bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring Perceptions of Natural Water Retention Measures and Their Implementation: A Case Study in Northeastern Italy
Authors: Bernello Giacomo , Mondino Elena , Bortolini Lucia
Published: March 2021

Heavy rainfall is one of the hydrogeological hazards increasingly connected with climatic changes. Natural Water Retention Measures (NWRMs) implementation represents a chance to build resilient communities and to reduce potential damage. This water management approach has several designs and can be adopted at different scales. However, NWRMs are not widespread, and in some cases they are even ignored by both citizens and public administrations. Understanding how people perceive NWRMs is the first step to promote the implementation of these structures. This study aims at exploring people’s knowledge of NWRMs and their attitudes towards them. We conducted a survey in the Veneto Region (Northeastern Italy) in 2020. Preliminary data exploration shows that the overall knowledge of NWRMs varies depending on the type of retention measure. Respondents’ attitudes towards NWRMs are positive in public areas (e.g. green spaces, parking lots), but are more heterogeneous when it comes to private properties (e.g. houses, private gardens). Further investigations are therefore needed concerning the last point. This study provides a deeper understanding of the dynamics behind water management systems’ implementation to reduce heavy rainfall and flood damage and can inform policymakers dealing with flood risk management.
Magmatic diversification of dykes is controlled by adjacent alkaline carbonatitic massifs
Authors: Kopylova Maya , Nosova Anna , Sazonova Ludmila , Vozniak Alexey , Kargin Alexey , Lebedeva Natalya , Volkova Galina , Pereseckaya Ekaterina
Published: March 2021

The study reports petrography, bulk major and trace element compositions of lamprophyric Devonian dykes in three areas of the Kola Alkaline Carbonatite Province (N Europe). Dykes in one of these areas, Kandalaksha, are not associated with a massif, while dykes in Kandaguba and Turij Mys occur adjacent (< 5 km) to coeval central multiphase ultramafic alkaline-carbonatitic massifs. Kandalaksha dyke series consists of aillikites - phlogopite carbonatites and monchiquites. Kandaguba dykes range from monchiquites to nephelinites and phonolites; Turij Mys dykes represent alnoites, monchiquites, foidites, turjaites and carbonatites. Some dykes show extreme mineralogical and textural heterogeneity and layering we ascribe to fluid separation. The crystallization and melt evolution of the dykes were modelled with Rhyolite-MELTS and compared with the observed order and products of crystallization. Our results suggest that the studied rocks were related by fractional crystallization and liquid immiscibility. Primitive melts of alkaline picrites or olivine melanephelinites initially evolved at P=1.5-0.8 GPa without a SiO2 increase due to abundant clinopyroxene crystallization controlled by the CO2-rich fluid. At 1-1.1 GPa the Turij Mys melts separated immiscible carbonate melt, which subsequently exsolved carbothermal melts extremely rich in trace elements. Kandaguba and Turij Mys melts continued to fractionate at lower pressures in the presence of hydrous fluid to the more evolved nephelinite and phonolite melts. The studied dykes highlight the critical role of the parent magma chamber in crystal fractionation and magma diversification. The Kandalaksha dykes may represent a carbonatite - ultramafic lamprophyres association, which fractionated at 45- 20 km in narrow dykes on ascent to the surface and could not get more evolved than monchiquite. In contrast, connections of Kandaguba and Turij Mys dykes to their massif magma chambers ensured the sufficient time for fractionation, ascent and a polybaric evolution. This longevity generated more evolved rock types with the higher alkalinity and an immiscible separation of carbonatites.
Landslide Geo-Information Services for the Alps
Authors: Malet Jean-Philippe , Michoud Clément , Oppikofer Thierry , Crosta Giovanni B. , Frattini Paolo , Pacini Fabrizio , Garcia Robles Javier , Foumelis Michaelis
Published: March 2021

The project “Geo-information Services for Landslides in the Alps (eo4alps-landslide)” has the main objective of exploiting the potential of new satellite data coupled to advanced modelling for gravitational hazards assessment in the Alpine region. The two-year project starts in early 2021 and consists of a broad consortium of universities, geological consultancies, ICT companies and geological services. More than 20 authorities and other stakeholders responsible for landslide disaster risk management are actively involved in all project phases. “eo4alps-landslide” aims at ensuring that satellite-based Earth Observation (EO) products are increasingly and more efficiently used in practice for science and operational DRM procedures. “eo4alps-landslide” produces harmonised and advanced landslide inventories and susceptibility/hazard maps for the Alps based on InSAR and optical ground motion services and landslide-specific models embedded in the Geohazards Exploitation Platform (GEP). These EO-based services and products can be complemented by local datasets and terrain data from the end users directly in GEP. Planned products of “eo4alps-landslide” includes 1) automatic landslide detection using satellite optical and InSAR-based services, 2) harmonised and advanced landslide catalogues resulting from the satellite based detection and local inventories, 3) susceptibility/hazard maps consisting of possible landslide source areas and landslide type-specific runout modelling. Further fields of application and products will be adapted to the needs of end users. The methods will be generic in order to be used at several spatial scales from Tier 1 (region) to Tier 2 (municipality) and Tier 3 (local slope). Furthermore, the products of “eo4alps-landslide” will be compatible with products and services of other “eo4alps” initiatives, as well as with the European Ground Motion Service (EGMS).
Raman spectroscopy for petrology : recent scientific milestones, technological trends and challenges
Authors: Beyssac Olivier
Published: March 2021

Over the last two decades, Raman microspectroscopy has known a spectacular development in various research fields of petrology opening new avenues for studies in sedimentology, metamorphism or magmatism and cosmochemistry. This has been made possible thanks to major technological improvements (e.g., Raman hyperspectral mapping) and a better theoretical approach (e.g., data processing and interpretation). Raman spectra are actually sensitive to even minor (chemical or structural) perturbations within chemical bonds in (even amorphous) solids, liquids, and gases. They can, thus, help identify, characterize, and differentiate between individual minerals, fluid inclusions, glasses, carbonaceous materials, solid solution phases, strain in minerals, and dissolved species in multi-component solutions. Such sensitivity and versatility make Raman a unique tool for petrology. Yet, it relies on a weak and subtle signal and a cautious approach is required to avoid pitfalls during the analysis and/or the interpretation of data. Some recent scientific milestones will be presented and discussed in various fields like geothermobarometry of metamorphic rocks, geochemistry of meteorites, speciation of deep fluids involved in fluid-rock interactions or the characterization of organic/mineral assemblages of astrobiological interest. For the particular c       ase of petrology, Raman microspectroscopy has the immense advantage that it requires minimal sample preparation, thus it can be performed in situ preserving the original microtexture of the sample with a rather high spatial resolution for analysis, typically 1 mm at 532 nm for modern systems. Therefore, this technique is now increasingly used to study poorly crystalline and chemically heterogeneous materials involved for instance in geochemical processes occuring at Earth surface. But it faces numerous challenges due to the reactivity of such phases making them fragile under the laser beam, or due to the quasi-systematic presence of intense backgrounds in the spectra overwhelming the Raman signal. The source of this background can be multiple as it can be observed with fine-grained samples and/or it can be generated by the presence of luminescence/fluorescence emission centers. More generally such background is not well understood although it is a major issue for Raman spectroscopy in many petrological applications. However, there too, recent technological developments, sometimes based on old ideas, offer new possibilities to investigate safely and accurately such materials : time-resolved spectroscopy and surface-enhanced Raman spectroscopy (SERS) will be presented as well as some applications for petrology of complex samples.
Subsurface seismic imaging with a hammer drilling source at an exploration drilling test center in Örebro, Sweden 
Authors: Ivandic Monika , Kaslilar Ayse , Juhlin Christopher
Published: March 2021

Seismic imaging while drilling technology offers possibilities of imaging ahead of the drill-bit, which could be useful for determining when to go from hammer drilling to core drilling. Moreover, seismic images of the surrounding rock can improve geological models which could be then used to guide drilling programs.

A seismic imaging while drilling field test was carried out in August 2020 at the I-EDDA Test Center next to the Epiroc factory in Örebro, which is an outcome of the EIT Raw Materials funded project “Innovative Exploration Drilling and Data Acquisition (I-EDDA)”. The purpose of the test presented here was to determine if the signals from hammer drilling can be used for seismic imaging around the drill-bit. The I-EDDA test site has been extensively investigated with geophysical investigations, geological mapping and diamond core drilling, and it therefore represents an ideal location to perform the proposed feasibility study.

The data were recorded along a west-east oriented line consisting of 45 active 1C vertical geophones with a spacing of about 2 m and the rig located approximately in the middle of the profile. A reference signal, which is usually recorded by the pilot sensor fixed to the top of the drill string to be used to convert geophone recordings to impulsive-like seismic data, was not available. The passive recordings on the surface were thus correlated with the trace from the geophone closest to the rig.

After data pre-processing and cross-correlation, the shot-gathers were vertically stacked over the length of a drill pipe to achieve further signal improvement. A comparison with the results of a modelling study shows certain agreement. However, it has to be noted that the velocity model obtained from earlier studies and used to generate the synthetic data set here is rather a simple one and the noise level in the real data set is still significant, in spite of careful processing. Besides the strong contamination by the rig noise, more typical for data with smaller offsets, the mono-frequency waveform footprints present in the cross-correlograms, which have been observed in similar experiments where a trace from the nearest geophone was used to approximate the bit signal, could also play a role. The recent results from the active seismic studies conducted at the site have not detected any clear reflections within the bedrock, which further hinders the quality assessment of the seismic signal.

 

 

This work was partly supported by VINNOVA with the project 2019-04832 titled Integrated Smart Test environment for the mining industry - SMIG. We gratefully acknowledge this financial support.
Remote-predictive geologic mapping of the Reykjanes Ridge: Implications for the volcanic and structural evolution of a slow-spreading Mid-Ocean Ridge
Authors: Panasiuk Sofia , Anderson Melissa O. , Höskuldsson Ármann , Martinez Fernando , Pałgan Dominik
Published: March 2021

The Reykjanes Ridge is a spreading center that presents an opportunity to track the dynamic formation of structural and volcanic features at an asymmetric slow-spreading plate boundary. The ridge spans the northern ~1000 km of the Mid Atlantic Ridge and has been spreading at a full spreading rate of ~20 mm/year [1]. The characteristic along-ridge basement depth, crustal thickness, and chemical gradient have been variably attributed to an active mantle plume beneath Iceland, or a passive mantle anomaly pre-dating the rifting [1]. A unique feature of the ridge is that it spreads obliquely to the spreading axis: a consequence of the change in spreading direction from ~125o to ~100o due to the failure of the triple junction between the Greenland, Eurasian, and North American plates 37 Mya [2]. Along with the sudden change in orientation, disjunct ridge segments were formed and separated by transform faults which have been continuously eliminating from north to south, thereby re-establishing the original linear geometry of the ridge [1]. The Bight Transform Zone is the final remaining transform fault and constitutes the boundary between the southern Reykjanes Ridge and the northern Mid-Atlantic Ridge. Despite the termination of strike-slip transform fault motion, the ridge remains in a state of active tectonic deformation as demonstrated by the time-dependant orientations of linear structures, lengths of spreading segments, and deviation from the previously asserted linear continuity of the ridge. Investigating the relationship between structures, volcanism, and regional geodynamics is possible with the application of a novel remote-predictive geological mapping method based on interpretations from newly acquired bathymetric and acoustic backscatter data. Notably, the bathymetric data provides significant high-resolution coverage of both on-axis and off-axis regions, allowing us to track the evolution of the ridge for up to 13 Mya. The acoustic backscatter data aids in the interpretation of geologic features and terrains whose distribution and morphology reflect both present-day and historic ridge dynamics. This analysis will produce new insight into the on-going first and second-order deformation of the Reykjanes Ridge, its controls, and its effects on diffuse low-temperature vs. focused high-temperature hydrothermal venting.

[1] Martinez et al., 2020. Reykjanes Ridge evolution: Effects of plate kinematics, small-scale upper mantle convection, and a regional mantle gradient. Earth-Science Reviews.

[2] Jones, Stephen M., 2003. Test of a ridge–plume interaction model using oceanic crustal structure around Iceland. Earth and Planetary Science Letters.
Changes in Vertical Velocity and Precipitation Mode in Flash Flood-Producing Storms in the Mississippi River Basin in a Future Climate
Authors: Dougherty Erin , Rasmussen Kristen , Newman Andrew , Gutmann Ethan
Published: March 2021

The Mississippi River Basin (MRB) is a flash flood hotspot in the United States, receiving the most frequent floods and highest rainfall accumulations across the country. In a future warmer climate, this region exhibits some of the greatest increases in rainfall associated with storms that produce flash floods. In order to better understand these future changes, convection-permitting simulations of a current and future climate are utilized to study changes to storm dynamics and precipitation in these convectively-driven flash flood-producing storms. 

First, nearly 500 flash flood-producing storms in the MRB are examined under a pseudo-global warming framework to examine the role of vertical velocity in modulating future rainfall changes. Three different categories of storms are designated based on their vertical velocity magnitude in the current climate–weak, moderate, and strong. While all storm categories display an increase in future rainfall accumulation, the amount of increase varies by the storm’s vertical velocity magnitude, which also changes in the future. 

Second, idealized WRF simulations are run based on a composite sounding of the flash flood-producing storms in the MRB that occurred during the warm season. Future temperature, moisture, and horizontal wind perturbations are added to the initial sounding using the CESM Large Ensemble Data Set under the RCP 8.5 emissions scenario. In these idealized simulations, the contribution of different precipitation modes to future changes in rainfall are examined. The relationship between changes in future precipitation mode and storm dynamics provides a better understanding of how storm processes influence future changes in rainfall in a flash flood prone region in the United States. 

 
Renewed thinking on groundwater age
Authors: Ferguson Grant , Cuthbert Mark , Befus Kevin , Gleeson Tom , Noyes Chandler , McIntosh Jennifer
Published: March 2021

Groundwater age and mean residence times have been invoked as measures of groundwater sustainability, with the idea that old or "fossil" groundwater is non-renewable. This idea appears to come from the link between groundwater age and background recharge rates, which are also of questionable use in assessing the sustainability of groundwater withdrawals. The use of groundwater age to assess renewability is further complicated by its relationship with flow system geometry. Young groundwaters near recharge areas are not inherently more renewable than older groundwaters down gradient. Similarly, there is no reason to preferentially use groundwater from smaller aquifers, which will have smaller mean residence times than larger aquifers for the same recharge rate. In some cases, groundwater ages may provide some information where groundwater recharge rates were much higher in the past and systems are no longer being recharged. However, there are few examples where the relationship between depletion and changes in recharge over long time periods has been rigorously explored. Groundwater age measurements can provide insights into the functioning of groundwater flow systems and calibration targets for numerical models and we advocate for their continued use, but they are not a metric of sustainable development. Simple metrics to assess groundwater sustainability remain elusive and a more holistic approach is warranted to maintain water levels and environmental flows.
Do field observations agree with satellite-based evaporation products in the Miombo Woodland of Southern Africa?
Authors: Zimba Henry , Coenders-Gerrits Miriam , Kawawa Banda , Schilperoort Bart , Nyambe Imasiku , H.G. savenije Hubert
Published: March 2021

Evaporation is a major constraining factor of water availability at the land surface which makes its assessment a highly significant prerequisite for application in hydrological, agricultural, climate studies and many other disciplines at various scales. However, its importance and calculation procedures have largely been crafted around and often limited to crop productivity. The overarching consequence of this is inaccurate estimates of evaporation for other land surfaces and particularly for forest systems. Due to limited field evaporation observations attention has been focused on the application of satellite-based products. However, in the case of Africa, and the Miombo ecosystem in particular, the number of flux towers is extremely limited (very few if any) which makes it extremely difficult to evaluate available satellite-based evaporation products. In this study we used the energy balance Bowen ratio approach to estimate field evaporation in a dense Miombo Woodland which we then used to evaluate four energy balance evaporation models. The models evaluated included the MOD16, SEBS, SSEBop and WaPOR. Furthermore, cluster analysis was used to assess the similarity of the models in simulating evaporation. The results show that at daily and dekadal scale the simulated evaporation by the four models significantly varied from field evaporation observations. However, less variations were observed at monthly scale.  Furthermore, all four models overestimated evaporation during the dry season (June-September) with RMSE ranges between 0.21 – 0.38 mm.day-1 and 6.64 - 9.91 mm.month-1. Based on the RMSE and biases the MOD16 (RMSE = 6.64 mm.month-1; Bias = 2.04 mm.month-1), SEBS (RMSE = 8.69 mm.month-1; Bias = 5.72 mm.month-1) and WaPOR (RMSE = 7.44 mm.month-1; Bias = 6.67 mm.month-1) ranked higher than the SSEBop (RMSE = 9.91 mm.month-1; Bias = 9.84 mm.month-1) in simulating evaporation in the Miombo Woodland. Three clusters were observed with the SEBS and WaPOR grouped together indicating their close similarity in simulating evaporation in the Miombo ecosystem while the MOD16 and SSEBop were each grouped separately. Results of this study could aid the interpretation of these evaporation models in Miombo Woodland covered basins such as the Zambezi River Basin in Southern Africa. This could help in monitoring basin water availability and ecosystem reactions and feedbacks to climate change and anthropogenic impacts.
Feature Extraction Techniques for Airborne Hyperspectral Images – Implication for Mineral Exploration
Authors: Chakraborty Rupsa , Kereszturi Gabor , Pullanagari Reddy , Durance Patricia , Ashraf Salman , Craw Dave
Published: March 2021

Geochemical mineral prospecting approaches are mostly point-based surveys which then rely on statistical spatial extrapolation methods to cover larger areas of interest. This leads to a trade-off between increasing sampling density and associated attributes (e.g., elemental distribution). Airborne hyperspectral data is typically high-resolution data, whilst being spatially continuous, and spectrally contiguous, providing a versatile baseline to complement ground-based prospecting approaches and monitoring. In this study, we benchmark various shallow and deep feature extraction algorithms, on airborne hyperspectral data at three different spatial resolutions, 0.8 m, 2 m and 3 m. Spatial resolution is a key factor to detailed scale-dependent mineral prospecting and geological mapping. Airborne hyperspectral data has potential to advance our understanding for delineating new mineral deposits. This approach can be further extended to large areas using forthcoming spaceborne hyperspectral platforms, where procuring finer spatial resolution data is highly challenging. The study area is located along the Rise and Shine Shear Zone (RSSZ) within the Otago schist, in the South Island (New Zealand). The RSSZ contains gold and associated hydrothermal sulphides and carbonate minerals that are disseminated through sheared upper green schist facies rocks on the 10-metre scale, as well as localized (metre-scale) quartz-rich zones. Soil and rock samples from 63 locations were collected, scattered around known mineralised and unmineralized zones, providing ground truth data for benchmarking. The separability between the mineralized and the non-mineralised samples through laboratory based spectral datasets was analysed by applying Partial least squares discriminant analysis (PLS-DA) on the XRF spectra and laboratory based hyperspectral data separately. The preliminary results indicate that even in partially vegetated zones mineralised regions can be mapped out relatively accurately from airborne hyperspectral images using orthogonal total variation component analysis (OTVCA). This focuses on feature extraction by optimising a cost function that best fits the hyperspectral data in a lower dimensional feature space while monitoring the spatial smoothness of the features by applying total variation regularization.
Deriving fluvial and pluvial flood risk curves using large ensemble climate simulation data with a fast 2-D flood model: A case study in Nagoya City, Japan
Authors: Tanaka Tomohiro , Kiyohara Keiko , Tachikawa Yasuto
Published: March 2021

Against flood disasters to be intensified in a future climate, we are required to implement adaptation strategies on a limited budget. In urban areas, heavy rainfall-based floods are classified into two types: pluvial and fluvial floods. It is well known that fluvial floods cause deeper inundation and stronger fluid force while pluvial ones occur more frequently. Such hydrodynamic characteristics have been intensively discussed in a literature; however, their impact and the resulting damage have not yet been examined in a comprehensive manner due to small samples of storm events in one region that leads to high uncertainty in frequency analysis. In the context of climate change impact assessment on extreme events, considerable ensembles of climate data have become available, contributing to smaller uncertainty in frequency analysis of flood damages. This study presents a case study of frequency estimation of fluvial and pluvial floods in an urban area set in Nagoya City, Japan. We applied a large ensemble climate simulation database, d4PDF, to a combined pluvial and fluvial flood model, from which we derived flood risk curves for each type of flooding. The results indicated that pluvial flooding presents comparable economic risk to fluvial flooding (16% and 17% lesser damage at 50- and 100-year return periods, respectively) despite its significantly shallower flood depths (area with flood depth over 45 cm was only 10.5% and 5.4%, respectively). This is because pluvial floods widely occur over the city, including areas further away from the river. Furthermore, probably similar with other mega cities with long history, fluvial flood risk has been managed by settling the central economic district (originally the Nagoya Castle founded several centuries ago) on higher altitudes. The results suggest that pluvial flooding could have comparable economic risks to fluvial flooding in urban areas where major economic assets are widely sprawled over the city as well as historical countermeasures are implemented against fluvial flooding. Pluvial floods, countermeasures against which tend to be smaller than fluvial floods, should be managed at a comparable level in urban areas.
Modeling ambient noise distributions for surface wave imaging based on full waveform inversion 
Authors: Zhou Changjiang , Xia Jianghai , Cheng Feng , Pang Jingyin , Chen Xinhua
Published: March 2021

Abundant noise sources in urban area has been widely utilized for subsurface investigations based on the seiemic interferometry. Reliable dispersion extraction between two seismic stations is an essential basis of surface wave imaging. Noise source directivity has become an inescapable obstacle and a main concern for passive seismic surveys: it basically breaks the physics of Green’s function retrieval in travel-time tomography; Moreover, the azimuthal effect of ambient noise sources would inherently cause different levels of early arrival on cross-correlation functions, so that the apparent velocity of surface wave could be overestimated in multichannel slant stackings.

 

Instead of the conventional frequency-time analysis, which aims to extract the apparent dispersions of phase/group velocity between seismic stations, we proposed a method to jointly invert noise source distributions and the corresponding unbiased surface wave velocities based on the theoretical framework of full waveform ambient noise inversion. Waveform itself could intrinsically contains the features of travel-time, energy and asymmetry of ambient noise cross correlation functions (NCF). And they could in return map the resulted NCF into the noise source distributions and velocity structures. The L2 norm of cross-correlating waveform misfits was taken as the objective function to conduct gradient based inversion (i.e. the L-BFGS algorithm). We parametrized the noise source distributions as a temporally ensemble averaged model, which was discretized as a spatially plane grid of normalized source strength. The surface wave velocity model was approximated as the straight-ray interstation velocity. The two kinds of variants were decoupled in waveform misfit function by their corresponding partial derivatives to iteratively update the model space.

 

The effectiveness of source-velocity joint imaging using above full waveform inversion work flow was qualified by both the synthetic test and the applied research in Hangzhou urban area. The inverted noise source model was comparable with the urban traffic- and construction- noise distributions. And the truthful surface wave velocities were achieved considering the constraint of noise source distributions, they were also prior constrained and later verified by local borehole datasets.
Detecting the Drought-Response Difference in Semiarid Ecosystems on the Mongolian Plateau: 10-Year Observation Using GOSAT SIF and MODIS PRI
Authors: Kiyono Tomoki , Noda Hibiki , Kumagai Tomo’omi , Oshio Haruki , Yoshida Yukio , Matsunaga Tsuneo , Hikosaka Kouki
Published: March 2021

Atmospheric aridity and soil drought control vegetation water use and affect the terrestrial water and carbon cycles. Separating these two types of drought is difficult but crucial because they relate to different ecosystem properties and their impacts depend on vegetation types. We examine how well satellite-observed solar-induced chlorophyll fluorescence (SIF) captures the drought responses of taiga and steppe in semiarid areas on the Mongolian plateau, which have experienced a historic drought since the late 1990s. Ten-year records of the GOSAT SIF and the MODIS-band-1 photochemical reflectance index (PRI, also known as chlorophyll/carotenoid index) from Aqua consistently suggest that the taiga is sensitive to vapor-pressure deficit but insensitive to surface-soil drought, and that the opposite is the case for the steppe. The MODIS PRI changes reasonably with temperature and drought stress, and also with canopy shades, which is attributable to the xanthophyll cycle. However the most influential factor on the PRI is leaf area in both vegetations, and temperature is the second in the taiga, indicating the dominant effect of its pigment-pool size. The leaf area index of the taiga has almost similar values and seasonal patterns in each year, while the SIF shows remarkable interannual changes. The SIF yield in the taiga decreases 36–48% on average with the increase of vapor-pressure deficit from 1 kPa to 3 kPa under high-PRI conditions. Almost all detectable information from the SIF yield in the steppe is correlated with PRI on a monthly basis. The SIF in the steppe decreases nonlinearly when the surface-soil-water content fell below ∼0.154 m3 m−3, which agrees well with an eddy-covariance result in this region and implies the capability of satellite-based wilting-point estimation. We will further clarify which biological factors affected the observed results of SIF and PRI using the process-based model 'Soil-Canopy-Observation of Photosynthesis and Energy fluxes' (SCOPE) and show the impact of drought on the gross primary production in the past decade.
The Last Interglacial in the Labrador Sea: a sedimentary ancient DNA investigation 
Authors: Grant Danielle , Steinsland Kristine , Mugu Sigrid , Sandnes Skaar Katrine , Ijaz Umer Z. , Ninneman Ulysses , Louise Ray Jessica , De Schepper Stijn
Published: March 2021

The Last Interglacial (LIG, ~128–116ka) was characterized by a warmer climate, increased sea level, and a reduced Greenland ice sheet compared to today. Climate projections suggest our future climate may resemble LIG conditions if anthropogenic climate change progresses unabated. Previous studies have identified key shifts in the Labrador Sea oceanography and climate before, during, and after the LIG, making this time interval an exciting target for exploring high-latitude marine ecological dynamics. In recent years, the application of sedimentary ancient DNA (sedaDNA) has provided new glimpses into past ocean and climate conditions. Here, we have explored sedaDNA alongside other, traditional, paleoceanography proxies, to better understand the changing Labrador Sea biome across climate transitions and in a globally warmer world. We have generated a sedaDNA record from a giant piston core at the Eirik Drift (Labrador Sea). Our sedaDNA record, dating back to ~135 ka, was sampled at 4 cm depth intervals and covers the glacial-interglacial transition, as well as the LIG. SedaDNA was purified using a commercial spin column kit and analysed using a metabarcoding approach targeting the V7 hypervariable region of the eukaryote small subunit RNA. Illumina MiSeq analysis of metabarcoding libraries revealed PCR-amplifiable eukaryotic DNA throughout the investigated downcore section. Shifts in relative taxon abundance and alpha- and beta-diversity metrics paralleled shifts in foraminifer isotope records (δ18Ο), palynological assemblages, and biomarkers suggesting that the molecular genetic signal preserved in downcore sediments shows promise for identifying ecological shifts across the LIG. We are currently investigating the potential utility of specific taxa identified in the sedaDNA record to act as indicators of the glacial-interglacial transition. This study strengthens the growing potential of marine sedaDNA as a supplemental proxy for climate reconstructions in the Late Quaternary.
New methodologies of GPR Assessment for analysing water content in sedimentary deposits; Application to the Hospital Sant Pau Urban Area in Barcelona, Spain
Authors: Rasol Mezgeen , Perez-Gracia Vega , Santos Sonia
Published: March 2021

Ground Penetrating Radar was used in this study as a non-destructive geophysical method. The main objective of this research is focused on enhancing the local seismic soil site analysis. The study employs GPR images to determine changes in the ground that can be associated with changes on the seismic soil response. To determine the GPR capacity in detecting changes in the ground materials and improve new methodologies of the radar data processing.

Results could be used to improve the selection of areas for more intensive scrutiny, enhancing the analysis of local seismic behaviour studies. Soil site studies are crucial in the analysis of seismic hazard in populated areas. This study and analysis will be carried out in an urban environment at the Sant Pau Hospital in Barcelona city (Spain). Data were acquired in the field along with two different directions: parallel and perpendicular to the coastline of the Mediterranean Sea in Barcelona city.

The procedure is based in integrated data from the laboratory experiments by using 1600 MHz centre frequency and obtaining real GPR field images in the field by using 25 MHz centre frequency antenna in the Sant Pau Hospital. Therefore, radar data will be first processed using the commercial software ReflexW, followed by a more specific processing sequence (both in amplitude and frequency domains) with a specific algorithm developed with MATLAB.

Finally, the mathematical processing of the radargrams in terms of water content compared to the information based on historical maps. Results show that GPR is a promising method and compared to previous studies a good agreement was observed in this specific case study. 
U-depleted versus U-enriched signatures in complementary crust-mantle sources of volcanic rocks from Asia
Authors: Rasskazov Sergei , Chuvashova Irina , Yasnygina Tatiana , Saranina Elena
Published: March 2021

The Nb/U~47 and Th/U~4 ratios are considered as indicative for the OIB source referred by some authors to lower mantle plumes that in fact have no specific geochemical signatures but HIMU component. The Th/U ratio may vary because of the different garnet–melt and/or clinopyroxene–melt partition coefficients of U and Th. Anomalously high or low Th/U values in rocks can also be related to the input or removal of U, the migration of which is controlled by its mobility under oxidizing conditions owing to the formation of water-soluble uranyl  compounds with hexavalent U. These variations definitely distinguish non-plume magmatic sources. The Th/U ratio decreases to 2.5 in the MORB source and increases to 6 in the continental lower crust one. We describe anomalous behavior of uranium in sources of Cenozoic basalts and basaltic andesites from Primorye, Lesser Khingan, Tunka Valley, as well as similar Cretaceous-Paleogene rocks from Tien Shan. Significant deviations of the Th/U and Nb/U ratios from the OIB values are characteristics mostly of garnet-free sources. The U-depleted and U-enriched signatures are used as sensitive indicators for deciphering crust–mantle transitional processes.

This work is supported by the RSF grant 18-77-10027.
Strong equatorial plasma bubble associated with prominent TEC enhancement observed at mid-latitude ionosphere under the quiescent condition
Authors: Huang Fuqing , Lei Jiuhou , Xiong Chao
Published: March 2021

Equatorial plasma bubbles (EPBs) are typically ionospheric irregularities that frequently occur at the low latitudes and equatorial regions, which can significantly affect the propagation of radio waves. In this study, we reported a unique strong EPB that happened at middle latitudes over the Asian sector during the quiescent period. The multiple observations including total electron content (TEC) from Beidou geostationary satellites and GPS, ionosondes, in-situ electron density from SWARM and meteor radar are used to explore the characteristic and mechanism of the observed EPB. The unique strong EPB was associated with great nighttime TEC/electron density enhancement at the middle latitudes, which moves toward eastward. The potential physical processes of the observed EPB are also discussed.
Solutal Convection in Layered Sorbing Porous Media
Authors: Kolchanova Ekaterina , Kolchanov Nikolay
Published: March 2021

We study convective instability in the vertically layered porous media saturated with mixture. The mixture consists of a carrier fluid and solid nanoparticles. The nanoparticles are considered as solute within the continuous approach. The porous media are two horizontal sublayers with different permeabilities. The solute concentration is maximal near the upper boundary and is zero near the lower boundary of the superposed sublayers. Thus, one has suitable conditions for the onset of solutal convection in the gravitational field.

The porous sublayers are reactive media, which can absorb nanoparticles. The mixture transport here is accompanied by immobilization. It is described by the mobile/immobile media model. The mobile phase is carried by fluid flow, while the immobile phase is absorbed by porous matrix. The linear kinetic equation for the mixture redistribution between the phases is applied. The Boussinesq approximation is used in the equations for convection in each of the sublayers. Numerical simulation is performed by the shooting method.

We apply a linear stability theory to find the threshold Rayleigh-Darcy number for the onset of solutal convection. This similarity criterion is determined through the average permeability and porosity of uncontaminated porous sublayers. For the first time, we introduce a solutal pore shrinkage coefficient, which is analogous to the thermal expansion coefficient for thermal natural convection. This coefficient shows that porosity decreases as the concentration of immobile phase grows in the presence of sorption. Particles in this case join the surface of pores and shrink the void space.

Firstly, we find the permeability ratios for bimodal marginal stability curves in the uncontaminated sublayers. Here, the sublayer permeabilities differ by approximately 100 times. The bimodal curves demonstrate the competition between two convective instabilities. One of them is for the local convective rolls that generate within the more permeable layer and the other is for the large-scale rolls penetrating both layers. The rolls are similar to thermal natural convection in the multi-layered porous media studied by McKibbin and O'Sullivan (1980). For sorbing porous media, the type of convective rolls strongly depends on the solutal pore shrinkage coefficient. Even a small change in its value can produce a large variation of flow streamlines from the convective rolls localized within the upper highly permeable sublayer to the rolls covering both the upper and lower sublayers. The observed sorption effect on the transition from local to large-scale convection is due to the fact that the permeability ratio depends on the solutal pore shrinkage coefficient. It is also found that sorption effect delays the onset of solutal convection.

The work was supported by the Russian Science Foundation (Grant No. 20-11-20125).
GRQA: Global River Water Quality Archive
Authors: Virro Holger , Amatulli Giuseppe , Kmoch Alexander , Shen Longzhu , Uuemaa Evelyn
Published: March 2021

Recent advances in implementing machine learning (ML) methods in hydrology have given rise to a new, data-driven approach to hydrological modeling. Comparison of physically based and ML approaches has shown that ML methods can achieve a similar accuracy to the physically based ones and outperform them when describing nonlinear relationships. Global ML models have been already successfully applied for modeling hydrological phenomena such as discharge.

However, a major problem related to large-scale  water quality modeling has been the lack of available observation data with a good spatiotemporal coverage. This has affected the reproducibility of previous studies and the potential improvement of existing models. In addition to the observation data itself, insufficient or poor quality metadata has also discouraged researchers to integrate the already available datasets. Therefore, improving both, the availability, and quality of open water quality data would increase the potential to implement predictive modeling on a global scale.

We aim to address the aforementioned issues by presenting the new Global River Water Quality Archive (GRQA) by integrating data from five existing global and regional sources:

Canadian Environmental Sustainability Indicators program (CESI)

Global Freshwater Quality Database (GEMStat)

GLObal RIver Chemistry database (GLORICH)

European Environment Agency (Waterbase)

USGS Water Quality Portal (WQP)

The resulting dataset contains a total of over 14 million observations for 41 different forms of some of the most important water quality parameters, focusing on nutrients, carbon, oxygen and sediments. Supplementary metadata and statistics are provided with the observation time series to improve the usability of the dataset. We report on developing a harmonized schema and reproducible workflow that can be adapted to integrate and harmonize further data sources. We conclude our study with a call for action to extend this dataset and hope that the provided reproducible method of data integration and metadata provenance shall lead as an example.
Deformation fabrics of phyllite in Gunsan, South Korea and implications for seismic anisotropy in continental crust
Authors: Han Seokyoung , Jung Haemyeong
Published: March 2021

Muscovite is a major constituent mineral in the continental crust that exhibits very strong seismic anisotropy. Muscovite alignment in rocks can significantly affect the magnitude and symmetry of seismic anisotropy. Thus, it is necessary to analyze natural mica-rich rocks to investigate the origin of seismic anisotropy observed in the crust. In this study, deformation microstructures of muscovite-quartz phyllites from the Geumseongri Formation in Gunsan, South Korea were studied using the electron backscattered diffraction technique to investigate the relationship between muscovite and chlorite fabrics in strongly deformed rocks and the seismic anisotropy observed in the continental crust. The [001] axes of muscovite and chlorite were strongly aligned subnormal to the foliation, while the [100] and [010] axes were aligned subparallel to the foliation. The distribution of quartz c-axes indicates activation of the basal, rhomb and prism slip systems. For albite, most samples showed (001) or (010) poles aligned subnormal to the foliation. The calculated seismic anisotropies based on the lattice preferred orientation and modal compositions were in the range of 9.0–21.7% for the P-wave anisotropy and 9.6–24.2% for the maximum S-wave anisotropy. Our results indicate that the modal composition and alignment of muscovite and chlorite significantly affect the magnitude and symmetry of seismic anisotropy. It was found that the coexistence of muscovite and chlorite contributes to seismic anisotropy constructively when their [001] axes are aligned in the same direction.
Space and Time Characteristics of Droughts in Kabul River Basin.
Authors: Tariq Nadeem , Rahim Akif , Aziz Farhan , Yousaf Muhammad
Published: March 2021

Drought is a complex and less understandable natural phenomenon. Historical characteristics of droughts helps to understand the dynamics of the regional drought patterns. Numerous studies have predicted that the Chitral-Kabul River Basin (CKRB) is prone poses to serious threat due to global warming. This may endanger 10 million in habitants. The aim of this study is to revisit the characteristics of droughts in Kabul watershed, shared by Pakistan and Afghanistan. The monthly Standardized Precipitation-Evapotranspiration Index (SPEI) grided data (0.5o 0.5o) generated by climate research unit (CRU)version 4 has been used for study during the period 1901–2018. The four characteristics features i.e.  Areal extend, Frequency, Duration and Severity has been studied on spatial and temporal scale. The results show that the Kabul Basin has experienced an increasing extent of severe drought between 1940 and 1960, which increased further after the year 2000. The frequency of drought events in the northern part of the basin is much higher than in the southern part of the basin. Whereas the duration of the drought shows a declining trend in the northern part of the basin. The southern and western parts of the basin experienced a growing trend in the severity drought. At the same time, the incidence of consecutive droughts in the Kabul River basin has also increased. This study suggests that dry conditions in Kabul river basin have been enhanced in recent years. Overall, this study confirms the importance of SPEI for assessing the effects of regional drought.

Keywords: Drought analysis, Frequency, Severity, Duration, Kabul river basin
Understanding the Soil Temperature Variability at Different Depths: Effects of Surface Air Temperature, Snow Cover, and the Soil Memory
Authors: Zhang Haoxin , Yuan Naiming , Ma Zhuguo , Huang Yu
Published: March 2021

The soil temperature (ST) is closely related to the surface air temperature (AT), but their coupling may be affected by other factors. In this study, by using linear analysis and nonlinear causality analysis—convergent cross mapping (CCM) and its time-lagged version (time-lagged CCM), significant effects of the AT on the underlying ST were found, and the time taken to propagate downward to 320 cm can be up to 10 months. Besides the AT, the ST is also affected by memory effects—namely, its prior thermal conditions. At deeper depth (i.e., 320 cm), the effects of the AT from a particular season may be exceeded by the soil memory effects from the last season. At shallower layers (i.e., < 80 cm), the effects of the AT may be blocked by the snow cover, resulting in a poorly synchronous correlation between the AT and the ST. In northeastern China, this snow cover blockage mainly occurs in winter and then vanishes in the subsequent spring. Due to the thermal insulation effect of the snow cover, the winter ST at layers above 80 cm in northeastern China were found to continue to increase even during the recent global warming hiatus period. These findings may be instructive for better understanding ST variations, as well as land−atmosphere interactions.