bluuebunny/crossref_metadata_2025 huggingface dataset:
How to make intensively used peat meadows sustainable for the future? Four management options to potentially reduce peat oxidation
Authors: van den Berg Merit , Fritz Christian , van de Riet Bas , Weideveld Stefan , Gremmen Thomas , van den Elzen Eva , Vroom Renske , Geurts Jeroen , Aben Ralf , Lamers Leon
Published: March 2020

Almost all peatlands in the Netherlands are drained for agricultural purposes or in the past for peat extraction. What remains is a peatland area of about 300.000 ha of which 85 % is used for agriculture. As a result of peat oxidation, these areas are still subsiding by about 1 cm per year. Another effect is the enormous emission of CO2, which contributes to about 4% of total Dutch greenhouse gas emissions. With the awareness of a changing climate and the need for protection against flooding of coastal areas, solutions are being searched to reduce or stop peat oxidation and coinciding land subsidence and CO2 emission.

In this presentation we will show four different management options which are currently being tested in the Netherlands. These options all focus on increasing the groundwater table to lower oxygen intrusion and consequently lower aerobic decomposition. Depending on crop choices water levels may need to stay 40 cm below the surface to maximize fodder plant yields. We expect a trade-off between land-use intensity (yields) and CO2 emission reduction. The management options range from maintaining the current land-use by elevating summer water levels with submerged drainage pipes to the development of peat-forming plant species by complete rewetting. Data of the effects of these management options on CO2 emission will be shown and with that the effectiveness of reducing peat oxidation.
Drones, dykes and too much data: mapping the Taburiente dyke swarm
Authors: Thiele Sam , Cruden Alexander , Micklethwaite Steven
Published: March 2020

Sheet-intrusions are the most common means of magma transport in basaltic volcanoes, so knowledge of their propagation paths is critical for volcanic hazard analyses. Recent advances in unmanned aerial vehicle (UAV) technology and modern photogrammetric techniques such as structure from motion have made it possible to capture and analyse exposed intrusions in unprecedented detail. Using these methods we have captured digital outcrop models of the spectacularly exposed basaltic dyke-swarm that formed the plumbing system of Volcán Taburiente on La Palma (Canary Islands, Spain), and mapped 500 dykes over a total exposed length of > 50 km. We then applied a semi-automatic method implemented in CloudCompare to extract dyke orientation and thickness measurements, as well as associated uncertainty, every ~10 cm along ~60 % of the dyke margins, resulting in more than ten million individual estimates. These highlight a broadly radial dyke swarm with a focal point in the southern section of Caldera Taburiente. The near-continuous exposure also allowed us to estimate the vertical and circumferential strain induced by the dyke swarm and show that although the dykes are radial, N-S orientations are more frequent and probably gave Volcán Taburiente an elongate geometry. A simple Maxwell visco-elastic model can account for the observed strain without requiring a basal detachment or gravitational spreading, and also replicate the observed dyke-aperture distribution.
Using Bayesian geostatistical models to correct gridded hydrological products relative to the actually observed streamflow
Authors: Roksvåg Thea , Steinsland Ingelin , Engeland Kolbjørn
Published: March 2020

Conceptual hydrological models are process-based models that are used to simulate flow indices based on physical or empirical relationships and input variables like precipitation, temperature and land use. For many applications the goal is to use the process-based model to construct a gridded map of the flow index of interest, e.g. for mean annual runoff. However, one challenge is that the resulting runoff map does not necessarily fit to the actually observed streamflow data when the grid nodes are aggregated to catchment areas. A solution to this problem is to correct the gridded hydrological product afterwards relative to the actually observed streamflow in areas where we have measurements. In this work, we explore different Bayesian geostatistical tools that can contribute to this correction. We suggest a model where the  observed streamflow is used as a response variable and the gridded hydrological product is used as a covariate. In particular, a geostatistical model with a spatially varying coefficient (SVC) is suggested, and we develop a linear relationship between the response and the covariate that is allowed to vary in the study area. This is achieved by modeling the regression coefficient as a Gaussian random field (GRF) that defines the spatial pattern of the linear relationship. We also test two simpler geostatistical models, and investigate how short records of runoff can be included in the correction procedure. 

The geostatistical models are tested by correcting a gridded mean annual runoff product from the HBV model relative to the observed  mean annual runoff. We use data from around 400 catchments in Norway from 1981-2010. The results show that all three geostatistical methods lead to a considerably better fit between the corrected product and the actually observed streamflow for the gauged catchments, which was our main goal. In addition, we also obtain improved predictions for many of the ungauged catchments in Norway.
Inference of sediment transport pathways in a gully system using the morphological method
Authors: Dai Wen , Lane Stuart N. , Tang Guoan
Published: March 2020

Gully erosion seriously threatens farmland and causes soil loss. Inferring sediment transport paths in a gully system is important for understanding the mechanisms of gully erosion. The morphological method successfully applied in estimating bed-material transport in both one dimension and two-dimensions in rivers, for some decades, has yet to be applied to gully erosion. Here, we infer sediment transport paths in a gully system using the morphological method. Two catchments in the Loess Plateau of China were selected as study areas. Multi-temporal high-resolution Digital Elevation Models (DEMs) were acquired using structure-from-motion multiview-stereo (SfM-MVS) photogrammetry for determining morphological changes. Then, both 1D sediment transport and 2D sediment transport paths were calculated based on morphological changes and topographic attributes. The results showed that the use of 1D treatment leads to substantial local errors in transport rate estimates, to a degree related to the number of branch gullies. The 2D application showed that a large proportion of the total transport was actually concentrated into one main channel in steep areas, the proportion of transport in branches is substantial in lower relief areas.
Modelling societal landslide risk in Italy
Authors: Rossi Mauro , Guzzetti Fausto , Salvati Paola , Donnini Marco , Napolitano Elisabetta , Bianchi Cinzia
Published: March 2020

Landslides cause every year worldwide severe damages to the population. A quantitative knowledge of the impact of landsliding phenomena on the society is fundamental for a proper and accurate assessment of the risk posed by such natural hazards. In this work, a novel approach is proposed to evaluate the spatial and temporal distribution of societal landslide risk from historical, sparse, point information on fatal landslides and their direct human consequence.s (Rossi et al., Accepted). The approach was tested in Italy, using a detailed catalogue listing 5571 fatalities caused by 1017 landslides at 958 sites across Italy, in the 155-year period 1861 – 2015. The model adopting a Zipf distribution to evaluate societal landslide risk for the whole of Italy, and for seven physiographic and 20 administrative subdivisions of Italy. The model is able to provide estimates of the frequency (and the probability) of fatal landslides, based on the parameters, namely (i) the largest magnitude landslide F, (ii) the number of fatal events E, and (iii) the scaling exponent of the Zipf distribution s, which controls the relative proportion of low vs. large magnitude landslides. Different grid spacings, g and circular kernel sizes, r were tested finally adopting g = 10 km and r = 55 km. Using such geometrical model configuration, the values of the F, E and s parameters were derived for each grid cells revealing the complexity of landslide risk in Italy, which cannot be described properly with a single set of such parameters. Based on such modeling configuration. This model configuration allowed to estimate different risk scenarios for landslides of increasing magnitudes, which were validated checking the anticipated return period of the fatal events against information on 130 fatal landslides between 1000 and 1860, and eleven fatal landslides between January 2016 and August 2018. Despite incompleteness in the old part of the record for the low magnitude landslides, and the short length and limited number of events in the recent period 2016 – 2018, the anticipated return periods are in good agreement with the occurrence of fatal landslides in both validation periods. Despite the known difficulty in modelling sparse datasets, the proposed approach was able to provide a coherent and realistic representation and new insight on the spatial and temporal variations of societal landslide risk in Italy.
Future scenarios of coastal flooding in north-east Italy
Authors: Giusti Riccardo , Martina Mario , Armaroli Clara , Figuereido Rui , Dottori Francesco
Published: March 2020

Climate change and subsidence will likely have a significant role to increase coastal flooding risk. The socio-economic impact of inundations can be very relevant, and, in a context of climate change, it is necessary to develop effective methods for assessing coastal flood hazard suitable for large-scale studies. This work focuses on the application of a new modelling approach for mapping flooding hazard for future scenarios characterized by sea level rise and ground lowering due to subsidence. The flood intensity index approach (Iw, Dottori et al. 2015) will be used to quantitatively evaluate the flood extent. This recent methodology allows to create reliable scenarios with low computational costs. The effects of the storm surge are assessed using a base scenario corresponding to 100 years return period event. IW inputs are represented by water height set as storm level plus a part of wave height. The scenarios will be created by quantitatively combining IPCC sea level rise projections with subsidence data that will be compared to high-resolution digital terrain models. The study area of this work is the ∼205 km long coastal plain of Northern Italy, from Venice to Rimini, composed of low-lying sandy beaches and which includes the Po delta area. The coast is characterized by large portions of the territory below mean sea level and by geological features made by recent quaternary sediments which have a natural subsidence rate. In the past (1960-1980) the subsidence rate had an exceptional increase caused by excessive groundwater withdrawal for agricultural and industrial activities, human consumption and by natural gas extraction.
On the scaling between precursory moment release and earthquake magnitude: Insights from the laboratory.
Authors: Acosta Mateo , Passelègue Francois , Schubnel Alexandre , Madariaga Raúl , Violay Marie
Published: March 2020

Recent seismological observations highlighted that both aseismic silent slip and/or foreshock sequences can precede large earthquake ruptures (Tohoku-Oki, 2011, Mw 9.0  (Kato et al., 2012); Iquique, 2014, Mw 8.1 (Ruiz et al, 2014; Socquet et al., 2017); Illapel, 2015, Mw 8.3 (Huang and Meng, 2018); Nicoya, 2012, Mw 7.6 (Voss et al., 2018)). However, the evolution of such precursory markers during earthquake nucleation remains poorly understood. Here, we report for the first time, experimental results regarding the nucleation of laboratory earthquakes (stick slip events) conducted on Westerly Granite saw-cut samples under both dry and fluid pressure conditions. Experiments were conducted under stress conditions representative of the upper continental crust, i.e confining pressures from 50 to 95 MPa; fluid pressures (water) ranging from 0 to 45 MPa.

At a given effective confining pressure, different precursory slip behaviors are observed. In dry conditions, we observe that slip evolves exponentially up to the main instability and is escorted by an exponential increase of acoustic emissions. With pressurized fluids, precursory slip evolves first exponentially then switches to a power law of time. There, precursory slip remains silent, independently of the fluid pressure level. The temporal evolution of precursory fault slip and seismicity are controlled by the fault’s environment, limiting its prognostic value. Nevertheless, we show that, independently of the fault conditions, the total precursory moment release scales with the co-seismic moment of the main instability. The relation follows a semi- empirical scaling relationship between precursory and co-seismic moment release by combining nucleation theory (Ida, 1972; Campillo and Ionescu, 1992) with the scaling between fracture energy and co-seismic slip which has been demonstrated experimentally (Nielsen et al., 2016; Passelègue et al., 2016), theoretically (Viesca and Garagash; 2015) and by natural observations (Abercrombie and Rice; 2005). We then compile data from natural earthquakes, and show that, over a range of Mw6.0 to Mw9.0 the proposed scaling law holds for natural observations. In summary, the amount of moment released prior to an earthquake is directly related to its magnitude, increasing therefore the detectability of large earthquakes. The scaling relationship between precursory and co-seismic moment should motivate detailed studies of precursory deformation of moderate to large earthquakes.
Risk analysis of multi-hazard in the Belt and Road region
Authors: Chai Danling , Wang Ming , Liu Kai
Published: March 2020

This paper focuses on the assessment of the multi-hazard natural disaster susceptibility and disaster risk in the Belt and Road (B&R) region. It is expected to provide a reference for cooperation in disaster risk reduction among B&R countries. Based on historical disaster data from 1980 to 2018, the disaster susceptibility of the B&R countries to multi-hazard has been analyzed using random forest model. The multi-hazard risk was further assessed based on the disaster susceptibility and Monte-Carlo method. Results show that regions with high susceptibility to meteorological hazards are mostly distributed in central Africa and the coastal areas of all continents. While Himalayan-Mediterranean seismic zone is susceptible to geological hazards. Due to the different distribution of regional exposures, the risks of economic loss and the risk of population casualties also appear differently. For economic loss risk, in grid scale very high and high level take 21% area. Europe, southeast China coast, and the Indian peninsula present higher economic loss risks. In population casualties risk, very high and high level take 15% area and in national scale the central and southern parts of Eurasia show higher population casualties risk. The results provide a comprehensive analysis of the spatial and temporal distribution, sensitivity, and disaster risk of natural disasters in B&R region, and provides a reference for regional disaster prevention and reduction cooperation.
Regional greenhouse gas (GHG) budget of Kokemäenjoki river basin, SW Finland
Authors: Rasilo Terhi , Holmberg Maria , Akujärvi Anu , Anttila Saku , Autio Iida , Karvosenoja Niko , Kortelainen Pirkko , Lehtonen Aleksi , Mäkelä Annikki , Minunno Francesco , Ojanen Paavo , Paunu Ville-Veikko , Peltoniemi Mikko , Rankinen Katri , Sallantaus Tapani , Savolahti Mikko , Tuominen Sakari , Tuominen Seppo , Vanhala Pekka , Forsius Martin
Published: March 2020

Natural ecosystems play an important role in regulating greenhouse gas (GHG) fluxes between land and water surfaces and the atmosphere. To evaluate the full GHG balance of a region, fluxes from natural ecosystems such as undrained mires, lakes and rivers, should be included in the GHG accounting together with fluxes from forestry, agricultural and anthropogenic activities. We present a method for collating regional GHG balances including natural ecosystem processes, to support strategies for climate change mitigation and adaptation. Our study area is Kokemäenjoki river basin (SW Finland), which includes two eLTER sites (Lammi and Hyytiälä/SMEAR). Empirical data of these sites are used for model developments and calibrations as well as regional extrapolation. We report spatially explicit estimates on sources and sinks of GHG such as carbon dioxide and methane, and nitrous oxide for some ecosystems, and aggregate the regional balance from vertical fluxes of these elements. Spatial data sources include CORINE land use data, soil map, lake and rivers shorelines, national forest inventory data, as well as statistical data on anthropogenic activities. The regionally aggregated vertical balance will be compared to observed total lateral flux to the Bothnian Sea. We quantify the fluxes on the basis of empirical evidence from eLTER site information, literature, as well as on calculations with a forest growth and gas exchange model (PREBAS).

 

Acknowledgements and funding:

Irina Bergström, Markus Haakana, Antti Ihalainen and Kari Minkkinen

eLTER H2020 GA 654359

IBC-Carbon Academy of Finland SRC 2017/312559

SOMPA Academy of Finland SRC 2017/312912

oGIIR

Freshabit LIFE IP LIFE14/IPE/FI/023
The effect of the cooling on a dry storage cask for spent nuclear fuel by different wind speed
Authors: Cheng LinYing , Lai Chi-Ming
Published: March 2020

In this study, we considered different the wind speeds affects the thermal performance when the dry storage cask for spent nuclear fuel , which used NAC- MAGNASTOR cask of system, and placed outdoors. We Ddiscuss the dry storage cask for spent nuclear fuel cooling by the thermal buoyancy ventilation of cask. Firstly, Compare the experimental data of low-speed wind tunnel experiments with the result of from a commercial software PHOENICS CFD (Computational Fluid Dynamics) for heat flow analysis, and confirm the reliability of the CFD simulation results of the software. Then we used the software to simulate higher wind speeds to understand the thermal performance of the cask for spent nuclear fuel by various wind speeds. With external wind speed is was more much faster, channel airflow of the cask hads increased, especially upper channel airflow of the cask and near steel cylindrical. The temperature of the windward side of the cask hads also been significantly reduced, The lee side hads a slower wind speed and a smaller temperature drop, and generates an eddy below the lee side, which helpeds to dissipate .heat,. However, as the wind speed gradually increases, the lee side changed to a downdraft, and the temperature drop was also slowed down. It is noticeable that the situation may occur when a typhoon comes.
Relocated micas in marble – indicators for postdeformational microfabric modification
Authors: Kühn Rebecca , Duschl Florian , Leiss Bernd , Schulze Torben
Published: March 2020

A relocation of mica grains in marbles can be observed as trace of newly precipitated calcite material in cathodoluminescence microscopy analysis. Mica grains relocate by rotation and/or translation from foliation parallel to new irregular orientations. The mica grains can be either located at calcite grain boundaries or within large calcite grains.

The process erases deformed, inclusion-rich calcite material and creates undeformed and mostly inclusion-free grains and can therefore be regarded as postdeformational. Not every mica present relocates and the choice of whether a specific mica relocates cannot be related to a specific primary orientation. Furthermore, no significant difference in composition between relocated and non-relocated mica grains can be observed. Newly precipitated calcite has less Mg than the dissolved grain material.

The precipitation of new calcite material at the calcite-mica interface is supposed to be the initial trigger leading to dissolution of inclusion-rich, deformed calcite material at the opposite side of the mica grain. The newly precipitated calcite material inherits the already existing calcite grain‘s crystallographic orientation.

Assuming this process occurs to a larger extent in a material, it might modify a deformation-related microfabric. Therefore, an interpretation in terms of deformation conditions should be done carefully, considering postdeformational dissolution-precipitation processes.
Automatic transient signal detection and volcanic tremor extraction using music information retrieval strategies
Authors: Zali Zahra , Scherbaum Frank , Ohrnberger Matthias , Cotton Fabrice
Published: March 2020

Volcanic tremor is one of the most important signal in volcano seismology because of its potential to be a tool for forecasting eruptions and better understanding of underlying volcanic process. Despite different suggested mechanisms for volcanic tremor generation, the exact process of that is not well understood yet. This signal usually comes along with large number of earthquakes happening during unrest period that affect the shape and amplitude of tremor. A delicate signal processing is required to separate earthquakes and other transient signals from seismic waveform to derive a time series of volcanic tremor which can provide a new insight into tremor source investigations. Exploiting the idea of harmonic and percussive separation in musical signal processing we have developed a method to extract volcanic tremor and transient events from the seismic signal. By using the concept of periodicity as underlying generation process of tremor, we are able to extract the volcanic tremor signal based on the self similarity properties of spectra in time-frequency domain. The separation process results in two spectrograms representing repeating (long-lasting) and non-repeating (short-lived) patterns.

From the spectrogram of the repeating pattern we reconstruct the signal in time domain by adding the original spectrogram’s phase information, thus creating an modified version of the long-lasting tremor signal.

Further, we can derive a characteristic function for transient events by integrating the amplitude of the non-repeating spectrogram in each time frame. This function has non zero value in transient event instances and zero value in time periods devoid of such events. Considering transient events as earthquakes we apply an onset detector to time first arrivals of the transient signal by using the slope of the function. First we determine local maxima of the function showing good correspondence to even the tiniest transient signals. From the peak locations we calculate the slope of each point within a period of 6 seconds preceding each peak. The uncertainty of positive P peaks is up to 0.32 seconds which is equal to the hope size of the calculated spectrogram. The advantage of timing earthquakes through this method is the ability of detecting very low seismic events, although due to the small window size of short time Fourier transform the process is time consuming. The result of this study is promising, while further testing is on-going to validate the method as well as determine applications and limitations.
Adsorption of six organic micro-pollutants from water and wastewater using Graphene Oxide-coated biochars
Authors: Regkouzas Panagiotis , Diamadopoulos Evan
Published: March 2020

The objective of this study was to produce regular and Graphene Oxide (GO) coated biochar adsorbents, using two types of biomass as feedstock, i.e. Rice Husks (RH) and Sewage Sludge (SS), in two pyrolytic temperatures (400°C and 600°C). The produced adsorbents were thoroughly characterized in terms of physicochemical properties, where biochars produced from RH at 600°C showed the most favourable results. Specifically, the SBET values of these samples were up to four times higher compared to biochars produced at 400°C and up to thirteen times higher, compared to the respective SS biochars. Moreover, the metal content of the samples was determined, in order to assess their safety, where all values were under the limits set by the European Union. Finally, biochars were tested as adsorbents for the removal of six organic micro-pollutants, i.e. 2,4-Dichlorophenol (2,4D), Bisphenol A (BPA), Androsterone (ADT), Norethindrone (NOR), Estrone (E1) and Ethinyl Estradiol (EE2), from table water and wastewater, in low (realistic) initial concentrations. The pollutants were successfully adsorbed by biochar, in rates of 40%-97.5% for the RH biochars and 10%-97.5% for the RH biochars, in 1h. GO-enriched RH biochars produced at 600°C were the most effective adsorbents, removing the pollutants in rates higher than 70%, in just 10min of adsorption time.
Time dependent 3D tomography of a mountain wave over the Andes with GLORIA IR limb imager
Authors: Krasauskas Lukas , Geldenhuys Markus , Preusse Peter , Ungermann jörn , Höpfner Michael , Friedl-Vallon Felix , Kaifler Bernd , Rapp Markus , Martin Riese
Published: March 2020

The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an aircraft-
based Fourier transform spectrometer with a 2D detector array jointly developed by Forschungszentrum
Jülich and Karlsruhe Institute of Technology. Air temperature and volume mixing ratios of various
trace gases are retrieved from the measured IR spectra. GLORIA's viewing direction can be panned between 45◦ and 135◦
w. r. t. the flight direction. Combining this capability with flight paths that encircle the observed
atmospheric region, multiple measurements of the same air mass can be performed, allowing for 3D
tomography of the atmosphere with a vertical resolution down to 250 m and horizontal resolution of
around 25 km.
GLORIA flew on the German HALO research aircraft during the SouthTRAC measurement cam-
paign held in southern Argentina in September-November 2019. One of the main goals of the campaign
was gravity wave study using GLORIA, as well as an upward looking ALIMA lidar instrument devel-
oped by Deutsches Zentrum für Luft- und Raumfahrt (DLR), and in situ instruments. During one of
the research flights, a large amplitude mountain wave was observed over the Andes. The air volume
near the mountains was encircled twice, providing a unique opportunity to study the time evolution
of an orographic gravity wave with a help of 3D time dependent temperature retrieval. We present
the initial analysis of this dataset, showing complex temperature structure with several overlapping
gravity wave families at altitudes of 9 to 14 km. GLORIA data is complemented by the ALIMA lidar
temperature retrieval at altitudes between about 20 and 60 km, providing insight into further upward
propagation and breaking of the observed mountain wave. We also compare our results with ECMWF model data.
Land use evolution over time using public data and a new environmental indicator. Application to the Valencia region (Spain)
Authors: Rodrigo-Clavero María-Elena , Romero-Hernández Claudia-Patricia , Rodrigo-Ilarri Javier
Published: March 2020

In this work a new environmental indicator for the analysis of land use change over time (ENV-IND) is presented. The ENV-IND indicator has been defined and assigned to every land use included on the SIOSE, the official Information System on Land Occupation of Spain. The methodology is based on assigning an ENV-IND value for every polygon considered by the SIOSE as a function of the areal percentage occupied by every land use inside each polygon.

SIOSE is integrated into the National Land Observation Plan (PNOT) whose objective is to generate a database of Land Occupation for all Spain, integrating all the information available from the regional and central Administration of Spain. The ENV-IND indicator has been defined for 80 different land use categories and its value depend in the joint consideration of the following factors: anthropization nature, water consumption, environmental sustainability and landscape value.

The evolution of the ENV-IND indicator over time has been obtained for the whole Valencia Region for three different dates (2005-2009-2015) and shows that the environmental value is decreasing with time in terms of the ENV-IND indicator. The ENV-IND indicator is therefore applicable as a tool to quantify and analyze trends of the environmental quality related with land use change.

 
Assessment of heavy rainfall risk of typhoon Hagibis (2019) associated with typhoon track
Authors: Hoshino Tsuyoshi , Yamada Tomohito
Published: March 2020

Typhoon Hagibis (2019) caused heavy rainfall and big flood damage in many river basins in Japan. In this research, we suggested the risk assessment method for heavy rainfall due to typhoon from the view point of a typhoon track by using records of rain gauges and typhoon track data from 1951. The relationships between typhoon position and rainfall intensity were obtained from the rain gauges and the typhoon track data for each rain gauge points. The relationships make it clear that typhoon track passes through the areas in which heavy rainfall occurred. The relationship can be used for risk assessment of heavy rainfall  in terms of typhoon track. The track of Typhoon Hagibis is the heaviest rainfall track for some points located in north of the typhoon track. However, some points close to the typhoon center or in south of the typhoon track are not the heaviest rainfall track. It means that if typhoon Hagibis shifted the track, the typhoon would cause heavier rainfall in some points. The result can be used not only for estimation of potential rainfall but also for selection of dangerous typhoons from large ensemble dataset. We assessed heavy rainfall risk of typhoons similar to typhoon Hagibis under historical and future climate by using the large ensemble climate dataset (d4PDF).
A Protocol for Establishing Soil Moisture Observations at the Complex Mountainous Region.
Authors: Jeong Jaehwan , Cho Seongkeun , Oh Seungcheol , Baik Jongjin , Choi Minha
Published: March 2020

Soil moisture, controlling the fraction of the water between grounds and atmosphere, has been observed from various measurements to understand the hydrological cycle. Remotely sensing techniques using active and passive microwaves are regarded as an effective method for monitoring soil moisture at the regional scale. To evaluate remotely sensed soil moisture products, ground measurements including Time Domain Reflectometry (TDR) or Frequency Domain Reflectometry (FDR), and Cosmic-Ray Neutron Probe (CRNP) are widely used. In other words, field experiments considering the characteristics of sensors and soil must be preceded to retrieve soil moisture using remote sensing data. Especially, it is more even more important when applying remote sensing in complex terrain such as a mountainous region. Although there are still many challenges in the use of remote sensing technology in complex terrain, monitoring of inaccessible areas is one of the advantages of remote sensing. Therefore this study aimed to establish the soil moisture station, which employs the integration of a CRNP and FDR sensors installed within the CRNP footprint at multiple measurement depths (10, 20, 30, and 40 cm) at the mountainous region. The CRNP was firstly calibrated and subsequently combined with field average soil moisture based on a simple merging framework, to provide a field-scale soil moisture product at each corresponding layer. It was used to evaluate for large scale soil moisture validation by comparing with several model and satellite-based soil moisture products including GLDAS, SMAP, AMSR2, ASCAT, and SAR Sentinel-1. From the preliminary application of field-scale soil moisture for remotely sensed soil moisture evaluation indicated a reasonable accuracy with the highest correlation to GLDAS soil moisture product (0.87 at 40 cm), suggesting the potential of this station. An introduced protocol for estimating soil moisture in the complex mountainous region is expected to provide a better understanding of terrain impacts on soil moisture variability by assimilating field data and satellite-based products through Land Surface Model for improving soil moisture measurements.
Impacts of Enhanced Soil Water and Heat Dynamics on Ecosystem Functioning
Authors: Su Zhongbo , Yu Lianyu , Wang Yunfei , Zeng Yijian
Published: March 2020

In the current Earth System Model (ESM), the soil water and heat transport in the land surface model (LSM) is not strongly coupled. As such, the discrepancy between the modelled land surface states and fluxes and the observed ones was mainly remedied by revising relevant simplified parameters, while the detailed physics (and/or physiography) was not necessarily consistent. While zooming in those studies over the cold region, the current ESMs do not consider the hydro-permafrost-carbon coupling. For example, the strong impact of soil moisture on spatial patterns of soil carbon stocks has been observed at sites, while the current ESMs cannot show this impact. On the other hand, soil moisture can affect the temperature sensitivity of decomposition rate and alter soil thermal dynamics significantly. To address the foregoing issues, it calls for an interdisciplinary approach to investigate soil-water-energy-plant interactions. Such approach is even more so desired for cold regions, where permafrost and seasonal frozen ground widely spread. This pressing need is mainly due to the carbon release from climate-induced permafrost thawing into the atmosphere, called as permafrost carbon feedback (PCF). It is also due to the tight coupling between hydrological processes and carbon dynamics, which, if ignored, will lead to the underestimation of global carbon turnover time by 36%. As a trial, this research coupled the detailed soil water and heat model with the biogeochemical model to investigate the mechanisms behind the impacts of enhanced soil water and heat dynamics on ecosystem functioning.
The life cycle of cyclones, dry intrusions and cold fronts and their role in air-sea interaction
Authors: Silverman Vered , Raveh-Rubin Shira , Catto Jennifer
Published: March 2020

Air-sea interaction in the midlatitudes is modulated by the passage of extratropical cyclones and their trailing fronts. Particularly strong ocean heat loss (both sensible and latent) is observed in the post-cold frontal region. In this region, airmasses within the dry intrusion (DI) airstream descend slantwise from the upper troposphere towards the cold trailing front. As the cyclone case-to-case variability is high, understanding the co-occurrence of DIs, cold trailing fronts and cyclones is important for understanding the variability of surface fluxes, especially in regions not usually associated with frequent frontal activity.

 

A climatological study quantifying the co-occurrence of fronts and DIs (Raveh-Rubin and Catto, 2019) found the presence of DIs to be associated with stronger surface heat fluxes. Here the climatological study is extended to account for the cyclone life-cycle by using feature-based identification and tracking in the ERA-Interim dataset, for the 1979-2018 winters. We focus on the relationship between extratropical cyclone characteristics, DIs and cold fronts, their co-evolution throughout the lifetime of a cyclone, and consequently their impact on air-sea interaction.

 

We show that 65-80% of the extratropical cyclones in the storm track region are matched with DIs, mainly during the early stages of the intensification period. Furthermore, cyclones associated with DIs are longer lived, induce up to 50% stronger precipitation in the frontal regions, and up to 60% stronger evaporation, especially in the DI region of influence, compared to non-DI cyclones. These transient events of strong evaporation induced by DIs account up to 40% of the observed climatology, demonstrating the significant role transient weather systems play in the air-sea interaction, at times through a fairly remote influence of the cyclones.
Climate change driven massive extirpation of native species from the Israeli Mediterranean shelf
Authors: Albano Paolo G. , Steger Jan , Bošnjak Marija , Dunne Beata , Guifarro Zara , Turapova Elina , Galil Bella , Rilov Gil , Zuschin Martin
Published: March 2020

We quantify a large-scale extirpation of native species from the Israeli Mediterranean shelf, a region strongly affected by rapidly changing environmental conditions and the introduction of non-indigenous species, based on an extensive sampling programme of mollusks on intertidal to subtidal soft and hard substrata. We reconstruct historical species richness from shelly death assemblages, quantify the time range they cover with radiocarbon dating, and compare their richness with today’s living assemblage diversity. The median native richness is 50% of the historical richness for the intertidal, but only 8% for the subtidal down to 40 m. Samples from the mesophotic zone show a much higher median of 42%, which is likely an underestimation due to sampling constraints. In contrast, non-indigenous species show assemblages matching the historical richness. Seasonality is very strong: autumn samples, after the summer heat peak, are highly impoverished in native species but enriched in non-indigenous ones. Additionally, a comparison between today’s and historical native species maximum size shows that shallow subtidal native populations are mostly non-reproductive. In contrast, non-indigenous species reach reproductive size. These results suggest that a recent large-scale change in environmental conditions is strongly favoring non-indigenous species and is the main cause behind the shallow subtidal native species decline. Such an environmental factor is likely seawater temperature that plays a greater role in the shallow subtidal than in the cooler mesophotic zone, and affects subtidal species more than intertidal ones, pre-adapted to a climatically extreme environment.
Preliminary identification of drivers and pathways of change in the Socio-Physical dynamics of the Western Indian Ocean Deltas
Authors: Paron Paolo , Duvail Stéphanie , Hamerlynk Olivier , Hervé Dominique , Hutton Chris , Juizo Dinis , Leone Michele , Mwansasu Simon , Nyingi Wanja , Robison Laurent
Published: March 2020

We present the output of a research combining field based, expert knowledge and remote sensing identification of the rates of change, pathways and drivers of these changes, during the past 35 years and more where possible, in four Western Indian Ocean River Deltas: Tana River and Delta (Kenya), Rufiji River and Delta (Tanzania), Limpopo River and Delta (Mozambique) as well as Betsiboka River and Delta (Madagascar). These findings are a set of preliminary results of the collaborative and multidisciplinary effort produced during the WIODER project () that brings together the National Museum of Kenya, Kenweb Kenya, University of Dar Es Salaam in Tanzania, University Eduardo Mondlane in Mozambique, Centre National de Recherches sur l'Environnement in  Madagascar, University of Southampton in UK, IHE Delft in the Netherlands, Institut de Recherches pour le Développement in France, and International Development Research Center in Canada and Kenya.

We highlight the similarities in the physical environment and, to some degree, also in the socio-economic-political environments that are leading the actual changes, affecting resilience of the local population and their sustainable development.

We focused on the substantial changes in the following aspects: precipitation seasonality and intensity, flooding patterns and frequency, land cover, dry forest cover, mangrove cover, crop production, soil erosion, fish population, human population, human migration flow, frequency of human conflicts within the delta population.

The IPCC foreseen changes in climate towards an aridification of the Southern Africa river basins and a wetter condition in the Eastern Africa region. Some signals of these climatic forecast are already recorded in both regions.

Assuming that these trends will continue for the next 10 years or so, we created and here we present two main scenarios of what will happen in these deltas: one with mainly climate change drivers, and another one with climate change and dam drivers.
regionalization of the potential to increase rainfall-runoff model performance by multi-objective calibration using modis data over Austria
Authors: Kubáň Martin , Sleziak Patrik , Brziak Adam , Hlavčová Kamila , Szolgay Ján
Published: March 2020

A multi-objective calibration of the parameters of conceptual hydrologic models has the potential to improve the consistency of the simulated model states, their representativeness with respect to catchment states and thereby to reduce the uncertainty in the estimation of hydrological model outputs. Observed in-situ or remotely sensed state variables, such as the snow cover distribution, snow depth, snow water equivalent and soil moisture were often considered as additional information in such calibration strategies and subsequently utilized in data assimilation for operational streamflow forecasting. The objective of this paper is to assess the effects of the inclusion of MODIS products characterizing soil moisture and the snow water equivalent in a multi-objective calibration strategy of an HBV type conceptual hydrological model under the highly variable physiographic conditions over the whole territory of Austria.

The methodology was tested using the Technical University of Vienna semi-distributed rainfall-runoff model (the TUW model), which was calibrated and validated in 213 Austrian catchments. For calibration we use measured data from the period 2005 to 2014. Subsequently, we simulated discharges, soil moisture and snow water equivalents based on parameters from the multi-objective calibration and compared these with the respective MODIS values. In general, the multi-objective calibration improved model performance when compared to results of model parametrisation calibrated only on discharge time series. Sensitivity analyses indicate that the magnitude of the model efficiency is regionally sensitive to the choice of the additional calibration variables. In the analysis of the results we indicate ranges how and where the runoff, soil moisture and snow water equivalent simulation efficiencies were sensitive to different setups of the multi-objective calibration strategy over the whole territory of Austria. It was attempted to regionalize the potential to increase of the overall model performance and the improvement in the consistency of the simulation of the two-state variables. Such regionalization may serve model users in the selection which remotely sensed variable or their combination is to be preferred in local modelling studies.
Comparison of various X-band radar products over the Paris area
Authors: Salih Wiam , Gires Auguste , Tchiguirinskaia Ioulia , Schertzer Daniel
Published: March 2020

Optimized management of storm water management in the Paris area is needed to both avoid urban flooding and maximize water depollution. Such management requires improving the ability to measure and model hydro-meteorological events at the highest possible resolution. Hence, the interest of meteorological radars, given their unique ability to measure rainfall in both space and time.

In this study, we focus on the data collected by a dual polarimetric X-band radar data operated by Ecole des Ponts ParisTech in the framework of the Fresnel Platform is used. The space resolution is of 250 m and the time one is of 3 min and 25 seconds. Seven rainfall events that occurred in 2018 are studied. They cover a wide range of meteorological situations, including hail. More precisely several products are compared; some relying on a simple Marshall Palmer power law relation between the measured reflectivity and the rain rate; and others using the dual polarization capabilities for heavy rainfall through a power law relation between the measured specific differential phase shift and the rain rate. Constant and varying parameters for these laws are tested. In addition, these radar products are compared with various products obtained with a C-band radar operated by Meteo-France and 8 rain gauges. Temporal evolutions of rain rates are compared and classical metrics (Nash Sutcliff, correlation…) are computed. In addition, outputs of hydro-dynamic models’ simulations using this rainfall data are compared.

It appears that the results strongly depend on rainfall event, and even given peaks, with no clear tendency between the radar products. In addition, a strong dependency on the radar data processing, and especially the coefficients of the radar relation, is found. This suggests that further work should be done to improve their determination for this area and depending on the weather conditions. In addition, this study highlights the need to develop morphological comparison techniques that would be valid not only at a single scale but across scales.

Authors greatly acknowledge support of the chair Hydrology for Chair of Hydrology for Resilient Cities (endowed by Veolia) of the Ecole des Ponts ParisTech.

 
Grass development in the Amazon drainage basin, evidence from the fossil and phytochemical record
Authors: Hoorn Carina , Kirschner Judith , Beer Maxine , Wei Caixia , Kukla Tyler , Jardine Phil
Published: March 2020

The Poaceae (the grass family) includes over 11000 species and covers large part of the Earth land surfaces. Their history is rooted in the Cretaceous, but this group only expanded fully over the globe during the late Miocene. In the Amazon drainage basin (ADB) grasses were at the core of a heated debate, in which it was hypothesized that during the Pleistocene glacial periods grasses replaced vast extents of the Amazon rainforest. Although this hypothesis is now rejected, the history of grasses in the ADB still remains to be resolved. In this paper we propose a 3-staged model for grass development in the ADB: (1) from c. 23 to 9 Ma western Amazonia was dominated by a megawetland (the ‘Pebas system’) that harboured large amounts of (aquatic?) grasses; (2) from c. 9 Ma Andean uplift prompted megafan and fluvial environments on the Andean slopes and in the Amazon lowlands respectively, these environments created new settings for grass colonization; (3) from c. 5 Ma grasses were firmly established in the tropical alpine vegetation (páramo), the tropical lowland floodplains (várzeas), and savannas (cerrado). To test these scenarios we analysed Neogene and extant Andes-Amazonian grasses by means of Fourier Transform Infrared spectroscopy, we performed a Light- and Scanning Electron Microscopy analysis, and compared the results with existing biomarker data from the Neogene sediments. Here we report on the preliminary results that, among others, suggest that in the middle Miocene aquatic (C3) taxa were comon in the Amazon lowlands. Although further study will have to confirm the precise nature of the ADB grass history, we anticipate that abiotic processes during the Neogene and Quaternary left a strong imprint in the grass phytogeography of northern South America.

 