bluuebunny/crossref_metadata_2025 huggingface dataset:
Debris flows risk assessment for Central Asia by application of Global Ensemble Output and Post-processed Precipitation
Authors: Mamadjanova Gavkhar , Shahgedanova Maria , Pillosu Fatima
Published: February 2023

Accurate predictions of heavy and intense rainfall are vital for impact-based forecasting that can be essential for mitigating the significant damage and loss of life across the globe. However, producing reliable forecasts capable of capturing the rainfall values is challenging in complex mountain terrain due to the forecast uncertainty and computational cost especially in data-scarce regions. Central Asia is one of these regions, where extreme rainfall leads to flash floods, landslides and debris flows in the mountains and foothills. The risk of these events increases with global warming, and the early warning systems based on reliable forecasts are particularly important to manage the risk in the region and adapt to climate change.In this study, we have evaluated and compared the skills of two probabilistic forecasts developed by the European Centre for Medium-Range Weather Forecasts (ECMWF): standard Ensemble Forecasts (ENS) which consists of an ensemble of 51 members and ecPoint Rainfall produced by statistical post-processing of the ENS and delivers probabilistic forecasts of rainfall totals for points within a model gridbox (18 km resolution) that can be particularly useful in the mountains. Skills of both forecasts were assessed in relation to the forecast of debris flows in Central Asia.Both forecast products were verified against SYNOP (surface synoptic observations) data for stations over Central Asia, mainly for the debris flow season (March-October) in 2022. In this case, two popular verification methods were used: Brier Score and Receiver Operating Characteristics (ROC) diagram for the exceedance of precipitation thresholds of 1 mm, 10 mm and 25 mm.Verification trials over the 2022 debris flow season in Central Asia show that the performance of ecPoint Rainfall depending on the forecast lead-time can be a good proxy for the range of point rainfall values to define the warning areas of debris flow risk over the study area. The ecPoint Rainfall is recommended for the operational application of heavy rainfall leading to debris flow formation which can support impact-orientated forecasting and early warning systems in Central Asia.
The impact of vertical mixing schemes on the position of the ITCZ in the eastern tropical Pacific
Authors: De Falco Chiara , Mooney Priscilla A. , Tjiputra Jerry
Published: February 2023

The presence of a double Intertropical Convergence Zone (ITCZ) in the tropical Pacific is a persistent feature of global coupled ocean-atmosphere models that gives rise to excessive precipitation south of the equator. The ITCZ position is extremely sensitive to changes in the magnitude and distribution of the Sea Surface Temperature (SST) in the tropical band, due to the strong coupling between SST and convective precipitation.  The complexity of the air-sea interactions makes it hard to disentangle the different mechanisms at play to identify the main driving processes behind this ubiquitous bias. Here, we use a coupled ocean-atmosphere regional model, the Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System, to investigate the impact that different parametrizations of the oceanic vertical mixing have on the water column dynamic, SST and subsequently the convective precipitation distribution in the eastern tropical Pacific. The model includes an atmospheric component, the Weather Research and Forecast Model (WRF), and an oceanic component, the Regional Ocean Modeling System (ROMS). The same atmospheric setup, with a resolution of 20km, has been forced with observed SSTs and with two ocean parameterizations. Different temperature gradients and oceanic stratification give rise to a double ITCZ or to a southward shift of the maximum precipitation band. Particularly in late winter and spring, a surface warming of a few degrees south of the equator around 5°S affects the distribution of the sea level pressure. The consequent changes in the surface wind pattern impact the usually asymmetric behavior of the trade winds, the south easterlies are no longer able to cross the equator and converge in the ITCZ in the northern hemisphere.  
Melting and subsolidus phase relations of Fe-Si-S alloys at Mercury’s core conditions
Authors: Dominijanni Serena , Anzellini Simone , Kurnosov Alexander , Morard Guillaume , Boccato Silvia , Fedotenko Timofey , Antonangeli Daniele
Published: February 2023

The internal structure of Mercury holds key information regarding the planet’s formation and its peculiar magnetic field. Waiting for incoming observations by BepiColombo, current knowledge of the interior structure of Mercury relies primarily on geodetic and surface chemistry data collected by MESSENGER. Results from spectral and compositional analysis supplemented by cosmochemical evidence indicate that light elements such as S, and Si are most likely alloyed to Fe in Mercury’s core. This notion is further supported by the very reducing redox conditions (from -2.6 to -7.3 log units below Fe-FeO oxygen buffer) predicted to occur during the planet’s differentiation that argue for significant quantities of Si and S partitioned into metallic iron. Thus, it is of primary importance to determine the Fe-Si-S phase diagram and to understand the high pressure and high temperature properties and thermodynamic behavior of Fe-Si-S alloys at conditions directly relevant for Mercury’s core. Very recently the binary Fe-FeSi phase diagram has been established at Mercury’s core conditions, but phase and melting relations in the Fe-Si-S ternary system still are poorly constrained, in particular at the relatively low pressures and temperatures relevant for Mercury’s core.To address this issue, we performed angular dispersive powder X-ray diffraction experiments in laser-heated diamond anvil cells on selected composition in the Fe-Si-S system (i.e., Fe-4S-6Si, Fe-16S-6Si, Fe-4S-12Si, and Fe-16S-12Si, all in wt. %) at the P02.2 Extreme Conditions beamline at DESY Synchrotron facility (Germany). For all compositions, eutectic melting and subsolidus phase relations were investigated up to about 45 GPa. Ex situ chemical analysis of the recovered run products were performed at the IMPMC laboratory on the extracted FIB thin sections cut throughout the heated spots.Here we will present preliminary results on the eutectic melting and Fe-Si-S phase relations as a function of pressure, temperature and composition, with specific focus to the conditions expected within the core of Mercury.
Preliminary findings from comparison of in-situ measurements of enhanced weathering proxies with model predictions
Authors: Skov Kirstine , Bierowiec Tzara , Edeh Ifeoma , Kelland Mike , Lewis Amy , Murphy Melissa , Pape Ryan , Turner Will , Wade Peter , Wardman Jez , Liu Xinran
Published: February 2023

Enhanced weathering of silicate rock is a promising natural carbon dioxide removal technology, both due to its scalability and associated agronomical benefits. During silicate rock weathering, dissolved carbon dioxide in the form of carbonic acid, reacts with rock minerals to form stable soil pore water bicarbonate or soil calcium carbonate. The carbon dioxide removal potential of enhanced weathering has been successfully demonstrated in short-term lab and mesocosm studies. Due to the transient nature of bicarbonate in the aqueous soil solution, in-field quantification of the carbon dioxide sequestered is tedious, labour-intense and poorly scalable for the verification of carbon credits. Various methods have been suggested in order to quantify the amount of carbon dioxide sequestered through rock weathering. This quantification is essential for verification bodies to award carbon credits. Although various methods have been proposed to demonstrate that in-field weathering is occurring, there is still no consensus for a scalable, profitable solution. In recent years, an increasing number of field trials have seen the light of day. However, large uncertainties about in-field weathering rates and the influence of natural environmental variability, such as drought and vaying temperatures, still exist. 
In this study we focus on two proxies affected by the weathering process, namely pH and EC. We compare field measurements of pH and EC from both in-situ sensors and extracted soil pore water with model predictions from a 1D-reactive transport model. The data originates from an ongoing field trial on an acidic, clay rich soil used for grassland pasture in central Scotland. Such in-field proxy measurements may provide information to help boost confidence in model predictions.
Run analysis of potential evapotranspiration and soil moisture for investigating flash droughts in Sicily
Authors: Aschale Tagele Mossie , Peres David J. , Palazzolo Nunziarita , Sciuto Guido , Cancelliere Antonino
Published: February 2023

Flash droughts develop and intensify rapidly under the influence of abnormally high temperatures, wind speed, radiation and declining of the normal precipitation rate. The changing of Potential evapotranspiration (PET) and soil moisture is considered as key early warning and development of flash drought indicators.In this study, we first analyse spatio-temporal trends of the PET at monthly, seasonal, and annual temporal scales in Sicily.  PET is estimated by the Penman-Monteith method based on a network of 46 meteorological stations, at daily metrological data. The Mann Kendall test and Sen’s slope analysis are applied to identify the significance of PET trends in the region. Result showed increasing trends for most of the months and the region. For instance, August had the highest increasing PET monthly trend, with a maximum of 1.73 mm per year and the highest increasing annual trend was 10.68 mm per year. Findings of this analysis provide preliminary insights on how climate change can influence PET.Then, we carry out a preliminary investigation of flash droughts based on a joint analysis of potential evapotranspiration and soil moisture. In particular, based both on the network of meteorological stations and reanalysis data  of soil moisture at hourly resolution, daily  potential evapotranspiration (PET) and soil estimations at different soil depths are analysed with the method of runs. Considering different thresholds, the runs of PET and soil moisture are compared to characterize flash drought periods and to understand the relation between the two variables. Results indicate a significant link between the variables, and thus a potential for developing flash drought monitoring tools.  Keywords: Flash drought, Potential evapotranspiration (PET), Spatiotemporal, Trend, Sicily 
Sustainable management of peatlands for climate and livelihoods in Perigi, South Sumatra, Indonesia
Authors: Artati Yustina , Baral Himlal , Rahman Syed A
Published: February 2023

Indonesian peatlands provide substantial direct and indirect benefits at local and wider scales. However, degradation of peatlands, which is often due to fire, causes serious impacts on humans and the environment. This research was conducted in Perigi Village, South Sumatra Province as a case study of farmers who were mostly involved in subsistence ‘sonor’ paddy cultivation, contributing to further peatland degradation. A 3-hectare agrosilvofishery experimental plot was established to assess the potential for improving livelihoods and conservation, making it a sustainable land-use alternative for peatlands. Based on farmers and experts’ assessments, the costs and benefits were estimated, which showed that the agrosilvofishery system had a higher net present value than the sonor system. Holding tree ownership could also create more secure rights to farmland and was prestigious in the community. Besides strengthening social cohesion, agrosilvofishery can help improve overall biodiversity and environmental quality, preventing peatland fire by requiring active management of the farm plot and surrounding areas, reducing degradation and carbon emissions. Farmers could potentially gain additional income from carbon farming. Farmers in Perigi were interested in practising agrosilvofishery systems to diversify farm products — for example, rice, pineapple, fish — while growing trees. Increasing adoption of this system may require capital and technical support to overcome capacity constraints. Keywords: Degraded peatland, sonor cultivation, agrosilvofishery system, carbon farming
Role of the subpolar North Atlantic region in skillful climate predictions for high northern latitudes: A pacemaker experiment
Authors: Drews Annika , Schmith Torben , Yang Shuting , Olsen Steffen , Tian Tian , Devilliers Marion , Wang Yiguo , Keenlyside Noel
Published: February 2023

Recent studies have suggested that the Atlantic water pathway connecting the subpolar North Atlantic (SPNA) with the Nordic Seas and Arctic Ocean may lead to skillful predictions of sea surface temperature and salinity anomalies in the eastern Nordic Seas. To investigate the role of the SPNA for such anomalies downstream, we designed a pacemaker experiment, using two decadal climate prediction systems based on EC-Earth3 and NorCPM. We focus on the subpolar extreme cold anomaly in 2015 and its subsequent development, a feature not well captured and predicted. The pacemaker experiment follows the protocol of the CMIP6 DCPP-A retrospective forecasts or hindcasts initialized November 1, 2014, but the models are forced to follow the observed ocean temperature and salinity anomalies in the SPNA from ocean reanalysis from November 2014 through to December 2019. Two sets of 10-year hindcasts are performed with 10 members for EC-Earth3 and 30 members for NorCPM. We here detail and discuss the design of this pacemaker experiment and present results, comparing with the initialized CMIP6 DCPP-A experiment assessing differences in decadal prediction skill outside the SPNA. We conclude that the pacemaker experiments show improved skill compared to the standard decadal predictions for the eastern Norwegian Sea, and therefore the SPNA is key for successful decadal predictions in the region.
Global Modeling of Microplastics in the Atmosphere
Authors: Yang Shanye
Published: February 2023

Global Modeling of Microplastics in the AtmosphereShanye Yang, Guy Brasseur, Stacy Walters, Pablo Lichtig, Cathy Wing Yi Li, Xiaofei WangGlobal model simulations driven by bottom-up emissions show that more than 100 kilotons of microplastic particles are suspended in the atmosphere. The calculations are based on estimated emissions associated to traffic, agriculture, domestic activities and ocean exchanges. They make use of our laboratory measurements of microplastic exchanges at the water-air interface that is considerably less intensive than the emissions from land. Approximately 20 million tons are deposited each year on the Earth’s surface, and 3 million tons in the oceans. These model simulations show that the microplastic particle abundance is considerably higher over the continents, which is consistent with current observations. Exposure risks are highest in the most populated areas. Worldwide, adults inhale 2.4 × 107 - 1.5 × 109 microplastic particles per year. Remote areas including Antarctica and the Arctic are also important receptor regions for the particles with a diameter smaller than 1.5 μm.
Attributing trends in the land carbon cycle using process-based DGVMs and global scale observations
Authors: O'Sullivan Michael , Friedlingstein Pierre , Sitch Stephen
Published: February 2023

The global land carbon sink has increased in parallel with anthropogenic CO2 emissions over the last several decades, taking up ~25% of these emissions, and acting as a strong negative feedback to mitigate climate change. However, we have a limited ability to confidently attribute past changes. Here we use the suite of Dynamic Global Vegetation Models (DGVMs) from the Global Carbon Budget to develop a process-attribution framework to identify where models agree and, just as importantly, disagree, and thus guide future modelling efforts. We take a holistic approach to answer the following questions:What are the 1) external drivers (concurrent rises in atmospheric CO2 and nitrogen deposition, climate, land-use and land-cover change (LULCC)), 2) main regions (tropics, extra tropics), and 3) processes (production vs turnover) primarily responsible for the changes in the net land carbon sink?We find the observed global net land carbon sink is captured by current land models. However, there is a lack of consensus in the partitioning of the sink between vegetation and soil, where models do not even agree on the direction of change in carbon stocks over the past 60 years. This uncertainty is driven by plant productivity, allocation, and turnover response to atmospheric CO2 (and to a smaller extent to LULCC), and the response of soil to LULCC (and to a lesser extent climate). Overall, differences in turnover explain ~70% of model spread in both vegetation and soil carbon changes.Using a top-down constraint of net land-atmosphere carbon exchange from atmospheric inversions and remote-sensed products of vegetation functioning, we show that DGVMs underestimate carbon uptake in northern latitudes. A large portion of model error can be explained by the simulated LULCC flux. In tropical lands, models likely overestimate net carbon uptake due to too strong CO2 fertilisation, which can, in part, beexplained by too high modelled forest area and carbon densities.
Using a record of bedload transport from Leverett glacier in western Greenland to understand proglacial sediment transport processes from the ice sheet
Authors: Gevers Marjolein , Mancini Davide , Lane Stuart , Delaney Ian
Published: February 2023

Increased glacier melt leads to a change in sediment transport capacity below glaciers, which impacts the sediment transport within proglacial areas as well as downstream ecosystems and geomorphology. Previous work on Alpine glaciers shows that strong diurnal discharge variations lead to fluctuations in sediment transport capacity such that deposition and erosion can occur in the proglacial area over the course of the melt season. However, the exact processes controlling sediment transport at the outlet glaciers of ice sheet margins and in their proglacial areas remain uncertain. Data suggest that the diurnal discharge variations are substantially reduced and baseflow discharge is much greater, likely capable of maintaining significant sediment transport throughout the melt season. This difference in the hydrological regime as compared with Alpine glacial systems may drive different rates and variations in sediment transport and, ultimately, in proglacial braid plain morphodynamics.We measure proglacial sediment transport at Leverett glacier, a land-terminating glacier located at the western margin of the Greenland Ice Sheet. As bedload transport is exceptionally difficult to measure in situ, two seismic stations were installed to evaluate bedload transport in the glacial meltwater stream in the summer of 2022. The first station is located close to the current glacier terminus, and the second one is about 2 km from the current glacier terminus. These two stations allow for the examination of the sediment transport processes within the proglacial area. By using a Fluvial Inversion Model the recorded seismic data is converted into bedload flux. The model is calibrated using active seismic surveys and statistical approaches to evaluate the physical parameters. Outputs of the Fluvial Inversion Model are validated with available water stage data.  The results provide insight as to whether the proglacial area is aggrading or eroding as sediment transport in the two locations at Leverett glacier evolves over the summer season. We discuss the relationship between bedload transport and level of the proglacial river, as well as the seasonal variations in proglacial sediment transport and deposition in Leverett glacier’s proglacial area.
Monitoring flood risk evolution: A systematic review of flood risk evolution assessments
Authors: Rindsfüser Nele , Zischg Andreas Paul , Keiler Margreth
Published: February 2023

Flood risk is changing over time. Climate change, land-use change, human interventions and socio-economic developments have an influence on the evolution of flood risk. Thus, the future dynamics of drivers influencing hazard, exposure and vulnerability and consequently flood risk evolution is uncertain. Therefore, flood risk management is confronted with deep uncertainties and need to continuously adapt to future circumstances. New management strategies are required to ensure the safety level of humans and their assets and reduce losses from floods. Adaptive flood risk management is a way to cope with such uncertainties. However, the implementation of adaptive flood risk management requires a flood risk monitoring system that screens critical developments of hazard, exposure, or vulnerability and warns the user when a critical point in flood risk evolution is approached. In order to develop a conceptual framework for a flood risk monitoring system, we conducted a systematic review of flood risk evolution assessments. We analysed how flood risk is conceptualised, which factors are assessed to analyse evolutions in one or more risk component, which methods are used to assess flood risk evolution and which risk outcomes are identified. We discuss the main concepts of monitoring the spatiotemporal changes of the components of risks and how the changes of these components contribute to the evolution of risk. We furthermore discuss the data sources, issues of spatial and temporal scales, and how the components of risk coevolve.
Use of high temporal resolution data to identify the key drivers and locations where walls of water occur in the UK
Authors: Fileni Felipe , Archer David , Fowler Hayley , McLay Fiona , Lewis Elizabeth , Yang Longzhi
Published: February 2023

Walls of water (WoW) are a subset of flash floods characterised by an extremely fast increase in the discharge rate of rivers. In the UK, WoWs, events where an almost instantaneous increase in river flow happens, are responsible for several deaths, even when the maximum peak flow of the said event is not as noticeable. Using a national 15-minute continuous dataset, this study identified WoWs for catchments in the UK. Next, the antecedent atmospheric conditions for these WoWs were extracted from gridded datasets. Furthermore, catchment descriptors such as catchment area, elevation, slope, land use, and permeability of every catchment were downloaded from the National River Flow Archive. Finally, with the use of machine learning algorithms, that is, tree regressions and neural networks, this study identified vulnerable catchments and key conditions for WoWs to occur. Early results indicate that WoWs are not solely driven by rainfall intensity and that larger catchments (>500km) with low permeability are the most vulnerable to these hazards. Further studies using additional atmospheric conditions, i.e., temperature and windspeed will allow a better understanding of the drivers of these events.
Recent inorganic carbon increase in a temperate estuary driven by water quality improvement and enhanced by droughts
Authors: Rewrie Louise , Voynova Yoana , Beusekom Justus , Körtzinger Arne , Ollesch Gregor , Baschek Burkard
Published: February 2023

Estuaries are an important component of the global carbon budget as sites of removal and transformation for carbon between land and coastal ocean. Drought conditions can lengthen river and estuarine water residence time, which can extend the retention and alter the cycling of organic carbon and nutrients. To better understand the functioning of an estuary under the current threat of climate change related droughts, we use the Elbe Estuary as an example, examining a period since 1997, when annual mean DIC in the mid to lower Elbe Estuary increased significantly, and with focus on the drought conditions since 2014. The recent (1997-2020) significant DIC increase by 6 to 15 µmol L-1 yr-1 we found is due to increase in upper estuary POC content of 8-14 µmol L-1 yr-1 in late spring and summer (May-August). The significant increase in POC was associated with dominating autotrophy (with negative AOU and pH > 9), and an overall improvement in water quality shown in significant (> 50%) decrease in BOD7 since 1997. We found that microbial respiration of organic matter from upstream regions accounted for most of the DIC produced in the mid-estuary, therefore, the increased POC is efficiently remineralized to DIC by the mid-estuary region.The Elbe River and estuary was subject to significantly lower river discharge between 2014 and 2020 (468 ± 234 m3 s-1), nearly 40% of the long-term average (1960-2020, 690 ± 441 m3 s-1). In addition, May was the only month with a significant negative trend in mean monthly river discharge from 1997, and down to 264 ± 19 m3 s-1 by 2020, a discharge usually observed during summer and early autumn. During the recent drought period (2014-2020), the internal gain in the carbon load as DIC in the mid to lower estuary was significantly higher, by up to 3 times, compared to the non-drought period (1997-2013). This suggests that the drought in the Elbe watershed caused a significant reduction in the average river discharge in May, likely increasing the residence time in the estuary, subsequently permitting a longer period for remineralisation of POC and greatest production of DIC in the mid-lower Elbe Estuary.
Traceable Calibration of Seismometers
Authors: Klaus Leonard , Larsonnier Franck , Winther Jacob Holm , Schwardt Michaela , Kobusch Michael , Bruns Thomas
Published: February 2023

At present, seismometers are not traceably calibrated. This means that their output sensitivity is not determined in a way that is traceable to the International Systems of Units (SI). The European research project 19ENV03 Infra-AUV, which is part of the EMPIR programme, develops methods and procedures to enable such traceable calibrations.In contrast to many other sensors, seismometers are operated stationary in their typical measurement application, i.e., they must not be moved after their deployment. Conventional calibration approaches which involve a laboratory calibration of the seismometer to be calibrated are therefore not feasible. For this reason, a new concept currently developed by different European partners within the Infra-AUV project proposes an on-site calibration scheme.For the on-site calibration, a reference seismometer is traceably calibrated to the SI in a laboratory. This reference is then used on-site to provide a secondary calibration of other seismometers, e.g. in a seismic station, using natural excitation sources [Schwardt et al., 2022, DOI: 10.1007/s10712-022-09713-4].The calibration of reference seismometers in the laboratory is carried out as a primary calibration. This means that the measured quantity (the velocity-proportional voltage output) is compared to a different quantity, in this case to a dynamic displacement measurement traced back to the units length and time, which can be measured very precisely by laser interferometry. In this calibration, the seismometer is excited with low-frequency mechanical vibrations generated by electrodynamic exciters. These calibrations must be performed for the horizontal and vertical axes. The frequency range of interest is from 20 Hz down to 0.01 Hz, depending on the seismometer under test. Either mono-frequency sinusoidal excitations of different frequencies are applied subsequently, or multiple frequencies are excited simultaneously using a multi-sine approach. The magnitudes and phases of both measured signals, the interferometric reference and the seismometer under test, are determined by using sine approximation algorithms or by applying a discrete Fourier transform (DFT).The results of the laboratory calibration, the transfer function of the reference seismometer, can then be derived from the ratios of the measured magnitudes and the differences of the phase angles for the different excitation frequencies. In addition, the associated measurement uncertainties are estimated and are part of the calibration result. Influences that may change the sensitivity of a seismometer, e.g., temperature effects, electromagnetic sensitivity, or ground stiffness need to be analysed and additionally taken into account for the uncertainty estimation.For the uncertainty of the on-site calibration, differences between the laboratory and the on-site environment also need to be taken into account. This includes, for example, aspects like typically different temperatures or different ground materials.
Cellular automaton based modeling of dynamic soil structures and their functions across scales
Authors: Ray Nadja , Prechtel Alexander , Rötzer Maximilian , Zech Simon
Published: February 2023

We present a spatially and temporally explicit mechanistic model for soil aggregation at the microscale. This consists of a cellular automaton model for the dynamic rearrangement of solid building units whose size and shape are derived from dynamic image analysis of wet-sieved, water stable aggregates. This model is combined with a particulate organic matter (POM) turnover model or a model for a growing fine root which exudes and distributes mucilage into the soil. Along this line the mutually interacting soil and POM dynamics and the intertwined processes at the root-soil interface are captured and evaluated simultaneously at the biologically relevant scale. Our comprehensive modeling toolbox allows us to conduct various simulation scenarios and to discriminate and evaluate the underlying processes and different drivers such as texture. We quantify our results by evaluating the stability of the created structures or the dynamical change in local porosity around a growing root. Finally, the insights gained at the microscale are used to parametrize a CO2 transport model at the profile scale. Thereby, the microbially mediated CO2 source is taken into account as well as the driver soil texture, and changing ambient environmental conditions such as water saturation, oxygen concentration and POM content.
A novel approach for predicting spring locations using machine learning algorithms in Indian Himalayan Region
Authors: Gairola Pradeep , Maiti Arabinda , Sannigrahi Srikanta , Bhatt Anand , Singh Rawat Soban , Kumar Sudhir , Singh Bisht Deepak , Bhatt Sandeep
Published: February 2023

Due to the concerning effects of climate change, groundwater will be one of the significant sources of water for both primary and secondary use in the future. Therefore, identifying the spatial patterns of groundwater distribution might help implement practical water resources management projects. Springs are a potential source of groundwater in the Indian Himalayan Region. The main objective of the current study is to explore a novel methodological approach that utilizes the Variance Inflation factor (VIF) to perform a feature selection procedure and most used machine learning (ML) algorithms, including Random Forest (RF), Gradient Boosting Machine (GBM), and Neural Network (NN) for generating a groundwater spring potential map of the Ravi Basin in Himachal Pradesh, India. Used, 1834 spring and non-spring locations were selected from the field and split into two groups. Of 1834 samples, 70% (1283) were used for model training, and 30% (551) were used for model validation. The model’s overall accuracy of 0.89, 0.87, and 0.88 for RF, GBM, and NN, respectively, around 10% area, has a very high potential for spring occurrence. The novel methodology can be employed to find the initial information for GW exploitation for inaccessible areas and the lack of data sources in this area.
Spatio-temporal variability of the Peninsula Front and the surface chlorophyll-a bloom in the Bransfield Strait
Authors: Veny Marta , Aguiar-González Borja , Marrero-Díaz Ángeles , Pereira-Vázquez Tania , Rodríguez-Santana Ángel
Published: February 2023

The Bransfield Strait (BS) is a relatively narrow region located between the South Shetland Islands (SSI) and the Antarctic Peninsula (AP), where the dominant cyclonic circulation is composed by two major inflows, which appear to influence the development of the seasonal chlorophyll bloom. On the one hand, the Bransfield Current transports Transitional Zonal Water with Bellingshausen influence (TBW) northeastwards along the SSI slope. TBW is characterised by well-stratified, relatively warm (Ɵ > -0.4ºC) and fresh (<34.45) waters. On the other hand, the Antarctic Coastal Current (CC) transports Transitional Zonal Water with Weddell influence (TWW) southwestwards along the AP coastline, being distinguished by homogeneous, colder (Ɵ < -0.4ºC) and saltier (>34.45) waters (Sangrà et al., 2017). These two water masses confront each other forming the Peninsula Front (PF; García et al., 1994; López et al., 1999). Interestingly, the chlorophyll-a (chl-a) spatial distribution in the BS has already been linked in the past to the spatial distribution of both water masses and their water column vertical stability, among other factors (Lipski and Rakusa-Suszczewski, 1990; Basterretxea and Arístegui, 1999). Thus, higher chl-a concentrations have been reported around the SSI and Gerlache Strait where TBW flows, while lower concentrations have been traditionally found north off the SSI and closer to the AP coastline, where more homogeneous surface waters prevail (AASW and TWW, respectively) (Corzo et al., 2005).In this work we aim to provide a further understanding on the bio-physical coupling occurring in the Bransfield Strait, focused on the physical drivers controlling the surface distribution of the chl-a bloom and the location of the PF at seasonal and interannual scales. To do this we use various remotely-sensed observations over the period 1998-2018: Sea Surface Temperature (SST), Sea-Ice Coverage (SIC), chlorophyll-a, wind stress and Photosynthetically Active Radiation (PAR). Preliminary results confirm that the spatial distribution of the surface chl-a bloom in the Bransfield Strait is strongly influenced by the location of the PF, both seasonally and interannually. Also, a shift in the strength of the chl-a bloom has been identified, where significantly stronger events are found from 2005 onwards; when mean chl-a bloom values are slightly greater, and about 0.61 mg m-3, than in previous years, when they averaged about 0.49 mg m-3. We hypothesize this shift might be linked to observed changes in the seasonal evolution of the SIC and SST over the same period. Ongoing analyses attempt to elucidate the major mechanisms accounting for this apparent variability of the bio-physical coupling controlling the chl-a blooms in the Bransfield Strait.
The role of urban forests in compound urban crises: focusing on floods, air pollution, and human thermal comfort
Authors: Park Kihong , Kim Hyeon-Joon , Jun Changhyun
Published: February 2023

The crisis in cities with high vulnerability are interlinked and cannot be addressed in isolation. The consideration of integrated approach to disaster management is essential to urban for resilience. This study aims to investigate the role of urban forests on reducing any potential risks from compound disasters in urban areas, represented by floods, air pollution, and human thermal comfort. At first, types of urban forests are investigated in a perspective of nature-based solutions (NbS) with various design criteria appropriate for urban rivers, potentially threatened by river flooding. Here, different kinds of scenarios are considered to figure out optimal design conditions as one of mitigating measures for individual disaster in urban areas adjacent to the river. From comparative analysis on hydrodynamic modelling with microclimate analysis and prediction, this study also evaluates main differences of changes in critical indicators for compound urban crises, such as water level, runoff, PM10, predicted mean vote (PMV), etc. Finally, it suggests how to maximize major functions of urban forests in the multi-criteria decision making context, towards a greener and more resilient city.AcknowledgementThis work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (2020R1G1A1013624) and in part by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (No. NRF-2022R1A4A3032838).
Soil disturbance: Responses of soil carbon to plateau pika bioturbation in alpine grasslands on the Qinghai Tibetan Plateau
Authors: Pang Xiaopan , Xu Xueting , Wang Yimo
Published: February 2023

Plateau pika (Ochotona curzoniae) is a small, common burrowing herbivore with average 150 g, native to grassland in the Asia, especially to alpine meadows in the Qinghai-Tibetan Plateau. Termed as bioturbator herbivores, this animal can create extensive soil disturbance through digging and burrowing activities. In the process of disturbing the soil, these animals break the soil surface layer, increasing water infiltration, soil moisture, and the capture of organic matter, which leads to change in soil ecological processes. This small burrowing herbivore can shape alpine meadows, even contributes to alpine meadow degradation because its density can range up to 300 individuals per hectare. Consequently, plateau pika is generally considered as a pest in China and extensive control efforts have been conducted to eradicate it. However, several studies have argued that plateau pika is a keystone species for alpine meadow ecosystem. To date, no consensus about the role of plateau pika in alpine meadow ecosystem has emerged among policy makers, professionals and herders, and more studies are needed to examine the impact of plateau pika on soil process. Therefore, take plateau pika as an example, our study focuses on accurately evaluating the service functions of the alpine grassland ecosystem including productivity, soil conservation, and C sequestration under the bioturbation by small burrowing herbivore.
Shifting consensus in moisture modifier of decomposition towards the optimum in well-drained mineral soils instead of mid- or high- moisture levels of organic soils in boreal forest
Authors: Tupek Boris , Lehtonen Aleksi , Yurova Alla , Abramoff Rose , Manzoni Stefano , Guenet Bertrand , Launiainen Samuli , Peltoniemi Mikko , Minkkinen Kari , Mäkipää Raisa
Published: February 2023

The lack of consensus of functional dependency of soil respiration on moisture among the Earth system models (ESMs) contributes significantly to uncertainties in their projections.Based on data of soil organic C stocks and CO2 emissions from the boreal ecotone between mineral soil forests and adjacent peatlands with organic soils in Finland, we derived the field-based moisture response of respiration in a maximum range of moisture conditions (extending from xeric and mesic forests to water saturated mires). Using Bayesian data assimilation technique, we coupled Yasso07 soil carbon model with the heuristic bell shape moisture function, approximating the enzyme and oxygen limitations. As expected, the Yasso07 model fitted with the revised moisture modifier on data from catena of organic-mineral soils outperformed the previous model version in peatlands.Unlike the most found optimum of decomposition in ESM in mid- or high- moisture levels, our optimum or the highest rate of decomposition correspond to well-drained conditions of mineral soils.We speculated that the reason for the shift in the moisture optimum of the functional form was its accounting for long-term processes leading to a larger C mineralization in mineral soils related to extreme events, such as prolonged elevated moisture or rewetting after droughts, which enhance microbial access to previously protected or labile C pools and may not be detected in short-term incubation studies.Although, the moisture modifier derived here improved the match between the modelled and measured SOCs of peatlands, a shift in consensus from current decomposition rate modifiers used in ESMs requires further evaluation before it can be largely applied for the landscape level semiempirical processed-based modelling of the mineral and organic soil C stocks and CO2 emissions.
On the severe East Asian dust outbreak in March 2021: from atmospheric dynamics to air quality impact
Authors: Mu Feifei , Luiz Eduardo Weide , Fiedler Stephanie
Published: February 2023

The Gobi and the Taklamakan Desert are the two main dust source regions in East Asia. Extra-tropical cyclones are known as atmospheric driver for severe dust outbreaks in East Asia. Although previous studies show that dust storm frequency in Northern China have decreased associated with a decrease in near-surface wind speed, a severe dust storm occurred in mid-March 2021. This exceptional dust storm was driven by a Mongolian extra-tropical cyclone and had adverse socio-economic and health impacts. The aim of our study is to investigate the atmospheric dynamics, dust-aerosol contributions from the Gobi Desert and the Taklamakan Desert, as well as dust emission mechanisms involved in the event. We use ground-based observations from Chinese observational networks, satellite images from MODIS, data from ERA5 re-analysis, CAMS forecasts, and MERRA-2 re-analysis.

The passage of the Mongolian cyclone first induced high dust-emitting winds along its cold front. The maximum wind speeds at 10m a.g.l. over the Gobi Desert exceeded the 99th percentile of the 30-year climatology (1992-2021) for March by around 6 ms−1 . The dust aerosols were emitted by these exceptionally strong near-surface winds and transported southeastwards along with the passage of the frontal system of the Mongolian cyclone from the afternoon of 14th March to the morning of 15th March 2021. Hence, high atmospheric PM10 concentrations were first recorded in Northern China on 15th March. As a consequence of the associated poor air quality caused by the high PM10 concentrations, 19 out of 218 stations recorded the lowest atmospheric visibility for March since the past 30 years.

The passage of the Mongolian cyclone then led to a cold air intrusion into the Taklamakan Desert from the afternoon of the 15th onward, which was a few hours after the dust emissions in the Gobi Desert. The cold air intrusion with the associated near-surface temperature inversion was favourable for the formation of Nocturnal Low-Level Jets (NLLJs), which are known as an important mechanism for dust emissions in the dust source regions (e.g., East Asia and North Africa). By comparing the NLLJs from radiosonde observations and an automated detection algorithm applied to ERA5, stronger NLLJs were seen in the Taklamakan Desert in the mornings of 16, 17, and 18 March. The NLLJs breakdown during the morning hours led to sufficiently strong dust-emitting winds in this desert. Consequently, dust emissions are simulated in the mornings of 16, 17, and 18 March 2021 by both CAMS forecasts and MERRA-2 re-analysis. The impacts of the dust aerosols from the Taklamakan Desert were, however, limited to the west of China, supported by spatio-temporal distributions of station observations of the atmospheric PM10 concentrations and visibility.
Global simulation of geospace electrons: eVlasiator in 3D
Authors: Alho Markku , Battarbee Markus , Kotipalo Leo , Grandin Maxime , Pfau-Kempf Yann , Ganse Urs , Cozzani Giulia , Bussov Maarja , Gordeev Evgenii , Horaites Konstantinos , Kebede Fasil Tesema , Papadakis Konstantinos , Suni Jonas , Tarvus Vertti , Turc Lucile , Zaitsev Ivan , Zhou Hongyang , Palmroth Minna
Published: February 2023

Models of the geospace plasma environment have been proceeding towards more realistic descriptions of the solar wind—magnetosphere interaction, from gas-dynamic to MHD and hybrid ion-kinetic models such as the state-of-the-art Vlasiator model. Advances in computational capabilities have enabled global simulations of detailed physics, with some inroads to electron physics made with eVlasiator, specifically, in a meridional 2D+3V simulation.In this work we present preliminary results from eVlasiator, an offshoot of the Vlasiator model, showing results from a global 3D+3V kinetic electron geospace simulation. Previous work in a spatially 2D environment has shown, despite truncation of some electron physics and use of ion-scale spatial resolution, that realistic electron distribution functions are obtainable within the magnetosphere. This work examines the differences between the spatially 2D and the new spatially 3D results, and describe these in relation to MMS observations. Electron precipitation to the upper atmosphere from these velocity distributions is estimated.
Quick-clay landslides; stability of soil influenced by sedimentological and hydrogeological factors
Authors: Pallesen Lene , Fredin Ola
Published: February 2023

Quick-clay landslides can occur suddenly in marine and glaciomarine deposits below the marine limit (the highest sea-level after the last glaciation), sometimes with catastrophic consequences. Through geological time, the most common trigger for quick-clay landslides is fluvial erosion, undercutting the unstable slope. However, in more recent years human activity has been shown to be an increasingly important triggering cause. The main problem in quick-clay hazard management is the difficulty in predicting where and when a quick-clay landslide will occur.

The deposition of marine clay and later isostatic uplift has exposed clay to leaching by fresh water, and formation of sensitive clay in previous glacial regions including Fennoscandia and Canada. The speed and limit of these processes depends on a variety of factors, including the presence of coarse-grained layers interbedded with clay, allowing groundwater to percolate into the deposit and leaching of salts that originally stabilize the clay.

This PhD project is in its starting phase and aims to further the understanding of the complexity of marine clay deposits. This includes statistical analysis of landslides in marine deposits, examining sedimentological architecture, and hydrogeological modelling. Examining multiple locations in Norway will allow for comparison of landslide occurrence in relation to morphology, stratigraphy, and erosion. This can aid in improving the hazard management in these areas, to consider if and where landslides are more likely to occur, and at which scale.
Manure Components and Their Effect on Phosphorus Sorption onto Semi-aridic Soils
Authors: Baram Shahar , Freiberg Yaniv , Fine Pinchas , Borisover Mikhail
Published: February 2023

Globally, rock-phosphate reserves are diminishing, while the amount of P-containing organic biowastes is ever-increasing. The use of such biowastes as organic amendments (OAs) in agriculture is the ultimate disposal goal of environmental and agricultural agencies throughout the world. This work aimed to evaluate the effect of OAs and their soluble and insoluble constituents on orthophosphate (IP) sorption to a wide range of semi-aridic soils. Using short-term (hours) and long-term (years) lab incubations and sorption experiments, we found that the effect of OA application on IP sorption depends on the properties of both the OA and the soil. These properties are the following: (i) the soil’s sorption capacity, (ii) the OA’s sorption capacity, (iii) the DOM and IP content of the OA, (iv) the soil’s clay content and type, (v) the concentration and type of the soluble cation in the soil solution. The overall effect on IP sorption (i.e., increased or reduced capacity) is the interplay between the soil, OA, and the OA DOM–soil interaction.