bluuebunny/crossref_metadata_2025 huggingface dataset:
Palaeoseismological constraints on the Anghiari normal fault (Northern Apennines, Italy): first results.
Authors: testa alessio , Boncio Paolo , Baize Stephane , Mirabella Francesco , Pucci Stefano , Pauselli Cristina , Ercoli Maurizio , Riesner Magali , Pace Bruno , Benedetti Lucilla
Published: March 2022

The Italian Apennines is a slowly deforming area, despite not properly being an intraplate region. This is particularly true for the Northern Apennines, where<= 2mm/yr of extension is accommodated by low-slip rate normal faults, often organized in parallel systems partitioning the regional deformation. As a result, large earthquakes on individual faults are separated by long (>~1ka) recurrence intervals. This makes earthquake geology a fundamental tool for characterizing the seismic hazard.

The Anghiari fault is a 11 km-long segmented NE-dipping normal fault bounding the western side of the Upper Tiber Valley (Northern Apennines, Italy), and belonging to the well-known Altotiberina low-angle normal fault system. Here, we provide unprecedented evidence of the Holocene activity of the Anghiari fault through geological, geophysical and palaeoseismological investigations.

The fault is composed of at least two nearly parallel splays. One splay runs at the base of the Pleistocene Anghiari ridge, downfaulting the late Quaternary alluvial deposits of the Tiber Valley against Middle Pleistocene continental deposits. The other splay is located within the Middle Pleistocene units of the Anghiari ridge. We focus on the latter.
Detailed geomorphological analysis, geological mapping and near-surface geophysics, enabled us to select two sites for palaeoseismological trenching. Radiocarbon dating of faulted sediments provides constraints for late Holocene and historical surface faulting events significantly contributing to the estimation of the seismic hazard in the region.
Role of silicon in polymerization process during lignin synthesis and cell wall properties
Authors: Dragišić Maksimović Jelena , Djikanović Daniela , Kalauzi Aleksandar , Tanasijević Gordana , Maksimović Vuk , Radotić Ksenija
Published: March 2022

Silicon (Si), as the second most abundant element in the Earth's crust beyond oxygen, represents an essential part of the mineral world. Si is a crystalline semi-metal or metalloid belonging to the same periodic group as carbon, but with chemical performances dissimilar from all of its group counterparts. Despite sharing the bonding versatility of carbon, with its four valence electrons, Si is a relatively inert element. Besides its abundance (27.6%), Si is not usually found in its pure state, but rather its dioxide and hydrates. Silica (SiO2) is the one stable oxide of silicon, and it is more energetically favorable for Si to create four single bonds with each oxygen rather than make two double bonds with each oxygen atom. This leads to a linking form of -Si-O-Si-O- networks called silicates. The core unit of silicates can bind together in a variety of ways, creating a wide array of minerals. As an inevitable soil constituent, Si is present at high concentrations in soil solutions ranging from 0.1-0.6 mM roughly two orders of magnitude higher than some macronutrients. Therefore, exposed to Si, plants developed mechanisms for its uptake, translocation, and deposition within the plant tissue. Mostly accumulated in cell walls (CW), the location and content of Si are being primed by the chemistry and structure of lignin. We investigated how Si interacts with the process of lignin formation in the CWs. In an in vitro system, we studied the interaction of SiO2 with the peroxidase-catalyzed polymerization of a lignin monomer into a lignin model compound, imitating conditions of the last step in lignin formation. FTIR and fluorescence spectroscopy and microscopy showed that Si is bound to the final polymer and that the structure of the Si-DHP differs from pure DHP. Fluorescence spectroscopy showed that Si does not bind to the monomers, so Si probably inhibits the formation of the larger lignin fragments, as evidenced by HPLC-DAD, by binding to dimmers formed during DHP synthesis. The structural changes of the polymer are related to the changed proportion of the fractions of various MW. The enzyme catalyzing DHP synthesis was not inhibited by Si. This may indicate that the complex formed with Si and short oligomers activates the enzyme, and prevents the formation of the large fragments. Obtained results may influence further investigations of Si interactions with lignin and understanding of Si effects on the CW structure.

 

Acknowledgements. This work was financed by the Ministry of the Education, Science and Technological Development of the Republic of Serbia, the contract No 451-03-9/2021-14/200053.
Climate projections of spatio-temporally compound extreme events (floods and droughts) using a multivariate drought index
Authors: Ansari Rubina , Casanueva Ana , Grossi Giovanna
Published: March 2022

The compound occurrence of two extremes of the hydrological spectrum (droughts and floods) either in space and/or time, could aggravate the associated socio-economic impacts with respect to those caused by the individual extreme event. Both extreme events share the potentially linked driving mechanisms and interconnected characteristics, therefore the better understanding of the dependence structures of the contributing variables is essential to avoid the underestimation of the possible risks of compound hazards. To this end, the present study focusses on spatio-temporally compound extreme events under a changing climate and identify/locate the most vulnerable hotspots in the Upper Jhelum Basin (South Asia), paving the way for adaptation and mitigation measures. Climate models are the main tools to assess climate projections and, particularly, to provide relevant information for sectoral applications. They often present systematic biases, thus some sort of bias adjustment is performed in impact assessments. The framework of the present study is two-fold: (i) evaluation of bias correction (BC) of climate model historical simulations and (ii) projection of extreme compound events in the near future (2040-2059) and far future (2080-2099) for three different Representative Concentration Pathways (RCP2.6, RCP4.5 and RCP8.5). Droughts and floods are characterized by using a multivariate drought index (namely the Standardized Precipitation Evapotranspiration Index, SPEI), which is derived from daily precipitation (P) and maximum (Tmax) and minimum temperatures (Tmin). In the first step, the intercomparison of different state-of-the-art BC methods (uni- and multi-variate) and BC approaches (direct and component-wise) for climate model simulations stemming from different experiments (CMIP6, CORDEX -WAS-44- and CORDEX CORE -WAS-22) is performed following a multivariate framework. The added value/performance of BC and climate model simulations is examined in terms of inter-variable physical coherence of involved key essential variables (P, Tmax and Tmin) and characteristics of extreme events (duration, severity, intensity, and frequency of floods and droughts) during the historical period. In the second step, projected changes in the extreme events characteristics and their compounding in space and time are analyzed for the near and far future under all available scenarios. Climate projections of this kind of extreme events, spanning different scenarios and other sources of uncertainty is essential to better implement adaptation and mitigation solutions that can help reduce the negative impacts of climate change.
Consolidating ICESat-2 ocean wave characteristics with CryoSat-2 during the CRYO2ICE campaign
Authors: Nilsson Bjarke , Andersen Ole Baltazar , Ranndal Heidi , Rasmussen Mikkel Lydholm
Published: March 2022

Using global high-resolution elevation measurements from the Ice, Cloud, and land Elevation Satellite 2 (ICESat-2), it is possible to distinguish individual surface ocean waves. As the majority of ocean surveying missions are radar satellites, ICESat-2 observations are an important addition to ocean surveys and can provide additional observations not possible with radar. By utilizing the coincident orbits between CryoSat-2 and ICESat-2 during the CRYO2ICE campaign, the observations from ICESat-2 are compared along long stretches of the ground tracks, rather than at the usual crossover points. Therefore, from August 2020 to August 2021, 136 orbit segments from ICESat-2 in the Pacific and Atlantic oceans are used in the comparison. To allow for comparison of ICESat-2 during the coincident orbits, CryoSat-2 is validated against in-situ stations as well as satellite altimetry measurements. Using the validated CryoSat-2 observations, the significant wave height (SWH) is determined from the individual photon heights observed by ICESat-2, by three different methods. First, by using the standard ocean data output (ATL12), the SWH determined from this can be further validated. Then, the two methods derived in this study contain a model of deriving the SWH directly from the observed surface waves, as well as a model using the same method as ATL12, to act as a baseline for the wave-based model. The validation of this wave-based model for extended stretches with CryoSat-2 would allow for the further use of this model for studies. The carried out comparisons result in correlations between ICESat-2 and CryoSat-2 of 0.97 for ATL12 and 0.95 for the wave-based model, with a small mean deviation between the altimeters. The observations from ICESat-2 experience a larger variance than other altimeter crossover-comparison studies, however being constrained by a larger time-lag (<3h) between the coincident orbits for ICESat-2 and CryoSat-2 this is expected. From the study, ICESat-2 is found to agree with observations from CryoSat-2, and utilizing the possibility of distinguishing the surface waves, would therefore provide beneficial for ocean observations.
Evolution analysis of the April 2019 Hoseynabad-e Kalpush landslide in Iran inferred from  multi-sensor satellite remote sensing and in-situ measurements 
Authors: Vassileva Magdalena , Motagh Mahdi , Roessner Sigrid , Akbari Bahman
Published: March 2022

Following intense precipitation records between mid-March and the beginning of April 2019, thousands of slope failures affected the mountainous regions in northeast and south of Iran. In particular, a catastrophic landslide occurred in Hoseynabad-e Kalpush village, in Semnan province in the Northeast of Iran, where more than 300 houses were damaged, of which 163 houses had to be evacuated due to the severity of the destruction and the danger to their residents. Several questions were raised in the aftermath of the disaster as to whether the landslide was triggered by the heavy precipitation only or by other factors such as additional load due to the increase of the hydraulic gradient and seepage from a nearby artificial reservoir built in 2013 on the opposite side of the slope. This paper provides multi-scale and multi-sensor remote sensing investigation for the pre-, co-, and post-failure slope stability of the Hoseynabad-e Kalpush landslide and assesses the role of potential external factors in triggering the 2019 catastrophic failure. C-band Sentinel-1A Interferometric Synthetic Aperture Radar (InSAR) measurements and very-high-resolution Planet scope imagery cross-correlation show a clear precursory and transient deformation in the lower part of the slope that culminated in a slope failure of more than 35 m in the upper part of the landslide in April 2019. The lower and middle parts of the landslide continued to move with a maximum displacement rate of 10 cm in the first 6 months. Satellite remote sensing results are integrated with rainfall data and in-situ records of the reservoir water levels to evaluate the role of meteorological and anthropogenic conditions in promoting slope instability. The outcomes of this study highlight how the complex interaction between climate and anthropogenic factors influence unstable hillslope conditions in space and time and the need for more integration of remote sensing measurements into early warning systems at regional and national scales. 
New insights from low-temperature thermochronology into the tectonic-thermal evolution of the Siberian Traps Large Igneous Province
Authors: Bagdasaryan Tanya , Latyshev Anton , Thomson Stuart , Veselovskiy Roman
Published: March 2022

We present results of apatite fission-track (AFT) and other geochronological data (apatite U-Pb (LA-MC-ICPMS) and Rb-Sr dating) from several intrusions located within the Siberian Traps Large Igneous Province: (1) alkaline-ultramafic ring plutons of Odikhincha, Yessey and Magan, (2) intrusions of Norilsk-1 and Kontay, (3) Padunsky sill and (4) Kotuy dike. The studied intrusions were emplaced close to the age of the voluminous phase of the Siberian Traps LIP based on the new apatite U-Pb and Rb-Sr ages, as well as other results obtained earlier by other researchers. The obtained AFT ages are distributed between ca. 207 and ca. 173 Ma, and are much younger than the available latest Permian to earliest Triassic U-Pb and Ar/Ar data on the Siberian Traps. We interpret the AFT ages as a consequence of sedimentary burial of the studied magmatic complexes to below the closure temperature of the AFT system, which took place after the formation of intrusions ca. 252-250 Ma. Later cooling as a result of exhumation of the studied rocks to near surface temperatures and decreasing of thermal flow then took place in the Late Triassic-Early Jurassic.
Magmatic and mud volcanism in East Java investigated with passive seismic methods.
Authors: Lupi Matteo , De Gori Pasquale , Valoroso Luisa , Baccheschi Paola , Minetto Riccardo , Mazzini Adriano
Published: March 2022

East Java features a transition from magmatic to sedimentary volcanism. In addition, the back arc basins are characterised by the presence of surface piercements structures that reveal the migration of mantle derived fluids. Despite a clear connection between the local tectonics and the distribution of the eruptive centrs, the mechanisms of driving fluid migration in East Java remain unclear. In 2006 a large sediment hosted geothermal system named Lusi, pierced the Kendeng basin in East Java and since then it continues to erupt relentlessly. This large-scale eruption represent the most recent manifestation of hydrothermal and mantle derived fluids in the sedimentary basin. We deployed a temporary seismic network from 2015 to 2016 to investigate the velocity structure of a large portion of the East Java region. Specifically, we studied the spatial and structural relationships between the volcanic arc and the back-arc domains, by performing a local earthquake tomography. We inverted the phase arrivals released by regional earthquakes to show sharp Vp and Vp/Vs transitions. We observe a marked reduction of P-wave velocities and a high Vp/Vs ratio in the back-arc basins. Our study point out a clear connection between the plumbing system of the volcanic arc and the back arc basins. By combining geochemical, geological and geophysical data we propose a conceptual model suggesting that magmas and hydrothermal fluids may migrate from the middle to the upper crust into the sedimentary basins capitalising on existing thrust faults. According to our proposed model, Lusi is located at the intersection of low-angle thrust faults and steep-dip strike slip faults, in region where the hydraulic transmissivity of the upper crust is enhanced.
The metabolic 'toolkits' of temperate trees are species-specific and vary little with modest soil moisture variability.
Authors: Guzman Thomas , Petriacq Pierre , Valls Fonayet Josep , Dubois Sabrina , Devert Nicolas , Cassan Cedric , Flandin Amelie , Wingate Lisa
Published: March 2022

During the process of photosynthesis, leaves capture CO2 from the atmosphere and rapidly convert it into a diverse array of primary and secondary metabolites. Plants maintain a core set of metabolic pathways that ensure the basic building blocks of life that are available for each plant species to function. However, as plants evolved on land, they began to allocate this carbon (C) to innovative secondary metabolites and organs (cuticles, roots, wood) that protected them from abiotic stress (UV radiation, aridity, freezing) and biotic attack (fungal pathogens and insect/animal herbivory). As plants expanded over the land surface and occupied different niches, the amount of C fixed by plants varied and the types of secondary compounds synthesised by plants began to differ. Little is known about the metabolic profiles of the dominant European tree species and how variable the metabolomes of individual tree species are to changes in site conditions such as nutrient availability or soil moisture status. This study took advantage of recent advances in high-resolution mass spectrometry (HRMS) and bioinformatic tools to compare the leaf metabolomes of 14 commercially important tree species grown across three common gardens. Alongside the metabolic profiles, important chemical and morphological data were also collected from the trees during sampling, including targeted analysis of specific leaf metabolites such as proteins and phenolic compounds to obtain quantitative information on how their concentrations varied between tree species and site. Our analysis showed that the metabolomes of each tree species statistically differ from one another, and this dissimilarity was highly conserved at all three sites, even though tree growth and mortality rates varied between species and site. Our analysis also clearly highlighted distinct metabolome shifts between angiosperm and gymnosperm tree species, with angiosperms displaying greater concentrations of chlorophyll and amino acids alongside lower C/N ratios. These differences were also accompanied by discrepancies in an important set of secondary metabolites detected with the metabolomic technique. Furthermore, we also found that certain secondary compounds were essential in distinguishing between deciduous and evergreen species or families where targeted analysis could not detect significant differences. Our results indicate that temperate tree species may have conserved chemical 'fingerprints' that provide information on fundamental differences in the activity of certain plant metabolic pathways. This thus provides a promising tool to investigate how and why different plant species allocate C differently over the growing season and defend themselves against diverse abiotic and biotic pressures.
Modeling solar wind background for CME propagation using the Alfven Wave Solar atmosphere Model (AWSoM)
Authors: Sachdeva Nishtha , Toth Gabor , Manchester Ward , van der Holst Bart , Huang Zhenguang , Henney Carl
Published: March 2022

The first step towards reliable prediction of the impact of solar transients that drive space weather is to accurately model the background solar wind into which these transients propagate. Uncertainties in the plasma environment into which CMEs propagate can lead to significant errors in time of arrival and impact prediction which is important for technology that humans are routinely dependent on as well as space-based explorations.

We use the physics-based 3D extended MHD Alfven Wave Solar atmosphere Model (AWSoM) within the Space Weather Modeling Framework (SWMF) developed at the University of Michigan to model the solar wind conditions during periods of high activity that include many strong solar transient events. These modeling efforts are validated by both in-situ and remote observations including EUV observations in the low corona from STEREO-A/B and SDO-AIA as well as plasma parameters at L1 from the OMNI database. AWSoM is driven by observations of the photospheric magnetic field. We use the ADAPT magnetic field maps that model the evolution of the observed magnetic field on the solar surface using physical processes like flux-transport, supergranulation and meridional flows. Our results show how our solar corona model behaves when driven by different data products like GONG and HMI observations.

In addition to the input magnetograms, the results also depend on model parameters. AWSoM is a self-consistent physics-based model with only a few free parameters. In our NSF funded Space Weather with Quantified Uncertainty (SWQU) project we systematically study the uncertainty quantification associated with various model inputs and parameters. We find that during periods of higher solar activity the Poynting flux parameter at the inner boundary needs to be adjusted to match the observations well to provide correct initial conditions for CME propagation. This work is in preparation for simulating CMEs launched from the Sun and propagating into correct solar wind background in order to achieve accurate and reliable space weather modeling and prediction.
Determining aerosol radiative adjustments from UKESM1 with Partial Radiative Perturbation
Authors: Coleman Max , Collins William , Shine Keith , Bellouin Nicolas , O'Connor Fiona
Published: March 2022

Radiative adjustments are additional contributions to instantaneous radiative forcing. They have the potential to strongly enhance the initial forcing, for example in the case of aerosol interactions with clouds. We investigate aerosol radiative adjustments in an Earth System model using an offline partial radiative perturbation (PRP) technique.

Radiative adjustments occur via many mechanisms. To understand them requires a variety of modelling techniques to separate individual adjustments. In PRP radiatively important variables simulated by the online model are input to an offline radiative transfer code to calculate the radiative effects of their adjustments. We apply the PRP method to adjustments arising from anthropogenic sulphate and black carbon industrial-era emission perturbations simulated by the UK Earth System Model 1 (UKESM1) using its offline radiative transfer code (SOCRATES) with settings closely matching the online simulations.

This method reduces errors introduced when using PRP with, or radiative kernels generated from, different settings or radiative transfer models to that used in the online climate model. We assess radiative adjustments arising from several factors, including cloud fields, and compare with their adjustments in the online simulations.
Comparing satellite and ground-based measurements of low-lying SO2 plumes during the Kilauea 2018 and 2020 eruptions
Authors: Delbrel Juliette , Burton Mike , Hayer Catherine , Esse Ben , Varnam Matthew
Published: March 2022

Ground and satellite SO2 measurements have been extensively compared for high altitude volcanic emissions but far less for grounded plumes. The 2018 and 2020 Kilauea eruptions offered perfect opportunities to compare our TROPOMI results with ground measurements. Not only is Kilauea a very well monitored volcano, so the ground measurements are abundant and reliable, the SO2 plumes were big enough to be picked up by satellite. We compared the results to assess the efficacy of TROPOMI as a remote sensing tool applied at low-lying SO2 plumes. We concluded that the fluxes for both agreed provided the wind speed is the same for both. Remote sensing is therefore an important tool for effusive eruption monitoring and could be used on its own at remote volcanoes where ground instruments are sparse or lacking.
Studying the effect of scarab beetle larvae on soil greenhouse gas fluxes in a mesocosm experiment
Authors: Görres Carolyn-Monika , Kammann Claudia
Published: March 2022

The arthropod family Scarabaeidae is estimated to consist of over 30,000 species worldwide, including important pests. Their larvae – commonly known as white grubs – are often part of the soil decomposer community feeding on living plant roots, plant residues as well as faeces. As a result, scarab beetle larvae have the potential to directly and indirectly affect the spatial and temporal variability of soil greenhouse gas (GHG) fluxes, especially through their capability to emit significant amounts of CH4. However, due to a lack of field data (Görres & Kammann 2020), little is known about their quantitative impact on soil GHG budgets. We conducted a mesocosm experiment with common cockchafer larvae (Melolontha melolontha) with the twofold aim to better understand their effect on soil CO2, CH4 and N2O fluxes as well as the methodological challenges associated with studying this soil fauna group under field conditions. The experiment was conducted in Germany (temperate zone) over an entire vegetation period in mesocosms with three different vegetation types (grassland, grassland + carrots, and carrots, respectively) and three different larval infestation rates (0, 8, and 16 larvae m-2, respectively). Greenhouse gas flux measurements were conducted with the static chamber method on a monthly basis, including the use of isotopic labels to focus especially on gross soil CH4 fluxes. In this presentation, we will focus on the methodological difficulties encountered during the experiment and the potential of field-based isotope pool dilution techniques for non-invasive studies of scarab beetle larval CH4 emissions.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 703107.

Reference

Görres, C.-M., Kammann, C. (2020). First field estimation of greenhouse gas release from European soil-dwelling Scarabaeidae larvae targeting the genus Melolontha. PLoS ONE 15(8): e0238057, doi 10.1371/journal.pone.0238057.
Microbial and Abiotic Effects of Experimental Nitrogen Deposition on Dryland Soil Organic Carbon Storage
Authors: Püspök Johann , Aronson Emma L. , Hanan Erin J. , Schimel Joshua P. , Allison Steven D. , Vourlitis George L. , Homyak Peter M.
Published: March 2022

Nitrogen enrichment due to atmospheric nitrogen deposition has affected plant growth and microbial activity globally, leading to an increase in soil organic carbon in many ecosystems. Drylands cover ~45% of the global land area and constitute ~32% of the global carbon stocks, but the response of dryland carbon storage to atmospheric nitrogen deposition remains unclear and understudied relative to mesic systems. Observations from mesic systems suggest that nitrogen enrichment can increase the efficiency by which microbes incorporate carbon into mineral-associated forms if pH stays constant. Under acidification, a common response to nitrogen deposition, microbial biomass and enzymatic organic matter decay often decrease, leading to a build-up in plant-derived particulate organic carbon. However, in drylands, where organic carbon often associates with mineral surfaces via Ca-bridging, acidification may also abiotically decrease mineral-associated organic carbon if Ca is leached. In this study we tested how experimental nitrogen deposition affects different soil organic carbon fractions in drylands through microbial and abiotic effects.

We used four long-running nitrogen deposition experiments in Mediterranean shrub- and grassland ecosystems in Southern California, where two of the sites showed strong nitrogen-induced acidification (pH drop by ~1.5 units). We studied changes in soil organic carbon fractions, soil extracellular enzyme activity, microbial carbon stabilization efficiency and exchangeable Ca. Experimental nitrogen deposition had relatively small effects on soil organic carbon storage, which appeared to be mostly driven by soil physicochemical changes. Particulate organic carbon did not increase despite previously reported increases in plant biomass and decreases in microbial biomass and extracellular enzyme activity in acidified sites. Furthermore, microbial carbon stabilization efficiency was unaffected by N fertilization in non-acidified sites and decreased in short-term but not long-term incubations in acidified sites. Importantly, mineral-associated organic carbon decreased significantly by 20% in response to N fertilization at one of the acidified sites, likely as result of pH-induced loss of Ca, which dropped by 48%. Our measurements suggest that long-term effects of nitrogen fertilization on dryland carbon storage might be primarily abiotic in nature, such that drylands, which may undergo acidification and where Ca-stabilization of soil organic carbon is prevalent, may be most at risk for loss of mineral-associated organic carbon.
Decade-long monitoring of seismic velocity changes at the Irpinia Fault System (southern Italy)
Authors: Russo Guido , De Landro Grazia , Amoroso Ortensia , D'Agostino Nicola , Esposito Raffaella , Emolo Antonio , Zollo Aldo
Published: March 2022

Repeated tomographic inversions in time (the so called 4D tomography) track physical properties and stress changes in the medium hosting fault systems by measuring changes in P and S seismic velocities. These changes may provide insights on fault system dynamics and earthquake triggering mechanisms. We applied 4D tomography to the volume embedding the Irpinia Fault System (IFS, southern Italy) using more than ten years of continuous seismicity monitoring. The IFS is one of the Italian most hazardous fault systems, being able to generate the 1980 Ms 6.9 earthquake, characterized by a multi-segmented rupture. Seismicity was divided into uneven epochs having almost the same spatial resolution of the volume hosting the IFS.

The resulting images show time-invariant features, clearly related to crustal lithology, and time-changing (up to 20%) velocity anomalies in the central region. Vp, Vs and Vp/Vs anomalies are referred to the tomographic model obtained using all the data set, and occur at depths ranging between 1 and 5 km, and between 8 and 12 km. These anomalies are temporally well-correlated with groundwater recharge/discharge series and geodetic displacements during the same time intervals. This correlation provides evidence for the existence of pulsating pore pressure changes in a fractured crustal volume at depth of 8-12 km, saturated with a predominant gas phase (likely CO2) and correlated with groundwater recharge processes,  

We suggest that tomographic measurements of the Vp-to-Vs spatiotemporal changes are a suitable proxy to track the pore pressure evolution at depth in highly sensitive regions of fault systems.
On combining background solar wind models and sun-to-spacecraft connectivity in the Parker Solar Probe and Solar Orbiter era
Authors: Pinto Rui
Published: March 2022

The solar wind is an uninterrupted flow of highly ionised plasma that is accelerated in the low solar corona and expands into the interplanetary space. Wind streams develop and are accelerated at different places of the strongly magnetised low solar atmosphere, before propagating through the less magnetically-dominated heliosphere. A wide range of space weather phenomena depend strongly on the structure and geometry of the solar wind flow, as well as on specific properties of the magnetic field that it crosses.
Determining the impacts of solar wind phenomena on Earth or at spacecraft locations require being able to causally link remote observations to in-situ measurements, or to predict Sun-to-spacecraft connectivity with accuracy.
I will discuss the impact of uncertainties in the determination of the magnetic field structure, of the solar wind acceleration profiles and of the rotational state of the corona as well as of mild coronal variablity. I will also highlight undergoing developments that aim at improving these tools, both on a physics-oriented perspective and in the frame of data-driven real-time monitoring.
Intense Downwelling and Diffuse Upwelling in a Nonlinear Ekman Layer
Authors: Rahnamaei Nikki , Straub David
Published: March 2022

It has long been appreciated that Ekman transport and pumping velocities are modified through interactions with underlying geostrophic currents. Nonlinearity involving interaction of the Ekman flow with itself is, however, typically neglected. This nonlinearity occurs when the Rossby number based on the Ekman velocity and horizontal length scale approaches order one values. Such values are common, for example, in the ice-ocean stress field across sharp gradients such as leads in the sea ice cover. Recent work has shown strong asymmetry in the pumping velocities, with cyclonic forcing producing diffuse upwelling and anticyclonic forcing producing sharp downwelling fronts. To better understand this dynamics, we consider the steady response to a simple specified prescription of the stress. In the (x-z) plane perpendicular to the stress, dynamics are described by the 2-D Navier-Stokes equation, with a forcing term dependent on vertical shear of velocity in the y-hat direction, specified by a pressureless momentum equation. An expansion in an Ekman-velocity based Rossby number is used to solve the system and to better understand the asymmetry. Interactions with stratification and underlying geostrophic currents are also considered, and examples of where these effects might be important are given.
Characterization of different flow paths, hydrogeochemical processes, and mixing of groundwater governing water quality within a urban volcanic multi-aquifer system in Costa Rica
Authors: Madrigal Solis Helga , Jiménez-Gavilán Pablo , Vadillo-Pérez Iñaki , Fonseca-Sánchez Alicia , Calderón-Sánchez Hazel , Quesada-Hernández Luis
Published: March 2022

The volcanic aquifers in the Valle Central, the most urbanized region of Costa Rica, are essential in providing drinking water to about 1.7 million people. Nonetheless, the underlying hydrogeochemical processes governing physical and chemical groundwater quality have been rarely studied. The main objective of this study was to evaluate the natural processes controlling groundwater quality in the urban Barva and Colima aquifers, by using multivariate statistical analyses and hydrochemical tools. A total of 571 groundwater samples collected quaterly, from 2016 to 2020, in 38 springs and wells were analyzed for physical parameters, silica, nitrate and major ions. The Principal Component Analyses (PCA) and Discriminant Analyses (DA) were employed to classify the samples the samples according to any of the four existing aquifers: Upper Barva, Lower Barva, Upper Colima and Lower Colima, while revealing the occurrence of two flow paths within Lower Barva and two flow paths within Upper Colima. Mann-Whitney statistical analyses showed no significant differences between dry and wet seasons in most of the sampling sites and chemical parameters, suggesting minor chemical seasonal variations.  This study also suggests the occurrence of hydraulic connections between Upper and Lower Barva in the highlands, between Lower Barva and Upper Colima among the southern flow paths, and between Upper Colima and Lower Colima in the southwestern area. According to the observed spatial chemical evolution, Lower Barva samples are enriched in bicarbonate, magnesium, calcium, sodium, and silica as groundwater travels downwards, mainly due to the hydrolysis of Ca-plagioclase and pyroxene in mafic andesitic-basaltic lavas. Nitrate in the Lower Barva increased from 0.3 to 55.6 mg/L (i.e., as nitrate) as groundwater travels from the forest and pasture-dominated uplands to the middle and lower sub-basins covered predominantly by coffee plantations and urban non-sewered areas, implying pollution due to leaching of N-fertilizers and waste waters from septic tank-systems. Compared to Barva, Colima aquifers showed higher silica and major ionic content, except for calcium, indicating longer residence times and dissolution mainly from felsic andesitic minerals, Na- plagioclase, i.e., albite, magnesium-rich minerals, i.e., hypersthene and olivine, and probably calcium adsorption by normal ion exchange.  It is concluded that weathering of aluminosilicate minerals is the main natural hydrogeochemical process governing groundwater quality, and that ion exchange, mixing of groundwater between the Barva and Colima aquifers and anthropogenic processes have modified the water chemistry.
Use of Rapideye images from the planet platform to update vegetation cover studies in Tenosique, Tabasco, Mexico.
Authors: Nieto Butrón Jacob Jesús , Ramírez Serrato Nelly Lucero , Jácome Paz Mariana Patricia , Ruiz Santos Tania Ximena , Manuel Núñez Juan
Published: March 2022

Tenosique is a small town located on the border between Mexico and Guatemala, on the banks of the Usumacinta River. The area is considered a tropical climate with swampy and jungle areas. Previous studies had exposed the changes in vegetation cover related to the public policies applied at the site. Some examples of these policies are: the 1917 agrarian reform of land distribution to the peasants for cultivation, in 1938 concessions were made to national and foreign companies to exploit forest resources; in 1958 the agrarian reform for cultivation made the agricultural zone advance towards the jungle forest; in 1965 the food crisis promoted livestock; in 1976 it opted for the extraction of oil, and with the economic crisis in 1982 the financial support to the peasants and their ejidos is withdrawn, and finally in 2008 this area becomes a flora and fauna protection area. Past studies have been developed from a social and artistic point of view as well as quantifiable with the use of Landsat satellite images, covering large temporalities as well as a regional coverage scale, however, the results resolutions have made their interpretation difficult, reporting only the 20% plant loss over time. The objective of this project is to update the pre-existing study using high-resolution images, on a smaller surface. For this, 5-meter resolution Rapideye satellite images were downloaded from the Planet platform (Planet Application Program Interface: In Space for Life on Earth) with the help of an educational license obtained from an artistic quality project. The temporality of the images ranges from 2010 to 2020. The methodology includes corresponding atmospheric corrections, the supervised classification, and the coverage analysis obtained from the application of the Normalized Difference Vegetation Index (NDVI).  Conclusions show the impact of the inputs resolution improvement in the study.
SnoDRI: A Machine Learning Based Index to Measure Snow Droughts
Authors: Rasiya Koya Sinan , Kar Kanak Kanti , Srivastava Shivendra , Roy Tirthankar
Published: March 2022

Snow plays a significant role in the hydrology of numerous regions across the globe. A major portion of precipitation above 45O N latitude falls as snow. The accumulated snow melts slowly and contributes to infiltration and runoff processes. Therefore, it is important to study the quantity and fate of water from snowmelt. Reduced snow storage would lead to snow droughts, which can have an enormous impact on the water resources of snow-dominated catchments, such as those in the western United States. For that reason, it is essential to efficiently identify the time and severity of snow droughts. This study proposes SnoDRI, a new index that could identify and measure snow drought events. SnoDRI is a machine learning-based index that is estimated from several snow-related variables utilizing novel machine learning algorithms. The model uses a semi-supervised learning algorithm of an autoencoder and feature extraction to assess the importance of each variable. We use ERA5-Land reanalysis data from 1981 to 2021 for the Western United States to study the efficacy of the new snow drought index. The results are validated by verifying the coincidence of actual snow drought events and the interpretation of our new index. We will discuss how well the new drought index can perform and help in better identification of snow droughts.
GEOS-SCREAM: A Stratospheric Composition Reanalysis with Aura MLS 
Authors: Wargan Krzysztof , Weir Brad , Manney Gloria L. , Cohn Stephen E. , Knowland Katherine Emma , Wales Pamela A. , Livesey Nathaniel J.
Published: March 2022

The past decade has witnessed a growing interest in the quickly developing field of chemical composition reanalyses, that is, multiyear records of assimilated observations of atmospheric constituent gases. Composition reanalyses typically assimilate observations of atmospheric constituents using full chemistry and transport models driven by assimilated meteorology. Most, although not all, of these reanalyses to date focus on tropospheric composition. This presentation introduces a new chemical reanalysis of stratospheric constituents developed and produced at NASA’s Global Modeling and Assimilation Office (GMAO). Named Global Earth Observing System (GEOS) Stratospheric Composition Reanalysis with Aura MLS (GEOS-SCREAM), this product consists of assimilated global three-dimensional fields of stratospheric ozone, water vapor, hydrogen chloride (HCl), nitric acid (HNO3), and nitrous oxide (N2O) mixing ratios and covers the period since the beginning of MLS observations in September 2004 to 2021. The assimilated instantaneous fields are produced at a three-hourly frequency. GEOS-SCREAM assimilates version 4.2 MLS profiles of the five constituents alongside total ozone column from the Aura Ozone Monitoring Instrument with the recently developed Constituent Data Assimilation System. It is also constrained by tropospheric water vapor from several satellite sensors and in situ measurements with the existing MERRA-2 meteorological data assimilation system. GEOS-SCREAM provides an accurate and dynamically consistent high-resolution data record of the five constituents, all of which are of primary importance to stratospheric chemistry and transport studies. We will present a description of GEOS-SCREAM and selected results of a process-based evaluation of this product using independent data. We will also discuss potential scientific applications of GEOS-SCREAM and outline plans for an upcoming comprehensive composition reanalysis that is being developed at NASA GMAO.
New insights into the formation of the pallasites from the Sericho meteorite from EBSD.  
Authors: Hiramatsu Reina , Lee Martin
Published: March 2022

The pallasite meteorites are composed of olivine crystals, Fe-Ni metal alloy and Fe-sulphide. Their formation environment was initially proposed to be at core-mantle boundaries of planetesimals (Scott et al., 1977., Geochemica et Cosmochemica Acta., p.349). However, recent studies using paleomagnetic techniques, and examining the metal concentrations across multiple pallasites, argues against the core-mantle boundary hypothesis (Nichols et al., 2021., Journal of Geophysical Research Planets., p.16). Ferrovolcanism models, which invoke Fe-FeS magma injection into mantle lithologies support paleomagnetism results, compositional trends, and olivine growth conditions (Johnson et al., 2020., Nature Astronomy., p.43). Here we present results from the recently found pallasite Sericho to further explore magmatic aspects of the ferrovolcanism hypothesis using optical microscopy together with SEM energy dispersive X-ray spectrometry (EDS) and electron backscatter diffraction (EBSD).

Sericho has a jigsaw-like texture of forsterite crystals in a troilite matrix. Crystallographic preferred orientations (CPO) of the olivine as determined by EBSD indicate a flow alignment, possibly due to the introduction of the Fe-Ni alloy resulting from upwelling within the planetesimal. Identification of a tabular inclusion within one of the olivine crystals suggests that Sericho experienced mild shock events in contrast to previously studied pallasites including Eagle Station. Our CPO results support the ferrovolcanism hypothesis and more work is underway to investigate olivine slip systems to find out type of internal misorientation is recorded within Sericho’s olivines.
Global Snow Water Equivalent Observations from Space
Authors: Barros Ana , Vuoyvich Carrie , Durand Michael , Tsang Leung , Houser Paul , Marshall Hans-Peter
Published: March 2022

Global snow water equivalent (SWE) data are required for understanding the role of snow in the Earth’s water, energy and carbon cycles, and are critical for informing water resource and snow-related hazards. While exciting progress has been made in recent decades, there are currently no global SWE data at the required frequency, resolution and accuracy to address scientific and operational requirements. These data are needed to inform science and application areas and, taken as a whole, are critical to global water and food security. New higher-resolution microwave instruments can provide this information, especially when combined with modeling.  We now have the capability to put these instruments in space to monitor SWE and volume at the required resolution for improved and useful water prediction globally.  This presentation will describe the requirements of a spaceborne SWE mission, review progress in snow remote sensing technology and algorithms, and describe a potential path forward to meet identified snow data needs.
IDF curves in nonstationary regions using regional frequency analysis and RCP scenarios in south korea
Authors: Kim Heechul , Seo Miru , Lee Taewon , Heo Junhaeng
Published: March 2022

Recently, extreme hydrological phenomena are increasing rapidly due to abnormal climate caused by global warming, and many damages are occurring as the change of precipitation characteristics. The intensity-duration-frequency(IDF) curve is widely applied in practice for designing the hydro-infrastructures. In addition, it is important to predict future changes in rainfall intensity due to climate change.

For this purpose, this study intends to derive the IDF curve, for future periods. In this study, the RCP scenario, a climate change scenario, was used based on historical data (1975-2020) and future rainfall data (2021-2100). Using these data, the stationary and nonstationary regions in the Korean are classified using regional frequency analysis, and the rainfall quantiles for non-stationary regions was calculated using the GEV(1,0,0) model with time varying location parameter. Finally, IDF curves for the historical and future data were derived and analyzed.

 
Homologous Coronal Mass Ejections Caused by Recurring Formation and Disruption of Current Sheet within a Sheared Magnetic Arcade
Authors: Jiang Chaowei , Bian Xinkai , Feng Xueshang
Published: March 2022

The Sun often produces coronal mass ejections with similar structure repeatedly from the same source region, and how these homologous eruptions are initiated remains an open question. Here, by using a new magnetohydrodynamic simulation, we show that homologous solar eruptions can be efficiently produced by recurring formation and disruption of coronal current sheet as driven by continuously shearing of the same polarity inversion line within a single bipolar configuration. These eruptions are initiated by the same mechanism, in which an internal current sheet forms slowly in a gradually sheared bipolar field and reconnection of the current sheet triggers and drives the eruption. Each of the eruptions does not release all the free energy but with a large amount left in the post-flare arcade below the erupting flux rope. Thus, a new current sheet can be more easily formed by further shearing of the post-flare arcade than by shearing a potential field arcade, and this is favorable for producing the next eruption. Furthermore, it is found that the new eruption is stronger since the newly formed current sheet has a larger current density and a lower height. In addition, our results also indicate the existence of a magnetic energy threshold for a given flux distribution, and eruption occurs once this threshold is approached.