bluuebunny/crossref_metadata_2025 huggingface dataset:
What information do young, laboratory-grown root systems provide about mature, field-grown root systems?
Authors: Landl Magdalena , Hank Brandon , Francis Geo , Schnepf Andrea
Published: February 2023

Plant root systems are crucial for sustainable agriculture, as their architecture determines the efficiency of water and nutrient uptake by the plant. To date, it is not clear how root architecture characteristics determined in the laboratory relate to root characteristics in the field. In this study, we want to investigate the extent to which root architectural traits and root measures of young plants in the laboratory and mature plants in the field correlate when experimental conditions are the same. Furthermore, we want to evaluate whether the effects of different plant genotypes and soil types on root system development are similar in the laboratory and in the field.

Two maize genotypes, a wild type and a root hair defective mutant, were grown in loam and sand in a soil column experiment in the laboratory and in a plot experiment in the field. In the laboratory, root architecture parameters were derived from the analysis of X-ray CT images of the root systems. In the field, root architecture parameters were derived from the analysis of root window images, crown root counts and soil core data. Root architecture parameter sets obtained from laboratory and field measurements were compared. Using the RSA model CPlantBox, laboratory and field parameter sets were used to simulate root systems and calculate root measures, i.e. total root length, total root volume, convex hull volume, which could then be compared.

This study shall contribute to a better understanding of root trait changes during plant development. In addition, this study will shed light on the importance of equal experimental conditions to infer root systems from laboratory experiments to root systems in the field. Furthermore, we aim to investigate the importance of RSA models for extrapolating from young, laboratory-grown root systems to mature, field-grown root systems.
Inferring The Impact Of Vaia Storm On Slopes Stability Using Sentinel-1 Data.
Authors: Beber Raniero , Bossi Giulia , Ceccotto Federica , Marcato Gianluca , Pasuto Alessandro , Mantovani Matteo
Published: February 2023

The Mediterranean storm “Vaia” hit the north-east of the Italian Alps at the end of October 2018. The strong wind gusts exceeding 200 km/h and the intense precipitation damaged more than 42,000 hectares of forests and caused floods that had a severe impact on the geo-hydrological balance of mountain basins. One of the most affected area, the province of Belluno, still bears the clear signs of the destructive effects of this extreme meteorological event, nevertheless the long-term impact on the slopes stability is yet far to be assessed. This study investigates the “Vaia” storm impact by analyzing time-series of the interferometric data acquired since 2015 by the European Space Agency’s Sentinel-1 mission.  Radar interferometry is, at present, the only technique capable to measure small ground displacements of large areas over long time periods. The rationale of the proposed approach assumes that changes in the response of radar targets, located over slopes, are proxy of change in the style of activity of landslides and in particular of their activation, re-activation and acceleration. The purpose is to evaluate the possibility to detect a statistical relationship between the occurrence of “Vaia” storm and the state of activity of mass movements. This type of analysis could be useful in helping to interpret the impact of extreme meteorological events on the landscape and in developing strategies for mitigating potential risks in the next future. This research is carried out in the framework of  Project VAILAND, a joint research agreement funded by the Veneto Region (Italy).
Evidence for External Reconnection Between an EruptingMini-filament and Ambient Loops Observed by Solar Orbiter/EUI
Authors: Li Zhuofei , Cheng Xin , Ding Mingde , Chitta Pradeep , Peter Hardi , Berghmans David
Published: February 2023

Mini-filament eruptions are one of the most common small-scale transients in the solar atmosphere. However, their eruption mechanisms are still not understood thoroughly. Here, with a combination of 174 Åimages of high spatio-temporal resolution taken by the Extreme Ultraviolet Imager on board Solar Orbiter and images of the Atmospheric Imaging Assembly on board Solar Dynamics Observatory, we present a detailed investigation of an erupting mini-filament over a weak magnetic field region on 2022 March 4. It is clearly observed that, as the mini-filament quickly ascends, two ribbons appear underneath it. Subsequently, when the erupting mini-filament interacts with the outer ambient loops, some dark materials blow out, forming a blowout jet characterized by a widening spire. At the same time, multiple small bright blobs of size 1–2 Mm appear at the interaction region and propagate along the post-eruption loops towards the footpoints of the erupting fluxes at a speed of  100 km s􀀀1, as well as giving rise to a semi-circular brightening. These features indicate that the mini-filament eruption first undergoes the internal and then external reconnection, the latter of which mainly transfers mass and magnetic flux of the erupting mini-filament to the ambient corona.
Physical study of what happens to a dew droplet on a hydrophobic and hydrophilic leaf
Authors: Ben-Asher Jiftah , Shomron Mordechay , Rachmilevitch Shimon , Arie Giboa
Published: February 2023

Modern scientific research have focused on the macroscopic  interaction between wetted vegetation surface and evaporative potential of the atmosphere . It was found that crop's water use efficiency (WUE) is improved  by dew but not much is known on the processes of a single dew droplet. The objective of this study was to reevaluate it microscopically.  A special device (OCA Germany)  followed the fate of  a single water droplet that fell on hydrophilic and hydrophobic leaves (HDPI and HDPO respectively).   The onset and cessation of a 2 mm3 water droplet simulated a dew  and visually observed the dynamic processes on both the abaxial and adaxial  leaves with 10 replications on each. A video camera recorded a contact angle between water and leaf, droplet height , the change of  droplet volume on the surface  and  spread of water on the surface vs time . The data were used to calculate water penetration rate into the leaves through the stomata and then establish  a model calculating  stomatal  conductance. Recorded data were linked to known data from literature to calculate  adhesion and cohesion  forces acting on a dew droplet in contact with a leaf.   It was found that in HDPI adhesion dominating gravitation and in HDPO cohesion and gravitation are  the dominant force . Capillary rise was found unrealistically high for HDPI (2.2 m.) and unrealistically low for HDPO (-1.8 m). We assume that it was caused by numerous interstices in the cell walls or the potential force pulling water inward for HDPI and  outward for HDPO. Stomatal conductance model yielded  5 and 12 mm s-1 for HDPO and HDPI respectively. Penetration time of  2mm3 into the leaf lasted about 100 second while macroscopic research  showed that  the impact of the dew phenomena  on plant last 4 to12 hours. It was therefore concluded that a synergy between fast absorption and controlled release of water  by stomata  may result in improved water use efficiency.
Expectations of the Ion-Profile in Mercury’s Magnetosphere during BepiColombo's Flybys 2021-2025
Authors: Teubenbacher Daniel , Narita Yasuhito , Laky Gunter , Varsani Ali , Schmid Daniel , Motschmann Uwe , Töpfer Simon , Exner Willi , Bourdin Philippe , Comişel Horia
Published: February 2023

The study of the structure and dynamics of Mercury’s magnetosphere is still an open research topic in space physics. Upon other mission objectives, the on-going BepiColombo mission will study the plasma environment around Mercury with multiple field and particle instruments. One of them is the Planetary Ion Camera (PICAM). It is an ion spectrometer designed to measure low-energy pick-up heavy ions (e.g. sodium). Due to ejection mechanisms and the solar wind influence, these particles are emitted from the surface of Mercury. The resulting electric currents, like perpendicular and field-aligned currents need to be studied to understand the global magnetospheric current structure as well as its variability due to the solar wind conditions.In this study, numerical simulations with a global 3D hybrid model are used to investigate and forecast the typical ion profile with energies up to 5 keV during the BepiColombo flyby trajectories in the years 2021-2025. Magnetotail reconnection causes the acceleration of particles towards the planet. The resulting field-aligned current is studied to about 3 RM in tailward direction. The simulations are conducted with the AIKEF (Adaptive Ion Kinetic Electron Fluid) model. The kinetic treatments of the ions will enable to directly compare magnetospheric particle species model results with PICAM observations.
Quantifying sediment transport from periodic transect measurements in rivers and estuaries
Authors: Hoitink Ton (A.J.F.)
Published: February 2023

Sediment transport in rivers and estuaries is typically monitored infrequently and discontinuously, which is a key reason why sediment budget estimations are often poor. On the contrary, water discharge is often monitored with high accuracy, and continuously, which requires periodic ship measurements for recalibration of rating curves. Even in tidal rivers, continuous flow measurements can be obtained by upscaling transect flow measurements to cover the entire cross-section, which rarely occurs for sediment transport (Kästner et al., 2018). This contribution discusses how existing discharge measurement schemes can be extended to yield continuous measurements of sediment transport, separating between suspended load and bedload sediment fluxes. A new approach is outlined, which relies on repeated cross-river transect measurements, using multiple acoustical and optical instruments. Innovative suspended load measurements make use of acoustic profilers with multiple sound frequencies and a spectrometer, which can measure suspended sediment mean particle size and carbon content from light absorbance (Sehgal et al., 2022). Inference of bedload transport from bedform tracking improves when taking secondary bedforms into account, which can migrate fast and persist in the lee of primary dunes, contributing significantly to the total bedload transport (Zomer et al., 2021). For sand-bed rivers in particular, a generic approach to upgrade existing discharge monitoring programmes to include continuous sediment transport may be feasible with limited additional ship survey time.Kästner, K., Hoitink, A. J. F., Torfs, P. J. J. F., Vermeulen, B., Ningsih, N. S., & Pramulya, M. (2018). Prerequisites for accurate monitoring of river discharge based on fixed‐location velocity measurements. Water resources research, 54(2), 1058-1076.Sehgal, D., Martínez‐Carreras, N., Hissler, C., Bense, V. F., & Hoitink, A. J. F. (2022). Inferring suspended sediment carbon content and particle size at high frequency from the optical response of a submerged spectrometer. Water Resources Research, 58(5), e2021WR030624.Zomer, J. Y., Naqshband, S., Vermeulen, B., & Hoitink, A. J. F. (2021). Rapidly migrating secondary bedforms can persist on the lee of slowly migrating primary river dunes. Journal of Geophysical Research: Earth Surface, 126(3), e2020JF005918.
Investigation of the growth rate and antibiotic production of Marine Actinobacteria in the International Space Station
Authors: Tsinidis Marialina , Simigdalas Manolis
Published: February 2023

The present experiment investigates the behavior of marine actinobacteria in the International Space Station (ISS). More specifically, the aim of the experiment is to examine the growth rate and antibiotic production of the actinobacteria and as a result the correlation between the growth rate and the viscosity of the liquid (mix of actinobacteria and nutrient agar). The experiment is performed in cooperation with Nanoracks and launched via Falcon 9, Space – X and remained in the ISS for a 90-day time period under constant temperature (4 degree Celsius), being stirred by the astronauts on a weekly basis. There is a medical and pharmacological interest since marine actinobacteria are a source of bioactive natural and antibiotic products, beneficial for the human organism, producing a variety of secondary metabolites. The experiment in the ISS indicates growth similar to the experiment on Earth, with slightly higher values showing that the bacteria survived the microgravity conditions. The viscosity is slightly greater in the ISS, potentially due to the change in the density of the liquid, following the growth of the bacteria. 
ISTPNext and the ITM Great Observatory: The need for international coordination in Heliophysics
Authors: Kepko Emil ,   COSPAR Task Group on Establishing an International Geospace Systems Program
Published: February 2023

Heliophysics is the study of the Sun and its effects throughout the solar system. It covers an incredible range of scales, from plasma physics at the electron scale to the boundary that separates our solar system from interstellar space. It also includes a diverse array of sub disciplines and expertise, with measurements spanning in situ particles and fields from the ionosphere out to the Sun’s corona, to remote sensing of the Sun, heliosphere, and near-Earth environment at multiple wavelengths and in energetic neutral atom observations. Many of the biggest unanswered science questions that remain across Heliophysics center around the interconnectivity of the different physical systems that comprise the Heliosphere, and the role of mesoscale dynamics in modulating, regulating, and controlling that interconnected behavior. These are complex, yet ultimately fundamental questions of how the Sun-Heliosphere and Geospace interact, and answers are needed to more accurately predict and model space weather impacts on and around Earth, the moon, and Mars. To answer these long-standing questions on the Sun-Heliosphere and Geospace as system-of-systems, we believe that Heliophysics requires a coordinated, deliberate, worldwide scientific effort. We suggest that the worldwide Heliophysics discipline should embark on a grand program to study these system-of-systems holistically, with coordinated, multipoint measurements, with particular emphasis on resolving mesoscale dynamics, and a whole-of-science approach that includes ground-based measurements and advanced numerical modeling. Without such a unified, next generation ISTP-type program, these questions will remain largely unanswered. In this paper we lay out the case for such an approach, and discuss how the ITM community is using the upcoming NASA GDC mission as a cornerstone to develop the ITM Great Observatory, a grass-roots, holistic approach modeled after ISTP to study the ITM system.
Adapting a snowpack model to simulate cold-based glacial hydrological processes in the McMurdo Dry Valleys, Antarctica
Authors: Pletzer Tamara , Cullen Nicolas , Conway Jonathan , Eidhammer Trude , Katurji Marwan
Published: February 2023

Glacial melt is the primary source of freshwater for the fragile microbial ecosystem in the McMurdo Dry Valleys (MDV) of Antarctica. These glaciers are cold-based, with internal temperatures around -18°C, however, air temperatures hover around 0°C for several weeks in the summer and föhn wind events can rapidly raise ice surface temperatures to the melting point. Thus, episodical glacial melt is sensitive to small changes in the climate.  The aim of this research is to adapt a detailed snowpack model embedded in a distributed hydrological model to simulate the surface energy balance and run-off of a glacier in the MDV. To do this, the snowpack model in the WRF-Hydro-Crocus modelling scheme, which has been used for avalanche forecasting and temperate glaciers, is adapted to the MDV. Several modifications are made to model calculations and parameters to allow the model to successfully simulate surface energy balance and runoff in this environment. For example, the parameters for the Crocus albedo scheme are adjusted to obtain band profiles for snow, firn and ice that replicate observed albedo and remain internally consistent between surface types. The modelling system is then validated against data from an automatic weather station, eddy covariance measurements and stream discharge. It is shown to be suitable for future efforts to model the full hydrological cycle of glacial meltwater in this region.
Insights into the fluid migration dynamics of Tajogaite eruption, La Palma
Authors: Carvalho Joana , Silveira Graça , Bento Virgílio , Schimmel Martin , Antón Resurrección
Published: February 2023

Volcanic eruptions are, generally, characterized by several recordable signals that can occur before, during and/or after the eruption. Such signals may reflect temporal changes in the seismic structure that can be associated with alterations in the seismic activity, fluid migration or outgassing, useful to track the volcano evolution through its eruptive phases.Cumbre Vieja ridge, in La Palma, is the most active volcanic field in the Canaries. The last eruption occurred at the Tajogaite cone, lasting from 19 September to 13 December 2021. It is considered one of the best-monitored volcanic crises in the Canary Islands, thus allowing us to study the eruption from different scientific perspectives.Ambient seismic noise interferometry has been widely applied to monitor temporal velocity changes, especially at volcanoes before the eruption. However, the causes of these velocity changes are not always fully understood. In this study we use a dataset of three years (2020 to 2022) recorded in two stations operating in La Palma to identify and characterize different physical processes before and after the eruption. For this purpose, we computed phase auto- and cross-correlations and stacked them through the time-frequency phase-weighted stack to create hourly cross-correlation functions.Seismic velocity changes cause phase shifts in the auto- and cross-correlation functions waveforms. The phase shifts can be measured through the waveform similarity, which consists in comparing each correlation function with a reference correlation function trace, in a defined window. The reference trace corresponds to a calm period, in this case, the period before the eruption. We also compared the waveform similarity results with the ground deformation inferred from GPS.Tajogaite eruption provides an opportunity to study the behaviour within the volcanic structure prior to the eruption and its recovery after the eruption and to improve our knowledge of the magmatic fluid migration. This recent and well-documented eruption may serve as a proxy for future eruptions.This work is a contribution to project RESTLESS (PTDC/CTAGEF/6674/2020) and it was also supported by the Portuguese Fundação para a Ciência e a Tecnologia (FCT) I.P./MCTES through national funds (PIDDAC) – UIDB/50019/2020-IDL.
Fast Earthquake Magnitude Estimation using HR-GNSS time series: a Deep Learning approach
Authors: Quinteros-Cartaya Claudia , Köhler Jonas , Faber Johannes , Li Wei , Srivastava Nishtha
Published: February 2023

Fast magnitude estimation of large earthquakes has been a key task for warning systems. In the last decades, Global Navigation Satellite Systems data with high-rate sampling (≥1 Hz; HR-GNSS) have provided us with useful information from displacement time series for analyzing large earthquakes; especially when the signals of earthquakes recorded in inertial sensors are saturated. Hence, improving algorithms to contribute to the fast analyses of the HR-GNSS data has been a recent challenge.In this work, we propose a deep-learning-based algorithm for earthquake magnitude estimation, which was trained by thousands of synthetic displacement time series corresponding to Mw > 6.5 earthquake signals. We adapted the model to a variable number of stations and lengths of the time series as input. Thus, it is possible to apply the algorithm without any restriction on the number of stations, and the flexibility in the length of the input time series facilitates the inclusion of data not only from local stations but also from regional stations if required. The influence of attributes such as noise, magnitude, number of stations, epicentral distance, and length of input time series on the model performance was evaluated. We aim to generalize this approach to the magnitude estimation of earthquakes from different tectonic regions. The robustness of the model was tested with both synthetic and real earthquake signals.
Drivers of soil microbial activities and greenhouse gas emissions along an elevational gradient
Authors: Han Xingguo , Pascual Anna Doménech , Casas-Ruiz Joan Pere , Donhauser Jonathan , Jordaan Karen , Ramond Jean-Baptiste , Priemé Anders , Romaní Anna M. , Frossard Aline
Published: February 2023

Mountain ecosystems contribute substantially to global carbon and nitrogen biogeochemical cycles. Although soil respiration, and microbial biomass, activities and diversity have been extensively studied at different altitudes worldwide, little is known on causal link between environmental drivers, microbial functions and emissions of greenhouse gases (GHGs) in soils of different elevation. Here, by measuring in-situ GHG fluxes, soil properties, organic matter (OM) quality, microbial enzyme activities, biomass and gene abundances, we investigate factors that control long-term GHG fluxes (carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O)) in natural soils with an elevational gradient of ~2400 m across Switzerland with different vegetation covers. Results showed that CO2 and N2O fluxes increased significantly with elevation from top to the treeline, but slightly decreased from the treeline to bottom. Contrastingly, no significantly patterns of CH4 fluxes across the whole elevation were observed. Spearman correlations revealed that the increased CO2 and N2O fluxes were highly correlated to the significant increases in soil temperature, moisture, organic matter (OM) quantity and quality (increases in the relative contribution of humic-like vs. fresh-like OM), bacterial and fungal biomass and gene abundances. Structural equation model, hierarchical partitioning and random forest regression further confirmed that, in addition to soil temperature and moisture, SOM quantity and quality are the most driving factors of microbial activity and respiration. Our study highlights the importance of OM quality as a driving factor of soil microbial metabolic activities in Alpine soils across the elevation, and predicts a potential increase in GHG emissions in high-altitudinal soils with the expected upwarding-shifting treeline under climate warming.
Machine learning for global modeling of the ionosphere based on multi-GNSS data
Authors: Mao Shuyin , Kłopotek Grzegorz , Awadaljeed Mudathir , Soja Benedikt
Published: February 2023

High-precision global ionospheric modeling is important for radio communication, navigation, or studies on space weather. Traditional spatial ionospheric modeling approaches include spherical harmonics and trigonometric B-splines. The Ionospheric Associated Analysis Centers (IAAC) of the International GNSS Service (IGS) use these methods to model vertical total electron content (VTEC) globally, and generate Global Ionospheric Maps (GIMs). Due to the limitations of spatial modeling approaches, conventional GIMs cannot comprehensively describe the spatial feature of the ionosphere. With the capability of capturing complex and non-linear relationships of diverse data, machine learning (ML) has been increasingly applied to ionospheric modeling. Currently, most of the existing ML-related studies focused on temporal prediction of ionospheric states and rarely considered the aspect of the spatial modeling of VTEC. Although some studies predicted global ionosphere maps using machine learning, they used conventional GIMs as inputs, implying that the precision of the ML-based spatial modeling could be limited by traditional methods and quantity of input GNSS observations utilized to generate GIMs.The goal of this study is the spatial interpolation of VTEC using ML methods for the generation of ML-based GIMs. We first determine VTEC using carrier-to-code levelling through Kalman filter and based on geometry-free multi-GNSS observations from GNSS stations of the IGS network. The derived satellite-specific VTEC time series are then used to train the ML models. Several algorithms, such as extreme gradient boosting and random forest, are applied and their performance is evaluated. Moreover, VTEC from satellite altimetry is used as an additional means to assess the quality of the generated ML models. Finally, we compare the acquired ML-based GIMs with conventional GIMs to investigate the advantage of using the proposed approach for global VTEC modeling.
The 3.9 km-thick Carboniferous-Permian Brécy Basin (SW Paris Basin, France), a missing link between late Variscan basins in southern and northern Europe
Authors: Beccaletto Laurent , Bourquin Sylvie
Published: February 2023

From the end of the Carboniferous onwards, the over-thickened and hot Variscan crust collapsed (late-orogenic collapse), accompanied by the rise of high-grade metamorphic domes along low-angle detachment faults and the development of mainly half-graben or pull-apart type asymmetric intramountain coal basins.These Carboniferous-Permian late orogenic basins widely developed around 300 Ma and were filled with siliciclastic continental material, accompanied by a widespread intrusive and extrusive magmatic activity. These basins crop out in the internal parts of the belt south of the Variscan Front in several limited locations in and around the Variscan basement of Western Europe (Massif Central, Vosges-Black Forest, Alps, Harz). They occur as small isolated and disconnected “basins” with incomplete sedimentary series. Their present-day area does not reflect their initial extent and thickness, which can be explored by studying their subsurface prolongation beneath their Meso-Cenozoic sedimentary covers.We propose a geological overview of the late Variscan Carboniferous-Permian Brécy basin (SW Paris basin, France), based on the reprocessing and interpretation of vintage seismic lines and related deep boreholes. We aim (i) to discuss its sedimentary filling, which is hidden beneath the Meso-Cenozoic cover of the Paris basin, (ii) to present thickness maps of its 3.9 km-thick sedimentary filling, and (iii) to describe its structural extensional features related to a syn- to post-rift tectonic scenario. We finally compared our new results to other Carboniferous-Permian deposits in France (to discuss its lateral correlation with neighboring basins) and northwest Europe, suggesting that the Brécy Basin may represent - due to its thickness and location - a missing link between late Variscan basins in southern and northern Europe.
The sprawl of the External Hellenides: from post-Alpine collapse to present-day kinematics
Authors: Bufféral Simon , Briole Pierre , Chamot-Rooke Nicolas , Pubellier Manuel
Published: February 2023

During the Neogene, the Aegean domain underwent intense deformation, leading to a thinning by a factor of two or more of the Alpine orogenic prism. Today, tectonic velocity gradients are still among the fastest in Europe due to the Anatolian extrusion induced by the Arabian indentation and by the Hellenic slab retreat. The present-day deformation essentially localizes in the subduction backstop. With respect to the central Aegean, which is almost stable today, this still-thick buttress has remained at a much earlier and brittle deformation stage. This is particularly the case in the ~east–west-extending External Hellenides (Southern Greece), shaped by a series of major NNW–SSE-oriented normal faults.How has the crustal deformation been accommodated by the various fault systems present in the Peloponnese since the Paleogene?
Which of those fault systems are still active today?
To what extent can boundary forces such as the Hellenic slab pull be sufficient to explain this extension?
Thanks to a significant increase in the GNSS network density in the Peloponnese, we present an updated local strain field. The resulting strain confirms the ~east–west sprawl of the External Hellenides, with extension also, to a lesser extent, in the other directions. Through identifying low-angle detachments by field and satellite morpho-structural analysis, we show that this spreading has been occurring since the Pliocene, mostly by reusing décollement layers of the Alpine nappes as extensional structures. We suggest that the main high-angle normal faults existing in the Peloponnese correspond to a localization of the extension in the weakest azimuth dictated by the Alpine backbone. We propose that this surface sprawl results not only from the Hellenic slab retreat but also from the exhumation of the deep Peloponnesian stacked units, and the subsequent crustal gravity collapse.
Exploration of Drop-to-Drop Variability with a with a Novel Measurement Technique
Authors: Boss Lili , Larsen Michael
Published: February 2023

Rain is known to be highly variable from drop to catchment scales. Properly quantifying this variability is important in efforts to accurately measure rain, reliably model hydrological processes, and validate previous work in the QPE community.On the individual drop level, this variability can be observed by measuring how droplet size, fall speed, shape, and composition differs for drops arriving in close spatial and temporal proximity at the surface. Here, we present a novel method of measuring some of these individual drop properties using a liquid nitrogen capture technique. This method allows for the capture and subsequent isolation of individual drops in a sterile environment, which permits more detailed study of the differences in composition between drops and how those changes in composition may be related to other properties of physical interest.The prototype capture system was utilized to capture drops across multiple rain events occurring near Charleston, South Carolina. Drop size measurements are compared to disdrometer measurements, and relationships between captured drop size and composition are explored.
Layer-optimized SAR processing with a mobile pRES to illuminate the internal layering of an alpine glacier
Authors: Oraschewski Falk M. , Koch Inka , Ershadi Mohammadreza , Hawkins Jonathan , Eisen Olaf , Drews Reinhard
Published: February 2023

The internal, isochronous layering of glaciers is shaped by accumulation and ice deformation. Information about these processes can be inferred from observing the layers using radar sounding. The reflectivity of the layers depends on density (permittivity) and acidity (conductivity) contrasts which tend to decrease with depth. At places like alpine glaciers where logistic limitations often only allow the deployment of lightweight and power-constrained ground-penetrating radar systems, it can therefore be challenging to illuminate the deeper radio-stratigraphy.The phase-sensitive Radio Echo Sounder (pRES) is a lightweight frequency modulated continuous wave radar which allows the use of coherent Synthetic Aperture Radar (SAR) processing techniques to improve the signal-to-noise ratio of internal reflection horizons. Using a mobile pRES we collected a radar profile on an alpine glacier (Colle Gnifetti, Italy/Switzerland). Here, we demonstrate how to apply layer-optimized SAR techniques to make deep internal layers visible, which could not be seen by a conventional pulsed radar. We evaluate the requirements on spatial resolution and positioning accuracy during data acquisition, necessary for applying layer-optimized SAR processing, as they constrain the feasibility of the method. We further discuss implications on how density and acidity contribute to decreasing dielectric contrasts.
Revealing the hidden signature of fault slip history in the morphology of degrading scarps
Authors: Steer Philippe , Holtmann Regina , Cattin Rodolphe , Simoes Martine
Published: February 2023

Multiple uplift events, either by discrete earthquakes or creep, will steepen and thus apparently rejuvenate fault scarps, raising the possibility that fault slip history leaves a hidden morphological signature. Here we explore this idea by proposing a new analytical formulation to simulate the scarp degradation generated by faulting at regular intervals. Our formulation fills the gap between the single rupture and the creeping fault proposed solutions. We show that the morphology of degrading fault scarps generated by one major or multiple minor earthquakes with the same final total uplift deviates by as much as 10-20%. Our inversion approach highlights the importance of trade-offs between fault slip history and erosion intensity. An identical topographic profile can be obtained either with a stable creep and an intense erosion or with a single seismic event and a weak erosion. Finally, our findings reveal that the previously noticed variation of the diffusion coefficient with time may be an artifact related to the kinematics of faulting. These inferences, derived from the simplest possible diffusion model, are likely to be even more pronounced in nature.
Estimating compounding heat waves and rainfall extremes under projected climate change over the island of Sicily, Italy
Authors: Remedio Armelle , Sirisena Jeewanthi , Bouwer Laurens
Published: February 2023

According to the IPCC AR6 report, the frequency and intensity of high temperatures and precipitation extremes, such as heat waves, and extreme rainfall events that can lead to flash floods have increased in recent decades and are projected to keep increasing. These extreme events, which can occur in separate or as compound events can lead to droughts and flooding, causing severe economic and health impacts including loss of lives. Especially when such events occur shortly or directly in sequence, they can cause more severe impacts than in isolation. Understanding their compound behavior and timing in current and future climates can help to better estimate associated risks and require protection and adaptation planning.In this study, the frequency and intensity of the compound events of heat waves and extreme precipitation over Sicily, Italy were analyzed and characterized for the present (1980-2010) and near future (2030-2050) periods. We used high resolution gridded datasets from observations (E-OBS) and from the EURO-CORDEX ensemble of regional climate change simulations. Heat waves were defined using a daily maximum temperature threshold persistent for at least three consecutive days while the extreme precipitation events were defined using the 95th percentile threshold of daily data. Results showed that the highest frequency of heat waves occured near the coastal regions of Sicily, while the extreme rainfalls were located in the west of Sicily.  We identified the areas where heat waves and extreme rainfall events have occurred in the past and we demonstrate how they are expected to change in the future, separately and as compound events. The results of this study will be used to develop a workflow for estimating climate risks in the region, which is part of the “risk workflow for CAScading and COmpounding hazards in COastal urban areas” (CASCO) project, and can be combined with other workflows on geophysical risks (earthquakes and tsunamis) to characterize overall natural hazard risks for the island of Sicily.
Stabilized Neural Differential Equations for Hybrid Modeling with Conservation Laws
Authors: White Alistair , Boers Niklas
Published: February 2023

Neural Differential Equations (NDEs) provide a powerful framework for hybrid modeling. Unfortunately, the flexibility of the neural network component of the model comes at the expense of potentially violating known physical invariants, such as conservation laws, during inference. This shortcoming is especially critical for applications requiring long simulations, such as climate modeling, where significant deviations from the physical invariants can develop over time. It is hoped that enforcing physical invariants will help address two of the main barriers to adoption for hybrid models in climate modeling: (1) long-term numerical stability, and (2) generalization to out-of-sample conditions unseen during training, such as climate change scenarios. We introduce Stabilized Neural Differential Equations, which augment an NDE model with compensating terms that ensure physical invariants remain approximately satisfied during numerical simulations. We apply Stabilized NDEs to the double pendulum and Hénon–Heiles systems, both of which are conservative, chaotic dynamical systems possessing a time-independent Hamiltonian. We evaluate Stabilized NDEs using both short-term and long-term prediction tasks, analogous to weather and climate prediction, respectively. Stabilized NDEs perform at least as well as unstabilized models at the “weather prediction” task, that is, predicting the exact near-term state of the system given initial conditions. On the other hand, Stabilized NDEs significantly outperform unstabilized models at the “climate prediction” task, that is, predicting long-term statistical properties of the system. In particular, Stabilized NDEs conserve energy during long simulations and consequently reproduce the long-term dynamics of the target system with far higher accuracy than non-energy conserving models. Stabilized NDEs also remain numerically stable for significantly longer than unstabilized models. As well as providing a new and lightweight method for combining physical invariants with NDEs, our results highlight the relevance of enforcing conservation laws for the long-term numerical stability and physical accuracy of hybrid models.
Illuminating Permeable Mineral Soil Groundwater Seepage Pathways Feeding Peatland Pools Using Thermal and Electrical Conductivity Signatures
Authors: Moore Henry , Comas Xavier , Briggs Martin , Reeve Andrew , Niedzinski Victoria , Slater Lee
Published: February 2023

Wetland environments are well documented to contain unique hydrogeomorphic subsystems that benefit from nutrient and temperature regimes provided by upwelling groundwater sources. Matrix seepage and preferential flow can both serve as groundwater inputs that control carbon-cycling within these environments. Recent work in a northern boreal peatland of Maine illuminates parallel dynamics to other wetland environments, with matrix seepage and preferential flow pathways (PFPs) identified and quantified proximal to peatland pools. PFPs around the peatland pools have been interpreted as peat pipes, known to transport nutrients within the peat matrix. Thermal signatures surrounding the peatland pool sources were mapped using point temperature measurements, handheld thermal imagery, and airborne thermal infrared mapping. Electrical geophysical methods were deployed to image the structure and stratigraphy of the underlying mineral sediments to delineate the source of focused upwelling around the peatland pools. Ground-penetrating radar (GPR) surveys show discontinuities in the impermeable glacio-marine clay controlling the hydrogeomorphic development of the peatlands studied. These mineral soil discontinuities in the GPR surveys, interpreted to be regional glacial esker deposits, are located proximal to the overlying peatland pools. Electromagnetic induction surveys were deployed to map the bulk electrical conductivity structures associated with the near-surface geology beneath the peatland pools. Point specific conductance measurements were taken at identified zones of thermal anomalies to further validate contrasts between peat pore water and mineral soil groundwater in the peatlands. Water samples were collected at the seepage sites and analyzed for iron and manganese trace elements to support the hypothesis that upwelling occurs from permeable glacial esker deposits. Focused groundwater inputs into peatlands may define a key hydrogeomorphic development process for peatland pool systems and the surrounding ecology. Further, these inputs could have implications for carbon-cycling, building on the established regional relationship between groundwater flow and carbon transport. Illuminating the focused groundwater flowpaths and interpreting their hydrogeologic origins may serve as a basis for future carbon-cycling exploration within peatlands at novel, fine-scales.
Mid-Latitude Controls on Monsoon Onset and Progression (the MiLCMOP project)
Authors: Turner Andrew , Volonte Ambrogio , Kretschmer Marlene
Published: February 2023

The Indian monsoon is critical since it supplies most of the water for drinking, sanitation, industry and agriculture for a billion people.  The onset of monsoon typically starts in southern India by 1 June, taking up to 6 weeks to cover the country.  Meanwhile, during the monsoon, variations on time scales of a week or more give rise to periods of excess and reduced rainfall, known as active and break events.Being able to better predict the onset of the rains, their progression, and of active and break events in the monsoon would be of great.  The timing of monsoon onset is already known to be influenced by tropical variability such as the Madden-Julian Oscillation.  New research has shown that the mid-latitudes also exert a powerful control, but the full extent of this extratropical role in monsoon onset progression and in the timing of active and break periods is poorly quantified and understood.The team behind the new MiLCMOP project earlier led the INCOMPASS field campaign to India, taking new measurements and generating new hypotheses on how the monsoon is controlled, including the concept that monsoon progression can be described as a “tug-of-war” between tropical and extratropical airmasses.  This "tug-of-war" is an unsteady process, with a back and forth of the two airmasses before the moist tropical flow takes over for the rest of the season.This poster describes some of the preliminary results on which the project is designed and explains the approach that MiLCMOP will use, including established techniques and development of new metrics to quantify the interactions between monsoon progression and extratropical forcing.  These methods will include use of vorticity budgets and Lagrangian feature tracking, applied to reanalysis and model data in case study years of fast and slow onset behaviour, to determine the dominant mechanisms controlling monsoon progression.  New model experiments will be designed and performed to isolate the mechanisms by which extratropical drivers affect monsoon onset and its progression.  Finally, novel causal inference techniques will be used to disentangle the effects of extratropical drivers from those in the tropics.The MiLCMOP project will eventually answer the following key questions:  (1) How are the pace and steadiness of Indian monsoon progression affected by interactions with the extratropics?  (2) What are the mechanisms of extratropical control on monsoon progression and variability?  (3) In what way do the causal extratropical and tropical drivers of ISM progression offset or reinforce each other and can the competing roles of tropical and extratropical processes be generalised to other monsoons?
Characterizing 4D post-failure slope kinematics of the 2020 Aniangzhai landslide combining different remote sensing measurements
Authors: Xia Zhuge , Motagh Mahdi , Li Tao , Peng Mimi , Roessner Sigrid
Published: February 2023

With the avalanche of satellite remote sensing sensors, significant efforts have been made to develop methods to integrate optical and SAR remote sensing efficiently to quantify the kinematics and lifecycle of landslides. In this study, we design a framework that integrates multi-sensor satellite remote sensing data to investigate post-failure kinematics of the 17 June 2020 Aniangzhai landslide in the Danba County of Southwest China. This ancient landslide was partially reactivated due to rapid river incision and toe erosion during a complex cascading event, which led to an evacuation and relocation of more than 20,000 people.First, time series of Planet images are exploited using the sub-pixel offset tracking method to generate horizontal deformation. Then advanced Multi-temporal InSAR (MTI) techniques are utilized to analyze the line-of-sight (LOS) displacements for 16 months after the failure. Eventually, the dynamics of the post-failure mechanism are modeled by integrating optical and radar data using an exponential decay model with independent component analysis (ICA) and least squares methods. Besides, the performance of a newly designed corner reflector (CR), consisting of two sets of semi-circular metal plates with a radius of 30-40 cm, is evaluated using both TerraSAR-X (TSX) and Sentinel-1 SAR data.Optical results show that the landslide underwent large deformation up to around 14.3 meters within 1.5 months after the failure, then the rate of deformation decreased slowly with time. InSAR analysis suggests that the LOS velocity reached a maximum of approximately 300 mm/year, indicating the active status of the ancient landslide body after failure. Using ICA decomposition, we extracted different features with various spatiotemporal patterns from the landslide body, which was then applied in data integration and 4D modeling of landslide kinematics. Our experiment using newly designed CRs indicates improvement in the background intensity in TSX images by around 30 dB, with signal-to-clutter ratio (SCR) exceeding 25 dB. The radar cross-section (RCS) of CRs in both TSX and S1 images remains relatively stable, ranging from 15-23 dB, making them suitable for CR-InSAR analysis.
From informal to institutional science-society-policy interactions: Introducing a climate advisory board in Frankfurt, Germany
Authors: Voelker Georg Sebastian , Becherer Ralf , Junge Carmen , Seifert Thomas
Published: February 2023

Climate change may be the most severe crisis humanity has faced to date. Both the social and natural sciences have well understood the causes and effects of climate change as well as the possible mitigation and adaptation measures. However, implementations of both mitigation and adaptation measures generally fall behind the goals defined by the Paris agreement.With increasing political awareness and progressing federal climate protection legislation in Germany communal politics is facing the challenge of charting explicit paths to net carbon neutrality. Due to diverse social and geographic settings as well as different existing infrastructures solutions have to be tailored to the local conditions. Local climate advisory panels are a common and if well constructed an effective way to support the local administration in the necessary transformation.Here we report on the successful efforts lead by the local group of the Scientists for Future in Frankfurt, Germany, to aid the city hall in establishing a communal climate advisory panel. Early stakeholder communication, broad alliances with local climate protection initiatives and the shared experience of the Scientists for Future network were key to successfully establish an institutionalized science-society-policy interface to permanently support local climate action activities.