bluuebunny/crossref_metadata_2025 huggingface dataset:
Hybrid turbidite-contourite sediments transport system in the Eastern Mediterranean upper continental slope
Authors: Katz Oded , Ashkenazi Leeron , Abramovich Sigal , Almogi-Labin Ahuva , Makovsky Yizhaq , Gadol Omri , Kanari Mor , Hyams-Kaphzan Orit
Published: March 2022

Nile derived siliciclastic sediments are the main source for sedimentation along the Levant continental margins. The sediments are transported along the southeastern Mediterranean coast via jet and longshore currents, mainly operating along the shelf. However, the cross shelf component of sediments transport, responsible for conveying sediments towards the upper slope, is less known. To better understand the cross-shelf vs. the longshore components of sediment transport, we studied two ~5.5 m piston cores: DOR280 and DOR350, sampled on the upper continental slope at 280 m and 350 m water depth, respectively.

We analyzed the particle size distribution (PSD) as well as the benthic-foraminiferal assemblages and their shells taphonomy, for documenting both the source and the transport mechanism of the upper continental-slope sediments. The radiocarbon sediment age at the DOR280 core-base is ~660 ±70 Cal Yrs. B.P., indicating an exceptionally high average sedimentation rate of ~800 cm/kyr. DOR280 consists of alternating two sedimentary facies: (1) Laminated (L) intervals with bimodal PSD and high ratio of allochthonous vs. autochthonous (allo/auto) foraminiferal species, characterized by a high percentage of benthic-foraminiferal broken and poorly preserved shells, indicating contribution of transported sediments originating from mid-shelf habitats. (2) Non-laminated (NL) intervals with unimodal PSD, low allo/auto ratio (<1) and low percentage of broken shells, indicating mostly in-situ deposition. The L intervals are interpreted as sediment laden gravity currents, possibly turbidites. Numerous centimeters-thick turbiditic events were identified, based on grain-size grading and discontinuous eroded lower stratigraphic-contacts. Sedimentation rate calculated only for the NL intervals is still exceptionally high, excluding hemipelagic sedimentation as the sole deposition. Thus, a contour bottom-current transported component is suggested for the NL sediments of DOR280 (i.e. contourites). DOR350 reveals higher sedimentation rates (age of ~350 ±80 Cal Yrs. B.P. at the core-base) and consists mostly of the L facies. Hence, the sediments of DOR350 are mostly consist of transported (by turbidities) sediments with only minor contribution of hemipelagic sedimentation or contourites.

We conclude that a hybrid contourite-turbidite system actively prevails along the Levant upper continental slope offshore Israel, apparently at water depth of less than 350 m.
Mapping Austrian organic soil by using hydro-geomorphological probabilities
Authors: Kroisleitner Christine , Glatzel Stephan , Ascher Sandra , Deng Yujing
Published: March 2022

For centuries mires were drained to generate agriculturally useable land. That applies particularly for Europe, where more than 40% of peatlands are considered disturbed and mainly ceased peat accumulation. For Austria, the fraction of disturbed peatland is considered 90%. Estimates assume 180 million tons of carbon stored in soils at grass- and cropland alone.

Despite recent approaches Austria lacks knowledge of peat area particularly on agricultural land, although it is recognized as a key environment for future carbon storage. After all, Austria indents to lower GHG emissions by 36% until 2030 in non ETS sectors by an increase of carbon sequestration in soils but the lack of a standardised and nationwide map on organic soils hampers reliable estimates on GHG emissions from peatland.

Therefore, this study aims to assess all available Austrian soil and environmental data in order to compile a map of probable organic soil areas.  As the Austrian soil map (eBOD2) was found the only applicable soil dataset, we focussed on developing an algorithm to specify probable organic soil areas with the combination of hydro-climatological, geomorphological and geological data. We used the climatic water balance in conjunction with groundwater table depth to specify areas with sufficient water supply. By using the topographic wetness index, slope and geomorphic landforms we derived areas with high water storage capacity. Further we used the probability of peat to appear in a certain geological setting as indicator for an impounding setting. We chose three case study regions and used the Austrian soil map to calculate probabilities for every input dataset to appear in conjunction with organic soil. The combined resulting maps show good accordance with organic soil areas compared to eBOD2 besides a tendency for overestimation in wide river valleys. This indicates deficiencies in distinguishing between peatland and other wetlands. To evaluate our approach, we took roughly 600 soil samples from 300 sampling points in the case study regions, which are currently analysed on their carbon content. Recent findings and insights from the field campaigns will be implemented in the map retrieval algorithm for total Austria.
Comparing the spatio-temporal differences of global NPP simulation data with different resolutions
Authors: Zhou Tao , Tang Xiaolu , Hou Yuting , Luo Xinrui , Yang Zhihan , Lai Yunsen , Yu Peng , Luo Ke , Zhao Runying
Published: March 2022

*Corresponding author: Xiaolu Tang (lxtt2010@163.com)

Net primary productivity (NPP) is a key parameter to characterize terrestrial ecological processes. NPP reflects the carbon sequestration capacity of vegetation to absorb atmospheric carbon dioxide, and plays an important role in mitigating atmospheric carbon dioxide content. Currently, the majority of studies focused on the model efficiency total NPP at the global scale. However, whether the model resolution of NPP affects the NPP amount at the global is still uncertainty. To fill this knowledge gap, we first collected 3307 NPP field observations from published literatures, and then model NPP using climate, soil, and vegetation variables using Random Forest (RF) to predicted global NPP at the spatial resolutions of 0.05°, 0.25° and 0.5°. Results showed that RF could well capture the spatial and temporal variability of NPP with the model efficiencies (R2) of 0.55, 0.52 and 0.53 for at the resolution of 0.05°, 0.25° and 0.5°, respectively. Similar spatial patterns were also found for NPP at different spatial resolutions and NPP decreased with increased latitude where the highest NPP was found in the tropical regions and the lowest NPP were distributed in high latitude areas, e.g. alpine tundra. However, a great difference was found for the magnitude of NPP resulting a great difference in total global NPP of 71.5, 78.6, 87.7 Pg C year-1 from 1981 to 2016 for the resolutions of 0.05°, 0.25° and 0.5°, respectively. These findings suggested the challenges to improve modelling accuracies of the global carbon fluxes used appropriate resolutions.

Keywords: Net primary productivity; Different resolutions; Random Forest; Spatial pattern; Appropriate resolution;

Acknowledgment: the study was supported by the National Science Foundation of China (31800365).
Inferring aquitard hydraulic conductivity using transient temperature-depth profiles impacted by ground surface warming
Authors: Bense Victor , Kruijssen Titus , van der Ploeg Martine , Kurylyk Barret
Published: March 2022

Aquitard hydraulic properties are notoriously difficult to assess, yet accurate aquitard hydraulic conductivity estimates are critical to quantify recharge and discharge to and from semi-confined aquifer systems via hydraulic head gradients. Such flux quantification is required to evaluate the risks of aquifer exploitation by groundwater abstraction and aquifer vulnerability to surface contamination. In this study, we consider a regionally important aquitard and compare existing hydraulic conductivity estimates obtained through traditional methods to those inferred from long-term hydraulic head monitoring and thermally-derived vertical groundwater fluxes (0.04--0.25 m/y). We estimate the fluxes using numerical modeling to analyse the propagation of decadal climate signals into temperature-depth profiles and fitting the simulated and observed inflection point depths (minimum temperature). Results reveal that climate-disturbed temperature-depth profiles paired with multi-level head data can yield accurate vertical fluxes and aquitard hydraulic conductivities. This approach for characterizing groundwater systems and quantifying flows to and from sedimentary aquifers is more efficient but yields results that are comparable to conventional methods.
Estimating the impact of seasonal extremal dependence with a Max-Stable process for modeling extreme precipitation events over Berlin-Brandenburg
Authors: Jurado Oscar E. , Rust Henning W.
Published: March 2022

Recent developments in Extreme Value Theory have led to the adoption of multivariate methods for modeling extreme rainfall in a way that the spatial dependence between the different measuring stations is used to "borrow“ information. A commonly used method, Brown-Resnick Max-Stable processes, extends the geostatistical concept of the variogram to suit block maxima, allowing to explicitly model the spatial extremal dependence shown by the data. This extremal dependence usually stems from physical processes that generate rainfall in such a way that several stations are affected simultaneously by the same extreme event, such as convective storms or frontal events. Depending on the region, this dependence can change in time, as different meteorological processes dominate the rainfall generation process for different seasons.

In this study, we analyze in the Berlin-Brandenburg region the change in extremal dependence for annual block maxima. We consider two different seasons – winter and summer – to investigate the effects of two different rainfall generating processes: frontal rainfall is more likely to occur in winter, while convection is dominating in summer. Furthermore, we investigate how this extremal dependence affects the accuracy of the estimation of return levels by using a Brown-Resnick Max-Stable process and comparing the estimated return levels to the results of a covariates model assuming spatial independence. We obtain the uncertainty of our estimates within a Bayesian modeling framework. The bivariate extremal coefficient shows a notable difference in the extremal dependence for summer and winter. Moreover, we observe a difference in the skill of the model when comparing the two seasons, suggesting that the difference in the extremal dependence has an impact on the marginal estimates from the model.
Transport and deposition behaviors of microplastics in porous media: Co-impacts of N fertilizers and humic acid.
Authors: Rong Haifeng , Tong Meiping
Published: March 2022

Due to the interaction of fertilizers with microplastics (MPs) and porous media, fertilization process would influence MPs transport and distributions in soil. The co-impacts of N fertilizers (both inorganic and organic N fertilizers) and humic substance on MPs transport/retention behaviors in porous media were examined in 10mM KCl solutions at pH 6. NH4Cl and CO(NH2)2 were employed as inorganic and organic N fertilizers, respectively, while humic acid (HA) was used as model humic substance. We found that for all three sized MPs (0.2, 1 and 2 μm) without HA, both types of N fertilizers decreased their transport/increased their retention in porous media (both quartz sand and soil). N fertilizers adsorbed onto surfaces of MPs and sand/soil, lowering the electrostatic repulsion between MPs and porous media, thus contributed to the enhanced MPs deposition. MPs with N fertilizers in solutions more tightly attached onto porous media and thus were more difficult to be re-mobilized by low ionic strength solution elution. Via steric repulsion and increasing electrostatic repulsion between MPs and porous media due to adsorption onto their surfaces, HA could increase MPs transport with N fertilizers in solutions.
European heat waves of summer 2021 in the context of past major heat waves
Authors: Lhotka Ondřej , Kyselý Jan
Published: March 2022

Climate change-induced rise in global temperatures is linked to changes in hot extremes. The recent summer of 2021 was marked by extremely high temperatures over the Mediterranean, which together with numerous wildfires considerably affected human society and natural environment. Using daily maximum temperatures from the ERA-5 reanalysis, we aim to assess the severity of heat waves in 2021 in the context of past major European heat waves (since 1950) through analysing their length, spatial extent, intensity, and overall magnitude. We show that the summer of 2021 was record-breaking in terms of total duration of heat waves and their magnitude was comparable to those in 2003 and 2010. The past two decades (2002–2021) almost completely redraw the spatial pattern of the occurrence of the historically most severe heat wave in European regions. Before 2002, heat waves of 1955, 1972, and 1994 were the most severe in many parts of Europe. Considering the whole 1950–2021 period, however, those heat waves remain as historically the most severe only over a small portion of their original area, and the map is dominated by the 2003, 2010, 2018, and 2021 events. This documents a rapid change in heat wave characteristics in Europe over the last two decades.
Neon isotopic signature applied to detrital provenance assignment in foreland basins
Authors: Ma Yan , Zheng Dewen , Zhang Huiping , Pang Jianzhang
Published: March 2022

Cosmogenic noble gas isotope 21Ne in terrestrial rocks has been used primarily to determine timing and rates of the Earth’s surface evolution. Here we explore the ability of detrital 21Ne as a provenance tracer, considering that Ne isotopes produced in source rocks could be preserved in minerals over geological time and might be predominant in total Ne inventory of sediments sunk in basins. This ability is predicated on potential source terranes of a given stratigraphic section with distinct neon isotopic signatures. Here we analyze neon isotopes of a well-dated Miocene–Pleistocene sedimentary archives in Kuqa foreland basin of southern Tianshan. The data suggest that the neon isotopic signature, which is expressed as εNe and defined in this work as the excess 21Ne/20Ne-ratio relative to atmospheric ratio, is stratigraphically sensitive to changes in local source terranes. This result is compatible with U/Pb provenance analysis and also supported by evidences from sandstone petrography and heavy mineral analysis. Influence of other non-source related 21Ne components in sedimentary archives on sensitivity of εNe has proven to be negligible. Furthermore, the integrated stratigraphic signatures of neon isotope and U/Pb age permit the detection of differential erosion in drainage basin, by which the tectonic or climatic effects on geomorphic evolution could be deciphered.
A robust evaluation a revised version of the MMF-TWI soil erosion model
Authors: Peñuela Andres , Garcia Gamero Vanesa , Vanwalleghem Tom
Published: March 2022

Soil erosion represents a serious challenge for agricultural production and for the environment. Soil erosion impacts, such as reduction of fertile soil, alteration of the carbon cycle and pollution and eutrophication of water bodies, represent a significant management concern. Modelling approaches can deliver indicators on the state of soil erosion impacts and its trends, and scenarios in relation to climate and land use change. This can help define efficient and targeted mitigation strategies. However, to define such strategies, there remains a lack of modelling approaches able to provide with long term baseline information which to measure the success of the mitigation strategies as well as model evaluation approaches robust enough so model results can be trusted by users, including researchers and land managers. The MMF-TWI soil erosion model has demonstrated its ability to simulate soil erosion and the effect of agricultural management practices over centennial scales in humid environments. However, it needs to be revised and evaluated before the model can be applied more widely in other climate areas. In this study, we present a revised version of MMF-TWI incorporating infiltration excess overland flow and a robust and innovative multi-proxy model evaluation approach in an olive orchard catchment in South Spain. The evaluation approach consists of a) the comparison of model simulations with estimations of past soil loss rates obtained from both Pu fallout radionuclide tracers and tree mound measurements and b) the evaluation of the plausibility of the model behaviour by means of global sensitivity analysis.
How does a hidden profession reveal hidden processes and what are the implications for flood damage assessment?
Authors: Brémond Pauline , Bouche Guillaume , Collard Anne Laure , Grelot Frédéric , Tarrit Reine
Published: March 2022

Flood economic damage results from complex phenomena involving biophysical processes that determine the damage of the components but also the decisions taken for reconstruction. The method most frequently used to estimate damage is based on the assumption that the property will be restored to its original condition. This method is supported by expert knowledge of damage processes and restoration costs. However, in practice, we wonder about the implementation by individuals of this identical restoration at a time when the build back better is an injunction that is found in many institutional discourses. In France, insurance experts are mandated by insurance companies within the framework of the cat-nat insurance process to ascertain and evaluate the damage suffered by insured persons following a flood. This experience gives them a privileged place to feed the ex ante damage assessment models.

However, although, the experts intervene to establish the damage at the very moment when the dwellings are dealing with reconstruction decisions, this profession remains little studied in the literature. In this study, we tried to determine, on the one hand, to what extent the posture of experts influences the assessment of damage and, on the other hand, what role they play in the process of reconstruction and individual adaptation of housing following a flood.

Since 2012, we have met with 15 insurance experts, conducted 20 individual interviews and two intermediate workshops on understanding damage mechanisms and estimating repair costs. This work has enabled us to develop damage functions for different sectors (households and economic activities) which were validated during a participatory workshop with the experts. We will present a critical analysis of this work, focusing on the view of damage held by insurance experts and the underlying assumptions. To complete this analysis, we have carried out additional work specifically on the role of insurance experts in the reconstruction process of households. Through a qualitative field survey in 2021, we met a dozen insurance experts. First, we established the standard expertise process used by the experts. Based on these procedures, we questioned them on how to conduct an expertise. Through narratives, we highlighted the roles that insurance experts actually play with dwellings. In particular, we showed that despite the technical and human skills available to the experts, the issue of reconstruction can only be dealt with informally and remains marginal due to the missions entrusted to the experts by the insurance companies. In conclusion, we will discuss the implication for damage estimation.
Blowout morphodynamics in southern Portugal 
Authors: Talavera Lara , Costas Susana , Ferreira Óscar
Published: March 2022

Blowouts are sandy depressions of different shapes formed by wind-induced erosion of foredunes or dune fields. Their initiation has been linked to air flow acceleration due to the occurrence of irregularities in the topography caused by natural or human causes, or by the lack of vegetation, and they contribute to maintain the available sediment budget in barrier islands migrating inland. In this study, we investigated the morphometric characteristics (area, orientation, and shape/structure) and spatiotemporal evolution of a series of blowouts present in the foredune of a coastal stretch of 1.3 km situated in Ancão Peninsula (South Portugal) that has been retreating for the last 60 years. For that, a set of historical aerial photos, orthophotos, and Google Earth images, covering a 45-year period from 1972 to 2017, was analysed. In addition to the blowout mapping, the dune foot, trampling paths and human occupation (e.g. restaurants, walkways, umbrellas) observable in the previous imagery were mapped in order to find possible causes that could help explaining the observed foredune fragmentation and blowout development. Finally, we characterised the present-day plant species distribution along and across the study area in order to understand the impact of these landforms in the plant community and possible eco-morphological feedbacks. The findings showed that during the analysed period: (1) blowout dimensions ranged from 1.2 m2 to of 2200 m2, with 50 to 80% of the blowouts displaying sizes below 100 m2; (2) the orientations of the smallest blowouts (below 100 m2) showed high variability (from SSE-NNW to W-E orientations), whereas the bigger ones (above 400 m2) were mostly SW-NE oriented, coinciding with the dominant winds in the area; (3) most of the blowouts had mixed shapes and branched structures, likely enhanced by human trampling; (4) the number  of blowouts and their morphometric parameters were not clearly related with the shoreline retreat/progradation; and (5) the transition between the blowout lobes and the stablished foredune suffered a change in the plant community dominated by species such as Artemisia campestris subsp. maritima, suggesting a shift to burial tolerant species.

Besides wind conditions and shoreline changes, human pressure seems a very likely trigger of blowout morphology reinforcement and even blowout initiation in the area, although the origin of some of these features seems related also to already-existing irregularities in the topography, suggesting the fragility of this sector and supporting its tendency to migrate inland.
A Model of the Energy Balance Gap Based on Atmospheric Stability and Surface Heterogeneity
Authors: Wanner Luise , Calaf Marc , Paleri Sreenath , Kadum Hawwa , Butterworth Brian , Desai Ankur , Mauder Matthias
Published: March 2022

Secondary circulations are one of the main causes of the energy balance gap that arises from the underestimation of sensible and latent heat fluxes by eddy covariance measurements because they cannot capture the energy transported by the mean wind, i.e. the so-called dispersive flux. The magnitude of the missed sensible and latent dispersive fluxes depends significantly on atmospheric stability and surface thermal heterogeneity, but there is currently no correction method that accounts for both of these relationships. Using an idealized large-eddy simulation study, we have further developed an existing approach that models the energy balance gap as a function of atmospheric stability by additionally including thermal surface heterogeneity in the parametrization. This new model has already been tested on eddy covariance measurements that were carried out at 17 stations over the course of three months during the CHEESEHEAD19 (Chequamegon Heterogeneous Ecosystem Energy-balance Study Enabled by a High-density Extensive Array of Detectors) measurement campaign and it provides promising results.
Prediction of drain flow fraction at high spatial resolution by combining physically based models and machine learning
Authors: Schneider Raphael , Mahmood Hafsa , Frederiksen Rasmus Rumph , Højberg Anker Lajer , Stisen Simon
Published: March 2022

In Denmark, about half of the agricultural land is artificially drained. These drainage systems have a significant effect on the hydrological system. Knowledge about the spatio-temporal distribution of drain flow is crucial to understand aspects such as groundwater recharge, streamflow partitioning and nutrient transport. Still, quantification of drain flow at regional and large scale remains a major challenge: Data on the distribution of the installed subsurface drainage system are scarce, as are measurements of drain flow. Large-scale simulations of drain with physically-based hydrological models are challenged by scale, as drain flow is controlled by small-scale variations in groundwater depth often beyond the model resolution. Purely data-driven models can struggle representing the complex controls behind drain flow.

Here, we suggest a metamodel approach to obtain a more accurate estimate of generated drain flow at high spatial resolution of 10 m, combining physically-based with data-driven models. Our variable of interest is drain fraction, defined as the ratio between drain flow and recharge per grid cell, which is an indicator for flow partitioning between drain and recharge to deeper groundwater.

First, we setup distributed, integrated groundwater models at 10 m grid resolution for 28 Danish field-scale drain catchments with observations of drain flow timeseries. A joint calibration of these field-scale models against observed drain flow resulted in an average KGE of above 0.5. Subsequently, the simulated drain fractions from the field-scale models were used to train a decision tree machine learning algorithm. This metamodel uses various mappable covariates (topography and geology-related) available at high resolution for all of Denmark. The metamodel then is used to predict drain fractions, within its limits of applicability, across relevant areas of Denmark with significant drain flow outside of the field-scale models.

Eventually, the predicted drain fractions are intended to inform national, large-scale physically based hydrological models: An improved representation of drain can, for example, make those models more fit to improve national targeted nitrate regulation.
Influence of terraced fields on eroded terrain indicators：take the second of gullied rolling area on the Loss Plateau as an instance
Authors: Qiao Bingjie , Yang Qinke , Wang Chunmei , Pang Guowei , Li Endan
Published: March 2022

In order to study the influence of artificial terrain (terraced fields) on topographic factors, this paper, based on the basic principles of soil erosion and soil conservation, uses aerial photogrammetry to obtain high-precision DEM in Zhifanggou watershed, and extracts the slopes of terraced and non-terraced areas , Slope、Length and Slope Length factor, Topographic Wetness Index, Connectivity Index and Relative Path Impact Index, and analyze the changes of these factors to understand the impact of terraces on eroded terrain. The research shows that: (1) The construction of terraces makes the slope slow down, the slope length is cut off, and the LS factor becomes smaller; (2) The construction of terraced fields reduces the connectivity at the field surface and increases the connectivity at the ridge; the IC value of terraced fields is greatly affected by slope, and the IC value of non-terraced fields is greatly affected by slope length. (3) With the increase of slope, the connectivity of sediment increases and soil erosion intensifies; runoff accumulation is likely to occur in local depressions, resulting in increased connectivity of sediment. (4) The relative path impact index is effective for identifying erosion risk areas susceptible to changes in water flow paths. This paper expounds the influence of terraced fields on eroded topographic indicators and hydrogeomorphology, which is of great significance for accurately assessing the impact of terraced fields on soil erosion and for soil erosion control in the Loess Plateau.
Correction of siphoning error in processed historical rainfall intensity data, a case study of data measured by Hellmann-Fuess type rainfall recorder 
Authors: Racz Tibor
Published: March 2022

The Hellmann rainfall recorders have been one of the primary instruments of the rainfall intensity measurement, mainly in the countries of the central part of Europe, during the 20th century. These water level measurement-based rainfall recorders ensure the continuity of measurement by periodically emptying siphoned measurement cylinder. During the emptying, the measurement is paused, resulting in under-measurement. The duration and number of emptying can be known, and the correction of under-measurement can be adjusted if the registration ribbon is available. In the case of historical data, the registration ribbon is often unavailable, and only extracted values of the most intensive periods of rainfalls can be gained from databases. A procedure for correcting such kinds of data is shown, and also the influence of the correction of Hellmann-Fuess recorder’s data on the IDF curves.

The procedure is based on the method published in 2002 by Luyckx and Berlamont, which was compiled based on the physical process of the siphoning, and it assumed the existence of the original records (ribbons), with the exact time of siphoning. The extracted data tables nor time nor number of siphoning was registered, so the method of Luyckx and Berlamont for the data correction cannot be used. The proposed procedure’s principal is the estimation of the number and length of pauses in the extracted measurement interval. These estimated data make passible to fix the rainfall quantity and intensity for the given interval. The measurement cylinder of the device is generally not empty at the beginning of the most intensive period of rainfall. The water level is assumed as a uniformly distributed probability variable what can be estimated with its expected value. The raw data comprise underestimation in all cases, so the raw data represent only the possible minima of the plausible intensity values. The fixed data result in the expected value of the plausible intensities, which are sometimes higher and sometimes lower than the actual intensity values, with the same probability; so, if there are a high number of fixed data, the positive and negative deviations diminish the errors statistically. The use of the correction formula is presented with the parameters of a Hellmann-Fuess rainfall writer. The correction range has been the highest over ten years of average recurrence, and its measure was 10%. For 30 minutes and longer sampling intervals, the magnitude of the correction is not relevant. After that, the correction is based on statistical estimation, the exact value of the rainfall intensity cannot be retrieved, but the underestimation can be decreased significantly. The fixed data modify the IDF curves as well, and in this way, the effect of climate change can be investigated more appropriately.
Dynamic and equilibrium surface tension of Rhamnolipid: Effect of real-time temperature.
Authors: Nguyen Thuc , Arye Gilboa
Published: March 2022

Surfactants are used in the soil for many purposes such as for aiding water infiltration into hydrophobic soils or remediating soil contamination. The effectiveness of surfactants in such applications relies greatly on surfactant surface properties - affected by environmental conditions such as temperature. Under the effect of climate change, soil temperature may fluctuate unpredictably, leading to an ambiguation on the appropriate use of surfactants. Therefore, for precise decisions of surfactant application in the soil, it is necessary to evaluate the impact of temperature on surfactant properties. In this study, we chose Rhamnolipid (RLP) -  a biosurfactant that potentially could be used in soils as an alternative for other non-sustainable synthetic surfactants. Our objective was to investigate the surface properties of RLP under the effect of temperature. Previous studies pre-treated RLP with heat and thereafter characterized its surface properties after reaching room temperature. Our study, on the other hand, monitored the dynamic surface tension of RLP at real-time temperature, ranging from 10 to 45 ºC. For a given temperature, the surface tension as a function of time was measured using the pendant drop technique by an optical tensiometer (OCA-22, Data Physics). The diffusion coefficient of RLP to the liquid/air interface and equilibrium surface tension was calculated. In this presentation, both the dynamic and equilibrium surface properties of the RLP mixture (mono and di-rhamnolipid) as a function of temperature will be shown and discussed.  
Isotope hydrogeochemistry investigations (223,224Ra, DI13C) on submarine groundwater discharge in a tidal bay (eastern North Sea)
Authors: Ehlert von Ahn Catia Milene , Jenner Anna-Kathrina , Scholten Jan , Schell Antonia , Schmiedinger Iris , Hoffmann Jasper , Roeser Patricia , Nantke Carla , Böttcher Michael
Published: March 2022

The impact of submarine groundwater discharge (SGD) on coastal biogeochemistry is currently under intense investigation. SGD can impact diagenesis and in general act as a potential source of elements, especially dissolved carbon, to coastal surface waters. However, qualitative and quantitative assessments of SGD are challenging since it requires the identification of suitable geochemical tracers for the complex hydrological and biogeochemical processes in the subterranean estuary. In this communication, we report on combined investigations carried out in Königshafen Bay (North Frisian island Sylt, Germany), a tidal area in the eastern North Sea. Sampling encompassed vertical porewater gradients, and surface waters collected through transects in the bay, and in tidal cycles at the outlet of the bay. Potential surface and subterrestrial freshwater endmembers are used to assess the results. Besides major and minor elements, this study focuses on the stable carbon isotope composition of dissolved inorganic carbon (DIC) and the activity of radium (Ra) isotopes. Our main aim is to characterize the interaction between diagenesis and the composition of SGD, as well as the resulting impact on the carbon system of the water column, and, via tidal exchange extended to the coastal North Sea. Porewaters showed usually an increase of isotopically light DIC with depth and a freshening already in the top 50 cmbsf at some sites. This indicates that both, carbon diagenesis and mixing of seawater with fresh groundwaters at depth impact the distribution of DIC. The activities of the short-living Ra isotope (224Raex) were higher in the bay compared to the open North Sea. Porewater activities were up to 30 times higher than in the bay’s surface waters with a maximum development at intermediate salinities. In the water column at the outlet of the bay, 224Raex and 223Ra showed maximum activities during low tide as a consequence of the highest contribution of waters in contact with the sediments of the bay. Moreover, due to the high hydraulic gradient developed during low tide more contribution from potential endmembers enriched in Ra can be expected. Further work is on the way to quantify the impact of SGD on the tidal basin and the indirect role for the North Sea carbon system on different temporal and spatial scales.

 The investigations are supported by the DFG-project KiSNet, the BMBF project COOLSTYLE (CARBOSTORE), the DAAD, the DFG RTG Baltic TRANSCOAST, and the Leibniz IOW.
Detection of changes in the mean monthly and yearly discharges in Slovakia 
Authors: Jeneiova Katarina , Danacova Zuzana , Blaskovicova Lotta , Labat Marija Mihaela , Poorova Jana
Published: March 2022

Due to climate change, the detection of changes in the long-term hydrological time series is an important topic in water management for timely set up of possible mitigation measures. In this contribution, the mean monthly and yearly discharges in Slovakia were analysed on the data from 43 selected water-gauging stations with hydrological regime minimally affected by human activities. The trend detection analysis of the mean monthly and yearly discharges in period 1961-2020 was concluded by Mann – Kendall trend test at significance level p = 0.05. The results of the trend analysis of the mean yearly discharges point out at the occurrence of statistically significant decreasing trend mainly in the western part of Slovakia. The trend analysis of the mean monthly discharges detected significant decreasing trend in the months of April, May, June, July and August. These results indicate possible changes in the mean monthly and yearly discharges in Slovakia and may be helpful in planning and policy making to mitigate the possible climate change impacts in Slovakia.

Acknowledgement: This work was supported by the Slovak Research and Development Agency under the Contract no. APVV-20-0374.
Extrapolating field-scale near-surface soil moisture information from Cosmic Ray Neutron Sensing to greater depth
Authors: Rasche Daniel , Blume Theresa , Güntner Andreas
Published: March 2022

Cosmic-Ray Neutron Sensing (CRNS) is a modern technique for non-invasive soil moisture estimation at the field scale. It closes the scale gap between point-scale observations (e.g. soil sampling, in-situ sensors) and coarse-scale satellite-derived estimates. While CRNS has a large horizontal footprint with a radius of roughly 150 m around the instrument, the average vertical measurement depth is only about 30 cm. Thus, extrapolating the CRNS-derived soil moisture to greater soil depths such as the entire root zone can be highly beneficial for hydrological applications such as landscape water balancing or irrigation management. To this end, previous studies have used, for instance, additional in-situ sensors and time-stability approaches or calibrated exponential filters against reference measurements in deeper soil depths.

However, additional permanent in-situ sensors and reference measurements in greater depths are not always available or feasible. Against this background, we use the physically-based soil moisture analytical relationship (SMAR) which can be used without calibration against reference measurements. We estimate the required model parameters from soil characteristics (e.g. porosity, water content at field capacity and wilting point) as well as from the CRNS soil moisture time series itself.

As CRNS for soil moisture estimation is developing rapidly, new transfer functions from observed neutron intensities to surface soil moisture have been introduced. We investigate the influence of using both the standard transfer function and the recently introduced universal transport solution (UTS) on the depth-extrapolated soil moisture time series. These depth-extrapolated soil moisture time series are then evaluated against soil moisture reference time series from in-situ soil moisture sensors down to 450 cm depth.
Gravity kernel method for implicit geological modeling
Authors: Liang Zhouji , De La Varga Miguel , Wellmann Florian
Published: March 2022

Gravity is one of the most widely used geophysical data types in subsurface exploration. In the recent developments of stochastic geological modeling, gravity data serves as an additional constraint to the modeling construction and can be included in the modeling process as the likelihood function in a Bayesian workflow. A fast but also precise forward gravity simulation is key to the success of the geological modeling inverse problem.

In this study, we present a gravity kernel method, which is based on the widely adopted analytical solution on a discretized grid. As opposed to a globally refined regular mesh, we construct local tensor grids for each sensor, respecting the gravimeter locations and the local sensitivities. The kernel method is efficient in terms of both computing and memory use for meshless implicit geological modeling approaches. This design makes the method well suited for many-query applications like Bayesian machine learning using gradient information calculated from Automatic Differentiation (AD). Optimal grid design without knowing the underlying geometry is not straightforward before evaluating the model. Therefore, we further provide a novel perspective on a refinement strategy for the kernel method based on the sensitivity of the cell to the corresponding receiver. Synthetic results are presented and show superior performance compared to the traditional spatial convolution method.
Closing the water balance of large watersheds using satellite gravimetry
Authors: Rietbroek Roelof , Penning de Vries Marloes , Zeng Yijian , Su Bob
Published: March 2022

At the level of a watershed, the conservation of mass imposes that the net moisture transport through the atmospheric boundaries is balanced by the river discharge and an accumulation/depletion in terrestrial sources such as the soil, surface waters and groundwater.

There are considerable uncertainties connected with modelled water balance components, especially since most models only simulate part of the system: either the atmosphere, the surface or the subsurface. Uncertainties in boundary conditions propagate as biases in the simulated results. For example, not accounting for anthropogenic groundwater extraction potentially introduces biases in arid regions, where groundwater is a non-negligible source of moisture for the atmosphere. The use of observations is therefore an important aid to evaluate model performances and to detect possible biases in water balance components.

In this contribution, we compare total water storage changes derived from the Gravity Recovery Climate Experiment (GRACE) and its follow-on mission, with modelled components of the water balance. We use ERA5 reanalysis data to compute (net) atmospheric transports, and river discharge from GloFAS (Global Flood Awareness System). Furthermore, we use precipitation estimates (e.g. from GPCC) together with evapotranspiration from the Surface Energy Balance System (SEBS). We finally perform an accounting of the water balance components for the world’s largest watersheds and show to what extent we can find agreements, inconsistencies and biases in the data and models.
Using numerical modelling to investigate the driving forces of permanent forearc deformation in northern Cascadia
Authors: Harrichhausen Nicolas , Loveless Jack P , Morell Kristin D , Regalla Christine , Lynch Emerson M
Published: March 2022

We use boundary element method modelling to investigate whether subduction zone coupling drives permanent forearc deformation in the northern Cascadia subduction zone. Recent work in this region shows that several active crustal faults accommodate permanent strain north of the Olympic Peninsula in Washington State, USA and British Columbia, Canada. These faults are similar in that they strike west-northwest, have oblique right-lateral slip senses, and have low slip rates (<1 mm/yr). Paleoseismic studies show that despite the region’s low permanent strain rates, these faults have produced large (~M 7) earthquakes. Therefore understanding how and why these structures accommodate permanent deformation is crucial to assessing regional seismic hazard. Previous work has hypothesized this type of permanent forearc deformation may be driven by stress resulting from interseismic subduction zone coupling. To test this hypothesis, we used a 3D boundary element method model to determine whether coupling-driven forearc deformation can account for the observed right-lateral fault slip on one of the recently studied structures, the Leech River--Devils Mountain fault. Our model predicts left-lateral slip on this fault if strain results from subduction zone coupling alone, inconsistent with the observed kinematics. Additionally, if we use our model to mimic strain partitioning, where only strain resulting from the strike-slip component of subduction zone coupling is accommodated in the forearc, the predicted fault slip is also inconsistent with observations of fault kinematics. These simplified models represent a first-order test that contradicts the hypothesis that subduction zone coupling is the primary driver of permanent forearc deformation in northern Cascadia.
Where does precipitation falling in agricultural regions come from, and to what extent does upwind vegetation contribute?
Authors: Devenet Clément , de Noblet-Ducoudré Nathalie , Pitman Andrew J.
Published: March 2022

In many places around the world, rainfall is changing in response to ongoing climate change. Changes in seasonality, frequency, intensity, and sometimes in annual totals, are expected to become more significant with increasing warming. Rainfed agriculture represents approximately 83% of the cropland surface worldwide, and even irrigated land depends on the availability of ground or surface water, which in turn depend on rainfall. Consequently, changes in precipitation during the growing season can place food production systems at risk.

Vegetation plays an important role in the water cycle, and thus precipitation, by releasing water vapor into the atmosphere via evapotranspiration. Recent studies show that, in tropical regions, air passing over forests is associated with more precipitation downwind.  However, it is still unclear to what extent upwind land cover and evapotranspiration influence the rainfall over the agricultural regions during the growing season and at any time of the year.

The purpose of this study is to investigate the relationship between the trajectories of air masses, the amount of vegetation overflown, and the amount of rainfall reaching the targeted regions.

For this study we use the ERA5-Land reanalysis dataset and focus on a small number of single grid points (size 0.1° x 0.1°) with intensive agriculture. These points are located in North America, South of the Amazon basin, and South Siberia. For each rainy day from 1981 until 2020, we look at the daily total precipitation, the mean daily wind direction and the cumulative leaf area index (LAI) upwind from the studied location. With this data, we draw wind roses to identify the wind regimes contributing to most of the precipitation for the full year and the growing season. In addition, we compute the correlation between upwind cumulative LAI and rainfall intensity, for the different periods of the year.
Effects of drought and warming treatments on CO2 fluxes in shrubland ecosystems across European environmental gradients
Authors: Li Qiaoyan , Tietema Albert , Reinsch Sabine , Guidolotti Gabriele , Schmidt Inger Kappel , de Dato Giovanbattista , Emmett Bridget , Lellei-Kovács Eszter , Larsen Klaus Steenberg
Published: March 2022

Shrubland ecosystems are vulnerable and typical ecosystems across European countries, but now they are facing a range of threats and an uncertain future because of climate change. Within the INCREASE project, six shrubland ecosystems along a geographical and climatic gradient across Europe from Wales and Denmark in the North, over The Netherlands to Hungary and Italy in the South, were exposed to ecosystem-level warming and extended periods of drought using automated curtain technologies. Sites ranged naturally from xeric to hydric. During our measurement period, mean annual precipitation (MAP) was reduced by 8-25%, while mean annual air temperature (MAT) was increased year-round by 0.2 - 0.9 ℃.

Previously, Reinsch et al. (2017) * showed that aboveground net primary production (ANPP) was relatively resilient to the climate treatments while soil respiration (Rs) was reduced in xeric to mesic sites but increased in the hydric site. However, quantification of the gross primary production (GPP) or ecosystem respiration (Reco) rates and their responsiveness to climate manipulations have not previously been published. We will here present data from the six shrubland sites along the European climate gradient of the responses of GPP and Reco to drought and warming expressed as annual relative change (%) from the untreated control along a Gaussen index (GI). Results are in contrast to the previously reported decrease in Rs responsiveness with increased aridity. For both Reco and GPP rates, our preliminary results indicate that the more arid sites have a stronger, negative effect of drought suggesting different response patterns of autotrophic and heterotrophic components of the ecosystems.

*Reinsch, S., Koller, E., Sowerby, A. et al. Shrubland primary production and soil respiration diverge along European climate gradient. Sci Rep 7, 43952 (2017). https://doi.org/10.1038/srep43952