bluuebunny/crossref_metadata_2025 huggingface dataset:
Agricultural human-water systems: challenges, advances, and knowledge gaps
Authors: Medeiros Pedro , Chen Xi , Gunda Thushara , van Oel Pieter , Vico Giulia , Marston Landon , O’Keeffe Jimmy , Yang Ethan , Liu Suxia , Roobavannan Mahendran , Gopalakrishnan Sathya , Gonzalez-Piedra Julio Iván , Castilla-Rho Juan , Cudennec Christophe , Sivapalan Murugesu
Published: March 2021

Dynamic interactions between humans and water have produced unanticipated feedbacks, leading to unsustainability. Current water management practices are unable to capture the relevant spatial and temporal detail of the processes that drive the coupled human-water system. Whereas natural and socioeconomic processes occur slowly, local communities and individuals rapidly respond to ensure supply-demand balance. In this context, agricultural human-water systems stand out, as roughly 70% of global water demand is for agricultural uses. Additionally, interactions between humans and agricultural water systems involve many actors and occur at multiple spatial and temporal scales. For example, farmers are influenced by risk perceptions, and decisions made at the farm level influence regional hydrologic and socioeconomic systems, such as degradation and depletion of water sources as well as prices of crops. Regional behaviors, in turn, affect national and international dynamics associated with crop production and trade of associated investments. On the other hand, global and national priorities can also percolate down to the regional and local levels, influencing farmer decision-making through policies and programs supporting production of certain crops and local investments. Over the last decade, relevant phenomena in the coupled agricultural human-water systems have been described, as the irrigation efficiency paradox, reservoir effect, and river basin closure. Along with the globalization in the food market, attempts have been taken to developing and applying benchmarks for water-efficient food production, focusing on water productivities, water footprints and yield gaps for agricultural products. Furthermore, significant advancements have been achieved by incorporating social dimensions of agricultural human-water systems behavior. Fusion of quantitative datasets via observations, remote sensing retrieval, and physically-based models has been explored. Advancements have also been made to capture qualitative or relatively intangible concepts of community values, norms, and behaviors, by interacting with stakeholders, identifying the most important elements of their environments, and incorporating these insights into socio-hydrological models. Based on what has been done during the IAHS Panta Rhei decade and what we have learned, and despite recent efforts towards a more comprehensive understanding of the effects of human interventions in agricultural systems, several challenges persist, of which we highlight: 1) Identification of the cross-scale causal effect on agricultural water uses; 2) Quantification of human behavior uncertainties shaped by social norms and cultural values; 3) Development of a high spatial and temporal resolution global dataset.
Insights into a dextral transtensional shear zone in NW Anatolia, Turkey: Preliminary results from the three dimensional strain and kinematic analyses of the Marmara Granitoid. 
Authors: Bayrak Salim Birkan , Ünal Alp , Güraslan Işıl Nur , Kamacı Ömer , Yiğitbaş Erdinç , Altunkaynak Şafak
Published: March 2021

Marmara Granitoid (MG) is an E-W trending sill-like magmatic body exposed in the center of the Marmara Island, NW Anatolia, Turkey. MG is lower Eocene in age and was concordantly emplaced into metamorphic basement rocks of Saraylar Marble and Erdek Complex. It is represented by a deformed granodiorite which widely displays protomylonitic-mylonitic textures with prominent foliation and lineation. Foliation planes display a mean dip direction-angle of 335/29 and mineral stretching lineations show mean trend-plunge of 286/34. Mica-fishes, rotated porphyroclasts and micro-faults are commonly observed and serve as shear gauges pointing out to a dextral movement. Mineral deformation thermometers such as myrmekite development, chessboard extinction, grain boundary migration (GBM), sub-grain rotation recrystallization (SGR), and bulging recrystallization (BLG) in quartz crystals indicate that solid-state deformation of the MG has experienced a high-temperature ductile deformation and superimposed ductile to brittle deformation.

Three-dimensional strain ellipsoid measurements are investigated on the MG in order to determine the relative amounts of pure shear and simple shear deformation and the mean kinematic vorticity number (Wm). The image processing of quartz grains is used as strain markers to obtain the three-dimensional best-fit ellipsoids. The results show that, Lode’s ratio (ν) of the samples change between -0.010 and -0.650 and Flinn’s k-values range from 1.026 to 11.157 indicating to a general constrictional (prolate) deformation. The calculated kinematic vorticity numbers change between 0.429 and 0.958 which show that shear deformation of MG is mostly dominated by simple shear. All of these micro and meso structural properties and three-dimensional strain and kinematic analyses collectively suggest that MG has experienced a dextral transtensional deformation.
Global mapping of the soil water characteristics curve using machine-learning, a comprehensive dataset and spatial covariates
Authors: Gupta Surya , Papritz Andreas , Lehmann Peter , Hengl Tom , Bonetti Sara , Or Dani
Published: March 2021

The representation of land surface processes in hydrologic and climatic models is critically dependent on the soil water characteristics curve (SWCC) that defines the hydrologic behavior of unsaturated soil. The SWCC depends not only on soil texture, but it is also shaped by biopores, soil structure, and clay type. To capture climate, vegetation and other soil formation processes on SWCC in spatial context, we predict how SWCC parameter values vary with local environmental covariates using a machine learning approach. The model was trained using (i) a novel and comprehensive compilation of global dataset of soil water retention measurements collected from the literature (approximately 13,000 pairs of water content and matric potential data) and (ii) global maps of environmental covariates and soil texture developed at 250 m resolution. Because in many cases only few measurements per sample are available to fit the SWCC, the estimated parameters are often highly uncertain and could yield unrealistic predictions of related physical quantities. To address these limitations, we added constraints to the values of residual and saturated water content based on clay content and mineralogy and ensured that the shape parameters related to air-entrance and pore size distribution honor other physical constraints, such as the characteristic length of evaporation and the ponding time. The resulting global maps of SWCC parameters are compared with predictions using pedotransfer functions (PTFs) based on soil information alone that were trained on data mainly collected for samples from arable land in temperate regions. We anticipate that our model including environmental covariates and geospatial data (covariate-based geotransfer functions CoGTFs) would enable us to provide more reliable predictions (compared to traditional PTFs) of SWCC that can be implemented in Earth system models.
Impacts of riverine terrestrial organic matter on the lower trophic levels of an Arctic shelf ecosystem
Authors: Bedington Michael , Torres Ricardo , Polimene Luca , Wallhead Phillip , Juhls Bennett , Palmtag Juri , Strauss Jens , Mann Paul J.
Published: March 2021

The Arctic ocean receives 11% of the entire global river discharge via several great Arctic rivers that drain vast catchments underlain with carbon-rich permafrost. Arctic marginal shelf seas are therefore heavily influenced by terrestrial dissolved organic matter (tDOM) supply, influencing coastal biogeochemical processes and food-webs, as well as physio-chemical properties (e.g. stratification or nutrient concentrations).

Whilst carbon and associated macronutrients supplied by tDOM may enhance the nutrient and carbon substrates for lower trophic levels (phytoplankton/zooplankton), promoting increased local and regional productivity, it can also have opposing effects through a series of indirect processes (e.g. increased light absorption limiting light penetration through the water column). Understanding the relative importance and timing of these processes, and how they vary spatially, is necessary to identify how land-ocean interfaces currently operate.

Future climate scenarios indicate increased quantities of riverine tDOM delivered to the near-shore, with increased freshwater runoff and greater terrestrial permafrost thaw and erosion. This is likely to be exacerbated by the disappearance of seasonal sea ice cover and increased coastal erosion rates. We can therefore expect changes in planktonic phenology and productivity, with concomitant changes in bacterial and higher trophic level success. Understanding how these factors interact and may change under future climate scenarios is therefore critical to predict the future impact on shelf sea Arctic ecosystems and the ecosystem services they provide.

In the Changing Arctic Carbon cycle in the cOastal Ocean Near-shore (CACOON) project (UK-Germany collaboration) we are using coupled hydrodynamic-biogeochemical models in the extensive shallow shelf of the Laptev sea to explore the relationship between these factors. The ecosystem model ERSEM has been adapted to explicitly include a tDOM component. This coupled model system allows us to investigate both the role of present day tDOM in an Arctic coastal ecosystem and to project the potential impacts of increased tDOM input in future.
Patterns of flood timing trend across the global river networks
Authors: Lin Peirong , Wood Eric , Pan Ming , Yang Yuan , Beck Hylke , Zeng Zhenzhong
Published: March 2021

Impacts of climate change on floods have been recently suggested to be more consistently seen in flood timing (or flood seasonality) as opposed to flood magnitude and frequency. Changes in flood timing can threaten the finely tuned water resource management systems and, if poorly understood, can alter flood risks in unpredictable ways. Nevertheless, patterns of global flood timing trend remain elusive. Whether climate change has played a significant role in shifting flood timing worldwide also remains unknown.

Here we obtained an unprecedented set of discharge records from tens of thousands of global gauges and model-reconstructed naturalized discharge at ~3 million river reaches to delineate flood timing trend across the global river networks from 1980 to 2019. Hydroclimate drivers possibly causing these trends, including maximum precipitation, antecedent soil moisture, and snowmelt timing, are also investigated to disentangle climate change signals on floods. We found that the flood timing has been significantly earlier over the lower Mississippi, the Amur and the Amazon river basins, as well as large parts of the high-latitude Northern Hemisphere. Significant later floods are observed over the Yangtze and the lower Congo river basins, and the southeast Asia. However, ascribing these flood timing shifts to changing climate is not as obvious as previously suggested, implying the need for further research on this topic.
An assessment of the Dead Sea level change using remotely sensed data
Authors: Mbideen Musab , Székely Balázs
Published: March 2021

Remote Sensing (RS) and Geographic Information System (GIS) instruments have spread rapidly in recent years to manage natural resources and monitor environmental changes. Remote sensing has a vast range of applications; one of them is lakes monitoring. The Dead Sea (DS) is subjected to very strong evaporation processes, leading to a remarkable shrinkage of its water level. The DS is being dried out due to a negative balance in its hydrological cycle during the last five decades. This research aims to study the spatial changes in the DS throughout the previous 48 years. Change detection technique has been performed to detect this change over the research period (1972-2020). 73 Landsat imageries have been used from four digital sensors; Landsat 1-5 MSS C1 Level-1, Landsat 4-5 TM C1 Level-1, Land sat 7 ETM+ C1  Level-1, and Landsat 8 OLI-TIRS C1 Level. After following certain selection criteria , the number of studied images decreased. Furthermore, the Digital Surface Model of the Space Shuttle Radar Topography Mission and a bathymetric map of the Dead Sea were used. The collected satellite imageries were pre-processed and normalized using ENVI 5.3 software by converting the Digital Number (DN) to spectral radiance, the spectral radiance was converted to apparent reflectance, atmospheric effects were removed, and finally, the black gaps were removed. It was important to distinguish between the DS lake and the surrounding area in order to have accurate results, this was done by performing classification techniques. The digital terrain model of the DS was used in ArcGIS (3D) to reconstruct the elevation of the shore lines. This model generated equations to detect the water level, surface area, and water volume of the DS. The results were compared to the bathymetric data as well. The research shows that the DS water level declined 65 m (1.35 m/a) in the studied period. The surface area and the water volume declined by 363.56 km2 (7.57 km2/a) and 53.56 km3 (1.11 km3/a), respectively. The research also concluded that due to the bathymetry of the DS, the direction of this shrinkage is from the south to the north. We hypothesize that anthropogenic effects have contributed in the shrinkage of the DS more than the climate. The use of the DS water by both Israel and Jordan for industrial purposes is the main factor impacting the DS, another factor is the diversion of the Jordan and Yarmouk rivers. Our results also allow to give a prediction for the near future of the DS: the water level is expected to reach –445 m in 2050, while the surface area and the water volume is expected to be 455 km2 and 142 km3, respectively. 
Foraminifera-sponge interactions – commensalism to parasitism in the Norwegian-Greenland Sea
Authors: Lintner Bianca , Lintner Michael , Wollenburg Jutta , Wurz Erik , Heinz Petra
Published: March 2021

This is the first study on the interactions between foraminifera and sponges. Although Cibicides and Hyrrokin are regarded as parasites on siliceous sponges, it is not yet clarified whether foraminifera specifically colonize sponges or are accidentally sucked in during the pelagic stage. To better elucidate these relationships, 12 sponges of different genera were examined and their foraminiferal communities analyzed. In 2018, the sponges for this study were collected with a ROV in water depths of 223 to 625 m in the Norwegian-Greenland Sea. Sponge parts were preserved in ethanol (96 %) and stained with Rose Bengal (2g l-1) to allow a differentiation between the living and dead foraminiferal fauna.

Each sponge sample contained several hundred live and dead foraminiferal individuals of up to 60 different species. Even on Geodia baretti, which is able to release barettin to avoid colonalisation of other organisms, few foraminiferal individuals were observed. On all sponges, the most abundant genus was Cibicides, with Cibicides lobatulus and Cibicides refulgens as the most common taxa. Other very common species were Discorbinella bertheloti or Epistominella nipponica. Also, Hyrrokkin sarcophaga was found on different sponges and following its lifestyle, penetrating the sponge surfaces. The fact that besides adult foraminifera splendid juvenile stages were found indicate that foraminifera reproduced while inside the sponges. This reproduction might be stimulated/triggered by enhanced food availability by the pumping sponge.

In summary, sponges are a special habitat for a high number of foraminiferal taxa. Their interaction ranges from parasitic lifestyle up to reproduction purposes. All these aspects highlight the importance of foraminifera-sponge interactions.
VGOS Intensives Ishioka-Onsala
Authors: Haas Rüdiger , Varenius Eskil , Diamantidis Periklis-Konstantinos , Matsumotu Saho , Schartner Matthias , Nilsson Tobias
Published: March 2021

The VLBI Global Observing System (VGOS) is the VLBI contribution to GGOS. During the last years, several VGOS stations have been established, the VGOS observation program has started, and by 2021 VGOS has achieved an operational state involving nine international VGOS stations. Further VGOS stations are currently being installed, so that the number of active VGOS stations will increase drastically in the near future. In the end of 2019 the International VLBI Service for Geodesy and Astrometry (IVS) decided to start a new and so-far experimental VGOS-Intensive series, called VGOS-B, involving Ishioka (Japan) and Onsala (Sweden). Both sites operate modern VGOS stations with 13.2~m diameter radio telescopes, i.e. ISHIOKA (IS) in Japan, and ONSA13NE (OE) and ONSA13SW (OW) in Sweden. In total 12 VGOS-B sessions were observed between December 2019 and February 2020, one every week, in parallel and simultaneously to legacy S/X INT1 Intensive sessions that involve the stations KOKEE (KK) on Hawaii and WETTZELL (WZ) in Germany. These 1-hour long VGOS-B sessions consist of more than fifty radio source observations, resulting in about 1.6 TB of raw data that are collected at each station. The scheduling of the VGOS-B sessions was done using VieSched++ and the subsequent steps (correlation, fringe-fitting, database creation) were carried out at the Onsala Space Observatory using DIFX and HOPS. The resulting VGOS databases were  analysed with several VLBI analysis software packages, involving nuSolve, c5++ and ASCOT. In this presentation, we give an overview on the VGOS-B series, present our experiences, and discuss the obtained results. The derived UT1-UTC results were compared to corresponding results from standard legacy S/X Intensive sessions (INT1/INT2), as well to the final values of the International Earth Rotation and Reference Frame Service (IERS), provided in IERS Bulletin~B. 
The VGOS-B series achieve 3-4 times lower formal uncertainties for the UT1-UTC results than standard legacy S/X INT series.  Furthermore, the root mean square (RMS) agreement with respect to the IERS Bulletin B is 30-40 % better for the VGOS-B results than for the INT1/INT2 results.
Improving the products of global GNSS data analysis by correcting for loading displacements at the observation level
Authors: Wang Lin , Thaller Daniela , Susnik Andreja , Dach Rolf
Published: March 2021

In recent years, the sensitivity of the GNSS station time series to the loading displacements is demonstrated by multiple studies, mainly for the non-tidal atmospheric loading (NTAL) and non-tidal ocean loading (NTOL). But the impact of the loading displacements is beyond the coordinate time series, including and not limited to geocenter motion, Earth Orientation Parameters, satellite orbits, etc. We extensively evaluate the impact on and the improvements of the reference frame products from reprocessed 25 years of GPS and GLONASS network solution with a consistent application of non-tidal loading and Continental Water Storage Loading (CWSL) displacement at the observational level. We also discussed the differences of correcting for the loading displacements at the observation level and correction at the product level on GNSS station coordinates and Geocenter motions, we elaborate the advantage of the inclusion of correction at the observational level.

 

Significant improvements are found in estimated coordinate time series, almost 90% of the station shows improved WRMS in North and Up directions and over 75% in East. CWSL dominates the contribution in the North direction. The annual Geocenter variations (over 80% of the x and y components) can be explained by the loading displacement. A small and consistent reduction of orbit disclosure is found among all 32 GPS satellites and most of the GLONASS satellites (23 out of 25) after the inclusion of all the loading displacements.  All the improvements demonstrate the urgent need for the adoption of loading displacements in the global GNSS analysis.
Calibration of a reinforcement learning method with the ClimEx large ensemble and a weather generator for water management 
Authors: Dallaire Gabrielle , Arsenault Richard , Côté Pascal , Demeester Kenjy
Published: March 2021

Hydropower is a renewable source of energy that relies on efficient water planning and management. As the behavior of this natural resource is difficult to predict, water managers therefore use methods to help the decision-making process. Reinforcement Learning (RL) has been shown to be a potentially effective approach to overcome the limitations of the Stochastic Dynamic Programming (SDP) method that is commonly used for water management. However, convergence to a robust and efficient operating policy from RL methods requires large amounts of data, while long-term historical data is not always available. The objective of this study consists in using tools to generate long-term hydrological series to obtain an efficient parameterization of the management policy. This presentation introduces a comparison of calibration datasets used in a RL method for the optimal control of a hydropower system. This method aims to find a feedback policy that maximizes the production of a hydropower system over a mid-term horizon. Three streamflow datasets are compared on a real hydropower system for RL calibration: 1) the historical streamflow (35 years), 2) streamflow simulated by a hydrological model driven by a high-resolution large-ensemble climate model data (3500 years) from the ClimEx project, and 3) streamflow simulated by a hydrological model driven by climate data generated with a stochastic weather generator (5000 years). The GR4J hydrological model is employed for the hydrologic modelling aspect of the work. The reinforcement learning method is applied on the Lac-Saint-Jean water resources system in Quebec (Canada), where the hydrological regime is snowmelt-dominated. A bootstrapping method where multiple calibration and validation sets were resampled is used to conduct a robust statistical analysis for comparing the methods’ performance. The performance of the calibrated management policy is evaluated with respect to the operational constraints of the system as well as the overall energy production. Preliminary results show that is possible to achieve effective management policies by using tools to generate long-term hydrological series to feed a RL method.
Did the Pleistocene tectonics in the Alboran Sea change the distribution and origin of submarine landslides? 
Authors: Lafosse Manfred , d'Acremont Elia , Lafuerza Sara , Rabaute Alain , Jollivet-Castelot Martin , Alonso Belén , Ercilla Gemma , Vazquez Juan-Tomas , Gorini Christian
Published: March 2021

The tectonics of the Alboran Sea control the distribution of topographic highs and depressions, influencing the water masses' paths controlling the deep basins sedimentation rates. Altogether tectonics and deep currents shaped the seafloor on which we map active faults, contourites, pockmarks, and submarine landslides.  Recent numerical models highlight that some of those landslides can generate tsunamis waves on nearby coastal areas, creating the need to describe better and understand those seabed features. Consequently, we put together bathymetric and seismic data to measure Pleistocene slides affecting the deep Alboran basin in an unprecedented collective effort.
We mapped and relatively dated 66 mass transport deposits (MTDs) in the West Alboran and Pytheas fields on the north and south flank of the Alboran Ridge.  We measured their surfaces, decompacted volumes, slopes, run out, scars heights, scars elevations, and described their type (debris flow or slide) qualitatively from their echo facies.  When possible, we also measured the run-off from the scar. We investigated the factor of safety (FOS) and computed based seismic moments based on empirical relationship and faults geometry to characterize the preconditioning factors and triggering mechanisms. The first important result is that post-1.12 Ma MTDs mobilized the most important volumes, in line with the Alboran Sea's topographic highs. Second, seismic lines and the bathymetric images evidence blind reverse faults related to fluid escapes that could contribute to local overpressures in shallow contouritic sediments. Third, we show that local slopes are too flat to allow slopes to destabilize under gravity force only, suggesting that other causal factors need to be considered. Fourth, known seismicity on strike-slip faults in the Alboran Sea is unlikely to trigger MTDs in most investigated areas, suggesting that a combination of preconditioning factors, such as local overpressures and/or reduced strength properties with reverse faults activity, seems the most plausible explanation to trigger the observed MTDs.
The overall results highlight that the Alboran tectonics explain the slope destabilization, with varying local sediment properties. However, those properties and past overpressures, deformations, and fluid flows remain to be locally detailed. Future works involving sediments characterizations and dating will follow after the ALBACORE survey scheduled in 2021.
What dataset should I choose? The influence of data choices on flood exposure estimations at national scales
Authors: Lindersson Sara , Mård Johanna , Brandimarte Luigia , Di Baldassarre Giuliano
Published: March 2021

There are currently several large-scale gridded archives available for the study of flood exposure, and the results will inevitably depend on the datasets included in the analysis. The purpose of this work is to demonstrate how country flood exposure, here represented as the presence of population within floodplains, is influenced by dataset choices.

We conduct this geographical analysis in two parts. First, we conduct a global analysis showing how different flood exposure metrics influence comparisons between countries. Second, we overlay five commonly used gridded archives (three population archives and two floodplain archives) for 32 countries. The purpose is to quantify the influence of data choices, while also giving an overview of the various dataset methodologies. We finally zoom in on areas where the five datasets yield very dissimilar results, to exemplify typical differences among the datasets.
Development and adaptation of sensors and samplers for vertical profiling using fixed-wing drones in the context of the Cooperation to Unravel the RolE of Atmospheric Aerosols over the Amazonian Basin (CURE-3AB).
Authors: Desservettaz Maximilien , Keleshis Christos , Antoniou Panayiota , Vouterakos Panagiotis , Liu Yunsong , Constantinides Christos , Agapiou Agapios , Sarda-Esteve Roland , Baisne Dominique , Kok Greg , Sciare Jean
Published: March 2021

The Cooperation to Unravel the Role of the Atmospheric Aerosol over the Amazon Basin using drones (CURE-3AB) project has yielded new technical solutions to perform high quality in-situ atmospheric observations in the lower troposphere (0-2 km) with Unmanned Aerial Vehicles (UAVs). An Ozonesonde (EN-SCI ECC, Model 2Z), designed for regular O3 radio sounding, has been adapted to perform on-line measurements of Ozone onboard the drone. A 3D printed low-cost pollen/spore collector has been developed to replicate reference instruments (VPPS2000) and adapted to perform onboard our UAV. Finally, an optical particle counter (AlphaSense) and a custom-made drying system have been fitted on a third drone. The three vehicle/instrument tandems will be deployed in the proximity of the Amazonian Tall Tower Observatory during the CURE-3AB campaign (delayed due to pandemic). We present the instrumental developments, setups, and preliminary test results performed with our UAVs at the Cyprus Institute private airspace.
Sediment and surface water microplastic contamination along the Ganges River, from the Himalayan foothills to the tidal reach downstream of Kolkata, India.
Authors: Nel Holly ,   Team SAPTANADI
Published: March 2021

Twenty rivers have been estimated previously to account for almost 70% of global plastic emissions to the marine environment. Of these, the Ganges River was second only to the Yangtze River. Yet, scale and complexity of the Ganges River network make assessing microplastic contamination along the watercourse, including the attribution of suspected pollution sources challenging. Here we analyse post-monsoon spatial variation of microplastics along a 2500km length of the Ganges. River sediments and surface water were sampled during Nov/Dec 2019 at 81 locations that covered a variety of hydrological conditions, morphological attributes and land-use categories (e.g., downstream of large urban areas, rural areas with agriculture, major tributaries). Sediment samples were collected from the riverbank (waterline) and stored in glass jars while 100L water samples were filtered on-site through a 63µm sieve. Plastic particles between 63 and 5000µm were extracted by means of density separation followed by organic matter digestion with Fenton reagent. Extracts were subsequently stained with Nile red to improve detection of ambiguous particles. Physical and chemical properties such as shape, size, and polymer type where characterised using Fluorescence microscopy, Confocal Raman, and FT-IR imaging to understand differences along the river continuum. Our findings were analysed in relation to other key water quality parameters, various land-use descriptors and hydrogeomorphological characteristics, which allowed us to better understand the main drivers of microplastic transport and fate. Our survey results reveal an increasing downstream trend in sediment microplastic concentrations. The existence of distinct microplastic pollution hotspots in areas of high population density as well as areas of high cultural and spiritual relevance are detected. Interestingly, longitudinal concentration profiles in sediment and surface water samples do not match, hinting at differences in source attributions as well as transport, accumulation and long-term storage mechanisms, which is especially important in light of the variations seen in microplastic shape and size distribution patterns. Our results can be used as a springboard for future research assessing local microplastic contamination and aid in the refinement of medium and large-scale models estimating microplastic export.
Weakening of the equatorial Atlantic SST variability under global warming
Authors: Crespo Lander R. , Prigent Arthur , Keenlyside Noel , Richter Ingo , Sánchez-Gómez Emilia , Svendsen Lea , Koseki Shunya
Published: March 2021

The eastern equatorial Atlantic is the region with the largest seasonal and interannual sea surface temperature (SST) variability in the entire tropical Atlantic Ocean. It is characterized by a rapid cooling during the boreal summer season, between June and September, that has large impacts in the regional climate. In this study we explore climate changes related to global warming in the cold tongue region using the CMIP5 and CMIP6 datasets as benchmarks. The historical simulations of both CMIP generations reproduce fairly well the spatial pattern of the observed warming – although weaker – in the Angola-Benguela region and most of the equatorial Atlantic band. The largest disagreements between model and observations are localized in the eastern equatorial Atlantic. The future business-as-usual scenario shows an intense and zonally homogeneous warming along the equatorial Atlantic band in CMIP5 and CMIP6. We also find a significant reduction of the June-July-August SST variability of 12% (17%) in the ensemble mean of the CMIP5 (CMIP6), in the future scenario (2050-2099) with respect to the historical period (1950-1999). The thermocline feedback, i.e., the local response of the SST anomalies to the thermocline depth anomalies, is weaker in the future scenario and appears to be the main driver of the change in interannual SST variability. The strong warming of the upper equatorial Atlantic Ocean in the future leads to a higher stratification which could explain the weaker thermocline feedback.
Modelling of long term brownification process in Southern Finland 
Authors: Rankinen Katri , Holmberg Maria , Cano Bernal José , Akujärvi Anu
Published: March 2021

Browning of surface waters due to increased terrestrial loading of organic carbon is observed in boreal regions. It is explained by large scale changes in ecosystems, including decrease in sulphur deposition that affects soil organic matter solubility, increase in temperature that stimulates export of dissolved organic carbon (DOC) from organic soils, and increase in precipitation and thus runoff. Land use changes and forestry measures are also observed to be one reason for increased transport of DOC. The effects of brownification extend to ecosystem services like water purification, but also freshwater productivity through limiting light penetration and creating more stable thermal stratification. We studied past trends of organic carbon loading from catchments based on observations since early 1990’s. We made simulations of loading by the physical Persist and INCA models to three small catchments at the Lammi LTER area. We upscaled simulations to the Kokemäenjoki river basin (17 950 km2). Even though river processes did not play a role in small catchments, they had influence on DOC concentration at the whole river basin. Brownification was driven mainly by the change in climate and decay of organic matter in soil, with smaller impact of land use change on organic soil types. Decrease in sulphur deposition had only minor effect on brownification.
Magma plumbing system and associated hydrothermal vents in the Guaymas Basin - geometry and implications
Authors: Galerne Christophe, Y. , Lizarralde Daniel , Berndt Christian , Neumann Florian , Höfig Tobias, W. , Stock Joann M. , Peña-Salinas Manet, E. , Negrete-Aranda Raquel , Teske Andreas, P. ,   Expedition 385 Scientists
Published: March 2021

We document the geometry of a massive sill at the root of an approximately 20-m high and 800 m-wide ring of hydrothermal formations, termed Ringvent, located 28.5 km off-axis on the northwestern flanking regions of the actively rifting Guaymas Basin (Gulf of California). Using petrophysical data collected during the IODP Expedition 385 and processed 2D seismic profiles, we present evidence on the mechanics of sill emplacement and how the related hydrothermal vent conduits were constructed. The currently active moderate-temperature hydrothermal vent field indicates that, despite being cold and crystallized, the magma plumbing system, is tapping into a deeper geothermal source of the basin. The vent system roots at the vertical end of the magma plumbing system with the top of the sill located at a depth range of 80 to 150 m below the seafloor. Our research aims at constraining how far deep the geothermal fluids are coming from, and identifying how close the hydrothermal system is from a steady-state condition, to draw implications for how frequently such a system may arise in nascent ocean basins.
Integrating field work and large-scale modeling to improve assessment of karst water resources
Authors: Hartmann Andreas , Liu Yan , Olarinoye Tunde , Berthelin Romane , Marx Vera
Published: March 2021

Comprehensive management of karst water resources requires sufficient understanding of their dynamics and karst-specific modeling tools. However, the limited availability of observations of karstic groundwater dynamics has been prohibiting the assessment of karst water resources at regional to global scales. This paper presents the first global effort to integrate experimental approaches and large-scale modeling. Using a global soil-moisture monitoring program and a global database of karst spring discharges, the simulations of a preliminary global karstic-groundwater-recharge model are evaluated. It is shown that soil moisture is a crucial variable that better distinguishes recharge dynamics in different climates and for different land cover types. The newly developed dataset of karst spring discharges provides first insights into the wide variability of discharge volumes and recharge areas of different karst springs around the globe. Comparing the model simulations with the newly collected soil-moisture and spring-discharge observations, indicates that (1) improvements of the recharge model are still necessary to obtain a better representation of different land cover types and snow processes, and (2) there is a need to incorporate groundwater dynamics. Applying and strictly evaluating these improvements in the model will finally provide a tool to identify hot spots of current or future water scarcity in the karst regions around the globe, thus supporting national and international water governance.
Green roof effects on the rainwater response in the Mediterranean area: first results of a Sicilian case study
Authors: Pumo Dario , Francipane Antonio , Alongi Francesco , Noto Leonardo
Published: March 2021

Over the last decades, we have been witnessing an increasing frequency of urban floods often attributed to the interaction between intensification of rainfall extremes due to climate change and increasing urbanization. Consequently, many studies have been trying to propose different new alternatives to mitigate ground effects of ever more frequent and severe extreme rainfall events in a context of growing urbanization, such as rain gardens, green roofs, permeable parking lots, etc., which are commonly referred to as green infrastructures.

With this regard, one of the most promising mitigation solutions is represented by multilayer green roofs. These systems, coupling classical green roofs with a rainwater harvesting system, results in a high capacity in retaining rainwater, thus improving the potential effects acted by classical green roofs on pluvial floods mitigation. These systems are particularly suited for applications in semi-arid climate, where a fraction of the rainwater can be detained during the more severe rainfall events, significantly reducing the pressure on drainage systems, and released in a later moment or reused, for instance, to sustain the vegetation during driest periods.

This study describes a multilayer green roof installed at the Department of Engineering of the University of Palermo (Sicily, Italy) and its preliminary results on its capacity to reduce the pressure of rainfall events on drainage systems in a Mediterranean context. The green roof has an extension of almost 35 m2 and is made of three different areas with different soil thickness (a mixture of volcanic material) and different Mediterranean vegetation. The green roof is equipped with multiple sensors to monitor the water level in the storage layer, soil water content, air and water temperature, and rainfall. Besides, a weighted rain gauge, a disdrometer, and a meteorological station for the collection of meteorological data are available as well.

An equal size classical roof area bordering the green roof installation is also monitored. Four different thermometers are used to measure the temperatures in different points of the roofs and a system of two rain barrels and two pressure sensors allows to collect and compare the rainwater coming from the green and the original roofs. Such an installation, differently from many others, has the advantage to allow a complete characterization of the potential benefits of a multilayer green roof through a comparison of the rainwater released by the two roof configurations at a rainfall event scale.

The study provides the preliminary results arising from the analysis of the two roof configurations' response to a series of rainfall events characterized by different duration and intensity.
Constraints on small-scale heterogeneity in Earth's inner core determined from transmitted P waves
Authors: Cormier Vernon , Wickramathilake Ravi
Published: March 2021

Scattered waves composing the coda of the PKiKP wave, reflected by the boundary of Earth's inner core at pre-critical range, reveal the existence of small-scale heterogeneity in the uppermost inner core. Since the shape this coda envelope is relatively insensitive to intrinsic viscoelastic attenuation, seismograms synthesized using the Axisem code (Nissen-Meyer, 2014) are exploited to determine whether heterogeneity spectra consistent with the coda envelope of PKiKP can contribute to the attenuation observed in long range PKIKP waves transmitted through the deeper inner core.  Peng et al. (2008) have shown that a range of possible parameters describing an exponential autocorrelation of small-scale heterogeneity can fit observed PKiKP coda envelopes, with the rms P velocity fluctuation trading off against the corner scale length parameter "a" of the heterogeneity spectrum. Testing the effects of a series of "a's" and velocity fluctuations that fit PKIKP coda envelopes we determined upper bounds to “a” and the rms P velocity fluctuation below 300 km depth in the inner core.  Parameter combinations of  “a” > 2 km and rms dVp/Vp > 2% can be eliminated from consideration because they produce too strong a coda following PKIKP. In the antipodal range (178o to 180o) we found that there exists a strong focusing of multiply scattered waves affecting the pulse width and coda of PKIKP.  The parameter combination "a"= 2 km and rms=1.2% produces a strong PKIKP coda, which is not observed in antipodal data.  This, coupled with the fact that Axisem ignores out-of-plane scattering, suggests that the attenuation of PKIKP observed beyond 160o is dominated by viscoelastic rather than scattering attenuation and that the rms P velocity fluctuation must decrease by at least a factor of 2 below 300 km to be consistent with the coda of antipodal PKIKP waves.

Peng, Z., Koper, K.D., Leyton, J.E., Shearer, P., J. Geophys. Res., 113(B9), B09312, doi:10.1029/2007JB/005412, 2008.

Nissen-Meyer, T., van Driel, M., Stähler, S. C., Hosseini, K., Hempel, S., Auer, L., Colombi, A., and Fournier, A. Solid Earth, 5, 425-446, https://doi.org/10.5194/se-5-425-2024, 2014.

 
Polarization lidar for detecting dust orientation: first measurements
Authors: Tsekeri Alexandra , Freudenthaler Volker , Amiridis Vassilis , Doxastakis George , Louridas Alexandros , Georgoussis George , Metallinos Spiros , Gasteiger Josef , Siomos Nikolaos , Paschou Peristera , Georgiou Thanasis , Tsaknakis George , Evangelatos Christos , Binietoglou Ioannis
Published: March 2021

The new polarization lidar nicknamed “WALL-E” is designed to monitor dust orientation. Dust orientation has not been extensively investigated for the Earth’s atmosphere, where dust is considered to be randomly-oriented. For monitoring dust orientation, the new polarization lidar emits linearly- and elliptically-polarized light at 1064 nm and detects the linear and circular polarization of the backscattered light. This is done with two lasers emitting in an interleaved fashion, and two telescopes collecting the backscattered light from both lasers. The measurements are performed at variable viewing angles and provide direct flags of dust orientation, along with more detailed information on particle microphysics. The first measurements for dust in Athens are presented.

 

 

 Acknowledgements. The work is supported by the European Research Council under the European Community’s Horizon 2020 research and
innovation framework program/ERC grant agreement 725698 (D-TECT). We acknowledge PRACE for awarding us access to MareNostrum
at Barcelona Supercomputing Center (BSC), Spain. The work was supported by computational time granted from the Greek Research &
Technology Network (GRNET) in the National HPC facility - ARIS - under project ID pa170906-ADDAPAS, pr005038-REMOD and pr009019-EXEED.
Simulating the emission and transport of gases on 100-meter resolution in a 100-kilometer domain.
Authors: de Bruine Marco , Jansson Fredrik , van Stratum Bart , Rijsdijk Pieter , Houweling Sander
Published: March 2021

Climate regulations and satellite monitoring on increasingly high resolution creates a demand for an insight into emissions on an urban scale. The aim of the Ruisdael Observatory (www.ruisdaelobservatory.nl) is to provide just that: detailed and high-resolution modelling and measurements of weather and air quality in a domain covering the Netherlands.

The Ruisdael Observatory created a renewed impulse in the developments of the DALES Large-eddy simulation (LES) model (Heus et al., 2010, Ouwersloot et al. 2016) to find and push the limits of atmospheric modelling. Typical simulations with DALES will use a spatial resolution in the order of 100m in domain sizes spanning over 100x100 km. This high resolution justifies the complexity and the multitude of emission sources and resulting transport of pollutants in the atmospheric boundary layer.

The combination of high resolution and large domain sizes allows us to investigate how emissions disperse in a turbulent environment which is forced by large-scale flow at the same time. Parameterizations are no longer needed to calculate horizontal or vertical transport in the boundary-layer. This way, we can provide new insight into the transport of emissions in the boundary layer and the detrainment of gases out of the boundary layer into the free atmosphere.

We will discuss the construction of our emission database for the Netherlands with a 100-meter and 1-hourly resolution. For this, we started from the official E-PRTR reported emission inventories (www.emissieregistratie.nl) and enriched with high resolution activity data from mostly open-source datasets. Moreover, large emissions sources (accounting for e.g. >80% of CO2 emissions) are subject to mandatory registration and their locations are known exactly. Emissions from different source categories can be tracked individually and compared to measurements from the Ruisdael Observatory measurement sites. Examples of simulations of fair-weather summer days will be compared to surface measurements and showcase the data richness of our new model and combination to measurements from our network.
Interactions between Decadal to Multidecadal Ocean Variability and Stratospheric Sudden Warmings
Authors: Ayarzagüena Blanca , Manzini Elisa , Calvo Natalia , Matei Daniela
Published: March 2021

Major sudden stratospheric warmings (SSWs) are largest instances of the boreal polar stratospheric variability. Their effects extend farther from the polar stratosphere, affecting for example near-surface circulation. According to observations, SSWs are not equally distributed along time, with decades with almost no events and decades with SSWs happening almost every winter. This suggests the existence of multidecadal variability of SSWs. Some previous studies have pointed to phenomena in the ocean surface as the main precursors of this low-frequency variability. However, the relatively short observational record and the need of long model simulations with daily output have not enabled an analysis of the influences of these oceanic phenomena on SSWs

The goal of this study is to investigate the effects of Atlantic Multidecadal Variability (AMV) and Pacific Decadal Variability (PDV) on SSWs. To do so, we use for the first time a large ensemble of historical experiments (Max Planck Grand Ensemble) that allows us to examine the modulation of the frequency, precursors and surface impact of SSWs by both types of oceanic variability. Our results reveal that PDV has an impact on the frequency of SSWs, with a significant higher rate of SSWs for its positive than the negative phase. As for AMV, the main effect of AMV is centered on the tropospheric response to SSWs, with almost no modulation in the occurrence of the event. This last finding would be useful in order to predict the tropospheric fingerprint of SSWs.