bluuebunny/crossref_metadata_2025 huggingface dataset:
Shifting China’s rice fields from nitrogen source to sink by innovative agricultural management
Authors: Huang Weichen , Jiang Wenjun , Zhou Feng
Published: February 2023

Rice field has been traditionally considered as a nonpoint source of reactive nitrogen (N) for the environment, while it, with surrounding ditches and ponds, also contributes to receiving N inputs from atmosphere and waterbodies and intercepting N outputs from rice field. However, due to the paucity of multi-site, long-term observation and control experiment data, as well as robust process-based model for nitrogen budget, a comprehensive assessment of the N source (i.e., outputs > inputs) or sink (i.e., inputs > outputs) of rice field for the environment, from site to regional scale, is lacking. Here, a 2-year systematic observation and process-based simulations of N budget across China, covering typical annual rice cropping systems including single rice, double rice and rotation, were conducted to identify the roles of rice field in nitrogen cycling in China. The cost-benefit analysis for shifting China’s rice fields from nitrogen source to sink in different climatic scenarios (wet, normal and dry year) by innovative agricultural management, without compromising crop yield or soil fertility, were further evaluated. Rice fields, with surrounding ditches and ponds, perform as a nitrogen sink for atmosphere but a source for waterbody, which was confirmed by both the observational data and regional assessment by process-based model, regardless of rice types or climatic scenarios. With the adoption of sustainable N and water regulation measures, single rice field across China could be shifted to N sink (12.9-29.9 kg N ha-1) while the N source of double rice would be reduced by 51%-66%. For middle rice field (rotation with other crops), N sink would be achieved in dry year, while 31%-55% would shift to sink in wet and normal year. However, with such great benefits, the costs only accounted for 41%-49% of the expenditure for waste water treatment. Furthermore, through sorting all the measures and adopting economic ones (lower cost with higher benefit) in priority, we found that rice fields across China have great space for source-to-sink regulation with zero cost, which means the benefits would exceed the regulation costs, and even achieve overall N sink in dry year. Together these findings help us to update scientific knowledge to the role of rice fields in ecosystems, as well as highlight the significance and possibility for achieving environmental-friendly rice field, by improving agricultural management technologies.
Integration of in situ Rb-Sr and in situ 40Ar/39Ar dates under diverse tectono-metamorphic scenarios
Authors: Kellett Dawn , Larson Kyle , Skipton Diane
Published: February 2023

40Ar/39Ar dating has been a valuable and widely used method for dating orogenic processes such as prograde and retrograde metamorphism and brittle and ductile deformation, through the analysis of K-bearing rock-forming minerals such as white mica. The in situ 40Ar/39Ar method, in which a short wavelength laser is used to ablate an analyte and deliver the liberated Ar to a noble gas spectrometer, is particularly valuable as an approach to dating deformation or metamorphism because it allows for targeting of specific chemical and structural domains, and the mapping of intragrain age distributions. Rb-Sr dating can also be applied to K-bearing minerals because of Rb’s propensity to substitute for K. The Rb-Sr method has been under-used in recent decades because the isobaric interference between parent 87Rb and daughter 87Sr has necessitated the chemical separation of Rb from Sr via ion exchange chromatography prior to mass spectrometric analysis, and hence bulk sampling of the target analyte. New tandem mass spectrometers, in which two quadrupoles are separated by an intervening reaction chamber into which a reactive gas can be introduced, have opened up the opportunity of applying laser-based in situ sampling approaches to beta decay geochronometers, including Rb-Sr (Zack and Hogmalm, 2016).We have collected new in situ Rb/Sr data for white mica from three different tectono-metamorphic settings previously dated using the in situ 40Ar/39Ar method: recrystallization of white mica in a Paleozoic low-temperature ductile shear zone; development of multiple cleavage domains in low-temperature metamorphic rocks deformed in the Paleozoic, and; slow cooling of rocks following regional amphibolite-facies metamorphism in a Paleoproterozoic orogeny. , This allows a direct comparison between these two approaches, with the goal of exploring the functionality and utility of in situ Rb-Sr data, and testing geological interpretations based upon the in situ 40Ar/39Ar method. Our results show that the in situ Rb-Sr method is a highly complementary approach to the 40Ar/39Ar method for white mica, particularly in cases for which the target mica population has a large internal spread in Rb/Sr. allowing for the rigorous testing of assumptions and hypotheses about timing and conditions of rock cooling, deformation, and fluid events developed using 40Ar/39Ar datasets. Zack, T. and Hogmalm, K.J., 2016. Laser ablation Rb/Sr dating by online chemical separation of Rb and Sr in an oxygen-filled reaction cell. Chemical Geology, 437, pp.120-133.
Understanding the Polarimetric Radio Occultation observable differential phase shift with the help of the NEXRAD polarimetric weather radars
Authors: Paz Carracedo Antía , Padullés Rulló Ramon , Cardellach Galí Estel
Published: February 2023

Lack of knowledge about the physical processes controlling heavy precipitation arises from the limited number of simultaneous observations of the vertical structure of precipitation and its thermodynamic environment. These limitations are caused by the degradation that the signals of some spaced-based sensors suffer in presence of thick clouds or the lack of high vertical resolution thermodynamic measurements.To overcome this problem, the ROHP (Radio Occultation and Heavy Precipitation) experiment provides high-quality thermodynamic profiles (temperature, pressure, water vapor pressure, etc.) and vertical information of the hydrometeors, simultaneously. This proof-of-concept experiment led by the Institut de Ciències de l’Espai (ICE-CSIC, IEEC) in collaboration with NOAA, UCAR, and NASA/Jet Propulsion Laboratory, is carried out aboard the Spanish low earth orbiter (LEO) PAZ. Its objective is to test the new Polarimetric Radio Occultation (PRO) concept, and it has been operating since 2018. The standard radio occultation technique consists of tracking the signals emitted by a Global Navigation Satellite System (GNSS) satellite from a LEO satellite that is rising or occulting behind the Earth’s limb. The novelty that PRO offers is that GNSS signals are collected using two different linearly polarized antennae (horizontal and vertical) as opposed to the standard technique, where GNSS signals are acquired using a circularly polarized antenna. Consequently, we can obtain an observable called the differential phase shift, defined as the difference in the accumulated phase delay between both polarizations (H-V). Since the hydrometeors surrounding heavy precipitation events stand out for being oblate spheroid-like, we will have an associated accumulated phase shift if rays are crossing heavy precipitation.For the sake of continuing with the validation of the PRO technique, we make use of the polarimetric weather data provided by the Next Generation Weather Radars (NEXRAD). NEXRAD is the network of dual-polarized Doppler radars operating at the S-band, that covers all the United States territory. By comparing the differential phase shift obtained with PAZ and the observables from NEXRAD, we can analyze the polarimetry of both systems. In this study, we focus on the vertical structures of NEXRAD-provided specific differential phase shift (Kdp) that can be compared to the PAZ observable accounting for some geometry and frequency factors. This comparison will help us to better understand the PAZ observables, and ultimately to better understand the microphysics underlying heavy precipitation events.
First glance of French soil contamination by pesticide residues and the interest for broad-scale monitoring
Authors: Froger Claire , Jolivet Claudy , Budzinski Hélène , Pierdet Manon , Caria Giovanni , Saby Nicolas P.A. , Arrouays Dominique , Bispo Antonio
Published: February 2023

The intensive use of pesticides in modern agriculture raised concerns about their environmental fate and impacts on the ecosystems. If the monitoring of those substances in water bodies has been established in Europe since the 2000’s, knowledge of soil contamination by such residues is scarce. However, the few studies addressing this issue pointed out the widespread occurrence of pesticides in soils and the risk they can pose for soil biodiversity. This study investigated 111 currently used pesticides in 47 soils sampled across France, mostly from arable lands but also from forest and grasslands theoretically exempted of pesticides applications. The sampling strategy was based on the French Soil Quality Monitoring Network (Jolivet et al., 2022) to evaluate the feasibility of using an existing network for pesticides monitoring in soils. The results demonstrated the widespread contamination of almost all soils samples by residues, including untreated areas such as forests and permanent grasslands. Up to 33 different substances in one soil sample were detected, at concentrations leading to a medium to high ecotoxicological risk for earthworms in arable lands. Several frequently detected residues have never been reported in the literature so far or were found at much lower detection rates. Finally, the comparison with pesticide application records provided by the farmers revealed the unexpected presence of some substance in sites where they were not applied and a longer than expected persistence of several compounds. These findings question the fate of currently used pesticides in the environment under current agricultural practices and advocate for the monitoring of pesticides in soils at broad scales. Filling the knowledge gap of pesticide presence in soil is necessary to understand the contamination of other environmental compartments and prevent their contamination.Jolivet, C., Falcon, J.A., Berché, P., Boulonne, L., Fontaine, M., Gouny, L., Lehmann, S., Maitre, B., Schellenberger, E., Soler-Dominguez, N., 2022. French Soil Quality Monitoring Network Manual RMQS2 : second metropolitan campaign 2016 – 2027. https://doi.org/10.17180/KC64-NY88
Carbon Burial in Shelf Sea Sediments – Anthropogenic Effects and Implications for Management
Authors: Porz Lucas , Yilmaz Rumeysa , Zhang Wenyan , Schrum Corinna
Published: February 2023

Many continental shelves host sediment depocenters which act as natural, long-term (>100 yr) carbon sinks. Human activities can strongly affect the efficiency with which carbon is sequestered in these depocenters, either through direct disturbances of the seafloor, or indirectly through climatic, light- or nutrient-induced changes, thereby affecting habitat and ecosystem functioning. In this study, we address the short- and long-term impacts of sea-use on carbon burial in the North Sea. Specifically, we focus on the role of bottom trawling as a crucial disturbance of seafloor sediments and benthic biota. In order to quantify the large-scale impact on carbon sequestration, we employ a numerical coastal ocean model to simulate the effects of demersal fishing gear on sediment transport, bioturbation efficiency and their interactions. Based on the results, the effects of potential management scenarios are discussed.
The derivation of denitrification conditions in groundwater: Combined method approach and application for Germany
Authors: Wolters Tim , Bach Thomas , Eisele Michael , Eschenbach Wolfram , Kunkel Ralf , McNamara Ian , Well Reinhard , Wendland Frank
Published: February 2023

Denitrification in groundwater is an important process that helps to maintain environmental standards, yet there are very few studies that determine the spatial variation of denitrification conditions in aquifers on a regional scale. We introduce a procedure to derive spatially continuous estimates of denitrification conditions in groundwater based on the interpolation of measurements of the redox-sensitive parameters oxygen, nitrate, iron, manganese and DOC, combined with the quantification of denitrification using a 2D-hydrodynamic model based on first-order reaction kinetics. We applied this procedure to Germany, using measured values from more than 24,000 groundwater monitoring sites from 2007 to 2016. Annual concentrations of the five parameters at the monitoring sites were regionalized using an optimized, iterative inverse distance weighting procedure within 15 aquifer typologies for spatial delineation. The annual grids (2007–2016) of each parameter were then overlaid and a median over time was calculated. Discrete ranks were then assigned to the concentrations of each parameter based on their redox class, and ultimately, after overlaying the five parameters, a mean value was calculated describing the nitrate degradation conditions in groundwater. After assigning half-life times and reaction constants to those denitrification conditions, we quantified denitrification in groundwater using the hydrodynamic model WEKU.To assess the plausibility of the derived denitrification in groundwater, we compared our results with the proportion of denitrified nitrate determined with the N2/Ar method at 820 groundwater monitoring wells in three German Federal States, which showed an overall good agreement. Accordingly, the method presented here is suitable to be used for the regionally differentiated derivation of denitrification conditions in groundwater. For regions with denitrifying groundwater conditions, the results provide an explanation for frequently observed discrepancies between high nitrate emissions from the soil and low nitrate concentrations in the groundwater of intensively used agricultural areas.
Urban water systems as entry points for river plastic pollution
Authors: Tasseron Paolo , Begemann Finn , Joosse Nonna , van der Ploeg Martine , van Driel Joppe , van Emmerik Tim
Published: February 2023

Accumulation of plastic in aquatic environments negatively impacts ecosystems and human livelihood. Urban areas are assumed to the main source of plastic pollution in these environments, because of high anthropogenic activity. Yet, the drivers of plastic emissions, abundance and retention within these systems and subsequent transport to river systems is poorly understood. In this study, we demonstrate that urban water systems function as major contributors to river plastic pollution, and explore the potential driving factors contributing to the transport dynamics. Monthly visual counting of floating litter at six outlets of the Amsterdam water system results in an estimated 2.7 million items to enter the closely connected IJ river annually, ranking it among the most polluting systems measured in the Netherlands and Europe. Subsequent analyses of environmental drivers (including rainfall, sunlight, wind speed and tidal regimes) and litter flux showed no strong correlations (r = -0.19 - 0.16), implying additional investigation of potential drivers is required. High frequency observations at various locations within the urban water system and advanced monitoring using novel technologies could be explored to harmonize and automate monitoring. Once litter type and abundance are well-defined with a clear origin, communication of the results with local communities and stakeholders could help co-develop solutions and stimulate behavioural change geared to reduce plastic pollution in urban environments.
Fast and Reproducible Aggregate Water-Resistance Index Determination Using Laser Diffraction
Authors: Kubát Jan-František , Vrána Michal , Zumr David , Kavka Petr
Published: February 2023

Soil aggregate stability is a measure of the resistance of soil aggregates to degradation and breakdown. It is a major factor influencing the soil health and fertility. The aggregates stability also affects soil erosion rates and water retention. Several factors can influence the stability of soil aggregates, including the type and amount of soil organic matter, the presence of soil biota, and the type and intensity of land management practices. Soil management practices that promote the incorporation of organic matter, such as cover cropping and reduced tillage, can increase soil aggregate stability. The aggregate stability is commonly measured using a variety of techniques, such as the water drop penetration test, in which the penetration of a water droplet is used to assess the strength of soil aggregates, and the wetting and drying method, in which the stability of soil aggregates is measured after they have been subjected to alternating wetting and drying cycles. A common method for measuring soil aggregate stability is the wet sieving method. Within this contribution we present a newly developed procedure based on the equation of Kemper & Rosenau that utilizes laser diffraction to estimate the aggregate water resistance index (AWRI). In developing this new method, emphasis was placed on comparability with the standard sieving procedure carried out with the Eijkelkamp wet sieving apparatus. The water resistance of the soil aggregates was tested for five different soil types (Haplic Luvisol, Chernozem, Regosol, Fluvisol, and Cambisol) sampled in the Czech Republic. The AWRI value determined by the laser diffraction procedure is based on an average particle size of the disturbed aggregates recorded for each fictitious sieve size. The results from a limited number of soil samples show promising agreement between the standard wet sieving and the laser diffractometer procedures. The main advantage of the method is the much faster processing of many samples and their replicates with less variability in the results. However, further measurements are needed to validate the procedure. This study has been supported by Grant of Technology Agency of the Czech Republic QK22020179 and EC H2020 Project 101000224 (TuDi)
Linking ITCZ migrations to the AMOC and North Atlantic/Pacific SST decadal variability
Authors: Moreno-Chamarro Eduardo , Marshall John , Delworth Tom L.
Published: February 2023

This contribution discusses the link between migrations in the intertropical convergence zone (ITCZ) and changes in the Atlantic meridional overturning circulation (AMOC), Atlantic multidecadal variability (AMV), and Pacific decadal oscillation (PDO). We use a coupled climate model that allows us to integrate over climate noise and assess underlying mechanisms. We use an ensemble of ten 300-yr-long simulations forced by a 50-yr oscillatory North Atlantic Oscillation (NAO)-derived surface heat flux anomaly in the North Atlantic, and a 4000-yr-long preindustrial control simulation performed with GFDL CM2.1. In both setups, an AMV phase change induced by a change in the AMOC’s cross-equatorial heat transport forces an atmospheric interhemispheric energy imbalance that is compensated by a change in the cross-equatorial atmospheric heat transport due to a meridional ITCZ shift. Such linkages occur on decadal time scales in the ensemble driven by the imposed forcing, and internally on multicentennial time scales in the control. Regional precipitation anomalies differ between the ensemble and the control for a zonally averaged ITCZ shift of similar magnitude, which suggests a dependence on timescale. Our study supports observational evidence of an AMV–ITCZ link in the twentieth century and further links it to the AMOC, whose long-time-scale variability can influence the phasing of ITCZ migrations. In contrast to the AMV, our calculations suggest that the PDO does not drive ITCZ migrations, because the PDO does not modulate the interhemispheric energy balance.
Hydrogeophysical characterization of a peatland hillslope in the Belgian High Fens
Authors: Henrion Maud , Van Oost Kristof , Li Yanfei , Lambot Sébastien
Published: February 2023

Despite the fact that peatlands play an important role in climate regulation, biodiversity support, water regulation, carbon storage etc., they are understudied biotopes. The objective of this study, conducted in the Belgian High Fens, was to characterize and understand the soil surface and subsurface long-term characteristics which are conditioning the shorter-term hydrogeophysical processes. To this end, Ground-Penetrating Radar (GPR) and Electromagnetic Induction (EMI) were used and this source of information was complemented with soil coring and in situ soil water conductivity measurements. The GPR and soil coring allows to reconstruct the soil structure which is composed of a layer of approximately 80 cm of peat that developed on an impermeable clay layer issued of the slate bedrock decomposition. The EMI shows a bulk soil electrical conductivity (EC) around 10 mS/m, which is consistent with the relatively low values observed in other peat studies. The EC is lower in the slope, where the water fluxes are higher. The EC was higher (of about 3 mS/m) in summer than in spring. The EC values and dynamics seem to be mainly controlled by the ion content of the soil solution. This ion content is controlled by the water fluxes on the site evacuating the ions downhill to a river. The soil water content is believed to have a low impact on the EC as the site is quite saturated most of the year. No clear correlation was found between the EC patterns and the soil structure. A novel drone-borne, low-frequency GPR (< 50 MHz) is being applied on the study site to allow for a faster and easier EC mapping. This study highlights the major influence of the ion content on the EC patterns and dynamics in a peat site. This study will also be a basis to interpret further measurements that will be made on the site (water, soil and vegetation monitoring).
Impacts of flow path water-saturation for debris-flow erosion modelling at Illgraben (Switzerland)
Authors: Könz Anna Lena , Hirschberg Jacob , McArdell Brian , Bartelt Perry , Molnar Peter
Published: February 2023

Debris flows can significantly grow along their flow path by entraining sediments stored in the channel bed and banks. This entrainment process is influenced by various factors such as flow properties (e.g., flow momentum, basal shear stress) and environmental conditions (e.g., soil water saturation, sediment availability). In recent years, different attempts to include the entrainment process in runout models have improved modelled flow properties and runout behavior by empirically linking entrainment volumes to individual modelled flow properties. Linking entrainment to environmental factors, however, has remained challenging.Here, we aim at implementing and testing the influence of flow path water-saturated conditions in debris-flow runout modelling in a Swiss debris-flow basin (Illgraben). To this end, the modified RAMMS runout model, which includes an empirical algorithm to describe entrainment as a function of basal shear stress (Frank et al., 2015), is coupled with a simple hydrological model to predict soil water saturation. In a first step, the RAMMS model was calibrated for the Illgraben site for seven events with detailed data on erosion/deposition along the fan as well as flow properties at the outflow of the simulation domain (de Haas et al., 2022). In the calibration procedure, the focus was placed on the erosion proportionality factor dz/dtau [m/kPa] (which links the maximum potential erosion depth to the basal shear stress) as it is assumed to be the driving saturation-induced increase of entrained volume. Preliminary results show that in most cases, including the entrainment process improves the reproduction of the flow properties, especially the ‘hydrograph’ front, and that the erosion proportionality factor dz/dt shows a significant degree of variation for different events. In a second step, the relationship between soil moisture conditions and maximum erosion depth expected along the flow path was investigated. The hydrologic conditions are simulated with a conceptual model solving the water balance for the basin’s headwaters. The headwater discharge serves as the water input for the channel on the fan, where an infiltration model is applied, and entrainment is investigated. The presented framework, which could be incorporated into other runout models, is expected to be useful for debris-flow entrainment modelling, as well as for assessing climate change impacts on debris-flow runout.Referencesde Haas, T., McArdell, B.W., Nijland, W., Åberg, A.S., Hirschberg, J., Huguenin, P., 2022. Flow and Bed Conditions Jointly Control Debris‐Flow Erosion and Bulking. Geophysical Research Letters 49. https://doi.org/10.1029/2021GL097611Frank, F., McArdell, B.W., Huggel, C., Vieli, A., 2015. The importance of entrainment and bulking on debris flow runout modeling: examples from the Swiss Alps. Nat. Hazards Earth Syst. Sci. 15, 2569–2583. https://doi.org/10.5194/nhess-15-2569-2015
Distinct and reproductible northem hemisphere winter teleconnection pattern during strong El Niño events : relative roles of Sea Surface Temperature forcing and atmospheric nonlinearities
Authors: Beniche Margot , Vialard Jérôme , Lengaigne Matthieu , Voldoire Aurore , Gangiredla Srinivas , Hall Nicholas
Published: February 2023

The strengthening and north-eastward shift of El Niño Northern hemisphere winter teleconnections relative to those of La Niña is a well-known asymmetry of ENSO (El Niño Southern Oscillation). It is generally attributed to atmospheric nonlinearities associated with the Sea Surface Temperature (SST) threshold for tropical deep convection. Here, we re-examine these teleconnection asymmetries in the context of ENSO SST pattern diversity. We find that the asymmetries are mainly attributable to strong El Niño events (eg. 1982-83, 1997-98, 2015-16), both in observations and in ensemble simulations with the atmospheric component of the CNRM-CM6 model. This strong El Niño teleconnection pattern also results in specific impacts, characterized by enhanced rainfall along the United States (US) west coast and warm anomalies over Canada and the Northern US. Our ensemble simulations further indicate that moderate “Eastern Pacific” El Niño events exhibit teleconnection patterns that are similar to those of “Central Pacific” El Niño, or to the opposite of La Niña events. We also find that the teleconnection spread between ensemble members or events is reduced for strong El Niño relative to moderate El Niño or La Niña events, with important implications for predictability. Sensitivity experiments in which the atmospheric model is forced by the opposite of observed SST anomalies are used to assess the mechanisms inducing the strong El Niño teleconnection pattern. In addition to the well-known influence of atmospheric nonlinearities, these experiments reveal an important contribution from the Eastward-shifted SST pattern during strong El Niño events. 
Evaluating the erosion risk using the USLE tool in a small agricultural area
Authors: Tomaščík Matúš , Danáčová Michaela , Grečnárová Jana , Výleta Roman , Hlavčová Kamila
Published: February 2023

AbstractUSLE (Universal Soil Loss Equation) was used as a standard tool for evaluating Slovakia's water erosion risk. Understanding interactions between land cover, land use management, and topographical properties of the land are essential to effectively control soil erosion by implementing best management practices. Two ways for LS factor calculation are recommended for use in practice. The first way is in the computing method based on the USLE 2D software, and the second is the other computing algorithms. Various forms can assess the LS factor but with different results. This article aimed to show the differences in LS factor assessment methods in the Myjava Hills – Sobotište study area, a small agricultural area strongly threatened by water erosion. All in two variants before and after the application of anti-erosion measures (water retention grass ditch). Changes in the LS factor were directly indicated in calculating the long-term average soil loss by water erosion. After applying a complex system of anti-erosion measures, results show a significant reduction of the mean long-term soil loss by water erosion in both comparisons.Keywords: USLE, LS factor, anti-erosion measures, soil lossAcknowledgement: This study was supported by PhD student project LABEX. The study was also supported by the VEGA grant agency under the contract numbers VEGA 1/0632/19.
Chronometry: On the redshift and relativistic gravity potential determination in GR
Authors: Philipp Dennis , Hackmann Eva , Laemmerzahl Claus
Published: February 2023

We derive exact expressions for the relativistic redshift and timing between observers in various configurations in stationary spacetimes for the purpose of chronometry, i.e., relativistic gravimetry based on clocks. These observers are assumed to be equipped with standard clocks and move along arbitrary worldlines. It is shown how redshift observations can be used to infer the (mass) multipole moments of the underlying spacetime, i.e., a decomposition of the gravito-electric potential. In particular, an Earth-bound observer is considered that is meant to model a standard clock on the Earth's surface (or on the geoid).  Its clock is continuously compared with a clock on a satellite to determine from redshift measurements a relativistic gravity potential in the vicinity of the Earth. Results shown here are in agreement with the Newtonian potential determination from the so-called energy approach. The framework is intended for applications within relativistic geodesy and is exemplified in different exact vacuum spacetimes for illustration.
key questions to guide hydropeaking research
Authors: Hayes Daniel , Bruno Maria Cristina , Alp Maria , Boavida Isabel , Batalla Ramon , Bejarano Maria Dolores , Noack Markus , Vanzo Davide , Casas-Mulet Roser , Vericat Damian , Carolli Mauro , Tonolla Diego , Halleraker Jo , Gosselin Marie-Pierre , Chiogna Gabriele , Venus Terese
Published: February 2023

Hydropeaking has received increasing attention in the last years, but many knowledge gaps remain, potentially hampering effective policy and management efforts in rivers under such type of hydropower production. In this study, we collected open hydropeaking research questions from over 200 experts in river science, practice, and policy across the globe using an online survey available in five languages. We used a systematic method of determining expert consensus (Delphi method) to identify 100 core questions related to the following thematic fields: (i) hydrology, (ii) physico-chemical properties of water, (iii) river morphology and sedimentology, (iv) ecology and biology, (v) socio-economics and energy markets, (vi) policy and regulation, as well as (vii) management and mitigation measures. The consensus list of questions shall inform and guide researchers in focusing their efforts to foster a better science-policy interface, thereby improving the sustainability of peak-operating hydropower in a variety of settings.
Forecasting the fate of unrest at basaltic calderas
Authors: Acocella Valerio , Galetto Federico , Hooper Andrew , Bagnardi Marco
Published: February 2023

Forecasting eruption is the ultimate challenge for volcanology. While there has been some success in forecasting eruptions hours to days beforehand1, reliable forecasting on a longer timescale remains elusive. Here we show that magma inflow rate, derived from surface deformation, is an indicator of the probability of magma transfer towards the surface, and thus eruption, for basaltic calderas. Inflow rates ≥0.1 km3/year promote magma propagation and eruption within 1 year in all assessed case studies, whereas rates less than 0.01 km3/year do not lead to magma propagation in 89% of cases. We explain these behaviours with a viscoelastic model where the relaxation timescale controls whether the critical overpressure for dike propagation is reached or not. Therefore, while surface deformation alone is a weak precursor of eruption, estimating magma inflow rates at basaltic calderas provides improved forecasting, substantially enhancing our capacity of forecasting weeks to months ahead of a possible eruption.
Humans, Water, and Climate change – Global analysis of Conflicts and Cooperation and their Potential Drivers
Authors: Kåresdotter Elisie , Li Siyuan , Pan Haozhi , Kalantari Zahra
Published: February 2023

Despite agreement that climate change is increasingly recognized as a threat multiplier in conflict pathways, connections between water flows and conflicts remain unclear. This is affected by incomplete datasets on water-related conflict-cooperation events and poor understanding of socioeconomic and biophysical causes of such conflicts. Disentangling various drivers of water-related cooperation and conflict pathways, with more complete datasets on water-related conflict-cooperation events and a detailed understanding of socio-economic and biophysical causes of such conflicts, is necessary for resolving conflicts and building peace As part of this study we have complied a new global dataset on water-related conflict-cooperation events that extends to 2019, updating previous datasets that covered only up to 2008, yielding important new insights on cooperation-conflict trends. Correlations between events and aspects such as changes in precipitation and socioeconomic variables were then calculated for different change scenarios. Analysis of events shows that cooperation can significantly reduce future conflicts in all tested change scenarios. In addition, cooperation positively affects countries’ socioeconomic development, further reducing the risk of conflict. The new dataset revealed a worrying trend with a shift in the cooperation-conflict balance in the 2000s, with conflict events increasing and outnumbering cooperation events in 2017. Regional analysis shows that changes towards more conflict and fewer cooperation events in Africa could be related to long periods of drought, while changes in Asia are related to irrigation and dam construction. This study shows that water cooperation can be effective for peacekeeping while simultaneously creating positive socio-economic development. The trend towards less cooperation and more conflict in current years highlights the need for effective water management adapted to local and regional drivers of change (climate or anthropogenic) focusing on forming collaborations based on current and projected water availability. Utilizing our newly created and openly available water-related conflict and cooperation database can provide a good opportunity for further research into actions required to change this trend and promote future water cooperation.Keywords: conflict; cooperation; peacekeeping; climate change; hydrology
Tropical Atlantic variability during the Last Millennium
Authors: Sobral Verona Laura , Wainer Ilana , Khodri Myriam
Published: February 2023

Climate variability in the Tropical Atlantic is complex with strong ocean-atmosphere coupling, where the sea surface temperature (SST) variability impacts the hydroclimate of the surrounding continents. One of the main modes of SST variability in this region is known as the Atlantic Niño. Its dynamics are dominated by the Bjerknes Feedback, much like the Pacific El Niño. It is characterized by the coupling between SST in the eastern Equatorial Atlantic, zonal wind anomalies, changes in the thermocline depth, and consequent upwelling anomalies. The development of SST anomalies in the Equatorial Atlantic can be explained in terms of an oscillator model of recharge and discharge of heat content. This model is represented by the Bjerknes Feedback Index, which is a set of components representing the mechanisms that enhance (i.e., Thermocline, Zonal Advective, and Ekman feedbacks) or limit (Thermal and Dynamical damping) the growth of the SST anomalies. The pre-industrial millennium is vastly studied with respect to the responses to natural forcing, given the similarity of the climate background with present-day conditions. In addition, this period is known for the occurrence of large volcanic eruptions that were able to change the ocean-atmosphere interaction. Here, we propose to investigate the interannual variability of the Tropical Atlantic during the Last Millennium (LM, 850 to 1849 CE) in terms of the Bjerknes Feedback Index. For that, we rely on results from the Last Millennium period from the Paleoclimate Modeling Intercomparison Project (PMIP4) contribution to Climate Model Intercomparison Project phase 6 (CMIP6).
Low-cost in-field determination of soil ion concentration using a portable 3D printed device based on ion-selective electrodes and textile threads
Authors: Saiz Ernesto , Guo Yafei , Ullah Sami , Sonkusale Sameer , Radu Aleksandar
Published: February 2023

Population keeps growing so as the need for food production. The increase in energy prices is putting a lot of pressure in energy intensive industrial processes such as the production of fertilizers. Farmers need to fine-tune the amount of fertilizer needed by the soil, so that they do not add in excess, elevating costs and polluting the environment, or do not fall short, suffering sub-optimal crop yields.This work reports the fabrication and characterization of a low-cost device for the continuous monitoring of the concentration of plant nutrients based on ion-selective electrodes and textile threads that work in direct contact with soils. Here, as proof of concept, we developed a thread-based, microfluidic sensor platform. We utilized traditional polymer membrane-based ion-selective electrodes (ISEs) for potassium, nitrate, ammonium and pH were drop-casted directly on top of a miniaturized, 3D-printed holder. Electrical contact is established via graphite-based contacts link to the electrochemical signal reader via electrical wires. The sensor platform was enhanced by the addition of five 30 cm long textile threads connected to an absorption pad on the opposite side. This is the key innovation as these threads mimic the roots and via capillary action wick the moisture from the soil to the sensing area. The entire sensor platform contained 4 ISEs for each chemical species and one reference electrode and was encased into a 3D printed housing. The device is placed next to the soil that is going to be analysed inserting the threads in the soil sampling area.Preliminary results show that thread-based sensor system is reproducible and consistently provides a near-Nernstian sensitivity of 55±5 and 50±3 for potassium, -58±1 and -63±2 for nitrate, and 60±1 and 60±12 (mV/decade) for ammonium between 2.8x10-6 and 1.3x10-2 M without (directly in solution) and with textile threads respectively. Analysis of soil samples with different soil moisture content (100%, 75%, 50% and 40%) using our low cost device gave a correlation coefficient of R2 = 0.91 for potassium and R2 = 0.92 for ammonium when compared to the values measured using traditional methods such as inductively coupled plasma optical emission spectroscopy (ICP-OES) and flow injection analysis (FIA), respectively. The promising performance of this low-cost device is encouraging towards its use as an extended network to measure soil ion concentration at high temporal and spatial resolution.
Change in soil organic carbon content in European mountain forests based on LUCAS soil databases 2009-2018
Authors: Gus-Stolarczyk Magdalena , Bartos Anna , Gołąb Agata , Musielok Łukasz
Published: February 2023

Forest ecosystems act as huge reservoirs of organic carbon by binding atmospheric carbon dioxide in the process of photosynthesis. Carbon in forests is stored both in aboveground and belowground biomass as well as in the form of dead organic matter in the soil. This soil organic carbon (SOC) pool may play a particularly important role in mitigating climate change through the long-lasting retention of organic compounds.Much of Europe's forests are located in the mountains, where low temperatures and high humidity protect dead organic matter from rapid oxidation. In addition, the area covered by forests is increasing due to forest succession in abandoned areas. Both land cover change, as well as tree species conversion, are the factors that can lead to significant changes in SOC content. Thus, the aim of this study was to determine the impact of land use, land-use change, and forestry (LULUCF) on SOC content in European mountain forest ecosystems.Data on land cover and SOC content in European mountains (areas above 500 m a.s.l.) were obtained from the 2009, 2015 and 2018 Land Use and Coverage Area frame Survey (LUCAS) databases. We compared the SOC content of sites that were under forests in 2009 or 2018, with or without changes in land use or species composition over the designated period. The highest increase in SOC content was noted at sites where conversion from meadow to deciduous forest took place (mean 3.46 g C kg-1 year-1). The SOC content decreased at sites that in the period 2009-2018 were constantly under mixed forests (mean -0.87 g C kg-1 year-1) and under coniferous forests (mean -0.21 g C kg-1 y-1), while at sites located under deciduous forests, the SOC content increased (mean 1.08 g C kg-1 y-1). These results suggest that forestation and maintenance of deciduous forests may have the greatest impact on carbon sequestration in mountain ecosystems in Europe.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 952327 (HES-GEO).
Long-term trends in European extreme floods from 1950 to 202
Authors: Tilloy Aloïs , Paprotny Dominik , Mentaschi Lorenzo , Treu Simon , Lange Stefan , Bianchi Alessandra , Salamon Peter , Grimaldi Stefania , Gomes Goncalo , Mengel Matthias , Feyen Luc
Published: February 2023

Hydrological extremes are non-stationary, displaying long-term trends and natural oscillations. These changes in extremes can be driven by multiple factors including climatic (climate variability, climate change) and socio-economic (land use changes, water management changes) factors. In this work, we analyse extreme river flows in Europe for the period 1950-2020. We aim to identify long-term trends in extreme floods and estimate the contribution of the two aforementioned factors in these trends. The assessment is performed with modelled streamflow data generated with the spatially distributed physically based model LISFLOOD. We force the model with bias-corrected and statistically downscaled climate data derived from the ERA5-Land climate reanalysis and the EMO-5 dataset. We also created a variant of the climate dataset with the global warming effect removed statistically from the data. Return periods of extreme flood events are estimated through a non-stationary extreme value analysis for each river point with an upstream area greater than 100 km2. To disentangle the influence of the different factors driving changes in extreme flows, the hydrological model is run under various scenarios: (i) historical (historical climate and dynamic socio-economic) (ii) static society (historical climate and static socio-economic), (iii) counterfactual climate (historical climate without global warming and dynamic socio-economic). Available preliminary results enable presenting long-term space-time dynamics of European floods.
Quantitative inverse scattering analysis for ground penetrating radar imaging
Authors: Fedeli Alessandro , Schenone Valentina , Pastorino Matteo , Randazzo Andrea
Published: February 2023

The inspection of underground scenarios is a challenging task required in several applications, from geophysical to archeological and civil areas. The ground penetrating radar (GPR) is a common tool that has been widely adopted to provide qualitative imaging of the underground scenario [1]. Recently, several approaches to process GPR data and retrieve quantitative images to characterize the inspected region have been developed [2-3]. Moreover, to compensate for the loss of information that usually happens in this scenario, GPR systems have been implemented not only in monostatic and bistatic configurations but also in multistatic settings [4].In this contribution, a quantitative inverse scattering approach is proposed to retrieve the distribution of the complex dielectric permittivity of a buried region, starting from scattering parameters collected through a multistatic GPR configuration. The approach is based on a finite-element (FE) formulation of the electromagnetic inverse scattering problem and, as solving procedure, a reconstruction method in variable exponent Lebesgue spaces is adopted [5]. On the one hand, the FE model embedded in the method is exploited to describe the structure of the measurement configuration without simplifying assumptions (except for the two-dimensional hypotheses and the numerical discretization of the problem). On the other hand, the inversion procedure in variable exponent Lebesgue spaces has been found quite effective to face the ill-posedness and nonlinearity of the problem. A numerical validation of this approach is reported. References[1] R. Persico, “Introduction to ground penetrating radar: Inverse scattering and data processing.” Hoboken, New Jersey: Wiley, 2014.[2] M. Pastorino and A. Randazzo, “Microwave imaging methods and applications.” Boston, MA: Artech House, 2018.[3] V. Schenone, A. Fedeli, C. Estatico, M. Pastorino, and A. Randazzo, “Experimental assessment of a novel hybrid scheme for quantitative GPR imaging”, IEEE Geoscience and Remote Sensing Letters, vol. 19, pp. 1–5, 2022.[4] M. Ambrosanio, M. T. Bevacqua, T. Isernia, and V. Pascazio, “Performance analysis of tomographic methods against experimental contactless multistatic ground penetrating radar”, IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, vol. 14, pp. 1171–1183, 2021.[5] V. Schenone, C. Estatico, G. L. Gragnani, M. Pastorino, A. Randazzo, and A. Fedeli, “Microwave-based subsurface characterization through a combined finite element and variable exponent spaces technique”, Sensors, vol. 23, no. 1, p. 167, 2023.
Evaluation of Parameter Transferability of Snowmelt Runoff Model in Chandra-Bhaga Basin, India
Authors: Vinze Parul , Azam Mohd Farooq
Published: February 2023

Snowmelt runoff is a significant component in the glacierized and snow-covered basins of the western Himalaya. Modelling is the most useful tool to quantify snowmelt contribution in mountainous rivers, but the paucity of in-situ observations makes the model calibration quite challenging and therefore model parameters are often adopted from the neighboring river basins. In the present study, we applied Snowmelt Runoff Model (SRM) in the Chandra-Bhaga Basin and Chhota Shigri Glacier Catchment in the western Himalaya. We systematically checked the transferability of the model parameters between the catchment and basin. Using snow cover area (SCA), precipitation, and temperature as inputs, the daily discharge for the Chhota Shigri Catchment and Chandra-Bhaga Basin was reconstructed over 2003–2018. The mean annual discharge was found as 1.2 ± 0.2 m3/s and 55.9 ± 12.1 m3/s over 2003-2018 for the Chhota Shigri Catchment and Chandra-Bhaga Basin, respectively. The discharge in the Chhota Shigri Catchment was mainly controlled by summer temperature and summer SCA, whereas in the Chandra-Bhaga Basin summer SCA and summer precipitation controlled the discharge. At both the catchment and basin scale, the decadal comparison revealed an increase (11% and 9%) and early commencement (10 days and 20 days) of the maximum monthly discharge over 2011-2018 compared to 2003-2010. In the Chhota Shigri Catchment, the model output is almost equally sensitive to the 'degree day factor' and 'runoff coefficient for snow,' but most sensitive to the 'runoff coefficient for snow' in the Chandra-Bhaga Basin. Even though the SRM parameters were calibrated in a data-rich Chhota Shigri Glacier Catchment, their application in the Chandra-Bhaga Basin led to a large discharge overestimation at the basin scale and was not transferable even in the same basin. We suggest to be cautious while adopting/transferring model parameters for SRM from other basins, particularly for the ungauged basins.