bluuebunny/crossref_metadata_2025 huggingface dataset:
A spatial microbial competition mechanism of soil carbon persistence
Authors: Franklin Oskar , T.L. Bonner Mark , Hasegawa Shun , Näsholm Torgny
Published: February 2023

Here we present a novel model supplementing existing theories of soil organic matter (SOM) decomposition, based on evolutionary-ecological principles rather than chemical or physical limitations to decomposition. We argue that decomposition of some substrates, in particular nitrogen-rich non-hydrolyzable matter (NHLS), may be constrained by spatial competition from opportunists (Bonner et al., 2022). Our model is based on two linked hypotheses: (1) From an evolutionary point of view, microbes should optimise their enzyme production to maximise the net fitness gain (F), and they should only decompose NHLS if the uptake of decomposition products (S) brings a net fitness gain (F > 0) in terms of growth minus costs of enzyme production. (2) F strongly depends on the fraction of decomposition products absorbed by the decomposer, i.e. the return on enzyme investment, which depends on the distance to the substrate and the competition from opportunistic bacteria. A minimum ‘safe’ distance for oxidative decomposition is included, based on the idea that cost of oxidative stress to the decomposer will surpass potential gain from decomposition when the activity is too close. Although the model predictions have not been tested directly against observations, they provide proof-of-concept that substrate can be spared decomposition and accumulate even when it is physically and chemically accessible. Due to the spatial competition effect, it is not profitable for either bacteria or decomposer fungi to decompose NHLS under certain conditions.  Our framework can help explain a variety of SOM dynamics, including priming and the suppression of decomposition by nitrogen addition. ReferenceBonner MTL, Franklin O, Hasegawa S, Näsholm T. 2022. Those who can don't want to, and those who want to can't: An eco-evolutionary mechanism of soil carbon persistence. Soil Biology and Biochemistry 174: 108813.
Challenges in volcano magma chamber imaging: A numerical study
Authors: Li Ka Lok , Bean Christopher J. , Gudmundsson Ólafur
Published: February 2023

Volcanic eruption is a continuous threat to many places in the world. Despite recent advances in volcano monitoring techniques and developments in monitoring networks, eruption forecasting remains a challenging task, partly because an accurate description of the current state of a volcano is missing. Such a description requires knowledge about the time varying internal structures of the volcano. An ultimate goal is, therefore, to obtain snapshots of the volcano structures across multi scales. However, due to limitations in imaging techniques in highly heterogeneous volcanic environments, e.g., strong velocity gradient near surface and rich in small-scale scatterers throughout the volcano, only relatively large-scale structures are normally recovered. This is relevant to imaging all important magma chambers, which have often been illusive. Recent studies reveal that magma chambers can have large aspect ratio, i.e., a thin body that extends laterally more than a few times its thickness. This extreme geometry adds to the complexity of the imaging problem. In this research, we present a systematic study of how different factors affect the ability to recover a clear image of a magma body and their relative importance in the imaging problem. Classes of synthetic models with different weights of these factors are generated. The models are then used to generate synthetic seismograms using numerical simulations of full wavefield seismic wave propagation. The seismograms are used as the input to various image techniques for recovering images of the synthetic models. Our preliminary results show that even in a non-scattering environment, imaging a magma chamber can be challenging due to, e.g., weak velocity contrast between the magma body and the surrounding rock materials. The imaging problem is compounded by strong scattering. The aim of the work is to understand the limitations of current imaging and acquisition approaches, and to better understand what we can “expect to see”.
Triangular-prism framework for the study of hydrodynamics in semienclosed basins
Authors: Valle-Levinson Arnoldo
Published: February 2023

A framework is presented for the study of hydrodynamics in semienclosed basins. The framework is anchored on a generalized momentum balance in which the drivers of momentum are tides, density gradients and winds. The drivers are balanced by friction and Earth’s rotation. The relative influence of either drivers or balancing agents may be cast in terms of their ratio, represented by nondimensional numbers. Thus, the relative influence between three different pairs of forcings is expressed as follows. Comparisons between tidal forcing and density gradients are cast in terms of a densimetric tidal Froude number. Similarly, the effect of wind forcing versus density gradients is contained in a Wedderburn number, and the impact of wind forcing compared to tidal forcing is described by a ‘Stress number’. Comparisons of balancing agents are contained in the Ekman number, representing the dynamic depth of a semienclosed basin – high Ekman numbers indicate dynamically shallow basins. The hydrodynamic interplay among drivers and balancing agents can thus be drawn on a triangular prism. Each face of the prism represents a parametric space that characterizes the relative dominance of any pair of forcing agents. The height of the prism denotes the dynamic depth. Every semienclosed basin, except any dominated by wind-wave forcing, can be represented on a face of this triangular prism or inside the prism, depending on the dominant hydrodynamics. Thus, any semienclosed basin can be described by a cloud of points inside and on the prism faces, representing the basin’s temporal and spatial variability in its hydrodynamics.  
The application of soil analysis in forensic taphonomy: using pigs as analogues for human corpses
Authors: Tagliabue Giulia , Cattaneo Cristina , Trombino Luca
Published: February 2023

Many studies have shown how Environmental Sciences can contribute to the forensic and medico-legal investigations on murder and body concealment dynamics. Nonetheless, most of the research is generally limited to botanical, entomological and anthropological fields leaving out the observation of the active interaction between a decomposing body and the surrounding environment, such as soil. Indeed, a clandestine grave can destroy the valuable forensic evidence as well as prevent the identification of the offender or the victim itself and even the determination of the post-mortem interval (PMI), post-burial interval (PBI) and, overall, the dynamics of the crime act. Therefore, the present experiment, built on the basis of a previous pioneer project carried out in the same area between 2009 and 2011, will be based on the re-enactment of real cases of body disposal, consisting in a combination of multiple methods of concealment, all of them including the inhumation of the remains in a woodland setting. It will consist of the excavation of 32 burials, all dug on the same day, at a depth between 40 and 60 cm involving just as many piglet cadavers (Sus scrofa) weighing between 3 and 5 kg. They will be divided into four different groups, each of which will undergo peculiar treatments: eight will be buried naked; eight clothed; eight will be buried in quicklime and the last eight will be previously hurt. The experiment will be conducted for a total of 730 days and the exhumations of the specimens will be performed in eight increasing time intervals, to achieve different PBIs for each group of subjects (15, 30, 60, 120, 240, 365, 545 and 730 days). At the time of each exhumation biological material, commodities and soil will be sampled and investigated from a geochemical, microscopic (polarizing microscope) and ultramicroscopic (SEM-EDS) point of view, aiming to underline any evidence of mutual exchange of material between the different substrates, as well as any symptom of disturbance, both biochemical and mechanical. As focusing on a multidisciplinary approach, not only this study will allow to reach a standardization for the right reading of trace evidence in real cases of clandestine burials inquiry, but it also will contribute to draw up some guidelines for the exploitation of the parameters registered by the geopedological analytical techniques, which have been neglected for years in the forensic and medico-legal context.
Effects of Nonstationarity on Flooding of Coastal Infrastructure
Authors: Everett Cassandra , Zimmerman Julia , Maze Grace , Chung Sukhwan , Savant Gaurav , Kurth Margaret
Published: February 2023

Urban flooding continues to be one of the most damaging natural hazards globally. Despite efforts to mitigate flood risk, it continues to increasingly cause damage and disruption; in the US, tropical cyclones, severe storms, and inland flooding events are the first, third, and fourth most costly billion-dollar disaster events, respectively (NOAA National Centers for Environmental Information, 2022). Flood events in the US, including those caused by tropical cyclones and severe storms, cost an average of 40.6 billion USD each year and 1.7 trillion USD since 1980 (NOAA National Centers for Environmental Information, 2022). Beyond physical damages, flooding impacts local transportation networks, disrupting mobility necessary for day-to-day functions as well as for recovery.In response, the US Department of Defense has increased efforts to evaluate and improve the resilience of the missions that are carried out at coastal military installations. Under a changing climate, many of the factors that contribute to flooding at installation locations are nonstationary in nature, such as sea level rise, river discharge trends, land subsidence, and storm severity and frequency. Hazard modeling and subsequent resilience analytics should take nonstationarity trends into account, which in turn may lead to plans and designs that deviate from historical status quo to better cope with new realities.In this study, Adaptive Hydraulics 2D Shallow Water (AdH-SW2D), a high fidelity, finite-element model, is used to simulate hydrodynamic conditions under nonstationary conditions in sea level and river discharge over one hundred years. Two locations are identified as case studies – Camp Lejeune, NC, USA and NAS Gulfport, MS, USA. Simulations are carried out under low, intermediate, and high sea level rise for nine annual exceedance probabilities in river discharge. Maps of flood depth and extent are generated to examine the effects of nonstationarity on urban flood conditions in each location over time. Inundation conditions form the basis for various inquiries including road network connectivity, installation mission resilience, and the compounding impact of multiple threats.Reference: NOAA National Centers for Environmental Information (NCEI) U.S. Billion-Dollar Weather and Climate Disasters (2022). https://www.ncei.noaa.gov/access/billions/, DOI: 10.25921/stkw-7w73
On the evolutionary aspects of solar coronal holes
Authors: Heinemann Stephan G.
Published: February 2023

Coronal holes (CH) are large, long-lived structures commonly observed in the solar corona as regions of reduced emission in EUV and X-ray wavelengths. They feature a characteristic open magnetic field configuration along which ionized electrons and atoms are accelerated into the interplanetary space. The resulting outflowing plasma is called high seed solar wind stream (HSS; see Cranmer 2009 and references therein). These HSSs are the major cause of minor to moderate geomagnetic activity at Earth (see Richardson 2018 and references therein).To be able to predict the arrival and impact of those disturbances accurately, their origin and evolution need to be studied in detail. And to do so, it is imperative that CHs are accurately and reliably extracted, thus leading to the development of the Collection of Analysis Tools for Coronal Holes (CATCH). By using the intensity gradient across the CH boundary, it is possible to robustly extract CHs whose properties can then be analyzed. We find that the area of long-living CHs generally evolves by growing to a maximum before decaying. However, the associated magnetic field does not evolve equally. Depending on the CH, we find a correlation, an anti-correlation or even no correlation over the course of its lifetime. Therefore, we believe that the evolution of a CHs magnetic field is primarily driven by the large-scale connectivity changes in the Sun's global magnetic field. Further, we find that the plasma properties within CHs show a significant center to boundary gradient, which may justify the distance-to-boundary parameter used in some solar wind modeling.To study the evolution of CHs in detail, a 360° view of the Sun is necessary; however, the magnetic far-side of the Sun still eludes. The few snapshots with Solar Orbiter provide only a fragmented picture of the magnetic field on the solar far-side. We found that by using EUV observations of the transition region (specifically using Stereo) it is possible to estimate the magnetic field density of CHs on the solar far side. In addition, we are currently investigating the incorporation of helioseismic observations into synoptic magnetograms to generate a maps that show the magnetic field of the whole Sun at a given time.
The southeast tropical Atlantic: improvements and persistent biases in CMIP models
Authors: Farneti Riccardo , Stiz Alessandro , Ssebandeke John B.
Published: February 2023

State-of-the-art climate models simulate warmer than observed sea surface temperatures (SST) in eastern boundary upwelling systems (EBUS), generating biases with profound implications for the simulation of present-day climate and its future projections. Amongst all EBUS, the bias is largest in the southeastern tropical Atlantic (SETA). Here, we provide a comprehensive evaluation of the performance in the SETA of the Coupled Model Intercomparison Project phase 6 (CMIP6), including fine resolution (HighResMIP) and ocean-forced (OMIP) models. We show that biases in the SETA remain large in CMIP6 models but are reduced in HighResMIP, with OMIP models giving the best performance. The analysis suggests that, once local forcing errors have been reduced, the major source of the SETA biases lies in the equatorial Atlantic. This study shows that finer model resolution has helped reduce the local origin of the SETA SST bias but further developments of model physics schemes will be required to make progress. 
A Proper Use of the Adjacent Land-Based Magnetic Field Data to Account for the Geomagnetic Disturbances During Offshore Directional Drilling
Authors: Kuvshinov Alexey , Kruglyakov Mikhail , Nair Manoj
Published: February 2023

Directional drilling in the oil fields relies particularly on the "on-fly" measurements of the natural magnetic field (measurements while drilling; MWD); the MWD are eventually used to construct the well path. These measurements are the superposition of the signals from the internal (core and crustal),  external (ionospheric and magnetospheric) sources, and the noise from magnetic elements in the borehole assembly. The internal signals are mostly constant in time and accounted for through the Earth's internal field models. The signals of external origin give rise to diurnal and irregular spatiotemporal magnetic field variations observable in the MWD. One of the common ways to mitigate the effects of these variations in the MWD is to correct readings for the data from an adjacent land-based magnetic observatory/site. This method assumes that the land-based signals are similar to those at the seabed drilling site. This study shows that the sea level and seabed horizontal magnetic fields differ significantly in many oceanic regions. We made this inference from the global electromagnetic induction modelling of the magnetic field using realistic models of conducting Earth and time-varying external sources. To perform such modelling, we elaborated a numerical approach to calculate efficiently the spatiotemporal evolution of the magnetic field. Finally, we propose and validate a formalism allowing researchers to obtain trustworthy seabed signals using measurements at the adjacent land-based site and exploiting the modelling results, thus without needing additional measurements at the seabed site.
Risk-based flood and drought management for multiple reservoirs in a non-stationary climate: application to the Seine River
Authors: Dorchies David , Delaigue Olivier , Kahiyeh-Moumin Idris , Ricquier Florian , Thirel Guillaume
Published: February 2023

Mitigation of drought and flood rely on objectives that are often a combination of several flow thresholds to be respected for different locations downstream the reservoirs. In this context, multi-objective optimisation techniques quickly show their limits due to the curse of dimensionality (Bellman, 1957). To tackle this issue, we propose an approach in which we first evaluate the risk of non-achievement of each objective independently for a given climatology and a given state of the system. Then, we derive management rules by prioritising the riskiest objectives in the daily decision making.This approach is applied on the Seine catchment (located in the North of France), which is equipped with a system of four large reservoirs to protect against floods and water shortages multiple locations downstream including the Paris region.First, catchment naturalized flows are modelled at a daily time step with a semi-distributed GR4J model based on the R package airGRiwrm (Dorchies et al., 2022) and forced by 11 GCM/RCM scenarios for both RCP4.5 and RCP8.5 between 1950 and 2100.Then, these flows are used to assess the risk of non-achievement of each objective taking into account the current reservoir volume, the day of the year and a selection of climate scenarios and periods. This assessment is derived from the statistical distribution of the minimum (resp. maximum) volume required in the reservoirs for a given drought (resp. flood) objective calculated by a single objective dynamic programming optimisation. The result of this assessment is available to the public through an interactive Shiny interface (http://irmara.g-eau.fr) that allows to experiment management scenarios in real time.Finally, management rules are derived by prioritising the riskiest objectives and balancing proactive and reactive decisions taking into account a hedging policy. The performance of this management is compared to the current management of the reservoirs over the historical and future periods.This approach has the advantage of providing a decision based on a risk assessment and prioritisation process that allows the manager to justify the decision and paves the way for an operational application.ReferencesBellman, R. Dynamic programming. Princeton, N.J.: Princeton University Press, 1957.Dorchies, David, Olivier Delaigue, et Guillaume Thirel. « airGRiwrm: Modeling of Integrated Water Resources Management based on airGR. R Package version 0.6.1 ». Portail Data INRAE, 7 mars 2022. https://doi.org/10.15454/3CVD1I.
Global Geomagnetic Perturbation Forecasting Using Deep Learning
Authors: Ferdousi Banafsheh , Upendran Vishal , Tigas Panagiotis , Bloch Téo , Cheung Mark , Ganju Siddha , Bhatt Asti , McGranaghan Ryan , Gal Yarin
Published: February 2023

Geomagnetically Induced Currents (GICs) arise from spatio-temporal changes to Earth's magnetic field, which arise from the interaction of the solar wind with Earth's magnetosphere, and drive catastrophic destruction to our technologically dependent society. Hence, computational models to forecast GICs globally with large forecast horizon, high spatial resolution and temporal cadence are of increasing importance to perform prompt necessary mitigation. Since GIC data is proprietary, the time variability of the horizontal component of the magnetic field perturbation (dB/dt) is used as a proxy for GICs. In this work, we develop a fast, global dB/dt forecasting model, which forecasts 30 min into the future using only solar wind measurements as input. The model summarizes 2 hr of solar wind measurement using a Gated Recurrent Unit and generates forecasts of coefficients that are folded with a spherical harmonic basis to enable global forecasts. When deployed, our model produces results in under a second, and generates global forecasts for horizontal magnetic perturbation components at 1 min cadence. We evaluate our model across models in literature for two specific storms of 5 August 2011 and 17 March 2015, while having a self-consistent benchmark model set. Our model outperforms, or has consistent performance with state-of-the-practice high time cadence local and low time cadence global models, while also outperforming/having comparable performance with the benchmark models. Such quick inferences at high temporal cadence and arbitrary spatial resolutions may ultimately enable accurate forewarning of dB/dt for any place on Earth, resulting in precautionary measures to be taken in an informed manner.
Soil respiration in a traditional olive grove in the southeast of Spain
Authors: Aranda-Barranco Sergio , Serrano-Ortiz Penelope , Kowalski Andrew Stephen , Sánchez-Cañete Enrique P
Published: February 2023

Olive groves occupy a large area in the Mediterranean and their management has repercussions on the carbon cycle in this region.  Weed suppression is the most common management in this crop, but its implications for soil respiration (Rsoil) are not well estimated due to the lack in continuous Rsoil measurements. In this research we present a full year of Rsoil in an irrigated olive grove in which a glyphosate-based herbicide was applied to prevent spontaneous weeds (conventional management). For that, an automatic multi-chamber Rsoil system was used (LI-8100 + LI-8150 with 6 chambers, Li-Cor). In addition, soil temperature (Tsoil) and soil water content (SWC) were measured next to each chamber. To study the influence of olive trees on Rsoil, 3 chambers were placed near the olive trunk and another 3 in the middle of the alleys.
Results show seasonal and spatial variability, with higher Rsoil in warm months and lower Rsoil in cold months. Also, Rsoil near the trunk was always larger than in the alleys. The spatial difference increased in the cold months. Diurnal variability was observed with higher Rsoil as the soil temperature increased in the alleys, but this was not observed near the trunks. Under the canopy, a decrease in the Rsoil is observed as the VPD increases, suggesting a major contribution of autotrophic respiration under the canopy. In addition, there is no positive and negative relationship with temperature and SWC under the canopy, while in the alleys, a strong hysteresis occurs in some periods. Finally, rain events were followed by Rsoil peaks. However, low intensity and short duration rain pulses did not manifest on the ground under the olive canopy, so interception is inhibiting this process in part of the agrosystem.
This work was supported by the projects PID2020-117825GB-C21 & PID2020-117825GB-C22 (INTEGRATYON3), B-RNM-60-UGR20 (OLEAGEIs), P18-RT-3629 (ICAERSA) and PPJIB2022-08 funded by University of Granada.
Has there been a recent shallowing of tropical cyclones?
Authors: Lai Tsz-Kin , Toumi Ralf
Published: February 2023

Many aspects of tropical cyclone (TC) properties at the surface have been changing but any systematic vertical changes are unknown. Here we document a recent trend of high thick clouds of TCs. The global inner-core high thick cloud fraction measured by satellite has decreased from 2002 to 2021 by about 10% per decade. The TC inner-core surface rain rate is also found to have decreased during the same period by a similar percentage. This suppression of high thick clouds and rain has been largest during the intensification phase of the strongest TCs. Hence, these two independent and consistent observations suggest that the TC inner-core convection has weakened and that TCs have become shallower recently at least. For this period the lifetime maximum intensity of major TCs has not changed and this suggests an increased efficiency of the spin-up of TCs.
Modelling of near-surface NO2 and O3 concentration over Germany using machine learning
Authors: Balamurugan Vigneshkumar , Chen Jia , Wenzel Adrian , Keutsch Frank N.
Published: February 2023

Chemical transport models (CTMs) are commonly used to model air pollutant concentrations. CTMs, on the other hand, require a lot of computing power and sometimes yield biased findings that result from emission inventories and chemical mechanisms employed. Machine learning algorithms are used in a wide range of fields, including Earth system science. Its popularity stems from its ability to learn complex non-linear relationships. As a follow-up of our previous study [1], we attempted to deduce the capability of Machine Learning (ML) in modelling air pollutant concentrations.In this study, we employed the Gradient Boosted Tree (GBT) algorithm to model near-surface NO2 and O3 over Germany at 0.1 degree resolution and daily intervals. The GBT model is trained using TROPOMI satellite column NO2, O3, HCHO data, as well as meteorology and road density as an information for NOX emission sources. Government air quality (NO2 and O3) observations from urban, suburban, and background stations are used as target variables; 321 stations are considered for NO2 ML model training and 256 stations are considered for O3 ML model training. The GBT model trained for near-surface NO2 explains 68-88% of observed concentrations, whereas, for near-surface O3, the GBT model explains 74-92% of observed concentrations. Road density and TROPOMI NO2 data are the most important features in the fitted model for near-surface NO2. This is due to the fact that road density (a proxy for traffic) is the main source of near-surface NOX emission, and the TROPOMI tropospheric NO2 column is a good representation of near-surface NO2 concentration. The downward UV radiation (DUV) at the surface and temperature are the most important features in the fitted model for near-surface O3. Since O3 is formed from the photolysis of NO2, DUV plays an important role in the fitted model for O3. Temperature is the driver of biogenic Volatile Organic Compounds (VOCs), which are an important precursor to O3. In all cases, the GBT model outperforms feed-forward neural networks. Furthermore, the developed GBT model for near-surface O3 is reliably transferable to other locations and countries (R2=0.87-0.94), whereas the developed model for near-surface NO2 is moderately transferable (R2=0.32-0.68). The reason could be that the road density is not the best representative of traffic NOX emissions and can be improved in a future study. Overall, we developed a new machine learning model to cost-effectively model the near-surface NO2 and O3 concentrations, which could help us to better understand the air pollution distribution at a moderate resolution.References:Balamurugan, V., Balamurugan, V. and Chen, J., 2022. Importance of ozone precursors information in modelling urban surface ozone variability using machine learning algorithm. Scientific reports, 12(1), pp.1-8.
Characterization of PM10 fraction before pandemic and during pandemic COVID-19 at the traffic station in Krakow, Poland
Authors: Samek Lucyna , Ryś Anna , Stęgowski Zdzisław , Styszko Katarzyna
Published: February 2023

Samples of PM10 were collected at the traffic station in Krakow, Poland during two periods: 2nd February- 30th May 2018 and 2nd February 17th June 2020. PM10 concentrations were determined gravimetrically. PM10 concentrations dropped by 50% from 74±29 µg/m3 to 37±13 µg/m3 in 2018 and 2020, respectively. Elemental concentrations were determined by energy dispersive X-ray fluorescence method (EDXRF) and ion concentrations by ion chromatography (IC). 18 elements and 8 ions were measured. Ratios of concentrations in 2018 to 2020 were above 1.7 for the following elements: S, Cl, K, Zn, Br and ions SO42-, Na+, NH4+. The above-mentioned ratio was equal to 1.4 for Cu, Fe and Co. Similar concentrations in 2018 and 2020 were observed for the following chemical species: Ca, Ti, Mn, Ni, Rb, Sr, K+, Mg2+, Ca2+, PO43-. Cr concentration was higher in 2020 compared to 2018. Four factors were obtained from PMF (Positive Matrix Factorization) modelling. The following sources were attributed: solid fuel combustion, secondary inorganic aerosols, traffic/industry/construction work and soil. The contribution of traffic/industry/construction work to PM10 mass was the highest. It was equal to 24.6 µg/m3 and 23.4 µg/m3 in 2018 and 2020, respectively. The contribution of solid fuel combustion and secondary inorganic aerosols was five times lower in 2020 than in 2018. Contribution of solid fuel combustion was 14.5 µg/m3 and 2.6 µg/m3 in 2018 compared to 2020. SIA was lowering from 15.7 µg/m3 in 2018 to 2.5 µg/m3 in 2020. Traffic/industry/construction work and soil contribution was on the similar level in both years. Two factors affected characteristic of PM10: one was a ban of using coal and wood for heating purpose introduced in Krakow in September 2019 and second one was pandemic of COVID-19 started in March 2020. Our study will be helpful for the local authority in preparing future plans for reducing air pollution within the city.Acknowledgments: This research project was supported/partly supported by the program “Excellence initiative—research university” for the University of Science and Technology. The bilateral cooperation  project nr BPN/BPT/2021/1/00001 between Poland and Republic of Portugal partially financed this work together with the subsidy of the Ministry of Science and Higher Education, grant number 16.16.220.842.
Experimental study on the creep behavior of buffer materials in the deposition hole of a repository
Authors: Huang Wei-Hsing , Ren Guo-Liang
Published: February 2023

With the extra long term consideration for safety in a geological disposal repository, the creep behavior of the buffer material in a deposition hole can have an effect on the long-term stability of the engineered barrier. In this study, the hydro-mechanical properties and creep modeling parameters were determined experimentally on MX-80 bentonite. These include swelling pressure, water conductivity, and shear stress-strain behavior obtained from constant-stress direct shear test. The experimental works involved testing the bentonite in 3 different modes, namely, unsaturated, saturation under constant volume, and saturation after pre-swell. The pre-swelling process was designed to simulate an expansion of the buffer material due to mass losses of bentonite upon resaturation in a deposition hole.          The experimental results show that in the constant volume mode and pre-swell mode, the swelling curve each has its own characteristics and, as the density of buffer decreases, the swelling pressure continues to decrease but in different trends. The shear strength obtained in the 3 modes is different while the values for the latter 2 modes are close. In the constant stress shear test, the higher the shear stress level, the faster the increase in shear strain rate. The shear strain rate is found to be higher in the pre-swell mode. Thus, for the long term safety of the deposition hole, the mass loss of buffer material should be limited to prevent degraded performance against creep deformation.          Finally, numerical simulation was implemented to predict the creep deformation in a deposition hole for extended periods of time, in order to provide a reference for the design of the deposition hole and disposal tunnel. It is estimated that, at the junction of the buffer material and the backfill material, the vertical displacement increases continuously and reaches its maximum at 100,000 years.
Flood Early Warning and Hazard Mapping for Railway and Dam Management
Authors: Murdock Heather J. , Otto Antje , Heidenreich Anna , Thieken Annegret H.
Published: February 2023

Floods in Europe regularly cause damage and disruption to communities and infrastructure. The extreme flood of July 2021 which affected Germany, Belgium, Luxemburg and the Netherlands provides an example of a flood event with a rapid onset time with corresponding short warning times and high uncertainty. This was a flood event with high velocities and volumes of debris. In addition to casualties there was extensive damage and disruption to infrastructure including roads, rail, water supply, and power transmission. Some negative impacts can be mitigated through the use of flood early warning systems (FEWS) and spatial planning using hazard maps. For such risk reducing measures, it is important to understand what challenges remain towards implementation. For example, challenges may differ between actors with different mandates and capacities.   

Infrastructure operators have an important role in flood risk management as the functioning of critical infrastructure (CI) is of high importance for society. CI in this context includes infrastructure, such as dams and railroad which we focus on, whose failure or impairment results in lasting disruptions to the overall system. Is it therefore possible that the prevention of damage and disruption to CI can reduce risk for society as a whole? Flood early warning information can support early action including moving mobile assets to higher ground, preventative closures, or protecting critical parts of a network with mobile flood barriers. Little empirical data exists, however, to address this question. It is therefore unclear to what extent flood risk management measures have become integrated into CI management by infrastructure operators.   

In this study we conduct expert interviews with CI operators in Germany and Belgium to investigate: (1) what FEWS information CI operators use, (2) how has it been applied during past flood events, particularly in 2021, (3) what information is shared with other stakeholders in an emergency context, (4) what flood hazard maps do operators currently use, and (5) how are flood hazard maps integrated into infrastructure planning. Our focus on dam and railway operators is due to the important role they play in water management and regional transportation, respectively. The interviews are transcribed and coded using MaxQDA to address the five points mentioned above. The empirical basis of this research can help to shed light on the effectiveness of available information to reduce risk in an emergency management context as well as for infrastructure planning. 
RadClim BSR - Towards a Radar-based Precipitation Climatology for the Baltic Sea Region
Authors: Lowry Blaine , Hoy Andreas , Hashemi Hossein
Published: February 2023

Project Background: The RadClim BSR project aims to establish the feasibility of developing a radar-based precipitation climatology in the Baltic Sea Region (BSR). The project involves partners in countries across the BSR including Sweden, Estonia and Poland. The status of radar data archiving, utility of the data, and any data harmonisation requirements across the partner countries and the BSR in general are being investigated. Partners in Sweden, Estonia and Poland are acting as country coordinators, reaching out to a large range of actors to thoroughly explore their needs pertaining to radar climatology, utilising a user needs survey (ongoing from early February-March 2023). Consultations with the national weather services in Germany and Finland, who have already undertaken steps in radar climatology development, are aiding in ensuring best practices are adhered to. This seed project has the intention of laying the framework for the full development of a radar-based precipitation climatology (datasets and visualisations) spanning the BSR, relevant for a large range of actors in the near future.EGU poster: At EGU 2023, we will present the results of the user needs survey that was distributed to a wide range of relevant actors in the project partner countries of Sweden, Estonia and Poland. The surveys were translated into each countries official language before being distributed, to maximise participation and ensure all representatives who should offer their perspective could, regardless of English language capacity. Through to the end of the project in early 2024, the results from this survey will be analysed and summarised, to form the user needs assessment for a radar-based precipitation climatology across the BSR.
Assessing urban gully occurrence at the scale of Africa
Authors: Dujardin Elise , Ilombe Mawe Guy , Lutete Landu Eric , Amery Arno , Makanzu Imwangana Fils , Hubert Aurélia , Dewitte Olivier , Vanmaercke Matthias
Published: February 2023

The rapid and typically uncontrolled growth of many African cities leads to a plethora of problems and challenges. One of these is the formation and expansion of large urban gullies (UGs) in many (sub)tropical cities. UGs typically lead to the destruction of houses and other infrastructures, displace large numbers of people and often claim casualties. As the formation of such gullies is strongly linked to land use and rainfall intensity, the problems associated with UGs are likely to aggravate in the near future as a result of continued urban expansion and climate change. However, this newly emerging geo-hydrological hazard hitherto received very little research attention. Several studies report on the occurrence and impacts of UGs. Yet, they remain limited to specific local case studies. A clear understanding of the patterns, impacts and driving factors of UGs at larger scales is currently lacking. To address this gap, we aim to better understand the spatial patterns and UG occurrence at the scale of Africa.In order to achieve this, we are documenting cases of UG occurrence across Africa through the visual analysis of very high spatial resolution satellite imagery. This mapping already allowed us to identify more than 3,500 UGs in 11 countries (mainly across D.R. Congo, Angola, Republic of the Congo, Nigeria and Mozambique). Using on this database, we develop a logistic regression model that accurately simulates the likelihood that UGs occur within (peri-)urban areas across Africa. Our preliminary results show that a combination of rainfall characteristics, topography, soil type and variables describing the land use/urban context can already robustly explain why certain cities are extremely susceptible to the problem and others not. Overall, our dataset and model are first crucial steps to better understand the current and future risks of UGs across Africa.
Stochastic perturbations of El Nino Southern Oscillations (ENSO) : a Wiener chaos approach
Authors: Aydogdu Yusuf , Baxendale Peter , Namachchivaya N. Sri
Published: February 2023

The phenomena of El Nino Southern Oscillations (ENSO) is modeled by coupled atmosphere-ocean mechanism together with sea surface temperature (SST) budget at the equatorial Pacific and has a significant impact on the global climate.  We consider a modeling framework that was originally developed by Majda and co-workers in (Chen et al. 2018; Thual et al. 2016), which is physically consistent and amenable to detailed analysis. The coupled model is mainly governed by the equatorial atmospheric and oceanic Kelvin and Rossby waves and it is shown that stochastic forcing gives rise to the model anomalies and unpredictable behavior. The purpose of our work is to investigate the influence of randomness on the model dynamics,  construct the appropriate model components with stochastic noise and calculate the statistical properties. We also provide analytical and numerical solutions of the model to prove the convergence of the numerical scheme developed in our work. We use Wiener-Chaos Expansion (WCE) to study stochastic ENSO models. The WCE method is based on reducing stochastic partial differential equations (SPDEs) into an infinite hierarchy of deterministic PDEs called propagators-Fourier modes (Lototsky and Rozovsky, 2006) and represents the stochastic solution as a spectral decomposition of deterministic components with respect to a set of random Hermite bases. We solve the WCE propagators, which are forced by a set of complete orthonormal bases,  by applying numerical integration and finite-difference methods. We compare WCE-based results with Monte Carlo simulations of SPDEs.Our results depict that the mean and variance of the solutions obtained from the WCE method provide remarkably accurate results with a reasonable convergence rate and error range.  We first test the WCE-based method on the ocean  model with white noise and show that 10-Fourier modes are able to approach the theoretical variance values. We also show that the OU process with a specific noise strength and dissipation over a one-time period can be recovered with less than 50-Fourier modes for the ENSO model.  To illustrate the particular weight of variance, we also generate the ensembles of solutions by using different stochastic bases. We also derive the analytical formulation of propagators for the coupled model with nonlinear SST by using the properties of Wick polynomials that construct the foundation of numerical schemes. 
High-resolution temporal gravity fields from SLR and DORIS using tailored base functions
Authors: Kusche Jürgen , Löcher Anno
Published: February 2023

Time-variable gravity field solutions from satellite missions prior to GRACE are of limited applicability in climate studies, due to their low spatial resolution. To overcome this disadvantage, we developed a novel parametrization in which the temporal changes of the gravity field are represented by a finite number of spatial patterns tailored to the expected signal power. These patterns are identified by an EOF analysis applied to the GRACE and GRACE Follow-On solutions. Using such tailored base functions does not break down the limits of the tracking technique, but allows to isolate large-scale mass variations with the full GRACE resolution, while the parameter space is kept extremely tight. In a previous publication, this approach has been successfully applied to compute a GRACE-like time series from five SLR satellites going back to 1992. To further enhance this solution, we now turned towards the DORIS constellation from which we processed data from ten satellites at altitudes up to 1000 km. It was found that our parametrization is highly suitable also for the DORIS system and results in a time series that agrees well with that from SLR. Such agreement is found even for the very first years when the DORIS solution is occasionally based on one single satellite. We note that we include the estimation of thermosphere model scaling parameters that can help in understanding neutral density change.The contribution will provide details of our DORIS processing and present total water storage maps and mass balances for selected regions from DORIS, SLR and from the combination of both techniques. We believe our results will contribute to long-term mass studies concerned with sea-level change, ice mass loss at high latitudes or water storage changes in large river basins. In addition, it will be shown that the presented time series can improve the force models for precise orbit determination at higher altitude. For example, a dynamic reconstruction of Jason-3 orbits from kinematic positions reveals that the SLR/DORIS solution performs competitively in this task when compared to the frequently applied EIGEN-GRGS.RL04 model, with some advantage in the later years when the EIGEN model provides pure predictions. 
DLITE—An inexpensive, deployable interferometer for solar radio burst observations
Authors: Carson George , Kooi Jason , Helmboldt Joseph , Markowski Blerta , Bonanno David , Hicks Brian
Published: February 2023

Solar radio bursts (SRBs) are brief periods of enhanced radio emission from the Sun which contain information concerning the plasma where the emission originates; consequently, SRBs can provide critical information concerning space weather events such as coronal mass ejections (CMEs). A new network of four-element interferometers is being developed and used to monitor SRBs. These interferometers, called the Deployable Low-band Ionosphere and Transient Experiment (DLITE) arrays, operate in a 30-40 MHz band and were originally designed to probe the Earth’s ionosphere using high resolution measurements (1.024-s temporal resolution, 16.276-kHz frequency resolution). The DLITE network has recently been demonstrated to be  a powerful tool for detailed observations of SRBs at these frequencies. We have used DLITE to detect long-duration Type II and Type IV SRBs. Each DLITE array provides a higher sensitivity (e.g. >10 dB) compared to single-receiver stations using the same antenna. We demonstrate DLITE's enhanced functionality by examining SRBs associated with a CME on May 11, 2022. The high resolution SRB data that DLITE provides can complement ground-based networks like e-Callisto or space-based observations, e.g., from Wind/WAVES. Future improvements could be made to DLITE arrays by utilizing the 20-80 MHz band and millisecond time-resolution possible by the antennas. This would expand DLITE’s detection ability to shorter Type I and Type III SRBs and improve its ability to track long-duration bursts. 
Geophysical characterization of the shallow subsoil at a heavily urbanized archaeological site: the Roman Amphitheater and the Scrovegni Chapel in Padua.
Authors: Cassiani Giorgio , Barone Ilaria , Pavoni Mirko , Boaga Jacopo , Deiana Rita
Published: February 2023

The characterization of the shallow subsoil at complex archaeological sites requires sufficient spatial coverage and resolution as to provide the necessary information. This is all but trivial, particularly where historical superposition of layers requires also sufficient depth investigation and resolution. The Scrovegni Chapel in Padua, with its Giotto's fourteen century frescoes, and recently added to the list of UNESCO World Heritage Sites, stands on the remains of the local Roman amphitheater. The hypogeum located under the chapel shares its western wall with a part of the wall of the amphitheater. To date, no information is available about the soil below the apse of the chapel. Over the past decade, several ERT and GPR measurements have been conducted outside the chapel, straddling the amphitheater structure for archaeological and geomorphological characterization of the area. In 2021, a first 3D active and passive seismic survey was conducted using about 1500 wireless sensors, aiming at using surface waves to provide a 3D image of the subsurface in terms of shear wave velocity. In 2022 three 20 m deep boreholes were drilled around the chapel and equipped with fiber optics, ground deformation sensors, and electrodes for cross-hole ERT, and about 200 1-C and 3-C wireless seismic sensors were placed around the drilling area. During the drilling, additional 3D seismic data were acquired from the surface, which completed the datasets acquired in 2021. The geophysical data thus acquired and the time-lapse monitoring that will be possible around the area of the Scrovegni Chapel in Padua will allow reconstructing the geomorphology of the subsurface on which the chapel rests, but also to better study and analyze the possible interactions between the structure of the chapel and the buried structure of the Roman amphitheater from the mechanical point of view as well as from the perspective of the seismic response of this specific site.