bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of a climatic thermal runaway on the tectonic regime of Venus
Authors: Manjón-Cabeza Córdoba Antonio , Rolf Tobias
Published: February 2023

The origin of the observed differences between Earth and Venus remains a mystery. On Earth, surface deformation is focused at narrow plate margins resulting in plate tectonics (or a mobile-lid regime). On Venus, a global network of connected plate margins is absent, but the surface is young and has preserved evidence of at least regional crustal mobility. Therefore, the planet must be in a yet-to-be-defined regime distinct from plate tectonics, for example an episodic-lid regime. The array of Venus missions planned for the next decade provides us with an unprecedented chance to refine our knowledge of this tectonic regime, but to use the upcoming data, we need hypotheses to test and a physical framework in which to contextualize the data. To explain the discrepancy on the tectonic regime, a popular hypothesis is that Venus’ higher surface temperatures foster a stiffer lithosphere due enhanced grain growth. Thermally assisted grain growth is supposed to increase the lithospheric viscosity, since diffusion creep depends on grain size, and therefore subduction becomes less efficient. In a previous work [Manjón-Cabeza Córdoba, A., Rolf, T., and Arnould, M: Feasibility of the mobile-lid regime controlled by grain size evolution. EGU General Assembly 2022], we showed that high grain reduction can decrease the interval of yield stresses for which the episodic regime applies, but the results on grain growth were not too conclusive. Here, we present a new set of convection models in spherical annulus geometry using different surface temperatures to specifically address the differences between Earth and Venus. Our results suggest that the effect of the climate thermal runaway depends on the strength of the lithosphere. For yield stresses that yield Earth-like behaviors at lower surface temperatures, an increase in surface temperature does not result in the episodic regime, but rather a sluggish-dripping regime with relatively low plateness. We conclude that either Venus is not in an episodic-regime, or a different explanation must be put forward for the tectonic regime of Venus (e.g., lack of liquid water at the surface).
Mapping spatio-temporal variations in ionospheric electrodynamics
Authors: Laundal Karl , Reistad Jone , Hatch Spencer , Gasparini Sara , Walker Simon , Madelaire Michael , Ohma Anders
Published: February 2023

The Swarm satellites accurately sample electromagnetic fields in-situ along the satellite tracks, but give little direct information about the spatial structures of the field away from the orbit. By making assumptions about temporal variations, in-situ satellite data is nevertheless useful for constructing climatological models that reveal average patterns of electromagnetic fields. Such models help us to understand large-scale average effects of solar wind-magnetosphere-ionosphere-thermosphere coupling, but their information about temporal variations is limited. For specific events, data from single satellites are insufficient for mapping spatio-temporal variations. Here we present a technique for combining Swarm data with measurements of magnetic and electric fields from other satellites, and from ground instruments. The technique, called Local mapping of polar ionospheric electrodynamics (Lompe) relies on the ionospheric Ohm’s law, and knowledge about ionospheric conductance. We discuss the importance of reliable conductance estimates for accurately relating magnetic and electric field observations.
Cluster-based hyperparameter optimisation for LSTM-based flow forecasting in Canadian catchments
Authors: Khan Usman T , Snieder Everett
Published: February 2023

Improvements in large dataset availability and computing power have led to an increase in large-sample hydrological (LSH) studies. While these studies bring a breadth of new knowledge, they also introduce new challenges. One such challenge is the optimisation of model hyperparameters, which can be prohibitively computationally expensive on a large scale. Machine learning (ML)-based flow forecasting models have been steadily rising in popularity due to their high accuracy and ease of development. While traditional physics-based models have hyperparameters rooted in hydrological concepts (e.g., the number of hydraulic response units is determined based on spatial heterogeneity), ML-based models do not typically use a physical basis for selecting hyperparameters (e.g., neural network topology). Instead, ML model hyperparameters are typically determined using heuristic or exhaustive search methods.  Clustering has been previously applied to watersheds for identifying homogenous regions for flood frequency analyses. In these cases, unsupervised clustering, based on static watershed characteristics and flow statistics, is used to identify homogenous regions on which to conduct frequency analyses. We propose an application of clustering to optimise ML model hyperparameters on a large scale. The objective of this study is to determine whether grid-search optimisations are transferrable to similar catchments, identified through unsupervised clustering. Our study is conducted using a subset of Canadian catchments (n>500) from the HYSETS database. For each catchment, an LSTM is trained to forecast flow at a daily resolution using hydrometeorological input features (flow, precipitation, temperature, SWE). Grid-search hyperparameter optimisation is conducted on model architecture (number of hidden states and layers), learning rate, dropout rate, and input sequence length. We evaluate the effectiveness of cluster-based hyperparameter optimisation based on a comparison against a non-optimised baseline, for an increasing number of clusters. The impacts of this work have the potential to improve the effectiveness of ML-based flow forecasting models in cases where exhaustive hyperparameter searches are not possible. The results will also allow us to make recommendations for typical hyperparameter values based on watershed characteristics.
Subsoil compaction impacts soil quality indicators in a Calcaric Chernozem
Authors: Fouladidorhani Maliheh , Lamandé Mathieu , Moitzi Gerhard , Nawaz Muhammad Mohsin , Nazari Meisam , Wagentristl Helmut , Arthur Emmanuel
Published: February 2023

Soil compaction caused by modern mechanized agriculture has severe impacts on soil functioning and negative consequences on crop production. In the subsoil, these effects are persistent and difficult to ameliorate. To further clarify the compaction effect on the subsoil, we imposed compaction on 21st April 2022 on a moist Calcaric Chernozem (silty clay loam) by pulling a full 2-axle slurry tanker (10 m3, pendulum tandem axle, max. wheel load 3 Mg) with a tractor (19.5 Mg total load) through the field. Six months after the compaction event (in autumn (18th October 2022)), we evaluated the effects on field-measured soil structural quality indicators (SubVESS, bulk density, penetration resistance) and saturated hydraulic conductivity, then compared them to laboratory-measured gas flow-related parameters on intact 100 cm3 soil cores at -100 hPa (air-filled porosity, gas diffusion, and air permeability) at one depth in the subsoil (30-40 cm) and quantified pore geometry and tortuosity and geometry.Simulation of traffic using TerranimoÒ indicated a risk of compaction down to 30 cm depth. The compacted treatment did not noticeably affect the soil bulk density. However, based on visual evaluation by SubVESS, compaction decreased porosity and aggregate friability. The overall soil structural quality (Ssq) scores were 2.1 and 1.4 for the compacted and control subsoil layers, respectively. Further, compared to the control treatment, a higher penetration resistance for the compacted treatment was observed from 5 cm to 35 cm. Field-measured saturated hydraulic conductivity decreased by 42% after compaction. Soil gas transport by convection (air permeability) and diffusion (gas diffusivity) decreased by 67% and 48%, respectively, after compaction. Furthermore, compaction decreased air-filled porosity and pore organization by 28 and 60%, respectively, and increased pore tortuosity. It can be concluded that although compaction did not increase bulk density in the subsoil, the negative effects of traffic was detectable by SubVESS, and the quantitative parameters related to air and water flow.
Learning Stochastic Dynamics with Probabilistic Neural Networks to study Zonal Jets
Authors: Shokar Ira , Haynes Peter , Kerswell Rich
Published: February 2023

In this study, we present a deep learning approach to deriving a reduced-order model of stochastically forced atmospheric zonal jets. The approach provides a four orders of magnitude speed-up in simulating the jets, over numerical integration, together with a lower-degrees-of-freedom latent representation of the system- used to yield insight into the underlying dynamics.We consider the behaviour of zonal jets on a beta plane as represented by a two-dimensional model driven by stochastic forcing, which parameterises the turbulence due to baroclinic instability. This idealised model gives a useful analogue for week-to-week variations in the large-scale dynamics of the tropospheric midlatitude jet - the driver of European weather. We establish that the time evolution of the jets depends both on the nonlinear two-way interaction between the mean flow and the eddies and, crucially, the time history of the stochastic forcing. As a result, the current state or recent history of the system does not predict the forward evolution but instead determines a distribution of possible time evolutions.To model the flow, we utilise methods in manifold learning to learn a transformation to a latent representation of the system and then use a probabilistic neural network to model the stochastic latent dynamics. We verify the neural network’s performance by comparing the statistical and spectral properties of an ensemble from the neural network, obtained via sampling in the latent space, with an ensemble of numerical integrations, with different realisations of the stochastic forcing- with identical initial conditions. To study jet variability, we use ensembles of trajectories in both the latent and observation space to quantify to what extent different system states are driven by deterministic or stochastic dynamics. 
The new summit hazard map from lava flow inundation at Mt Etna volcano
Authors: Zuccarello Francesco , Bilotta Giuseppe , Ganci Gaetana , Cappello Annalisa
Published: February 2023

Mt. Etna is one of the most active basaltic volcanoes worldwide, characterized by both explosive and effusive eruptive activity. Lava flows represent the main hazard linked to the volcanic activity, which can be emplaced at high rates during paroxysmal eruptions from the main vents located at summit, or through vents located on the flank of the volcano. In the last decades, the eruptive activity interested mainly the summit area, particularly the South East Crater (SEC), with vigorous lava fountains, as during the 2011-2013 and 2020-2022 series, alternated by effusive activity through fissures opened at the base of the scoria cone, as during the July-August 2014, February-April 2017, May-July 2019 and May-June 2022 eruptions. This posed the need to quantify the hazard from lava flow inundation in the summit area, which is essential during volcanic emergencies and for mitigation actions.In this study, we present the new lava flows hazard map of Etna’s summit, which has been developed through a probabilistic approach that combines the statistical analyses of the volcanological historical data with the numerical simulations of lava flows on a 2022 Digital Surface Model (DSM). The probabilistic approach includes: i) the estimation of the spatiotemporal probability of future vent opening; ii) the calculation of the occurrence probability of the eruptive classes, which are defined considering the distribution of the lava volume erupted and the durations of eruptions; iii) the simulation of the lava flow paths for all the defined eruptive classes from each potential vent using the GPUFLOW model; iv) the mapping of the probability of inundation by combining the numerical simulations with the probability of future vent opening and the occurrence probability.A grid of potential vents have been defined over an area corresponding to the Ellittico caldera, while the eruptive classes have been derived by considering both the short- and long-lasting eruptions that occurred at Etna’s summit since 1998. The highest probabilities of inundation of lava flows provided by the obtained map are linked to the vents located in the SEC’s area, according to the observation of the eruptive dynamics in the last decades.
Reconfigurating hydro-social territories after the 2021 flood in Germany. Pathways towards resilience?
Authors: Kuhlicke Christian , Reckhaus Zora , Mariana de Brito , Danny Otto
Published: February 2023

With the loss of 180 lives, the 2021 flood was not only one of the most devastating natural disasters in Germany history, it can also be seen as another missed opportunity to use the reconstruction phase to rebuild more resilient and sustainable settlement structures. This paper presents first results of a study aiming at identify key contextual factors driving the reconstruction process. Therefore it relies on the concept of hydro-social territories. With this analytical framework we focus on social practice and narratives and how they interact with multiple human and non-human factors. By doing so, we attempt to move away from an external mechanistic perspective on reconstruction efforts towards an endemic perspective that is interested in social practices and the associated diversity of perspectives of different actors. The analysis is based on 30+ qualitative interviews conducted with representatives of the civil society, planning agency, municipalities as well as water management authorities. Based on the interviews we identify some of the key cultural, political, institutional and social contextual factors shaping how hydro-social territories are reconfigurated.
Small scale soil heterogeneity shows stable subsoil preferential flow paths of water and DOC over a 5 year period in a Dystric Cambisol
Authors: Socianu Sebastian , Böhme Hanna , Leinemann Timo , Liebmann Patrick , Kalbitz Karsten , Mikutta Robert , Guggenberger Georg
Published: February 2023

Preferential flow paths (PFPs) are intertwined soil regions that link top and subsoil and through which water and consequently nutrients flow across the soil profile. PFPs enable newly available carbon sources to reach deeper soil layers, enabling soil microorganisms to flourish in an otherwise substrate-poor subsoil. A reliable assessment of organic carbon (OC) translocation into the subsurface requires an understanding of the small scale variability of dissolved organic carbon (DOC) concentrations and fluxes into the subsoil.Using segmented suction plates over a 5-year period, we measured DOC and water fluxes, and subsequently OC translocation, at three depths in three soil profiles down to 1.5 m in a sandy Dystric Cambisol in Lower Saxony (Germany). DOC fluxes and water fluxes were correlated and decreased with depth. Overall fluxes were dependent on seasonal fluctuations of precipitation, with the winter and spring months bearing the highest water fluxes. We found significant flux variability between suction plates and soil depths. Rank analysis showed stable regions of high and low water and DOC fluxes, suggesting stable subsoil PFPs over these five years. Furthermore, the significance of small scale spatial heterogeneity as estimated by intraclass correlation was higher than the seasonal variability in each hydrological year, strengthening the idea that PFPs in a soil profile persist over years. In addition, SUVA analysis showed a decrease in OM aromaticity with depth in all three profiles and it was moderately correlated with water fluxes, indicating selective retention of complex organic matter along the soil profile.These findings highlight the potential for long-term stability of PFPs in subsoils and their significance for the development and maintenance of biogeochemical subsoil C hotspots, and that small scale soil heterogeneity plays a major role in controlling water and nutrient movements across the soil profile.
The shallow subsurface characterization in relation to geothermal resources in the Mallow area, Ireland, using passive seismic and gravity data inversion
Authors: Rezaeifar Meysam , Bean Christopher J. , Kiyan Duygu , O’Reilly Brian , Hogg Colin , Meere Patrick , Fullea Javier , Lebedev Sergei , Ye Tao , Chambers Emma L. , Scully Aisling , Tomar Gaurav ,   DIG team
Published: February 2023

One key aim of the DIG (De-risking Ireland’s Geothermal Energy Potential) project is to determine and evaluate the potential low-enthalpy geothermal resources at reservoir scale in the Mallow warm springs area (MWSA), by performing a joint interpretation of new and existing geophysical, geochemical and petrophysical datasets together with structural geology and hydrochemistry results.As a first step, based on the ambient detected noise sources in the study area, about 100 seismic stations (5Hz nodes) were deployed for two weeks along the railway, straddling fault structures that are thought to control hot spring fluid flow in the Mallow area. We performed seismic interferometry imaging on the recorded train-induced vibrations to map shallow subsurface (top ~2 km) structures and to extract the physical properties (e.g. seismic velocity and density) of these structures. Preliminary result shows a good correlation between S-wave velocity variation and the near-surface lateral changes of lithology, especially across the Killarney-Mallow Fault Zone (KMFZ).In the next step, 2D interactive modeling of the gravity data was performed, using physical properties determined from the previous step to constrain shallow structures. Additionally, we used the result from the receiver function method that is applied to the data recorded by four broadband stations in the study area, in order to better constrain the deeper interfaces. The 2D inversion of gravity data reveals an anomalous zone in the vicinity of the KMFZ that could be related to the possible fault conduit, associated with the Mallow warm springs area.The project is funded by the Sustainable Energy Authority of Ireland under the SEAI Research, Development & Demonstration Funding Programme 2019 (grant number 19/RDD/522) and by the Geological Survey Ireland.
Investigating the effects of river regulation and water quality on macroinvertebrate communities in the Goulburn basin during the millennium drought
Authors: Banad Sudeep , Wei Yongping , Dhanya Chandrika Thulaseedharan , Johnstone Ron
Published: February 2023

Macroinvertebrates are essential components of the aquatic ecosystem, and their assemblages are influenced by a variety of abiotic and biotic factors. The effects of water quality parameters on macroinvertebrate assemblages were studied in regulated and unregulated reaches of the Goulburn River, Australia. Analysis of similarities (ANOSIM) revealed significant differences in macroinvertebrate community compositions between river reaches and revealed that regulation plays a vital role in the composition of macroinvertebrates. SIMPER analysis was conducted to determine the contribution of each species to the average similarity between unregulated reach R1 and regulated reach R2, which is influenced by hydropeaking. The results show that Psephenidae, Eustheniidae, and Synthemistidae play a significant role in the observed differences between the two reaches. Redundancy analysis (RDA) and threshold indicator taxa analysis (TITAN) identified the water quality parameters and their associated indicator species, and the appropriate response threshold was determined. The results show that dissolved oxygen is the most important water quality parameter influencing macroinvertebrate community assemblage in unregulated reaches, whereas total suspended solids and ammonia nitrogen influenced community structure in regulated reaches. This research provides insight into the relative effects of water quality parameters on macroinvertebrate assemblages and their resilience to anthropogenic disturbance.   
Free surface effects and rupture dynamics : insights from the 2019 Mw=8 northern Peru intraslab earthquake
Authors: Vallée Martin , Xie Yuqing , Grandin Raphaël , Villegas-Lanza Juan Carlos , Nocquet Jean-Mathieu , Vaca Sandro , Meng Lingsen , Ampuero Jean Paul , Mothes Patricia , Jarrin Paul , Sierra Farfan Ciro , Rolandone Frédérique
Published: February 2023

The 2019/05/26 Northern Peru earthquake (Mw=8) is a major intermediate-depth earthquake that occurred close to the eastern edge of the Nazca slab flat area. We analyze its rupture process using high-frequency back-projection and seismo-geodetic broadband inversion. Both imaging techniques provide a very consistent image of the peculiar space-time rupture process of this earthquake : its 60-second long rupture is characterized both by a main northward propagation (resulting in a rupture extent of almost 200km in this direction) and by a reactivation phase of the hypocentral area, particularly active 35s to 50s after origin time.Given the depth of this earthquake (125-140km), the reactivation time window coincides with the arrival time of the surface-reflected elastic wavefield. Computed values of the dynamic Coulomb stresses associated with this wavefield are of the order of ten to several tens of kPa, in a range of values where dynamic triggering has already been observed. The reactivation phase of the Peru earthquake may thus originate from fault areas that were brought close to rupture by the initial rupture front before being triggered by stress increments provided by the reflected wavefield. Source time function complexity observed for other large intermediate-depth earthquakes further suggests that such a mechanism is not an isolated case. 
SHIELD and observations in the LISM
Authors: Richardson John ,   SHIELD Team
Published: February 2023

Voyager is maaking the first in situ observations of the locaal interstellaar medium (LISM). We show recent observations from Voyager 1 and 2 which show the Sun affects the LISM tens of AU beyond the heliopause with shocks, pressure fronts, cosmic ray anisotropies and plasma oscillations all driven by solar transients.  SHIELD is a NASA DRIVE data center dedicated to understanding the interaction of the heliosphere and the Sun. Four different research thrusts have goals of understaanding specific aspects of the heliosphere. We will discuss SHIELD activities and how the relate to the Voyager and other observations of the heliosphere.
Soil fertility and drought stress episodes explain the variations in diameter growth of the hyperdominant Amazon tree species Eschweilera coriaceae
Authors: Durgante Flavia , Higuchi Niro , Ohashi Shinta , Householder John Ethan , Wittmann Florian , Trumbore Susan ,   collaborators
Published: February 2023

Amazonian forest productivity is related to gradients in climate and soil fertility, and impacted by extreme climate events such as drought. However, interactions between soil fertility and drought in influencing regional and interannual variations in tree diameter growth are still poorly explored. To fill this gap, we used radiocarbon measurements to evaluate the variation in tree growth rates over the past decades for 30 individual trees from an important hyperdominant species, Eschweilera coriacea (Lecythidaceae). Trees were sampled from six sites in the state of Amazonas, Brazil, spanning a range of soil properties and climate. Using a linear mixed model, we show that temporal variations in mean annual diameter increment for a specific time period reflects interactions between soil fertility and SPEI drought index (Standardized Precipitation and Evapotranspiration Index). Overall differences between sites in mean tree growth, wood density and biomass production primarily reflected soil fertility, while temporal variations in growth response to drought also strongly dependence on soil fertility. Whereas drought strongly limited tree growth in fertile environments, its impact on tree growth was attenuated in poorer soils. Our results suggest that the growth response of trees to drought is strongly dependent on soil conditions, a facet of Amazon forest productivity that is still underexplored. As the Eschweilera coriacea is a hyperdominant species in the Amazon and is ranked second for highest biomass production in the basin, the pattern of tree growth in response to soil-climate interactions influences the carbon balance of the entire Amazon basin. This result has a large potential to improve predictions of how tropical tree growth affect the global carbon cycle in the face of climate change.
How much does new particle formation near the tropical tropopause contribute to stratospheric aerosol number concentration?
Authors: Jensen Eric , Brock Charles , Williamson Christina , Ziemba Luke , Brown Matthew
Published: February 2023

Nucleation of ultrafine aerosols near the tropical tropopause, followed by transport throughout the stratosphere by the Brewer-Dobson circulation, is thought to be the primary source of stratospheric aerosol number concentration.  However, depending on how rapidly the aerosols grow by condensation, many of the ultrafine particles generated by new particle formation (NPF) may be lost due to coagulation with accumulation-mode aerosols.  In this study, we use recent high-altitude aircraft measurements of aerosol size distribution, along with microphysical calculations, to investigate this issue.  Initial ultrafine and accumulation-mode size distributions are specified based on the aircraft measurements, and a bin microphysics model is used to simulate the evolution of the aerosol size distributions.  Coagulation and condensation of gases such as sulfuric acid, ammonia, and nitric acid are included.  Preliminary results indicate that for typical conditions, most of the ultrafine aerosols generated by NPF are removed by coagulation, resulting in a relatively small contribution to the total aerosol number concentration.  We have used the model to investigate the sensitivities of total number concentration evolution to aerosol size distributions and condensation rates.
GEOSCOPE: 40 years of global broadband seismic data
Authors: Leroy Nicolas , Vallée Martin , Zigone Dimitri , Bernard Armelle , Thoré Jean-Yves , Pardo Constanza , Bes de Berc Maxime , Stutzmann Eléonore , Broucke Céleste , Pesqueira Frédérick , Maggi Alessia , Rivera Luis , Le Cocq Michel , Sirol Olivier
Published: February 2023

The GEOSCOPE observatory provides more than 4 decades of high-quality continuous broadband data to the scientific community. Started in 1982 with a few stations, the network has grown over the years thanks to numerous international partnerships. The 33 operational GEOSCOPE stations are now installed in 18 countries, across all continents and on islands throughout the oceans, filling important gaps in the global Earth coverage (in Africa, Antarctica, Indian Ocean, Pacific Ocean islands and more). Most of the first installed stations are still running today allowing for long term observations and new sites are being prospected for future installations.Over the years GEOSCOPE contributed to define today's global seismology standards through the FDSN (data format, data quality level, instrumentation requirements), being the french contribution to the international effort (with GSN, GEOFON and others) towards global seismic observations. The stations are equipped with the best quality seismometers (from the very first STS1 in the early 80's to the last STS-6A and Trilium T360 nowadays) and digitizers (Q330HR and Centaur), in order to record with a high fidelity the ground motions generated by all types of seismic sources. Furthermore, most of the stations are also equipped with accelerometers, pressure and temperature sensors allowing for a wider range of observable events such as the recent Hunga-Tonga eruption. All the data are sent in real-time to IPGP data center and are automatically transmitted to other data centers (IRIS-DMC and RESIF) and tsunami warning centers.In 2022, a workshop has been organized to celebrate the 40th anniversary of GEOSCOPE and illustrate the main scientific achievements made possible by all the global networks. After a brief look at the history of the network and a feedback on the workshop, the recent evolutions of the observatory (new stations in Africa, new generation 360s sensors upgrades, IT infrastructure) and the perspectives (future stations) will be presented.
Imaging Oceanic Sedimentary Basins Using Machine Learning
Authors: Totten Eoghan , Bean Chris , O'Brien Gareth
Published: February 2023

Machine Learning has accelerated the ability of seismologists to relate seismic waveform databases to the geological properties of the subsurface through which they travel. With sufficient training, neural networks can infer two and three-dimensional maps of seismic velocity, at a fraction of the computational cost of conventional methods, which are reliant on full waveform forward modeling.

Several studies have replaced convolutional neural networks (CNN) with Fourier Neural Operators (FNOs) due to their computational efficiency. In addition to replacing expensive convolution operations with simple multiplication, FNOs take low frequency, low resolution seismic data as input, and still predict successful outputs at the required resolution, provided that the population of waveforms and velocity models used to train them have statistical distributions representative of the ‘ground truth’. One outstanding research question is: how close do seismic datasets need to represent real-world ground truth, to maximise insights from neural networks?

This research investigates general approaches to populate training data for FNOs, by creating families of synthetic seismic waveforms in a hybridised statistical-deterministic approach. In practice, this entails accounting for site-specific geological constraints like drilling logs and alternative geophysical surveys. The objective is to improve neural network performance, so that fewer field observations are needed to recover the full seismic model, shifting the collation of massive data to the numerical domain. Here we show results in progress that focus on Irish offshore sedimentary basin settings.
Impact of different rainfall events on overland flow using a 2D hydrodynamical model on a steep-sloped watershed
Authors: Ámon Gergely , Bene Katalin
Published: February 2023

 Gergely Ámon1, and Katalin Bene2  1,2National Laboratory for Water Science and Water Security, Széchenyi István University, Department of Transport Infrastructure and Water Resources Engineering, Egyetem square 1., H-9026 Győr, Hungary Flash floods and low-flow events often severely impact small, steep watersheds. Water resources engineers need to understand and prepare for these events. On small, steep-sloped watersheds, meteorological and watershed characteristics influence the behaviour of the overland flow. In this research, we applied different precipitation events in time and intensity on the watershed to determine the impact on outflow characteristics.The Hidegvíz-valley watershed on the north-western side of Hungary, a well-measured and instrumented experimental watershed, was selected for surface flow modelling. A 2D hydrodynamical model was developed and calibrated on a measured rainfall-runoff time series. Two measured rainfall events and triangular design rainfalls with different return periods were applied to the calibrated model to determine the impact on surface runoff attributes. Peak outflow, runoff ratio and runoff volume were selected to describe outflow characteristics. The results show that the peak flow at one rainfall event is much greater than at the other rainfall events. The volume of a rainfall event increases for longer-duration events. After certain rainfall events, the runoff ratio and runoff volume did not change much.The research will help to better understand runoff processes due to different rainfall events and durations and help to improve the design approach for flood and drought protection.Keywords: numerical modelling, hydrodynamics, overland flow, watershed model The research is carried out within the framework of the Széchenyi Plan Plus program with the support of the RRF 2.3.1 21 2022. 00008 project. 
Volcanism and tearing in the Tyrrhenian subduction system: the CAVEAT project
Authors: Scognamiglio Laura , Palano Mimmo , Di Luccio Francesca , Pezzo Giuseppe , De Gregorio Sofia , Greco Filippo ,   CAVEAT Team
Published: February 2023

In retreating subduction zones the proposed lithosphere tearing processes at slab edges are typically related to segmentation of subducting plate. A direct response to lithosphere tearing is the channeling of new asthenospheric mantle that can initiate magmatism. Tearing mechanisms have also been proposed for the Calabrian Arc, where slab migration led to the formation of the southeastern Tyrrhenian basin and was progressively accommodated by inherited and newly formed vertical tear faults whose oldest (~2 Ma) and youngest (~0.8 Ma) tectonic expressions in the upper plate are the Sisifo-Alicudi and the Aeolian-Tindari-Letojanni fault systems, respectively. The Western and Central-Southern Aeolian Islands nested along these structures as highlighted by a large number of geological and geophysical studies in the last decades. CAVEAT aims to apply a multidisciplinary approach to study in detail the local lithospheric structure, the pattern of crustal deformation and the geochemical signature of the Central-Southern Aeolian Islands. The acquisition of new data will provide a broad overview of the ongoing geodynamics of the southern Tyrrhenian region and will allow us to properly study the interplay of present-day tectonics and volcanic deformation and the related role and nature of the fluids and the hydrothermal activity.
A low-cost airbox network to assist air quality policy-making and citizen involvement: Eindhoven city, Southeast Brabant, the Netherlands
Authors: Zhang Jun , Goudriaan Ruben , Tokaya Janot , Hensen Arjan , van Dinther Daniëlle , Kaandorp Sjaak , Blom Marcus , Plomp Arjan
Published: February 2023

Air pollution may threaten both human health and ecosystem vitality in Eindhoven city, the Netherlands. Although air quality changes are monitored hourly with high-end equipment at multiple national stations, it remains difficult for individual cities or citizens to trace local air quality based on national-scale information. A monitoring network of 44 low-cost airbox sensors was established around Eindhoven city to measure atmospheric concentrations of particulate matter (PM10, PM2.5, PM1) and nitrogen dioxide (NO2) at 10-min intervals from January 2021 onwards, with ultra-fine particle (UFP) sensors added at 3 dedicated sites around the airport. To address local government and citizen’s health concerns, the monitoring network was spread among three major areas: urban area (23), Eindhoven airport (3), and rural area outside of the city (18). The urban area was further divided into clean-background area, downtown, industrial zone, traffic intensified ring-roads and highways. Based on a one-year seasonal and diurnal analysis, we concluded that at least 70% of the average PM concentration was determined by the regional background contribution whilst 60% - 72% of total PM10 was contributed by fine particles with a diameter below 2.5 µm. On average, the PM values of the urban background area were still 10 - 15% higher than those for the rural area despite the assistance of city-greening facilities (such as tree-lined streets and parks). However, higher PM10 values were also frequently observed downwind of the livestock farms within the rural area across seasons. On the other hand, NO2 concentrations were mainly driven by local sources’ behavior, notably traffic emissions during morning and evening rush-hours. The three UFP sensors located around the airport showed more frequent peaks and higher values related to flight activities and airport traffic, also outside the airport terrain. The combined results underline the importance of taking spatial variability of urban air pollution sources into explicit account. Moreover, a good-quality airbox real-time monitoring network will allow local policy-makers to take proper actions to mitigate air pollution, inform local citizens and reduce health impacts at the appropriate scale.
On the effect of damage on the recent changes in the Amundsen Sea Sector
Authors: Mosbeux Cyrille , Jourdain Nicolas , Gagliardini Olivier , Råback Peter , Gilbert Adrien
Published: February 2023

Ice mass loss from Antarctic Ice Sheet is increasing, accelerating its contribution to global sea level rise. In the Amundsen Sea sector, recent observations of rapid ice-shelf thinning and grounding line retreat have been attributed to increased basal melting driven by inflows of warm Circumpolar Deep Water. However, recent studies have shown that basal melting alone might not be sufficient to explain the recent acceleration, retreat and thinning of the outlet glaciers in the sector.As part of the European Horizon 2020 research project PROTECT ­— that assesses and projects changes in the land-based cryosphere to produce robust projections of SLR — we conduct numerical simulations to determine the role of damage on changes observed over the last two decades in the Amundsen Sea Sector. More particularly, we use a Stokes flow formulation combined with a Continuum Damage Mechanics model of the open-source ice flow model Elmer/Ice to simulate the ice flow evolution. We initialize our ice sheet model with data assimilation methods using 1996 observations of surface velocities as well as a corrected geometry based on the current ice-sheet geometry and the ice thickness rates of change observed over the past 20 years. From this initial state, we run forward simulations over 20 years with and without damage mechanics, and compare the model evolution to observed surface velocities and ice thickness rates of change, as well as observations of grounding line positions. Our results shed light on the importance of damage in the evolution of the region, in particular an acceleration of several hundred meters per year due to the decreasing buttressing effect of the ice shelves triggered by the increasing damage.
An Adjoint-based Method for Inverting for Heterogeneous Material Properties and Fault Slip From Earthquake Surface Deformation Data
Authors: Becker Thorsten , Puel Simone , Villa Umberto , Ghattas Omar , Liu Dunyu
Published: February 2023

Analysis of geodetic and seismological data helps constrain earthquake dynamics and the physics of lithospheric deformation. Here, we discuss a new modeling approach based on an open-source finite-element framework to invert surface deformation data for constitutive laws and their parameters, such as the Poisson’s ratio or shear modulus in the crust and mantle wedge.These inversions can be realized by using adjoint-based optimization methods which efficiently reduce the misfit between the calculated and observed displacements. To quantify the associated model uncertainties, we extend the inverse approach to a Bayesian inference problem. Since the data are usually informative only in a few directions in parameter space, we use a low-rank Laplace approximation of the posterior distribution to make the inverse problem computationally tractable. The mean and the posterior covariance are approximated by the solution of the inverse problem (MAP point) and the inverse of the Hessian of the negative log posterior evaluated at the MAP point, respectively. We show how smoothly varying parameter fields can be reconstructed satisfactorily from noisy data.To improve the spatial resolution of the inverse solution we solve a Bayesian optimal experimental design problem to find the best station configuration by maximizing the expected information gain, defined as the Kullback-Leibler divergence between posterior and prior distributions. We show how and why the optimal network improves the material property inference more than evenly spaced stations. Based on our previous work on inverting for fault slip without Green’s function computations, we combine the two inversion schemes to jointly infer both model parameters, the coseismic slip, and material properties distribution. Lastly, we test this numerical forward/inverse framework with an application, the 2011 Tohoku-oki M9 earthquake. Both continuous land-based and six offshore acoustic GNSS stations located around the earthquake epicenter are inverted to jointly estimate the shear modulus and the fault slip during the megathrust event.Our results demonstrates the potential of our computational framework and the general approach for inferring constitutive laws to evaluate sensitivity to parameters, and define strategies to improve our understanding of relevant parameters for earthquake dynamics.  
Observing glacier elevation changes from spaceborne optical and radar sensors
Authors: Piermattei Livia , Brun Fanny , Sommer Christian , Braun Matthias H. , Zemp Michael
Published: February 2023

Quantifying glacier elevation and volume changes is critical to understanding the response of glaciers to climate change and related impacts, such as regional runoff and global sea-level rise. Spaceborne remote sensing techniques enable the quantification of spatially distributed glacier elevation changes at regional and global scales using multi-temporal digital elevation models (DEMs). A growing number of spaceborne studies exist to assess glacier elevation changes but they show widespread differences often beyond the error bars. Here, we present the results of a community-based inter-comparison experiment using spaceborne optical (ASTER) and radar (TanDEM-X) sensors to assess elevation changes for selected individual glaciers and regional glacier samples. Using a predefined set of DEMs, participating groups provided their own estimates using various processing strategies.  For the selected individual glaciers, the results were validated using airborne data. The validation shows that the median of the spaceborne ensemble is biased by a few decimetres per year with a standard deviation of about half a meter per year. An interesting finding is that no sensor and no processing strategy perform significantly better for all experiment sites. At the regional scale, we find that the co-registration of DEMs is the most relevant processing step for an accurate assessment of elevation change. Other corrections such as gap filling, filtering, and radar penetration have less impact in general but can be essential for individual cases. Temporal corrections (i.e. seasonal and annual) can have a great impact; however, they are not yet well resolved by the remote sensing community.Our study confirms that the currently available spaceborne geodetic assessments result in relatively widespread glacier elevation changes. Therefore, we recommend an ensemble approach of observations from multiple observational sources. Furthermore, there is a need to establish best practices for related uncertainty estimates.
In-network Sewage Surveillance Allow Source Apportionment for Public Health Pathogens of Concern
Authors: Korach-Rechtman Hila , Fux Gali , Moran Gilad Jacob
Published: February 2023

Wastewater based epidemiology has been on a fast track of adoption since COVID-19 pandemic. Methodologies for SARS-CoV-2 and other pathogens sewer surveillance evolve around the world, defining best practices for sampling to reach an accurate viral load estimation. These methodologies focused on samples collected from wastewater treatment plants (WWTP). In this session, we present an approach for sewage in-network monitoring that allows a better and targeted understanding of morbidity for SARS-CoV-2 and Influenza viruses. This approach can narrow infected regions and potentially allocate limited resources when needed in a specified community.

 

Keywords: Wastewater Based Epidemiology (WBE); Source apportionment; Public health monitoring.
Arbuscular mycorrhizal fungi and their associated plant communities jointly respond to long-term nutrient deficiencies in a managed grassland
Authors: Jenab Kian , Alteio Lauren , Gorka Stefan , Guseva Ksenia , Darcy Sean , Fuchslueger Lucia , Canarini Alberto , Martin Victoria , Wiesenbauer Julia , Spiegel Felix , Imai Bruna , Schmidt Hannes , Hage-Ahmed Karin , Pötsch Erich M. , Richter Andreas , Jansa Jan , Kaiser Christina
Published: February 2023

Arbuscular mycorrhizal fungi (AMF) form mutualistic associations with roughly 70% of vascular plant species, supporting the nutrient acquisition of their host plants and deriving carbon in return. AMF and plant communities are linked to each other by host-specificity and the ecological selection of favorable nutrient and carbon trading strategies. Changing soil nutrient availabilities can affect both plant and AMF communities directly and also indirectly via the response of their partners.  We aimed to elucidate the combined response of AMF (belowground) and plant (aboveground) community compositions to changing soil nutrient availabilities.We sampled soil and roots from a long-term nutrient deficiency experimental grassland in Admont (Styria, Austria). The grassland plots have been fertilized with different combinations of nitrogen (N), phosphorus (P), and potassium (K) over 70 years. Aboveground biomass cuts were removed three times each year, leading to long-term deficiencies of nutrients not replaced by fertilizers. Soil and root AMF community compositions were measured by DNA and RNA amplicon sequencing of the 18S rRNA gene. In addition, we assessed the plant community composition of the sampled roots by amplicon sequencing of the chloroplast rbcL (RuBisCo large subunit) gene region, and visually recorded the plant community composition on each investigated plot.Our results demonstrate that N and P deficiencies influenced soil AMF community composition, whereas K deficiency had a major impact on root AMF community composition. Interestingly, the plant community composition was affected by N and P, similar to the soil AMF community composition. Both, soil and root AMF community compositions were significantly correlated to plant community composition across all treatments, the correlation was however stronger for soil AMF communities (R2 = 0.55, p< 0.001). By using bipartite network analysis, we identified several fungus-plant pairs that responded consistently to treatments.Our results indicate that the response of grasslands to nutrient deficiencies is potentially driven by strong feedbacks between plant and belowground AMF community compositions. We here demonstrate that the known interactions between grassland plants and AMF - which are often investigated from a single plant or monoculture perspective - are major drivers of how diverse plant community compositions will respond to environmental change, such as fertilization. In conclusion, considering the ecology of the subsurface AMF communities may strongly benefit our understanding of plant communities in a future environment.