bluuebunny/crossref_metadata_2025 huggingface dataset:
During the rainless season, arid soils exhibited large diurnal fluctuations in carbon and nitrous oxides emissions, while displaying a uniform pattern of methane emissions throughout the day. 
Authors: Gelfand Ilya , Grabovsky Vasily I.
Published: March 2024

Drylands, constituting approximately 56% of the Earth's terrestrial surface, stand as the largest biome. Despite their vast expanse, our understanding of soil trace gas emissions from these regions remains limited. This knowledge gap arises from an uneven distribution of soil trace gas flux measurements across continents. While North American and East Asian drylands have been extensively studied, reports from other drylands are scarce. This lack of information hinders our ability to effectively constrain the atmospheric budget of reactive carbon and nitrogen gases and to develop predictive models for changes in soil trace gas emissions amid ongoing global environmental changes.To address this gap, we conducted a comprehensive study in the Negev Desert, Israel, utilizing an array of seven automatic soil static chambers coupled to two infrared gas analyzers. This allowed us to measure soil emissions of methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) near-continuously every 15 minutes over three rainless months, measuring ~5000 individual soil fluxes. Our focus was on bare soils with varying organic carbon content (0.2%, 0.5%, and 0.6%) and nitrogen content of ~0.1%.Our findings reveal significant diurnal variations in both CO2 and N2O emissions. CO2 emissions peaked at noon (1318.2±440.4 µg C m-2min-1) and reached their lowest point at midnight (373.4±228.8 µg C m-2min-1). In contrast, soil N2O flux was highest at 9:00 (0.07±0.02 µg N m-2min-1) and lowest at 21:00 (0.03±0.01 µg N m-2min-1). Soil CH4 flux exhibited minimal variation, with maximum and minimum emissions of 0.43±0.24 and 0.16±0.09 µg C m-2min-1, respectively.Notably, the distinct peak emission times for CO2 and N2O suggest different underlying mechanisms for the production of these gases in the soil. Furthermore, we observed a strong correlation between soil CO2 emissions and soil water fluxes, while all gaseous fluxes correlated with the organic carbon content of soils. This emphasizes the role of water and soil organic carbon as primary driving factors for trace gas production in desert soils during rainless periods. Specific mechanisms of soil trace gases production in dry desert soils, however, will require further research.
Airborne Synthetic Aperture Radar and Electromagnetic Technologies of the Italian earth observation platform ITINERIS
Authors: Catapano Ilaria , Barone Andrea , Berardino Paolo , Bernini Romeo , Esposito Carmen , Mercogliano Francesco , Natale Antonio , Perna Stefano , Rosero Legarda Jorge Andres , Tizzani Pietro , Lanari Riccardo , Soldovieri Francesco
Published: March 2024

ITINERIS - Italian Integrated Environmental Research Infrastructures System is the Italian hub of research infrastructures in the environmental scientific domain, whose creation is financed by the national recovery and resilience plan (PNRR).Among the large number of technological solutions made available by the infrastructure, thanks to its skills in the fields of remote sensing and electromagnetic monitoring of the environment, the Institute for Electromagnetic Sensing of the Environment of the National Research Council (CNR-IREA) has in charge the development and optimization of technologies for the Soil-Subsoil System (SSS) observation.Specifically, CNR – IREA is carrying out activities concerning two technological assets. The first one is made up of airborne Synthetic Aperture Radar (SAR) systems and computing resources suitable to manage large amounts of data and generate SAR derived products. The second one involves mobile (also by exploiting drones) and fixed in-situ sensors, consisting of magnetometers, gradiometer, multi-antenna ground penetrating radar and optical backscatter reflectometer, which are suitable for high resolution imaging and monitoring of the shallower layers of the subsoil, including the groundwater. These activities also involve the design of innovative data processing procedures, aimed at increasing the effectiveness of each one of the observation technologies, as well as the definition of measurement protocols and strategies devoted to the integration of airborne and in-situ sensors, with the final goal to perform a multi-scale and multi-resolution non-invasive monitoring of the dynamic processes affecting the SSS.A detailed summary of the performed and planned activities will be presented at the conference together with the technical specifics of the purchased instrumentations. Acknowledgement: The communication has been funded by EU - Next Generation EU Mission 4 “Education and Research” - Component 2: “From research to business” - Investment 3.1: “Fund for the realisation of an integrated system of research and innovation infrastructures” - Project IR0000032 – ITINERIS - Italian Integrated Environmental Research Infrastructures System - CUP B53C22002150006.The authors acknowledge the Research Infrastructures participating in the ITINERIS project with their Italian nodes: ACTRIS, ANAEE, ATLaS, CeTRA, DANUBIUS, DISSCO, e-LTER, ECORD, EMPHASIS, EMSO, EUFAR ,Euro-Argo, EuroFleets, Geoscience, IBISBA, ICOS, JERICO, LIFEWATCH, LNS, N/R Laura Bassi, SIOS, SMINO.
Storm surge warning for the German North Sea coast
Authors: Schenk Ludwig , Methe Marlies
Published: March 2024

Storm surges along the German North Sea coast are tidal surges that reach a peak of 1.5 metres or more above mean high water (MHW). Severe and very severe storm surges exceed 2.5 and 3.5 metres above mean high water respectively. Storm surges along the German North Sea coast are triggered by westerly winds from approx. 7 to 8 Beaufort. At the Hamburg, St. Pauli gauge, the long-term average is 5 to 6 storm surges per year; less frequent are severe (2 in 3 years) and very severe storm surges (every 5 years). The period of occurrence is essentially limited to the winter half-year.The Federal Maritime and Hydrographic Agency (BSH) is responsible for warning of storm surges along the Baltic and North Sea coasts and the tidal river sections of the Ems, Weser, Jade and Elbe. Warnings of storm surges are distributed in very different ways. Warnings have been broadcast on the radio for many decades. In Hamburg, firecrackers are set off by the police. In recent years, dissemination via the BSH website and a customisable telephone distribution system has become established. Since the 2021/22 storm surge season, warnings have been fed into warning apps such as NINA via the Modular Warning System (MoWaS) of the Federal Office of Civil Protection and Disaster Assistance (BBK) and thus reach more directly affected citizens.The possibilities offered by new media make it necessary to further develop warning strategies. For example, we are currently working closely with the BBK on the automated provision of warnings via the NINA warning app. This leads to faster and more precise distribution of storm surge forecasts.The warnings and forecasts described take place against the background of the mean sea level rise and the associated rise in mean high water level. It is also the responsibility of the Federal Maritime and Hydrographic Agency to monitor this and to provide and analyse it at tide gauges such as Cuxhaven Steubenhöft, where measurements have been taken for around 180 years.When creating the forecasts, we set up the Flood Early Warning System (FEWS), which pools and helps to process the data and creates and publishes reports. With the help of our developed Model Output Statistics System (BSH-MOS), precise and individualised forecasts up to one week into the future are possible for up to 40 gauges. Among other things, MOS evaluates water level measurements, wind forecasts from the German Weather Service (DWD) and area-based modelled water level forecasts from the BSH model system.
A deep learning-based super-resolution DEM model for pluvial flood simulation
Authors: Zhu Yue , Burlando Paolo , Tan Pauy Yok , Geiß Christian , Fatichi Simone
Published: March 2024

High-resolution Digital Elevation Model (DEM) data provides essential information for pluvial flood simulation. Although the increased accessibility and quality of publicly available DEM datasets can facilitate geospatial analysis at various scales, existing DEM datasets with global coverage mostly lack sufficient spatial resolution for pluvial flood simulations, which require detailed topographic information to be included in the simulation. Simulating flood scenarios with low-resolution DEMs (>30m) can result in substantial deviations from real cases. This issue becomes even more severe for flood-prone areas in data-scarce developing countries.Image super-resolution is a technique for reconstructing low-resolution information into high-resolution data. Various deep-learning models have been employed for this task, primarily focusing on generating high-resolution natural-colour images. However, the effects of these deep learning models on enhancing the resolution of DEM data have not been extensively investigated. One of the state-of-the-art super-resolution models, the Residual Channel Attention Network (RCAN), has gained popularity due to its accuracy and efficiency. Leveraging publicly available low-resolution global DEM data and high-resolution regional DEM data, this study assesses the performance of RCAN models in a DEM super-resolution task. The experimental results suggest that, compared to conventional interpolation methods, the tested RCAN model exhibits superior performance in constructing high-resolution DEM data. The generated super-resolution DEM data were then tested in pluvial flood simulations and achieved substantially higher realism in modelling floodwater distribution. The proposed method for constructing super-resolution DEMs opens up the possibility of simulating flooding at hyper-resolution globally.
Modeling Olive Phenological Phases for Agro-Climate Risk Assessment in a Changing Future Climate over the Euro-Mediterranean Region
Authors: Didevarasl Ali , Costa-Saura Jose M. , Spano Donatella , Snyder Richard L. , Deiana Pierfrancesco , Rechid Diana , Bülow Katharina , Mulas Maurizio , Nieddu Giovanni , Trabucco Antonio
Published: March 2024

Under a future changing climate, the Mediterranean is considered a region extremely prone to global warming and intensified climate events, which will possibly change the timing of phenological phases and alter conditions and risks for olive tree growth. This situation may restrict olive cultivation which is economically strategic in the Mediterranean countries. Since, the timing and management of agronomic practices (planting, irrigation, fertilization, crop protection, harvesting, etc.) are based on phenological phases and plant growth, accurate phenological projections are essential to assess climate risks and guide optimal management apt to mitigate climate change effects on olive development. Initially, the present investigation aims to introduce innovative phenological modeling, i.e., Chill, Anti-Chill, and Growing Degree Days combined model (CAC_GDD) applicable in heterogenous areas with limited and scattered observations. Then, we project future changes in olive phenological phases (i.e., sprouting, blooming, and pit hardening) and relevant agro-climate stressors during these phases over the Euro-Mediterranean for both early and mid-late bud break cultivars. For model parametrization and validation, the phenological observations were gathered from nine experimental sites in Italy and temperature time-series from the European Centre for Medium-Range Weather Forecasts, Reanalysis v5. To project the timing of phenological phases and then calculate the agro-climate stressors we used an ensemble of high-resolution climate projections at 0.11° from EURO-CORDEX (Coordinated Regional Climate Downscaling Experiment) repository, for two historical (1976-2005) and future (2036-2065) 30-year periods under three emission scenarios (i.e., RCP2.6, RCP4.5, and RCP8.5). The CAC_GDD modeling showed the best performance (RMSE: 4 days) for the blooming phase of mid-late cultivars, suiting similarly and in some cases even better than the more complex model to our experimental conditions. The spatial phenological projection illustrated that at least 75% of the Euro-Mediterranean area will experience significant phenological advances for olive crops. Meanwhile, current olive cultivations in the Mediterranean basin may face accelerated climate extremes mainly at blooming and pit hardening stages in the future. Hence, we expect possible future shifts in olive-growing areas from the Mediterranean to colder regions with more thermal suitability for the mid-late cultivars.
Ice-ocean-subglacial hydrology interactions, and recent evolution of the Thwaites glacier
Authors: Gourmelen Noel , Jakob Livia , Holland Paul , Goldberg Dan , Dutrieux Pierre
Published: March 2024

The retreat of the Antarctic Ice Sheet is conventionally attributed to ocean melting of fringing ice shelves, potentially enhanced by internal instability due to the proximity of its grounding lines to retrograde bed slopes. Ocean melting is enhanced by increased intrusion of modified Circumpolar Deep Water (mCDW) within ice shelf cavities. Several processes can enhance the ability of mCDW to melt ice shelves. Upwelling from the release of subglacial melt water at the grounding line is arguably one of the least well constrained and understood and is currently not accounted for in projections of ice sheet loss.The Thwaites glacier in the Amundsen Sea sector of the west Antarctic ice sheet has been the focus of recent investigations given its current rapid retreat, potential instability, and its impact on rates of future sea level change. In 2013, a network of subglacial lakes under the Thwaites glacier drained, the combined outflow reached a peak discharge in excess of 500 m3 s-1 and likely reached the grounding line. During this period, several other processes took place at the grounding line and under the fringing floating ice. This event offers a natural experiment to examine the impact of subglacial outflow on ocean melting of ice shelves.In this presentation we revisit the various events affecting the Thwaites system during this period and generate several new observations of lake discharge, rates of ice shelf basal melting, and grounding line thinning and retreat. We focus the discussion on the potential feedback between lake discharge, variation in ocean melting, and grounding line retreat, and on the contribution of subglacial discharge to the recent retreat of the Thwaites glacier.
Bayesian Evidential Learning Approach to Uncertainty Quantification in THM Model of Geothermal Energy Extraction in Deep Mines
Authors: Zhang Le , Daniilidis Alexandros , Dieudonné Anne-Catherine , Hermans Thomas
Published: March 2024

Utilizing existing deep mining systems for geothermal extraction not only facilitates the development of geothermal systems but also helps meeting the cooling requirements for deep mining operations. In this study, a thermo-hydro-mechanical model of geothermal extraction in deep mines is developed to investigate the evolution of mine galleries stability and temperature, and the temperature changes in geothermal production wells. The uncertainty in system responses is predicted through the Bayesian Evidential Learning framework.Due to our limited understanding of the material properties and the scarcity of measurement data, uncertainties emerge in the forward simulations. Ideally, a comprehensive uncertainty analysis would be conducted to predict all possible outcomes and assess any risks. However, In light of the intractability of performing comprehensive uncertainty analyses in scenarios with vast unknown data, particularly due to the computational overhead of multiple inverse problem-solving, we employ the Bayesian Evidential Learning framework, which provides a feasible and rapid alternative for approximating prediction post-distributions and choosing the most informative data sets. Before implementing BEL, we employed Latin Hypercube Sampling to create 500 sets of realizations for forward simulations, and subsequently utilized global sensitivity analysis to evaluate the data's informational value, aiming to diminish the uncertainty in predictions. In this paper, the BEL framework is utilized to achieve two: firstly, to stochastically predict the responses of the system (stability and temperature) within the BEL framework, using machine learning to discover direct correlations between predictors (sensitive parameters) and targets (system responses). Subsequently, newly collected data can be utilized to predict the approximate posterior distributions of the corresponding gallery stability, temperature, and production well temperature, thus circumventing traditional data inversion steps. This framework can be adjusted to accommodate any predictions related to subsurface conditions; hence, our second goal involves predicting the system's long-term responses within the BEL based on short-term data collection, forecasting posterior distributions from the acquired short-term data, and validating the efficacy of this approach.Our study indicates that in practical engineering, by (1) obtaining data of material properties and (2) key responses of short-term simulation, it is possible to predict the critical responses of the system in long-term geothermal extraction, thereby maximizing the information content of any measurement data while minimizing budget constraints and computational costs.
Tectono-metamorphic evolution and crustal-scale shear zone origin in the high-grade crust of southern Madagascar
Authors: Rarivoarison Heninjara Narimihamina , Hasalová Pavlína , Andriamamonjy Alfred Solofomampiely , Miha Tongasoa , Štípská Pavla , Závada Prokop , Martelat Jean-Emmanuel , Schulmann Karel
Published: March 2024

In southern Madagascar two main tectono-metamorphic events, corresponding to the East African Orogeny (ca. 630–610 Ma) and the Kuunga Orogeny (ca. 580–515 Ma) were recognized. An early structures include recumbent folds and sub-horizontal foliation S1 that were transposed during a regional east–west shortening resulting into north–south-oriented upright folds, with horizontal axes and new vertical axial planar foliations S2. This second deformation event is coeval with the development of a network of vertical ductile shear zones such as the Ejeda SZ, Ampanihy SZ, Beraketa SZ, Ihosy SZ, Zazafotsy SZ and Tranomaro SZ. These megascale 15–25 km-wide intracrustal near-vertical N-S or NW-SE trending strike-slip ductile shear zones crosscut the entire high-grade metamorphic basement of southern Madagascar and separate lower-strain domains where complex fold interference patterns are visible. These high-strain zones developed between 580 and 530 Ma with a slight diachronism from the west to east and south to north and are coeval with melting and UHT/HT granulite facies conditions. The granulite facies metamorphism is widespread throughout the whole basement in all lithologies, in the southern part reaching peak conditions of 900–1000°C at 6–10 kbar and slightly lower temperature conditions (≤800°C) to the west, north, and in the Ikalamavony fold-thrust belt to the north–northeast. Importantly, the shear zones reveal large fluid/melt transfer from the depth that caused extensive fluid/melt rock interaction (in the shear zone as well as in the surrounding basement) that resulted in localized charnockitisation of the granulites. The melt/fluid flux here was structurally controlled and seems to be penetrative throughout the basement rocks. This offers a unique opportunity to study fluid-assisted pervasive melt migration controlled by localized deformation across the whole crust. In this context, our objective is to investigate the tectonometamorphic changes occurring in the intensely deformed high-grade lower to middle crust located in southern Madagascar. Additionally, we seek to delineate the chronological connection between the deformations and high-temperature metamorphism (U)HT, along with the associated processes of crustal anatexis and magmatism.
The seismic signature of skiing
Authors: Igel Heiner , Brass Sophie , Lindner Fabian , Van Noten Koen , de Plaen Raphael , Wassermann Joachim , Bernauer Felix , Lecocq Thomas
Published: March 2024

In March 2023 the annual winter school SKIENCE (www.skience.de) was held in the Bavaria alps, south-east of Munich. The topic was environmental seismology with a focus on seismic monitoring using ambient seismic noise. The winter school had strong practical training aspects. Prior to the meeting 12 5Hz nodes (SmartSolo) were deployed in the valley near Bayrischzell with the goal to explore local structure and site effects using interferometric methods. During the midweek free afternoon the 12 SmartSolo nodes were installed on both sides of a slalom run with several gates through which participants of the winterschool skied one after each other. First inspection of the data showed that clear signals of the skiers could be identified. Here, we report on attempts to use the seismic data records to recover the tracks of the skiers as moving seismic sources. Questions associated with this experiment are at which points in the tracks seismic energy is generated, where exactly the incoming signals propagate and with what velocities, and how well the source locations can be backprojected. A simple theoretical model is used to develop the inversion tools to recover the moving sources.   
Temporal development of the scour hole next to the riprap sloping structure
Authors: Harasti Antonija , Gilja Gordon , Vuco Josip , Boban Jelena , Valyrakis Manousos
Published: March 2024

Riprap sloping structure is effective as bridge pier scour protection in the immediate vicinity of piers. In turn, riprap disrupts the flow conditions in a larger area than is the case with piers without scour protection in place. While these structures effectively dissipate the turbulent energy around piers, scouring occurs at the toe of the riprap and threatens the stability of the riprap and adjacent riverbed or hydraulic structures in proximity. This research presents the temporal evolution of the scour hole forming next to the riprap sloping structure. The research combines flume experiments with a physical model and numerical simulations using FLOW-3D software calibrated with experimental data measured with an optical surface scanner. Investigating the change in the scour hole dimensions over time provides valuable insights into the understanding of scour development and the associated undermining of the riprap toe during flood events that can jeopardize the bridge stability. The results show that, while scour generally increases with the duration of the flood, there are also evident backfilling events that need to be recognized and accounted for during the bridge design.References:[1] Harasti, A.; Gilja, G.; Potočki, K.; Lacko, M. Scour at Bridge Piers Protected by the Riprap Sloping Structure: A Review. Water 2021, 13, 3606. https://doi.org/10.3390/w13243606[2] Harasti, A.; Gilja, G.; Adžaga, N.; Žic, M. Analysis of Variables Influencing Scour on Large Sand-Bed Rivers Conducted Using Field Data. Appl. Sci. 2023, 13, 5365. https://doi.org/10.3390/app13095365AcknowledgmentsThis work has been supported in part by Croatian Science Foundation under the project R3PEAT (UIP-2019-04-4046).
Impact of climate change on the hydrological cycle of the Great Alpine region by means of regional climate convection permitting high resolution simulations and hydrological model simulations. 
Authors: Vargas-Heinz Luiza , Coppola Erika , García-Valdecasas Ojeda Matilde
Published: March 2024

In the last 10 years, the very high resolution regional climate models have started to be used and recently the newly available regional climate model ensemble for the Great Alpine region, at the convection permitting (CP-RCM) resolution (> 3 km), has been released by the CORDEX Flagship Pilot Study on Convective phenomena at high resolution over Europe and the Mediterranean (FPSCONV). At such resolution, the improvement of the representation of local hydrological processes becomes relevant because the climate impact on the hydrological cycle at that scale is expected to be much better captured.  To this aim, the CETEMPS hydrological model (CHyM) is used coupled off-line with the different CP-RCM ensemble members.  The model has been run in two different configurations, using either temperature and precipitation from the driving CP-RCM or directly the runoff. The hydrological simulation ensemble has been validated against local station data for the Po river and central Italian river basins, by using hydrological indicators, such as the Kling–Gupta efficiency (KGE). The climate change projections are compared with previous lower resolution simulation driven by convection parametrized regional climate models from the Euro-CORDEX ensemble.  
Site effects and their relationship with geological structure in Tainan, Taiwan
Authors: Yang Chih Yang , Rau Ruey Juin , Wu Cheng-Feng
Published: March 2024

Tainan area is one of the areas have the highest risk of earthquake disasters in Taiwan. This research focuses on the microtremor characteristics and site effect of the Tainan Plain, the tableland, lowland and the foothills regions. We analyze the predominant frequency, amplification and fragility index of the seismic stations. Horizontal-to-vertical spectral ratio (HVSR) is used for the evaluations of site effect, and the data used are the micro-tremor received by the 173 single stations placed in the Tainan area from March to June 2021, and the duration of each station is 1-3 months. We used the stratigraphy borehole data as the initial model, f-k and HV-INV methods to obtain the velocity model in this area, and combined this velocity model with H/V to estimate the interface thickness. This is then used to compare different geological structures showing different site effect. The results at this stage point out that the stratum in the Tainan area contains two predominant frequencies, 0.2 Hz and 1~3 Hz respectively. Between them, the frequency of 0.2 Hz is dominant in the plain and the lowland areas. The stations above the tableland and the hills are dominated by 1~3 Hz, and their amplification is 2~3 times larger than that of the plain area. This illustrates that the site effect in the area is controlled by local geological conditions, and when seismic waves approach tableland and hills that the amplifications become stronger due to the site effect. However, the maximum value of PGA and the destroyed houses observed in the 2016 Mw 6.4 Meinong earthquake were found in the lowland area. This may be due to the multiple reflection signals observed in this area. We will sum up the fragility index for the entire interested frequency bands hoping to understand the overall geological strength of Tainan. In addition, we will compare the HVSR differences between the daily microtremor and the earthquake strong ground motion. If there is a certain relationship between them, we can use daily microtremor to estimate amplification and predominant frequency when earthquakes strike, and use this to evaluate the severity of disasters that may occur in different geological environments.
Mitigation measures of crop cultivation to reduce climate-impacting emissions from denitrification
Authors: Stenfert Kroese Jaqueline , Buchen-Tschiskale Caroline , Cordes Johannes , Dechow Rene , Dittert Klaus , Dix Bryan , Fuchs Kathrin , Gattinger Andreas , Greef Jörg-Michael , Grosz Balazs , Hauschild Michael , Mahboube Jarrah , Kühne Johannes , Mielenz Henrike , Potthoff Thade , Scheer Clemens , Schulz Franz , Simpson Conor , Wolf Benjamin , Well Reinhard
Published: March 2024

The joint project 'Measures to reduce direct and indirect climate-impacting emissions caused by denitrification in agricultural soils - MinDen' addresses the topics of reducing nitrous oxide emissions and improving nitrogen efficiency through modeling, the evaluation of possible mitigation measures and the evaluation of denitrification on spatial scale. Gaseous emissions from denitrification cause N losses relevant to crop cultivation and cause direct N2O emissions from crop cultivation. Climate protection measures in crop production in the areas of fertilization, soil cultivation and crop rotation have hardly been researched with regard to the role of denitrification. Crop management that optimizes N efficiency and minimizes N emissions at the same time has therefore not yet been reliably defined. The overall objective of the present project is to identify practicable crop management measures to minimize N2 and N2O emissions from denitrification for arable cropping systems in Germany by improving the knowledge on denitrification-related N losses through field and laboratory studies and using it for parameterization, validation and application of simulation models. Our objectives are as follows:Regionalization of N losses due to denitrification in Germany based on existing models
Determination of the effect of crop protection measures on N2 and N2O losses on field scale
Testing of mitigation options on the model, laboratory and field scale, taking into account the topsoil and subsoil for different soils
Further development of denitrification models to improve the mapping of mitigation measures using existing and new field data
Testing of mitigation options for Germany using the improved models, taking into account yield, economic efficiency, technology requirements, N2O emissions, N efficiency, fertilizer requirements, NH3 emissions and nitrate leaching.
We provide an overview of the approach and the current status of the joint project, which started at the beginning of 2023.
Using AEOLUS Aerosol Assimilation to pave the way for EarthCARE
Authors: Georgiou Thanasis , Tsikerdekis Athanasios , Rizos Konstantinos , Proestakis Emmanouil , Gkikas Antonis , Drakaki Eleni , Kampouri Anna , Baars Holger , Floutsi Athena Augousta , Marinou Eleni , Benedetti Angela , McLean Will , Retscher Christian , Melas Dimitris , Amiridis Vassilis
Published: March 2024

EarthCARE, ESA’s and JAXA’s joint mission, is expected to launch in 2024 carrying ATLID, a high-spectral resolution lidar with depolarization capability. The instrument will provide valuable data for characterizing atmospheric aerosols and for improving atmospheric composition modelling. The aim of this study is to show how working with ESA’s Aeolus wind mission prepares us for taking advantage of ATLID.Aeolus, which launched in 2018 and deorbited in 2023, was not specifically designed to observe aerosols but still provided aerosol products. Due to the lack of a cross-polar channel, it underestimated the aerosol-related backscatter by as much as 50% in scenes with non-spherical particles. During the ESA L2A+ project, an enhanced aerosol product was developed through data fusion with other data sources (such as NASA’s CALIPSO mission) to account for Aeolus deficiencies. The impact of this new product was assessed through assimilation experiments in regional NWP models, showing both the direct improvements of the new product, as well as the betterment of aerosol fields in regional models through assimilation of a profiling instrument. Our results were validated using data from the ESA-ASKOS tropical campaign, which took place in Cabo Verde during Summer and Autumn of 2021 and 2022.The open-source tools created for Aeolus are further developed to support EarthCARE. Working with simulated data, we show the impact of ATLID profile assimilation on both the representation of aerosols in the model, as well as the impact on numerical weather prediction through radiative feedback. The experiments are done using the Weather Research and Forecasting (WRF) model, alongside the Data Assimilation Research Testbed (DART), with AEOLUS and EarthCARE support added.The L2A+ team acknowledges support by ESA in the framework of the "Enhancing Aeolus L2A for depolarizing targets and impact on aerosol research and NWP project (4000139424/22/I-NS). This work was supported by computational time granted from the National Infrastructures for Research and Technology S.A. (GRNET S.A.) in the National HPC facility - ARIS - under project ID pr014048_thin.
Evaluating Vegetation-Influenced Roughness Estimation Methods to Improve Hydrological Modelling
Authors: Masoodi Azam , Kraft Philipp
Published: March 2024

Overland flow is a critical aspect of the hydrological cycle, and understanding its dynamics is crucial for managing water-related issues such as flooding and soil erosion. This paper investigates the impact of various roughness estimation methods on simulating overland flow during intense rain events, with a specific focus on the influence of vegetation height. The study assesses various approaches to vary roughness as a function of water sheet thickness and vegetation height, including two different constant Manning's coefficients, a simple linear approach, an exponential function, a power law function, an empirical formula, and a physics-based approach.The investigation emphasizes the importance of accurate roughness estimation for improving the reliability of hydrological models and enhancing flood prediction capabilities. Experimental data from artificial rainfall experiments on 22 different natural hillslopes in Germany are used to calibrate the OpenLISEM hydrological model, adjusting parameters such as saturated hydraulic conductivity and soil suction at the wetting front.Subsequently, various Manning's coefficient estimation methods are applied, and the model's performance is evaluated numerically. Preliminary results indicate satisfactory calibration outcomes, with NSE values ranging from 0.75 to 0.95 in most cases for various sites. To validate the models, 100 different experimental rainfall events are used for each roughness method.Validation findings suggest that the physics-based approach, the linear function, and constant Manning roughness, demonstrate the best performance based on NSE values. According to our results, areas with more vegetation coverage demonstrate higher saturated hydraulic conductivity value, indicating that, for two sites with the same soil type, the locations with dense vegetation exhibit higher infiltration parameters. Consequently, it is crucial to evaluate the influence of vegetation on runoff, considering not only its effects on Manning's coefficient but also on saturated hydraulic conductivity.This research contributes valuable insights into the selection of roughness estimation methods for enhancing the reliability of hydrological models, emphasizing the importance of vegetation cover in infiltration parameters.
On the value of slug tracer injections and the naturally occurring radon for observing hyporheic exchange
Authors: Bacher Mortimer , Klaus Julian , Ward Adam , Krause Jasmine , Segura Catalina , Glaser Clarissa
Published: March 2024

The exchange of stream water and groundwater (hyporheic exchange) plays an important role in hydrological and biogeochemical processes in rivers. Hyporheic flow comprises a distribution of subsurface flow paths characterized by distinct transit times and flow path lengths. Much of the previous research relied on the interpretation of slug tracer experiments that only capture a portion of the overall hyporheic exchange, given their relatively short (minutes to hours) duration. Therefore, there is a need to go beyond the characterization of shorter flow paths in hyporheic research to understand flow paths of the entire transit time distribution. We hypothesize that environmental tracers provide complementary information into longer hyporheic flow paths. Here we derive and compare commonly used transport metrics for hyporheic exchange derived from radon and slug tracer injections and aim to identify combinations of model parameters that predict the concentrations of both tracers along experimental stream reaches. For this purpose, we measured the environmental tracer radon (222Rn), that increases with time along hyporheic flow paths, at several stream sections along Oak Creek, Oregon (USA). We conducted slug tracer (sodium chloride) injections at the same stream sections. We employed a transient storage model that includes radon specific processes such as radioactive decay to ensure comparability in the information acquired on hyporheic exchange from radon and the typically applied slug tracer experiments. We calibrated final stream discharge and hyporheic exchange metrics through a global identifiability analysis and subsequently calculated relevant transport metrics using the refined parameters. Results with the field data will be obtained soon. Hence, this study will contribute to a more holistic understanding of hyporheic flow paths and related processes, such as the biogeochemical turnover processes in rivers.
Discovery of a major seafloor methane release site in Europe: The Landsort deep, Baltic Sea.
Authors: Ketzer Marcelo , Stranne Christian , Chang Cheng , Owari Satoko , Yu Changxun , Migeon Sebastien , O'Regan Matt , Jakobsson Martin
Published: March 2024

A recently acquired multidisciplinary dataset comprising acoustic surveys (high-resolution sub-bottom profiles, multi-beam bathymetry, and broad band mid-water echo sounder), geochemistry (gas chemical and isotopic composition, porewater chemistry), and sedimentology (core lithology and X-ray CT) in the area of the Landsort deep (450 m of depth), south of Stockholm Archipelago, revealed the existence of an extensive (20 km2) region of the seafloor where massive gas release is occurring in the form of multiple bubble streams. This new discovery represents a major seafloor methane release site in Europe and is comparable in area to other large sites worldwide such as the ones in Svalbard and in the South Atlantic Ocean associated with gas hydrate provinces. The gas is formed mostly by methane of microbial origin. Surprisingly, bubbles rise 100’s of meters above the seafloor and reach surface waters above the halocline/oxycline at around 80 m of depth. Some bubbles appear to reach the sea-air interface and their potential methane contribution to the atmosphere is under investigation. Another surprising observation is the absence of major seafloor features like pockmarks in the gas release area. The reasons for the seafloor methane release in the Landsort deep are still not entirely clear, but our preliminary acoustic and sedimentological data suggest that bottom currents may have acted to facilitate the accumulation of organic-rich sediments in a thick drift deposit during the Holocene and the modern warm period (latest 100 years). Our data further suggest that the high sedimentation rate in the drift deposit continuously supplies fresh organic matter that is quickly buried below a thin sulphate reduction zone, fueling vigorous methanogenesis and abundant methane formation. Similar methane release sites might be discovered in other known large drift deposits in the Baltic Sea.
A database for ancillary information of three-dimensional soil surface microtopography measurements.
Authors: Nouwakpo Kossi , Eltner Anette , Candido Bernardo , Li Yingkui , Wacha Kenneth , Nichols Mary , Washington-Allen Robert
Published: March 2024

Understanding the complex processes occurring at the soil surface is challenging due to the intricate spatial variability and dynamic nature of these processes. An effective tool for elucidating these phenomena is three-dimensional (3D) reconstruction, which employs advanced imaging technologies to create a comprehensive representation of the soil surface at high spatial resolution, often at the mm-scale. Three-dimensional reconstruction techniques are increasingly available to scientists in the fields of soil science, geomorphology, hydrology, and ecology and many studies have employed these novel tools to advance understanding of surface processes. Much of the data being collected in these studies are however not interoperable, i.e., 3D data from one study may not be directly combined with 3D data from other studies thus limiting the ability of researchers to advance process understanding at a broader scope. The limited interoperability of existing data is due in part to the fact that 3D surface reconstruction data are influenced by many factors including experimental conditions, intrinsic soil properties and accuracy and precision limits of the 3D reconstruction technique used. These ancillary data are crucial to any broad-scope efforts that leverage the increasing number of 3D datasets collected by scientists across disciplines, geographic regions, and experimental conditions. We have developed a relational database that archives and serves ancillary data associated with published high-resolution 3D data representing soil surface processes. This presentation introduces the structure of the database with its required and optional variables. We also provide analytics on the currently available records in the database and discuss potential applications of the database and future developments.
How to avoid unreliable formulas for time of concentration in ungauged basins
Authors: Evangelista Giulia , Woods Ross , Claps Pierluigi
Published: March 2024

Estimating design flood hydrographs in ungauged basins requires the determination of hydrological response parameters. These parameters are derived from relationships that often lack a solid foundation in the specific physical characteristics of the basin. Among the parameters subject to greater uncertainty, the characteristic time of the IUH function certainly stands out. Indirect methods for estimating this parameter involve the use of empirical or analytical formulas and, in the engineering practice, the use of one or more formulas is often justified on heuristic grounds, lacking solid scientific considerations to guide the choice towards the most appropriate formulation.Here, we propose a methodological approach to provide support in choosing a robust formulation for estimating basin flood response time. We have selected 35 formulas from the literature, all containing parameters related to the basin's length and slope. After verifying the real meaning of the input parameters and units required by the formulations in the original articles where they were published, the structure of the formulas considered has been analyzed in dimensional terms, using a reasoning scheme consistent with the hydraulic relations of resistance formulas. In this way, 17 hydraulically consistent formulas have been identified.At this stage, we point out the advantage of comparing the formulas in terms of equivalent average flow velocity rather than in terms of observed travel times. Starting from the celerities obtained as the ratio between the length of the basin's drainage path and the response times provided by each formula and using the morphology of the river network of 135 basins in northwestern Italy, we compared the variability of estimated mean travel velocities. In line with literature observations, which highlight a slight increase in mean velocities with basin size, some formulas are deemed physically inconsistent, while 5 of them were identified as hydraulically robust and consistent with empirical observations. These formulas are Chow (1962), NERC (1975), SCS (1954), McEnroe and Zhao (1999), and Watt and Chow (1985).The results obtained analytically identify the relationships between the exponents of length and slope in each formula and those governing empirical relationships between lengths and slopes of main river reaches in the basins. These relationships allow us to identify the range of values for the exponents of length and slope in the formulas for the characteristic time for which velocity estimates increase with the basin area. Based on these relationships, it is also possible to provide a guideline for the calibration of new formulations.
A key role of surface atmospheric circulation changes in setting global ocean warming magnitude
Authors: Sadhvi Kwatra , Lengaigne Matthieu , Vialard Jérôme , Danielli Vincent , Suresh Gopika , Iyyappan Suresh
Published: March 2024

Surface air-sea feedbacks play a pivotal role in modulating the amplitude of global ocean warming. Zhang and Li (2014, ZL14) introduced a simple theoretical framework to identify the driving processes responsible for the Sea Surface Temperature (SST) increase under global warming. This method involves decomposing changes in latent and upwelling longwave surface heat fluxes into two parts: one tied to direct atmospheric forcing and the other directly associated with local (SST) changes, termed feedback. Applying this heat budget equation across 53 CMIP5 and 6 models underscores the pivotal role of increased surface downwelling longwave radiation (DLR) in steering the amplitude of future global ocean warming. However, ZL14 solely considered DLR as a direct forcing, overlooking its substantial feedback response to surface warming.In this study, we employ a novel methodology from Shakespeare and Roderick (2022, SR22) to decompose DLR changes into a direct radiative forcing and SST-related feedbacks, evaluating the implications of integrating the DLR feedback in the ZL14 framework. Our analysis is in line with SR22’s findings across 5 CMIP5 models, our results across 53 models indicate that roughly 90% of DLR increase emerges from feedbacks associated with the rising SST. The large ocean heat capacity transfers warming to the overlying atmosphere, increasing its DLR primarily through direct air temperature increase and the increasing greenhouse effect associated with increased water vapour.Incorporating the DLR feedback in ZL14 framework yields a dominant effect of latent heat flux forcing on global ocean warming for both multi-model mean and intermodel diversity. This latent heat flux forcing is related to the evaporative cooling modulation associated with projected changes in the surface atmospheric circulation, and is highly correlated with the magnitude of the global average warming. This underscores the substantial influence of projected atmospheric circulation changes on the level of global average warming.