref n="3" />, S. Bandyopadhyay<fnref n="4" />, Y. Kerr<fnref n="4" />

SMOS (passive microwave) mission provides the soil moisture product with a fine temporal resolution (approximately 3 days), but with a relatively coarse spatial resolution (approximately 50 km) (Kerr, Y.H. et al., 2001). On the other hand, the active microwave satellites are capable of providing fine spatial scale (less than 100 m) soil moisture products but with a poor temporal resolution (around 3 weeks) (Moran, M.S. et al., 2004). There exists a good potential to merge data from both the sensors to provide the soil moisture products at a higher spatial and temporal resolution, which would be helpful in various applications like agriculture, hydrology, atmospheric sciences etc. The current study presents a methodology for the spatio-temporal downscaling of the SMOS retrieved soil moisture product with the help of active microwave data (RADARSAT-2), and the methodology is tested in an experimental watershed, Berambadi, South India. The watershed is being studied under the Indian AMBHAS project (http://ambhas.com/) and French RBV network of observatories (http://rbv.ipgp.fr/).

First, a non parametric algorithm based on the Cumulative Distribution Function (CDF) transformation was developed to retrieve the soil moisture from RADARSAT-2 data sets. The developed algorithm was validated using the 28 satellite images of RADARSAT-2 and field data collected in 50 agricultural fields spanning over 3 years. The developed algorithm provided a good estimate of the surface soil moisture with a RMSE of 0.05 (v/v). Then the surface heterogeneity (soil texture, land use and SMOS mean antenna patterns) was analysed by up-scaling and comparing the validated RADARSAT-2 soil moisture maps with the SMOS retrieved soil moisture. It was observed in the study area, that up-scaling based on the land use outperformed the other approaches. Further, considering the significant effect of land cover on up-scaling, a model was developed to downscale the soil moisture from SMOS based on a combination of the statistical downscaling of variance observed at large scale (Blöschl, G. et al., 2009) and spatial patterns obtained from the RADARSAT-2 derived soil moisture. First, the model was calibrated using the 14 RADARSAT-2 images, and then it was validated using the separate 14 RADARSAT-2 images and field data. The developed methodology showed the promising results with a RMSE of 0.05 (v/v).

<footnote n="1">¹CESBIO, Toulouse, France</footnote>

<footnote n="2">²Indian Institute of Science, Civil Engineering, Bangalore, India</footnote>

<footnote n="3">³Costel, UMR 6554 CNRS LETG, Rennes, France</footnote>

<footnote n="4">⁴Indian Space Research Organization, Bangalore, France</footnote>
# Long term estimation of evapotranspiration over Kabini basin at 250 m spatial resolution using MODIS data

E. Rajasekaran<fnref n="1" />, S. Muddu<fnref n="1" />, B. Bhattacharya<fnref n="2" />

Knowledge about evapotranspiration (ET) over a long time period is critical for proper understanding of the hydrological cycle. In India, though streamflows and ground water levels are observed periodically, reliable data on the quantity of water reaching the atmosphere through ET is not available. This lack of data causes high uncertainties in closing the water budget and estimating the quantum of water available for human consumption. Remote Sensing (RS) sensors like MODIS and AVHRR are providing datasets for estimation of ET over a long time period, however only at a spatial resolution of 1000 m. The 1000 m spatial resolution may be too coarse to capture the field level variation (~100 m) in ET in the Indian context. Hence there is a need to generate a reliable and consistent ET product with a spatial resolution of few hundreds of metres over Indian river basins.

Kabini, originating in the Western Ghats is a tributary of the river Cauvery in south India. The Kabini river basin has a unique climatic gradient and contrasted landuse/landcover. The basin is a part of French network of observatories and some of the sub-watersheds of the Kabini basin are monitored for several hydrological, meteorological and geochemical studies. The objectives of this study are (i) to estimate ET at 1000 m resolution over the Kabini basin in South India using MODIS data from 2002-2013 and (ii) to develop a spatial disaggregation algorithm to bring down the ET at 1000 m resolution to 250 m.

In this study, ET was estimated as a product of Evaporative Fraction (EF) and net available energy (Difference of net radiation and soil heat flux, hereinafter abbreviated as NAE). The triangle method was used for estimation of EF and a simple clear sky radiation model was utilized for NAE estimation. No ground data was used in ET estimation. The adopted approach for ET estimation was validated at five different sites in India using data from Bowen Ratio Energy Balance (BREB) towers. The final day-time averaged ET product at 1000 m resolution had RMSE and bias of 47 Wm⁻<fnref n="2" /> and 12 Wm⁻<fnref n="2" /> respectively for all the five sites put together. Since the approach adopted for ET estimation was found to perform with reasonable accuracy at different sites, the same approach was applied over the Kabini basin to estimate ET at 8 day interval at 1000 m resolution.

For disaggregation of the ET product, a disaggregation model called DEvap using the relationship between ET and a vegetation index (VI) was developed in this study. In order to find the VI that gives a better disaggregated ET product, three different VIs NDVI, FVC and NDWI were tested and compared for their use in the DEvap (hereafter referred as DEvap<sub>NDVI</sub>, DEvap<sub>FVC</sub> and DEvap<sub>NDWI</sub>) model. Since NDWI is available only at 500 m resolution, testing was done by disaggregating ET at 1000 m to 500 m. When compared with the BREB tower estimates, the day-time averaged disaggregated ET had RMSE of 49 Wm⁻<fnref n="2" />, 49 Wm⁻<fnref n="2" /> and 63 Wm⁻<fnref n="2" /> for DEvap<sub>NDVI</sub>, DEvap<sub>FVC</sub> and DEvap<sub>NDWI</sub> variants respectively. Similarly the bias in the disaggregated product was 9 Wm⁻<fnref n="2" />, 9 Wm⁻<fnref n="2" /> and 27 Wm⁻<fnref n="2" /> respectively for DEvap<sub>NDVI</sub>, DEvap<sub>FVC</sub> and DEvap<sub>NDWI</sub> variants. The DEvap<sub>NDWI</sub> variant produced higher errors than the original 1000 m ET estimate. It was observed that DEvap<sub>NDVI</sub> and DEvap<sub>FVC</sub> performed very similar to each other and both were superior to the DEvap<sub>NDWI</sub> variant. Furthermore, disaggregation using DEvap<sub>NDVI</sub> and DEvap<sub>FVC</sub> variants captured the sub-pixel level ET variability that is otherwise averaged out at 1000 m resolution.

After the initial performance assessment, NDVI was chosen for use in the DEvap model. MODIS 8-day surface reflectance product at 250 m was used for computing NDVI at 250 m. This 250 m NDVI was combined with 8-day 1000 m ET product to produce 8-day ET product at 250 m over the Kabini basin for the period 2002-2013. It was observed that the ET time series at 250 m was able to capture the seasonal trends in ET. However there were gaps in the ET product due to cloud cover in the summer

<footnote n="1">¹Indian Institute of Science, Department of Civil Engineering, Bangalore, India</footnote>

<footnote n="2">²Space Applications Centre (ISRO), Ahmedabad, India</footnote>
monsoon season (June-September). Future study will focus on filling this gap and producing a time
continuous ET product over the Kabini basin at 250 m spatial resolution.
# Ground surface response to groundwater level changes in Neustrelitz region, Germany: Insight from Terrasar-X interferometry analysis

M. Motagh¹, S. Itzerott¹, I. Heine¹

¹GFZ German Research Center for Geosciences, Geodesy and Remote Sensing, Potsdam, Germany

Monitoring of surface deformation and landscape changes associated with water level fluctuations in lakes could provide important constraints on rheological properties of the crust and lithosphere. The extent and complexity of surface motion in unstable areas is also important for designing preventive and remedial measures in regions subject to surface loading and unloading.

In this work, we have investigated the capability of X-band (wavelength ~ 3.1 cm) SAR Interferometry (InSAR) for monitoring ground surface deformation in response to groundwater level changes in Großer Fürstenseer See of Neustrelitz region in Germany. The data include 82 SAR data acquired by German TerraSAR-X from September 2008 to August 2010, which we process using the time-series technique of Persistent Scatterer (PS) Interferometry (PS-InSAR). Although challenging for classical InSAR processing because of the dense vegetation cover, the preliminary results show that time-series analysis of X-band SAR data from TerraSAR-X satellite with a repeat interval of 11 days is promising in providing important insight into possible response of the ground surface deformation to sub-surface hydrological processes operative in Neustrelitz.
# Natural and Drained Temperate Bog-Forest Ecosystems: Carbon Sink or Carbon Source?

J. Hommeltenberg¹, M. Drösler², M. Mauder¹, H. P. Schmid¹

¹Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research, Garmisch-Partenkirchen, Germany

²University of Applied Sciences Weihenstephan -Triesdorf, Chair of Vegetation-Ecology, Freising, Germany

About 30% of the worldwide soil carbon is stored in peat-soils. However, this long-term carbon storage is threatened by climate- and land use change. Most of these climate sensitive areas are used for agriculture and forestry. The impact of these processes on the greenhouse gas (GHG) balance of peatlands is still far from being unraveled. Studies of carbon exchange of peatlands, and in particular of peatland forests, are still rare. Furthermore, reported GHG-balances of peat-forests are highly variable and strongly depended on climate, nutrient supply and tree population. Until now, there is still no full agreement whether peatlands drained for forestry are net GHG sinks or sources.

This study aims to shed more light on the GHG exchange of peatland forests in the temperate, pre-alpine region of southern Germany. Therefore, we compared the GHG-exchange of a classically managed, drained spruce forest (Mooseurach) with a near-natural bog-pine ecosystem (Schechenfilz), by eddy covariance measurements. The sites are separated by only a few kilometers, thus weather conditions and peat-formation history are the same, and differences in the GHG exchange can be entirely attributed to differences in land use and management. We can present results of four years of CO₂measurements from both sites, and data of almost two years of methane exchange from the natural site. Annual net budgets of CO₂ exchange indicate currently about three times stronger CO₂ uptake at the drained site compared to the natural ecosystem. Furthermore, considering the methane emission at natural site, the bog-pine ecosystem is still a small GHG-sink, but the CO₂ uptake induced climate cooling effect is reduced by about 80%. Consequently, the measurements show that the drained spruce forest is a much stronger GHG-sink than the natural bog-forest ecosystem. However, the measurement period of a few years can only reflect the current stage of the observed ecosystems. For an unbiased interpretation of the flux measurements at the drained site, we need to validate the impact of drainage and spruce afforestation on the long-term carbon balance. Therefore, peat loss-induced carbon emissions, as well as the net carbon fixation within the spruce life-cycle have to be considered. This rough estimate indicates a strong net carbon loss that could not be compensated within one spruce rotation period. In contrast, the natural bog-pine ecosystem has likely been a small but steady GHG-sink for decades, which our results suggest is very robust regarding short-term changes of environmental factors.
# Methane and nitrous oxide emissions from rice and maize production in diversified rice cropping systems

S. Weller¹, R. Kiese¹

¹KIT IMK-IFU, Garmisch-Partenkirchen, Germany

Traditional irrigated double-rice cropping systems have to cope with less water availability. To quantify the shift in CH₄ and N₂O fluxes when changing from traditional to diversified double cropping- systems, an experiment including flooded rice, non-flooded "aerobic" rice and maize was conducted at the international Rice Research Institute in the Philippines. Two automated static chamber-GC systems were used to measure CH₄ and N₂O fluxes continuously in the three cropping systems combined with three fertilizer treatments (N=3): zero-N (no fertilizer), conventional (130 kg ha⁻¹) and site-specific (180-190 kg N ha⁻¹). Turning away from flooded cropping systems leads to shifts in greenhouse gas emissions from CH₄ under wet to N₂O emissions under dry conditions. The global warming potential (GWP) of the non-flooded crops was lower compared to flooded rice as high CH₄ emissions under flooded conditions override the N₂O emissions. The yield-scaled GWP favored maize over aerobic rice, due to low yields of aerobic rice. Significant (p<0.001) lower CH₄ emissions from non-flooded systems implements high greenhouse gas mitigation potential for the diversification of double-rice cropping systems with aerobic rice or maize in the dry season. Furthermore, subsequent measurements indicate lower CH₄ emissions from diversified rice systems during flooded rice production in the wet season and further reduction of CH₄ emissions from aerobic rice production in the following dry season.
# The influence of meteorological variability on the seasonal course of pre-Alpine managed grasslands

M. Zeeman¹, R. Steinbrecher¹, E. Eckart¹, K. Heidbach¹, M. Mauder¹

¹Karlsruhe Institute of Technology, IMK-IFU, Garmisch-Partenkirchen, Germany

The seasonality of pre-Alpine grasslands is controlled by a combination of environmental drivers and management. The variability in environmental drivers originates from climate, weather and topographic effects, with management interacting through adaptive behavior, policy and traditions. The topography in the pre-alpine regions, with elevation and exposure differences in particular, introduces heterogeneity in environmental drivers, which in turn controls grassland productivity.

We investigated the seasonal and spatial variability of exchange fluxes at the start and end of the growing season in relationship to environmental controls and management. Of particular interest were the timing and duration of snow cover. In the pre-Alpine region, precipitation as snow is common. But the amount and persistence of the snow cover varies. The resulting time line of exposure of the surface influences the re-growth dynamics after winter. Further, meteorological variation leading to shifts in the start and end of a season are not always accounted for in the timing of management, and we quantified that effect.

We show first results of a comparison of plant-atmosphere carbon and energy fluxes for TERENO pre-alpine managed grassland sites that are situated in close proximity but at different elevations in the River Ammer catchment in the South of Germany.
# Up-scaling of greenhouse gas source strengths for spatial inhomogeneous soil emissions

K. Schäfer<fnref n="1" />, D. Weymann<fnref n="2" />, R. Grant<fnref n="3" />, A. Raabe<fnref n="3" />,<fnref n="4" />, S. Emeis<fnref n="1" />, J. Böttcher<fnref n="1" />,<fnref n="5" />

## 1. Background & Objectives

Emissions of greenhouse gases as nitrous oxide (N₂O) from soils are commonly characterized by huge spatial variability so that the measurement results are scale dependent. An up-scaling of classical small-scale chamber measurements may add uncertainty to emission inventories or emission factors. Also urban - rural exchange process studies require such data. Further, the development of non-intrusive micrometeorological flux measurement methods is necessary because such techniques are available for CO₂, CH₄ and H₂O only, i.e. they are yet not applicable for the greenhouse gas N₂O and other trace gases.

In this presentation a flux gradient method utilizing a non-intrusive path-averaging measurement method is described. Measurements in two heights (0.5 m and 2.7 m, respectively) are performed by an open-path Fourier Transform Infrared (FTIR) spectrometer for the N₂O concentrations (100 m average) and by three-dimensional (3D) ultrasonic anemometers for the three orthogonal wind components. The significance of measured concentration gradients and turbulence statistics are investigated to get reliable flux data.

Since micrometeorological techniques are limited by stable atmospheric conditions, we used a closed tunnel equipped with an open-path FTIR spectrometer to (i) evaluate its feasibility for measuring field-scale N₂O fluxes from an unfertilized grassland soil and (ii) compare those results with small-scale fluxes obtained from closed chambers.

Further improvements of these methodologies are underway which are of relevance for TERENO.

## 2. Materials & Methods

The investigations were conducted from June 2006 until June 2008 in the flat catchment area of the Fuhrberger Feld aquifer on a permanent grassland with Festuca rubra as the predominant species.

### Open-path flux-gradient method:

While there is relatively high confidence in flux measurements made under unstable atmospheres with mean winds greater than 1 m s⁻<fnref n="1" />, there is great uncertainty in flux measurements made under free convective or stable conditions. Different approaches for calculating the flux data were applied using the empirically-derived turbulence parameters and using those following the Monin-Obukhov similarity theory with stability corrections. Additionally, the N₂O fluxes were calculated with the concentration gradient and the diffusivity as exchange coefficient.

### Measuring tunnel:

The measuring tunnel, consisting of a 99×5×0.6 m aluminium liner structure, was closed with a commercial plastic cover prior to each measurement. The cover was sealed at the frame and the soil using sand-filled hoses. Based on those measurements, we used a non-steady-state approach to calculate the predeployment N₂O flux (q₀) by taking into account diffusive gas transport between soil

<footnote n="1">¹Karlsruhe Institute of Technology, IMK-IFU, Garmisch-Partenkirchen, Germany</footnote>

<footnote n="2">²Forschungszentrum Jülich, Agrosphere Institute, Jülich, Germany</footnote>

<footnote n="3">³Purdue University, Deaprtment of Agronomy, West Lafayette, Germany</footnote>

<footnote n="4">⁴University of Leipzig, Institute of Meteorology, Leipzig, Germany</footnote>

<footnote n="5">⁵Leibniz University Hannover, Institute of Soil Science, Hannover, Germany</footnote>
and tunnel atmosphere. We estimated q₀ inversely using measured concentration courses at the FTIR
beam height.

N₂O fluxes from concurrent static chamber measurements were calculated using the non-steady-state
diffusive flux estimator (NDFE).

**3. Results & Discussion**

Open-path flux-gradient method:

During two measurement campaigns (16 - 17 October 2007 and 17 - 18 June 2008) the mean N₂O emission rates differed considerably between the applied methods.

Measuring tunnel:

During twenty-four measuring campaigns the tunnel systemwas generally feasible for calm and dry
weather conditions. Therefore, we restricted the measurements to the evening hours.

**4. Conclusions**

The application of flux-gradient methods is difficult because there are either (1) low wind speeds with poorly defined wind speed gradients and typically high vertical concentration gradients or (2) high wind speeds with small concentration gradients. The FTIR spectrometer must routinely provide the necessary precision and detection limits.

The tunnel evaluated here can be applied to heterogeneous field conditions or to reveal difference in
emissions among treatments so that it can fill an experimental gap between small-scale chamber and
ecosystem-level micrometeorological methods.The extension of the application of the tunnel could be
achieved by an improved, solid, double-walled cover or a mechanical system, that facilitates tunnel
closure, and by using mirrors for the FTIR radiation beam to change the tunnel length and thus the
covered soil area.
# Modeling the influence of atmospheric parameters on N₂O-Emissions

C. Thieme¹, C. Klein¹, C. Biernath¹, F. Heinlein¹, E. Priesack¹

¹Helmholtz-Center for Environmental Health, Institute of Soil Ecology, München, Germany

The trace gas N₂O, mainly produced by microorganisms in agricultural soils, is a very stable and thus potent greenhouse gas and is the main contributor for the recent depletion of ozone in the stratosphere. Therefore N₂O-emissions need to be mitigated and thus much effort has been made to reveal the causes of N₂O-formation in soils. At present some crucial drivers for N₂O-fluxes are known, but underlying processes of N₂O-fluxes are not yet understood or described adequately. An important shortcoming is the description of the upper boundary layer at the soil-atmosphere interface.

Therefore, the aim of this study is to develop a mechanistic simulation model, which considers both the formation of N₂O in agricultural soils, and the impact of the atmospheric conditions on the transport of soil-born N₂O into the atmosphere. The new model simulates N₂O-flux as a function of meteorological values instead of a model that just releases the whole amount of N₂O into the atmosphere.

For this purpose the modular ecosystem model framework Expert-N, which allows to simulate the formation of N₂O in the soils will be extended to a model with a more detailed description of the upper boundary condition at the soil-atmosphere interface. In detail, this is realized in the form of a resistance approach, where N₂O-fluxes are constrained by resistances analog to Ohm's law.

The newly developed model will be validated using Eddy Covariance measurements of N₂O-fluxes. Measurement device for the N₂O concentrations is a Quantum-Cascade-Dual-Laser produced by Aerodyne Research Inc. (Billerca, Mass., USA). The measurements are conducted on an intensively managed field at the TERENO research farm Scheyern (Germany), which is part of the TERENO Bavarian Alps / Pre-Alps observatory.
# Impact study on spatial and temporal variability of greenhouse gas emissions of an agricultural landscape conducted with different farming systems since 22 years

P. Koal¹, R.Schilling¹, G. Gerl², K. Pritsch¹, J. C. Munch¹

¹Helmholtz Zentrum München, Institute of Soil Ecology, Neuherberg, Germany

²Helmholtz Zentrum München, Research Farm Scheyern, Scheyern, Germany

In order to achieve a reduction of greenhouse gas emissions, management practices have to be adapted by implementing sustainable land use. At first, reliable field data are required to assess the effect of different farming practices on greenhouse gas budgets. Our long time field experiment covers and compares two main aspects of agricultural management under same site conditions, namely an organic farming system and a conventional farming system, implementing additionally diverse tillage systems and fertilisation practices. Furthermore, the analysis of the alterable biological, physical and chemical soil properties enables a link between the impact of different management systems on greenhouse gas emissions and the monitored cycle of matter.

Measurements were carried out on long-term field trials at the Research Farm Scheyern located in a Tertiary hilly landscape approximately 40 km north of Munich (South Germany). The organic and conventional farming system trials were started in 1992 on comparable fields (similar physical and chemical soil properties). Since then, parcels in the fields (each around 0,2-0,4 ha) with a similar interior plot set-up have been conducted. So the 20 years impacts of different tillage and fertilisation practices on soil properties including trace gases were examined.

Emissions of CH₄, N₂O and CO₂ are monitored since May 2007 for the integrated farming system trial and since February 2012 for the organic farming system trial using an automated system which consists of chambers (per point: 4 chambers, each covering 0,4 m² area) with a motor-driven lid, an automated gas sampling unit, an on-line gas chromatographic analysis system, and a control and data logging unit (Flessa et al. 2002). Each chamber is sampled 3-4 times in 24 hours. Physical, chemical and biological soil properties (i.a. texture, mineral nitrogen and soil organic carbon) were monitored weekly and event-based to aggregate the parameters and processes influencing the greenhouse gas emissions. Weather data, i.d. air temperature and precipitation were recorded by on-field weather stations.

The main outcomes are the temporal and spatial dynamics of greenhouse gas emissions as influenced by management practice events (fertilisation and tillage) and weather effects (drying-rewetting, freezing-thawing, intense rainfall and dry periods) in both established systems and the creation of an impact study comparing the conventional farming system trial with the organic farming system trial over a time period of one and a half year. Annual emissions are calculated as the mean of measured values. Moreover, to take the economical interests of farmers into account emissions per product yield are assessed. Furthermore, to understand processes leading the greenhouse gas emissions, additional experiments under laboratory conditions (e.g. soil potential for trace gas formation) are included. Net global warming potential of the two different management systems are calculated. In addition, potential trade-offs between soil carbon sequestration (ascertained in certain time steps) and greenhouse gas emissions will be assessed.
Estimation of N₂O emissions using LandscapeDNDC in Poland, during the period 1960 - 2009

J. Nyckowiak¹, J. Lesny¹, R. Juszczak¹, J. Olejnik¹, E. Haas², R. Kiese², K. Butterbach – Bahl²

¹Poznan University of Life Sciences, Meteorology, Poznan, Poland

²Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, Garmisch-Partenkirchen, Germany

The aim of this work was to estimate the quantity of nitrous oxide (N₂O) fluxes simulated by the process-based biogeochemical model known as LandscapeDNDC in Polish conditions. The model was calibrated based on the data of N₂O fluxes measured by static chambers method at Brody Copland sites in the vegetative period of 2012. It is located on the soil which is classified by FAO as Albic Luviosols (Typic Hapludalfs according to the USA Soil Taxonomy), with pH = 6.0 and the content of fraction below 0.02 mm in the amount of 12 % on average. The calibration was based on measurements conducted in four experimental plots where, during 2003 - 2012, the following crops were grown: alfalfa, potatoes, winter wheat, rye, spring barley and winter triticale. With the accurate data available, as far as management is concerned, the main emphasis was placed on the period from 28th March 2012 to 13th of August 2012 because of measurements of nitrous oxide emission conducted then in particular plots. Additionally, the results of measurements of soil water content and soil temperature at the depth of 10 cm were compared with modelled quantities. Thus calibrated model was used for developing simulations of N₂O emissions from arable lands in Poland in the years 1960 - 2009 for two major areas of Poland, located in the East and West of the country, respectively. The former is characterized by a higher level of farming technology, whereas the latter, farms are typically small and dispersed. These differences stem from historical events that occurred in Poland for the past 200 years. Daily values of meteorological parameters from thirteen meteorological stations as well as annual data as regards the land exploitation were used for modelling. The following crops were considered for simulations by LandscapeDNDC model: cereals (winter wheat, winter barley, oat), beetroots, potatoes, rape and maize. Estimated crop values obtained by the model were compared with real quantities, which allowed to prove the accuracy of the model. The results obtained from 13 areas mentioned above were extrapolated for the whole country for the years 1960 - 2009.
# Soil greenhouse gas fluxes under conditions of climate-induced drought and heavy rain from agricultural soils in the Pannonian area

H. Berthold¹, B. Kitzler², K. Michel², J. Hösch¹, A. Baumgarten¹

¹AGES - Austrian Agency for Health and Food Safety, Department for Soil Health and Plant Nutrition, Vienna, Austria

²Federal Research and Training Centre for Forests, Natural Hazards and Landscapes, Department of Forest Ecology and Soils, Vienna, Austria

IPCC models for the development of the precipitation in the Pannonian area in Austria predict increasing drought periods due to an overall reduction of precipitation. The remaining amount of precipitation is thought to be concentrated to a few heavy rain falls. However, there is a lack of understanding of how altered precipitation and thus soil moisture regime affect changes in greenhouse gas (GHG) emissions and underlying processes. The objective of the present study, which was part of the project LYSTRAT, was, therefore, to determine the effects of climate-induced droughts and heavy rain on GHG fluxes (CO₂, N₂O and CH₄) and to identify potential drivers.

For this purpose, the GHG fluxes from three soils typical of the Pannonian area was determined biweekly in a field trial with controlled irrigation using the closed-chamber method from March 2011 to December 2013. The field trial is located at the lysimeter facility Hirschstetten, Austria, which consists of 18 backfilled gravitation lysimeters (six replicates per soil type). Three replicates of each soil type (calcic chernozem, calcaric phaeozem and gleyic phaeozem) were watered according to the precipitation pattern predicted for the period from 2071 to 2100 simulating drought periods and heavy rain events (variant prog.rain). The remaining nine lysimeters (control; variant curr.rain) were irrigated with respect to the 30 year mean of rainfall (amount and distribution) in Großenzersdorf, Marchfeld, Austria. To identify potential drivers of GHG fluxes in the soils investigated soil samples were taken at least four times per year and analyzed for important chemical (pH, NH₄⁺ and NO₃⁻ concentrations) and microbiological properties (e.g. microbial biomass C and N).

The GHG fluxes from all three soils types responded to changes in the precipitation patterns. Compared to the calcaric and gleyic phaeozem, the response of the calcic chernozem was delayed. However, no general trend can be derived from the data. For the whole experimental period no significant effect of precipitation patterns was found. Soil temperature and, to a minor degree, air temperature were identified as the most important factors controlling GHG fluxes from the control and the prog.rain treatment of the three soils investigated. Other potential controlling factors such as soil water content, available N and the amount of microbial biomass present were not related to GHG fluxes. Overall, an alteration in the precipitation pattern as simulated in the LYSTRAT experiment will not result in distinct changes of GHG fluxes and potential controlling factors in major soil types of the Pannonian area in the short term.
Data Publication in TERENO-Northeast (NE)

M. Schroeder<fnref n="1" />, V. Stender<fnref n="1" />, J. Klump<fnref n="1" />,<fnref n="2" />

The contributions to TERENO by the participating research centers are organized as observatories.
The challenge for TERENO and its observatories is to integrate all aspects of data management, data
workflows, data modeling and visualizations into the design of a monitoring infrastructure.

TERENO Northeast is one of the sub-observatories within TERENO and is operated by the Helmholtz
Centre Potsdam German Research Centre for Geosciences (GFZ). This observatory investigates
geoecological processes in the northeastern lowland of Germany by collecting large amounts of
environmentally relevant data. The success of long-term projects like TERENO depends on well-
organized data management, on data exchange between the partners involved and on the availability
of the captured data. Data discovery and dissemination are facilitated not only through data portals of
the regional TERENO observatories but also through a common spatial data infrastructure TEODOOR
(TEreno Online Data repOsitORry). TEODOOR bundles the data provided by the different web
services of the single observatories and provides tools for data discovery, visualization and data
access. The TERENO Northeast data infrastructure integrates data from more than 200 instruments
and makes data available through standard web services. Geographic sensor information and services
are described using the ISO 19115 metadata schema. TEODOOR accesses the OGC Sensor Web
Enablement (SWE) interfaces offered by the regional observatories.

In addition to the SWE interface, TERENO Northeast also publishes data through DataCite. The
metadata required by DataCite are created in an automated process by extracting information from the
SWE SensorML to create ISO 19115 compliant metadata. The GFZ data management infrastructure
panMetaDocs is then used to register Digital Object Identifiers (DOI) and preserve file based datasets.
A DOI uniquely identifies an object, such as an electronic document or data set, by giving it a
persistent identity while its location on the internet may change. In analogy to DOI, the International
Geo Sample Numbers (IGSN) is used to uniquely identify research specimens. GFZ is in the process
of implementing an infrastructure to register IGSNs.

<footnote n="1">¹Deutsches GeoForschungsZentrum GFZ, Centre for GeoInformationTechnology (CeGIT), Potsdam,
Australia</footnote>

<footnote n="2">²CSIRO Earth Science and Resource Engineering, Kensington WA, Australia</footnote>
# The climate and soil moisture network TERENO Northeastern Lowlands Observatory - DEMMIN®

D. Spengler<fnref n="1" />, G. Blasch<fnref n="1" />, E. Borg<fnref n="2" />, M. Brell<fnref n="1" />, C. Georgi<fnref n="1" />, K. Heupel<fnref n="1" />, C. Hohmann<fnref n="1" />, D. Jahncke<fnref n="2" />, R. Klinke<fnref n="1" />, F. Renke<fnref n="2" />, S. Itzerott<fnref n="1" />

The goal of the TERENO initiative is the long-term monitoring and documentation of proposed climate change, changes in land use, social-economic developments and anthropogenic influences on terrestrial ecosystems. Therefore long-term observations of multitemporal environmental parameters at different scale are the basis for gathering information on changes of the available water resources, material flows, or further ecological changes.

The Durable Environmental Multidisciplinary Monitoring Information Network (DEMMIN®) located in the North-east of Germany was installed by German Aerospace Center in 1999 for Calibration and Validation of Remote Sensing data at agricultural areas. Due to its physiographic composition and typical agricultural management the area is a perfect test site for monitoring of relevant environmental parameters. Since 2009 the DEMMIN® test field of 50 x 50 km is part of the Northeastern German Lowland Observatory (TERENO-NE), which is coordinated by Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences.

Within the TERENO project the existing 28 climate stations (DLR) are supplemented by DLR with an automated lysimeter hexagon station (TERENO SoilCan), and by GFZ with additional 20 climate stations and 63 soil moisture stations below agricultural used fields. That enables to analyse variations of: air temperature / air moisture, wind speed / wind direction, WET leaf wetness, incident and reflected solar radiation, incident and emitted thermal radiation, barometric pressure, precipitation, soil temperature (different depths) and soil moisture (different depths) at local scale. The in-situ-measurement component is completed by an information technology infrastructure, that allows the near-real time storage and processing of the measured in-situ data. Because of the remote sensing focus of the DEMMIN® test site it is a perfect area to evaluate the potential of linking ground based in-situ data with remote sensing data analysis with view to the COPERNICUS initiative of the European Union (EU) and the European Space Agency (ESA).

The study presents an approach for the retrieval of area based environmental parameters based on the local data of the climate and soil moisture network in combination with Digital Elevation Model and Vegetation Information retrieved by remote sensing data. Therefore multitemporal remote sensing (RS) data of different sensors, reaching from optical multispectral and hyperspectral data, over thermal data up to microwave data are analysed concerning vegetation type and status and also soil parameters. The following data products have been developed or are under development:

- Air Pressure → climate stations + DEM

- Precipitation → climate stations

- Air Temperature / air moisture → à climate stations + RS data

- Wind Speed → climate stations + RS data

- Soil Moisture → climate stations + soil moisture stations + RS data

The results will be presented in terms of validation, limitation and future developments.

<footnote n="1">¹Helmholtz-Centre Potsdam - GFZ German Research Centre for Geosciences, 1.4 Remote Sensing, Potsdam, Germany</footnote>

<footnote n="2">²German Aerospace Center (DLR), Earth Observation Center, Neustrelitz, Germany</footnote>
# The Observatory for Climate and Environment in Luxembourg

I. Trebs¹, O. Faber¹, L. Giustarini¹, J. F. Iffly¹, C. Tailliez¹, L. Pfister¹

¹Centre de Recherche Public - Gabriel Lippmann, Department of Environment and Agro-Biotechnologies (EVA), Belvaux, Luxembourg

The Centre de Recherche Public - Gabriel Lippmann (CRP-GL) operates a dense hydro-climatological measurement network in Luxembourg in cooperation with public authorities (Administration de la Gestion de l'Eau and Administration des Services Techniques de l'Agriculture). Since the establishment of the first two limnographs in 1995, the Observatory has continued to expand and now manages data from 35 permanently installed meteorological stations, 67 pluviographs, 25 piezographs and 57 limnographs in the Grand-Duchy of Luxembourg. In addition to operating and maintaining the hydro-climatological monitoring network, the Observatory also hosts a comprehensive repository of historical data. This includes daily precipitation, air temperature and discharge data series going back to 1838. The currently operated limnographs of the CRP-GL are mainly located in headwaters and tributaries of the Alzette River basin and are complementary to the stations operated by the public authorities on the main rivers. The network includes catchments of various sizes (0.44-1176 km²) and physiographic characteristics. The instruments mainly provide data with a time resolution of 15 minutes. The Observatory is in charge of establishing and maintaining stage-discharge relationships for the stream gauge stations of the CRP-GL. Besides operating the stations, the Observatory's mission is to validate, centralize, archive and manage acquired field data, including those of the public authorities. Consequently, a series of automated quality control chains are developed and implemented to provide validated data. The Observatory also offers a range of services associated with the management and processing of geographic information and is responsible for the implementation of a data base management system. The acquired data provide a basis to study the interactions between hydrosphere, ecosystems and atmosphere and support the realization of projects in fundamental and applied research. The data help to improve the understanding of rainfall-runoff transformation processes and to study the spatial and temporal variability of the components of the water cycle (e.g., DFG-FNR CAOS project). The measured data are also crucial for the validation of perceptual models of hydrological systems, e.g. identifying and reducing the uncertainties in the modelling of flood events, and to foster major progress and developments in flood management.
# OPE-Andra ecosystem monitoring stations in forest, crops and grasslands in the eastern part of France

S. CONIL<fnref n="1" />, P. GROSS<fnref n="2" />, L. HEID<fnref n="2" />, K. KLUMPP<fnref n="3" />, B. LONGDOZ<fnref n="2" />, M. SIMON<fnref n="1" />

The French authorities have mandated Andra (The French National Radioactive Waste Management Agency) to assess the feasibility of a deep underground nuclear waste repository in eastern part of France. If authorized by the government, the preparation, construction and further operation phases will last more than 100 years. After the operation phase, the observation phase will also last at least an additional 100 years. Within this framework, Andra has set up a long term environmental observatory, the OPE, to survey and monitor the quality of the environment in a 900 km2 area around the site of investigation in the eastern part of France. The OPE territory is situated in a sparsely populated area, covered by agricultural fields (~50%), forests (around 30%) and grassland (11%). The area, reaching 400m altitude, is located on the eastern part of the Parisian Basin. The climate is a transition between oceanic and continental, with an annual mean temperature of 10°C and annual precipitation of 1000mm. The main objective of the observatory is to collect data from the atmosphere, biosphere/geosphere and biodiversity/population in order to establish a baseline of ecosystems functioning and vulnerabilities to natural (mainly climatic) and anthropogenic forcing in the study area. Data on biodiversity, air and water quality, vegetation and agricultural practices are generated through the survey of several gridded (for soil monitoring for example) or ecologically stratified network (for bird or forest monitoring for example) as well as atmospheric, water and ecosystems instrumented field stations. These data will contribute to define the reference state of the environmental conditions before the start of the construction phase and then to monitor the operational phase and the observation phase. An environmental specimen bank has been built to archive the environmental samples collected (soil, flora, fauna, ...).

In order to monitor and understand the ecosystems functioning and in particular, the vegetation growth in relation to the agricultural/forestry practices and the biotic and abiotic conditions, three atmosphere-vegetation-soil flux monitoring stations (i.e. eddy covariance flux towers) have been setup inside the OPE. Those sites allow to assess ecosystem functioning under very close pedoclimatic conditions, and to monitor CO2 and water fluxes, meteorological and phenological conditions as well as energy exchanges (radiation, latent and sensible heat fluxes and soil heat fluxes. The forest site is equipped with a 45m flux tower located at the center of a 2000ha beech forest (around 55 years old). The crop site is located on an 18ha crop field and is adjacent to the 6ha grassland site. Regular biomass samplings and observations as well as soil inventories will complement the instrumented monitoring. The measurements at the stations and inventories are performed according to ICOS protocols and recommendations.

The observation systems set up has started mainly in 2011 and first data has been generated. The observation time is however not sufficient yet to draw definite conclusions. Here, we like to show the aims of the OPE long term observatory, the flux stations design and some preliminary results.

<footnote n="1">¹Andra, Bure, France</footnote>

<footnote n="2">²Ecologie et Ecophysiologie Forestières, INRA, Champenoux, France</footnote>

<footnote n="3">³Unité de Recherche sur l'Ecosystème Prairial, INRA, Clermont Ferrand, France</footnote>
# The TERENO Northeastern German Lowland Observatory: studying Earth surface processes and structures in a glacially formed landscape

K. Kaiser<fnref n="1" />, O. Bens<fnref n="1" />, E. Borg<fnref n="2" />, A. Brauer<fnref n="1" />, M. Gessner<fnref n="3" />, A. Güntner<fnref n="1" />, S. Itzerott<fnref n="1" />, G. Jurasinski<fnref n="4" />, R. Lampe<fnref n="5" />, S. Liebner<fnref n="1" />, G. Lischeid<fnref n="6" />, T. Raab<fnref n="7" />, T. Sachs<fnref n="1" />, M. Sommer<fnref n="6" />, V. Stender<fnref n="1" />

Since 2008 a network of Terrestrial Environmental Observatories (TERENO) has been established in Germany by the Helmholtz Association as a long-term interdisciplinary research platform, focusing on the impact of climate and land-use change on terrestrial ecosystems and on related process understanding. This observation network consists of four main observation areas that extend across Germany from the Alps to the lowlands, forming in the latter area the Northeastern German Lowland Observatory (TERENO-Northeast). TERENO-Northeast, located in a glacially formed and intensively used landscape, investigates four subject groups and is supported by a central data management. These closely cooperating subject groups work on geoarchives (lake sediment formation, dendrochronology), geopedology (present-day and historic soil carbon redistribution, soil formation, trace gas balances of peatlands), hydrology (lake-groundwater interactions, water balances of lake and river catchments), and remote sensing (soil moisture retrieval, soil mapping). Combining geoarchives (lake sediments, trees, soils) with monitoring enables us to distinguish short-time fluctuations from long-term climatic and anthropogenic trends and to extend time series into the unobserved past. Instrumentation of TERENO-Northeast started in 2011 and will be completed in 2014. The observatory comprises five research sites that differ significantly in area size (from a few hectares to several thousands of hectares) and landscape structure (e.g. geology, hydrology, land cover) including intensity and history of land use. Within TERENO-Northeast one of the study sites was chosen for the future establishment of a Critical Zone Observatory, comprising a forested and lake-rich part of the Müritz National Park (CZO Fuerstensee). Several partner organizations are involved in TERENO-Northeast, forming a regional network of non-university research institutions and universities. Further information, publications and data are available via the central TERENO portal: http://teodoor.icg.kfa-juelich.de/overview-de. (Remark: The authors named represent the coordination board of TERENO-Northeast and the main partner organizations, respectively. Several further persons are involved in TERENO-Northeast.)

<footnote n="1">¹GFZ German Research Centre for Geosciences, Potsdam, Germany</footnote>

<footnote n="2">²German Aerospace Center (DLR), Neustrelitz, Germany</footnote>

<footnote n="3">³Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Neuglobsow, Germany</footnote>

<footnote n="4">⁴University of Rostock, Rostock, Germany</footnote>

<footnote n="5">⁵University of Greifswald, Greifswald, Germany</footnote>

<footnote n="6">⁶Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany</footnote>

<footnote n="7">⁷Brandenburg University of Technology (BTU-CS), Cottbus-Senftenberg, Germany</footnote>
Long-term, multi-scale documentation of the hydrologic cycle and vegetation
dynamics in West Africa: the AMMA-CATCH observation system.

S. Galle<fnref n="1" />, C. Peugeot<fnref n="2" />, M. Grippa<fnref n="3" />, B. Cappelaere<fnref n="2" />, J. Demarty<fnref n="2" />, E. Mougin<fnref n="4" />, T. Lebel<fnref n="1" />, . and
the AMMA-CATCH working group<fnref n="5" />

AMMA-CATCH is a multi-scale observation system dedicated to long-term monitoring of the water cycle, the vegetation dynamics and their interactions with climate and water resources in West Africa. In the context of the global change, long-term observations are required to i) gain understanding in eco-hydrological processes over this highly contrasted region, ii) help their representation in Earth System Models, and iii) detect trends and infer their impacts on water resources and living conditions.

It is made of three meso-scale sites (~ 1°x1°) in Mali, Niger and Benin, extending along the West African eco-climatic gradient. Within this regional window (5° by 9°), each of the three sites comprises a multi-scale set-up which helps documenting the components of the hydrologic budget and the evolutions of the surface conditions over a range of time scales: raingages, piezometers, river discharge stations, soil moisture and temperature profiles, turbulent fluxes measurements, LAI/biomass monitoring,...This observation system has been continuously generating datasets for 10 to 30 years depending on the datasets. It is jointly operated by French and African (Mali, Niger and Benin) research institutions. The data-base is available to the community through the internet (www.amma-catch.org).

AMMA-CATH already participates to several global or regional observation networks, such as Flux-
Net, Carbo-Africa, International Soil Moisture Networks (ISMN), ... and to calibration/validation
campaigns for satellite missions such as SMOS (Europe/France/Spain), or MEGHA-TROPIQUES
(France/India). AMMA-CATCH fills a gap over a region, West Africa, where environmental data are
largely lacking, and thus, it can usefully contribute to the international networking effort for
environmental monitoring and research.

<footnote n="1">¹IRD, LTHE, Grenoble, France</footnote>

<footnote n="2">²IRD, HydroSciences, Montpellier, France</footnote>

<footnote n="3">³CNAP, GET, Toulouse, France</footnote>

<footnote n="4">⁴CNRS, GET, Toulouse, France</footnote>

<footnote n="5">⁵IRD/CNRS/Universities, France, Mali, Niger, Benin, France</footnote>
# The North Wyke Farm Platform, a national capability for research into sustainability of temperate agricultural grassland management: data & modelling opportunities

P. Harris¹, E. al¹

¹Rothamsted Research, Okehampton, United Kingdom

The North Wyke Farm Platform (NWFP) at Rothamsted Research in the South-West of England, is a large, farm-scale experiment for collaborative research, training and knowledge exchange in agro-environmental sciences; with the aim of addressing agricultural productivity and ecosystem responses to different management practices. The 70 ha NWFP site, captures the spatial and/or temporal data necessary to develop a better understanding of the dynamic processes and underlying mechanisms that can be used to model how agricultural grassland systems respond to different management inputs. Here, via beef and sheep production, the underlying principle is to manage each of three farmlets (each consisting of five man-made, hydrologically-isolated sub-catchments) in three contrasting ways: (i) improvement through use of mineral fertilisers; (ii) improvement through use of legumes; and (iii) improvement through innovation.

The connectivity between the timing and intensity of the different management operations, together with the transport of nutrients and potential pollutants from the NWFP is evaluated using various data collection and data modelling exercises. The primary data collection strategy involves the use of a ground-based, wireless sensor network, where in each of the fifteen sub-catchments, water characteristics such as flow, turbidity and chemistry are measured at a flume laboratory that captures the sub-catchment's water drainage (via a system of directed French drains). This sensor network also captures: precipitation and soil moisture data at the centroid of each sub-catchment; greenhouse gas data ($N_2O$ and $CO_2$) across three of the fifteen sub-catchments; and meteorological data (other than precipitation) at a single site only (which is assumed representative of the NWFP site, as a whole). Such high temporal resolution data sets (but with limited spatial resolution) are coupled with a secondary data collection strategy, for high spatial resolution data sets (but with limited temporal resolution). These latter data sets include (multi-spectral and hyper-spectral) remote sensing data, together with more traditional field studies that provide information on soils nutrients and biodiversity. Both the primary and secondary data collection strategies are complemented by a dedicated geodatabase for the geographical layout of the NWFP site that includes soil class and LiDAR data.

We describe all such NWFP data sets and introduce some of the modelling opportunities that are possible. Models can stem from a mathematical, a hydrological, a process-based, or a statistical viewpoint; where various hybrid model forms are also possible. Models may need to account for: (a) data quality; (b) data support; (c) sample configuration and interval; (d) data distribution; (e) data relationships; (f) spatial, temporal and scale dependencies; (g) data heterogeneities; and (h) discontinuities and barriers (such as roads and hedges). Clearly, the modelling strategy is expected to be a challenge, but must be designed so that the key research objectives are met (i.e. those focused on sustainability with respect to high productivity coupled with low environmental damage). Thus to rationalise the modelling tasks, an inter-linked, four-stage programme of analysis is proposed; consisting of: (1) Quality Assurance; (2) Exploratory Data Analysis; (3) Interim Model Fits; and (4) Full Model Fits. Stages (1) to (3) will tend to investigate data sets in isolation; relate just a few of them at a time; or relate many data sets very simply. These outputs will feed into and direct the more complex models of stage (4), where many data sets will be used. All model results should be presented in both advanced and basic forms, depending on the target audience. The use and development of simple, but powerful visualisation techniques are promoted in this respect.
# The North Wyke Farm Platform, a national capability for research into sustainability of temperate agricultural grassland management: Infrastructure and instrumentation

B. Griffith¹, E. al¹

¹Rothamsted Research, Okehampton, United Kingdom

The North Wyke Farm Platform (NWFP) at Rothamsted Research in the South-West of England is a large, farm-scale experiment for collaborative research, training and knowledge exchange in agro-environmental sciences; with the aim of addressing agricultural productivity and ecosystem responses to different management practices. The 70 ha NWFP site, captures the spatial and/or temporal data necessary to develop a better understanding of the dynamic processes and underlying mechanisms that can be used to model how agricultural grassland systems respond to different management inputs. Here, via beef and sheep production, the underlying principle is to manage each of three farmlets in three contrasting ways: (i) improvement through use of mineral fertilisers; (ii) improvement through use of legumes; and (iii) improvement through innovation. Each of the farmlets is equipped with a range of state of the art, in situ, environmental monitoring equipment, sensing in real time: the quantity and quality of run-off; a range of soil variables; meteorological parameters and greenhouse gas emissions.

The three farmlets are further sub-divided into five (15 in total) hydrologically-isolated sub-catchments through a combination of the existing topography, the impermeable nature of the clay soils and through the introduction of French drains bounding the perimeters. The drains, dug to 0.8m, containing a perforated pipe and backfilled to the surface with stone, intercept surface and subsurface flow and channel it to one of 15 H-Flumes. Flow rates are calculated using a combination of primary and secondary flow measurement devices. The primary devices, the H-flumes, restrict the run-off from each catchment through a known geometry, while the secondary devices, bubbler-flow meters, use compressed air and a pressure transducer to calculate the head of water within the flume and convert to a flow rate (Litres per second, LPS). Providing there is sufficient flow (>0.2 LPS), a 13 litre by-pass cell is filled and emptied on a 15 minute cycle by a bi-directional peristaltic pump. The cell contains a suite of sensors that measure the following parameters: Ammonium; Dissolved Oxygen; Turbidity; pH; Conductivity; Temperature; Nitrate N and Dissolved Organic Carbon. In addition, Total P is measured at one site within each farmlet. An auto-sampler is also located at each of the 15 flume sites allowing for the physical collection of water samples for lab analysis of unmeasured parameters or for sensor validation. Each sub-catchment also contains a soil moisture station, measuring soil moisture at 3 depths (10, 20 and 30 cm), soil temperature at 15 cm, and precipitation using a tipping bucket rain gauge. The NWFP also has a fully equipped, centrally located automatic weather station.

All of these instruments are connected to a UHF radio telemetry network (www.adcon.com) consisting of remote telemetry units (RTUs) in the field which communicate with a centrally located base station. This station manages the network, receiving and storing the data before passing it to the Adcon AddVantage-pro software which collects, stores, processes and displays the data via its intergraded web server. At present the NWFP has a network of 45 RTUs, connected to 108 instruments collecting data on 198 parameters every 15 minutes.

In addition to the water, soil and meteorological instrumentation, the NWFP also has 3 automatic long-term chamber systems that are used on a campaign basis to measure N₂O and CO₂ fluxes from the soil on each of the farmlets.
# Modelling of historical hydrological conditions in the Mol area, Campine region, NE-Belgium: possibilities and limitations

B. Leterme¹, K. Beerten¹, M. Gedeon¹

¹SCK-CEN, Institute for Environment, Health, and Safety, Mol, Belgium

Usually, hydrological models are calibrated and validated using instrumental data, thereby limiting the modelling time window to the last few decades. However, as such short time windows do not capture the full variability of hydrological conditions and their driving forces, it seems necessary to test model performance also for historical periods, using reconstructed parameters and historical or proxy data. Furthermore, modelling of past conditions would allow to identify different drivers of environmental change (climate, human activities) and their influence on the hydrological cycle. By testing our ability to simulate what happened in the past few hundreds years, this type of study also may provide insights into the confidence we have in climate change and land use predictions and simulated impacts for the future.

The study aims at the reconstruction of present and past hydrological conditions in a small interfluve area (18.6 km²) in NE Belgium. We compare the current state with four reference time periods in the past (1500 AD, 1770 AD, 1880 AD and 1940 AD) representing the main stages of landscape evolution in the study area. Historical information and proxy data were used to derive conceptual model features such as topography, surface water geometry (lakes, canals, drains...), as well as land cover, soils and vegetation distribution. We then used this information to parameterize a coupled vadose zone - groundwater model of the study area. The groundwater model is implemented in MODFLOW-2000 (Harbaugh et al. 2000) and unsaturated zone processes are treated by the HYDRUS package (Seo et al. 2007) for MODFLOW.

A limitation of this work concerns the comparison of simulated past hydrology with relevant data derived from validation paleo-records. The potential of a few indicators (recharge, groundwater table depth, seepage zones) for the validation of paleohydrological studies is discussed.

## References

* Harbaugh AW, Banta ER, Hill MC, McDonald MG (2000) MODFLOW-2000, the U.S. Geological Survey modular ground-water model user guide to modularization concepts and the ground-water flow process. USGS, Denver, CO

* Seo HS, Šimůnek J, Poeter EP (2007) Documentation of the HYDRUS Package for MODFLOW-2000, the U.S. Geological Survey Modular Ground-Water Model. GWMI 2007-01, Int. Ground Water Modeling Center. Colorado School of Mines, Golden, CO
Adaptive Wireless Ad-hoc Sensor Networks for Long-term Ecosystem Research

J. Bumberger<fnref n="1" />, P. Remmler<fnref n="1" />, M. Schaedler<fnref n="2" />, H. Mollenhauer<fnref n="1" />, R. Schima<fnref n="1" />, T. Hutschenreuther<fnref n="3" />, H. Toepfer<fnref n="4" />, P. Dietrich<fnref n="1" />,<fnref n="5" />

Environmental systems are often characterized by their high heterogeneity and dynamic, so individual measurements for their complete representation are often not sufficient. The application of wireless sensor networks in terrestrial and ecosystems offer significant benefits as a better consideration to the local test conditions, due to adapting the sensor distribution, the sensor types and the sample rate. Another advantage of wireless ad-hoc sensor networks is their self-organizing behavior, resulting in a major reduction in installation and operation costs and time. A concept and realization is given in the field monitoring of micrometeorology and soil parameters for the interaction of biotic and abiotic processes. This long term analyses are part of the Global Change Experimental Facility (GCEF), a large field-based experimental platform to assess the effects of climate change on ecosystem functions and processes under different land-use scenarios. This network includes 250 sensor nodes with one photosynthetic active radiation sensors and three soil und air humidity/temperature sensors in 3 depths and heights per node. Additionally precipitation and global radiation (incoming and surface reflected) is monitored at specific points. Regarding to the adaptive behavior of the network, the development of new sensor types and methods are under investigation to derive secondary parameters. This work will also present first test results of developed low cost radiation and photogrammetric sensors for detecting plant activity and leaf area index.

<footnote n="1">¹Helmholtz Centre for Environmental Research - UFZ, Department Monitoring and Exploration Technologies, Leipzig, Germany</footnote>

<footnote n="2">²Helmholtz Centre for Environmental Research - UFZ, Department of Community Ecology, Halle, Germany</footnote>

<footnote n="3">³Institut für Mikroelektronik- und Mechatronik-Systeme - IMMS, Department of System Design, Ilmenau, Germany</footnote>

<footnote n="4">⁴Ilmenau University of Technology, Department of Advanced Electromagnetics, Ilmenau, Germany</footnote>

<footnote n="5">⁵Eberhard Karls University, Centre of Applied Geosciences, Tübingen, Germany</footnote>
# Monitoring of Ecosystem Development at the Constructed Catchment Chicken Creek

W. Gerwin¹, W. Schaaf², C. Hinz³, R. F. Hüttl¹

¹BTU Cottbus-Senftenberg, Forschungszentrum Landschaftsentwicklung und Bergbaulandschaften, Cottbus, Germany

²BTU Cottbus-Senftenberg, Chair of Soil Protection and Recultivation, Cottbus, Germany

³BTU Cottbus-Senftenberg, Chair of Hydrology and Water Resources Management, Cottbus, Germany

The constructed catchment Chicken Creek was established in 2005 as an experimental landscape laboratory for ecosystem research. The 6 ha area with clearly defined horizontal as well as vertical boundary conditions was left for an unrestricted primary succession. The developing ecosystem offers the opportunity to study most processes occurring at the interface of bio-, pedo-, geo- and hydrosphere. Particularly interactions and feedbacks between different evolving compartments as well as the establishment of ecosystem functions and services can be investigated during the ongoing ecosystem development. The catchment is extensively instrumented since 2005 in order to detect transition stages of the ecosystem. Comprehensive data recorded with a high spatial and temporal resolution include hydrological, geomorphological, pedological, limnological as well as biological parameters.

This site offers the unique situation of an early stage ecosystem with highly dynamic system properties. The first years of development were characterized by a fast formation of geomorphological structures due to massive erosion processes at the initially non-vegetated surface. Hydrological processes led to the establishment of a local groundwater body within 5 years. In the following years the influence of biological structures like vegetation patterns gained an increasing importance. Feedbacks between developing vegetation and e.g. hydrological features became more and more dominant. As a result, different phases of ecosystem development could be distinguished until now.

This observatory offers manifold possibilities to identify and disentangle complex interactions between ecosystem compartments in situ under natural conditions. The originally low complexity of the system is growing with time facilitating the identification of influences of newly developing structures on ecosystem functions. Thus, it is possible to study effects of small-scale processes on the whole system at the landscape scale. In addition, the highly dynamic initial system properties allow the observation of multifaceted changes of ecosystem properties and functions within short periods of time.
# Consequences of climate change on ecosystem functions, water balance, productivity and biodiversity of agricultural soils in the Pannonian area - project LYSTRAT

H. Berthold¹, A. Baumgarten¹, A. Bruckner², J. Hösch¹, B. Kitzler³, K. Michel³, E. Murer⁴, J. Wissuwa², J. Zaller²

¹AGES - Austrian Agency for Health and Food Safety, Department for Soil Health and Plant Nutrition, Vienna, Austria

²BOKU, Department for Zoology, Vienna, Austria

³BFW, Department of Forest Ecology and Soils, Vienna, Austria

⁴BAW, Department for Hydrology, Petzenkirchen, Austria

Regional climate change scenarios for 2050 predict fewer but heavier rainfall during the vegetation period without substantial changes in the total annual amount of rainfall for Eastern Austria (Pannonian region). An experiment was carried out at the lysimeter station of the Austrian Agency for Health and Food Safety (AGES), comprising the three main soil types of the pannonian agricultural area (Calcaric Phaeozem, Gleyic Phaeozem, Calcic Chernozem) with six replications of each. The lysimeter station was covered by a greenhouse whose ventilation panels are automatically regulated in synchronization with rain, wind and temperature sensors. Precipitation rates have been modified according to the predicted scenario for the second half of this century in comparison to the current precipitation pattern.

The overall aim of the project was to obtain more information on possible changes in the soil-plant system due to lasting droughts and heavy rain events.

Different cultivation and irrigation during three years showed differences in the crop yields, the abundance and diversity of soil arthropods (Collembola, Oribatid and Gamasid mites), greenhouse gas measurements, analysis of mycorrhization, weed invasions and analysis of phospholipid fatty acids.

The analysis of Phospholipid Fatty Acids (PFLAs) and greenhouse gas (GHG) dynamics should highlight possible responses of the microbial community.

From March 2011 to November 2013 gas samples were taken regularly in the field to gain insight into the dynamics of the GHG CO₂, CH₄ and N₂O. Gas sampling using the closed-chamber method was carried out biweekly from April to October and monthly from November to March. At each sampling date, soil samples were taken from all lysimeters to determine the gravimetric water content and soil temperature in 5 cm depths was measured.

Phospholipid Fatty Acids (PFLAs) are essential structural components of microbial cellular membranes. Phospholipids are present in all cell membranes, except accumulations, and are broken down very quickly after cell death in the soil. Therefore, they are excellent indicator molecules for soil microorganism. Functional groups of microorganisms are characterized by specific phospholipid fatty acids - the basis of this "pattern" can thus be used as a "fingerprint" of the microbial community structure of a soil sample. PLFA's have been monitored within the project for three years, three times a year (spring, summer and autumn).

Already after the first few months, a response of the PLFA's could be detected. Whereas at the beginning of our experiment (in May) no difference between the precipitation treatments occurred, only after 3 months higher biomass levels were measured following the change of precipitation.
# Rainfall-runoff mechanisms on a hill island

R. R. Frederiksen¹, K. Rømer Rasmussen¹, S. Christensen¹

¹Aarhus University, Geoscience, Aarhus, Denmark

A number of studies have indicated that the hydrological system of stream valleys on the outwash plains in western Denmark is often complex. Here the flow paths between stream and aquifer may be quite diverse because of superficial semi-permeable layers. Only little is known about the second major geological element in this region - the hill islands - in which we concentrate our study in the relatively small Abild catchment (65.8 km²) on Skovbjerg hill island. Existing discharge data comprise a few summer measurements while there are no time series of stage or discharge. Abild stream joins with the upper Vorgod which is only marginally larger than the Abild stream. The hydrograph from a discharge station in the Vorgod shortly downstream the confluence of the two streams present a paradox since it appears to be strongly influenced by quick flow indicating that shallow control by low permeable sediments is important. Nevertheless irrigation is intensive in the Abild catchment which indicates that the soil and shallow sediments are permeable. The topography of the watershed is characterized by gently rolling hills with wide valleys (25-80 MASL). The upper 0-20 m consists of Quaternary meltwater deposits and tills underlain by clay, quartz sand and lignite of Miocene age.

The objectives of this study are to investigate what are the dominating processes and what are the flow paths and fluxes for groundwater-surface water interaction on a hill island.

Stream flow is measured quarterly (ADCP and propeller) at 11 sites and monthly at five sites along the stream representing different spatial scales. Stream stage is measured continuously at seven sites with pressure transducers. Early April 2014 we installed temperature loggers in pairs of two at 10 sites in the downstream part of the stream. One at streambed and one close below water table at both sides of the channel. Furthermore we have mapped topography, soil types, geomorphology, ditches, drains and land use through field observations and digital maps. The shallow subsurface geology has been mapped using logs from a large number of old wells and geophysical data (airborne TEM).

To further investigate the spatial hydrogeological variation and its influence on stream discharge within the catchment we will:

- establish Q-h relationships at the five gaging stations

- qualify flux components at representative stream sections through temperature method

- map the shallow subsurface in more detail

- choose appropriate locations for further monitoring of discharge at different spatial scales

- monitor hydraulic head variations and quantify hydraulic parameters

- build a model for analysis of rainfall-runoff processes in this particular hydrogeological environment

We will present a short overview of the initial investigations with focus on either the Q-h relationships or the results from the temperature loggers (poster).
# Highly resolved long-term 3D hydrological simulation of a forested catchment with litter layer and fractured bedrock

Z. Fang<sup>1,2</sup>, H. Bogena<sup>1,2</sup>, S. Kollet<sup>1,2</sup>, H. Vereecken<sup>1,2</sup>

<sup>1</sup>Agrosphere Institute, Forschungszentrum Jülich GmbH, Jülich, Germany

<sup>2</sup>Centre for High-Performance Scientific Computing in Terrestrial Systems, HPSC TerrSys, Geoverbund ABC/J, Jülich, Germany

Soil water content plays a key role in water and energy balance in soil, vegetation and atmosphere. According to Wood et al. (2011) there is a grand need to increase global-scale hyper-resolution water-energy-biogeochemistry land surface modelling capability. However, such a model scheme should also recognize the epistemic uncertainties on the characteristics and processes of a grid element, as well as the nonlinearity and hysteresis in its dynamics. Unfortunately, currently it is not clear how to parameterize hydrological processes as a function of scale and how to test deterministic models with regard to epistemic uncertainties. In this study, funded by the BMBF research programme "MiKlip", high resolution long-term simulations were conducted in a highly instrumented TERENO hydrological observatory (Wüstebach catchment). Soil hydraulic parameters were derived using inverse modeling with the Hydrus-1D model using the global optimization scheme SCE-UA and soil moisture data from a wireless soil moisture sensor network. The estimated parameters were then used for 3D simulations using the integrated parallel simulation platform Parflow-CLM. The simulated soil water content, as well as evapotranspiration and runoff, were compared with the field observation to illustrate how well the model was able to reproduce the water budget dynamics. With variable model setup scenarios, we investigated how depth-to-bedrock and lateral flow processes above the underlying fractured bedrock affects the simulation results. Furthermore, we also explored what role the litter layer of the forest soil plays in the simulation of water flow processes. Method of empirical orthogonal function (EOF) was also used for analysis on spatial patterns of simulated and observed soil water content.

## Reference

Wood, E. F., et al. (2011): Hyper-resolution global land surface modeling: Meeting a grand challenge for monitoring Earth's terrestrial water, Water Resour. Res., 47, W05301, doi:10.1029/2010WR010090.
# Periglacial Slope Deposits and the CZ - on their genesis and influence on soil water content by a case study from the Bavarian Forest, Germany (TUM-CZO)

J. Völkel¹, J. Huber¹

¹Technische Universität München, Wissenschaftszentrum Weihenstephan, Freising, Germany

Periglacial slope deposits (PSD) are widespread in mid latitudes' Pleistocene non-glaciated areas. In the mid-mountainous regions of Germany like the Bavarian Forest these sediments appear as characteristic layered material on any slopes. Typically, the PSDs consist of three different layers: Upper, Middle and Lower Head. Their properties are governed by their genesis at different climates and according to periglacial morphodynamics. Additionally, bedrock lithology and source of strata are influencing factors. The PSDs are crucial part of the critical zone as the uppermost layer between surface and the lowest groundwater level and responsible for layer-characteristic soil water movements. The latter are hydrological processes, like interflow and storage, depending on the PSDs.

In this investigation selected profiles of the Otterbach catchment are analysed in consideration of the pedological and sedimentological properties. Stratigraphical features and numerical dating techniques (OSL) help to interpret landscape evolution and genesis of its critical zone. In addition, soil water measurements within the single PSDs show the influence of the layers on soil water movement and the importance of the periglacial slope deposits as part of the critical zone.