bluuebunny/crossref_metadata_2025 huggingface dataset:
Interactive effect of biochar rates and elevated temperature on organic matter cycling, nutrient availability and extracellular enzyme activity in a silt loam Aridisol
Authors: Shahzad Tanvir , Mir Rummana , Ahmad Afzal
Published: February 2023

Biochar has largely been proven to be an effective soil carbon storage option. However, the research on effect of climate warming on interaction of biochar with soil organic matter (SOM) cycling is inadequate. We designed this study where a biochar-amended silt-loam Aridisol was incubated at 20 °C (normal temperature) or 30 °C (elevated temperature) for 73 days and various SOM cycling processes were measured. Biochar was derived by pyrolysing sugarcane bagasse at 450 °C for two hours. It was added to soil at 1% (low dose) or 5% (high dose) on weight basis. Biochar increased soil respiration by 12.4% and 21.2% at low and high dose respectivley. Elevated temperature induced 4.7% increase in respiration in the un-amended soil. While 1%BC and elevated temperature did not show any effect, 5% BC at elevated temperature further increased soil respiration by 19%. Biochar at 1% and 5% addition significantly increased microbial biomass by 109.3% and 91.3% respectively. However, elevated temperature significantly mitigated this BC-induced increase in microbial biomass. Similar to soil respiration, BC addition significantly increased activity of C-cycling β-glucosidase. However, unlike respiration, elevated temperature significantly reduced β-glucosidase at both rates of BC addition. This result combined with those of microbial biomass and soil respiration indicate that the elevated temperature shifted microbial biomass more towards maintenance mode thereby leading to mitigated microbial growth and increased soil respiration at 5% BC addition. Chitinase activity was reduced by >50% in response to BC addition, while elevated temperature reduced it by 80% in un-amended soil. Elevated temperature further reduced chitinase activity when BC addition was 1%, whereas, elevated temperature did not change it when BC addition was 5%. Activity of another N-cycling enzyme, leucine aminopeptidase did not change in response to BC or elevated temperature or their combination. On the other hand, nitrate content increased with biochar addition. Moreover, increase in temperature alongside BC addition increased ammonium content while decreasing the nitrate content. These results show that increase in temperature in BC amended soils complicates the dynamics of N availability and N-cycling enzyme in soil. Principal component analysis showed that the microbial biomass is positively linked with biochar addition, only at room temperature whereas microbial biomass is negatively affected by elevated temperature even when BC is added. Moreover, chitinase activity was inversely related to nitrate content in soils, with no clear relationship with ammonium. Overall, the treatments arranged on two opposite axes with respect to temperature while rate of biochar addition had little influence signifying that the effects of biochar are overwhelmingly modulated by elevated temperature.
Finding regions of similar sea level variability with the help of a Gaussian Mixture Model
Authors: Poropat Lea , Heuzé Céline , Reese Heather
Published: February 2023

In climate research we often want to focus on a specific region and the most prominent processes affecting it, but how exactly do we select the borders of that region? We also often need to use long-term in situ observations to represent a larger area, but which area exactly are they representative for? In ocean sciences we usually consider basins as separate regions or even simpler, just select a rectangle of the ocean, but that does not always correspond to the real, physically relevant borders. As alternative, we use an unsupervised classification model, Gaussian Mixture Model (GMM), to separate the northwestern European seas into regions based on the sea level variability observed by altimetry satellites.After performing a principal component (PC) analysis on the 24 years of monthly sea level data, we use the stacked PC maps as input for the GMM. We used the Bayesian Information Criterion to determine into how many regions our area should be split because GMM requires the number of classes to be selected a priori. Depending on the number of PCs used, the optimal number of classes was between 12 and 18, more PCs typically allowing the separation into more regions. Due to the complexity of the data and the dependence of the results on the starting randomly chosen weights, the classification can differ to a degree with every new run of the model, even if we use the exact same data and parameters. To tackle that, instead of using one model, we use an ensemble of models and then determine which class does each grid point belong to by soft voting, i.e., each of the models provides a probability that the point belongs to a particular class and the class with the maximal sum of probabilities wins. As a result, we obtain both the classification and the likelihood of the model belonging to that class.Despite not using the coordinates of the data points in the model at all, the obtained classes are clearly location dependent, with grid points belonging to the same class always being close to each other. While many classes are defined by bathymetry changes, e.g., the continental shelf break and slope, sometimes other factors come into play, such as for the split of the Norwegian coast into two classes or for the division in the Barents Sea, which is probably based on the circulation. The North Sea is also split into three distinct regions, possibly based on sea level changes caused by dominant wind patterns.This method can be applied to almost any atmospheric or oceanic variable and used for larger or smaller areas. It is quick and practical, allowing us to delimit the area based on the information we cannot always clearly see from the data, which can facilitate better selection of the regions that need further research.
Monitoring subsidence around the Raniganj coalfield by integrated GPS and PSInSAR approaches
Authors: Ghosh Debjyoti , Kumar Ashvini , Kannaujiya Suresh , Roy Paresh Nath Singha
Published: February 2023

The Raniganj coalfield of West Bengal, India, has been producing non-coking coal of exceptional quality for 246 years, making it the oldest coal mine in India. In this coal mining region, the "room and pillar" mining method is employed to dig coal, resulting in local subsidence that comprises a number of huge subsidence ponds and minor area collapses. Subsidence significantly impacts the environment, resulting in a cataclysmic disaster that destroys public infrastructure and even causes death. The majority of land subsidence is produced by forces that apply pressure on the surface, such as groundwater extraction, mining, excessive development, and similar reasons. A very precise Differential Global Positioning System (DGPS), which is an enhanced GNSS, is used to monitor the movement of the ground. There are nine rover stations and three base stations, which are reoccupied at an interval of months and installed for hours. Since 2019, the DGPS has been used for this purpose. In addition, Synthetic Aperture Radar (SAR) images have been employed to provide a bird's-eye perspective, thereby employing the PS-InSAR method. PS-InSAR (Persistent Scatterer Interferometry) has shown its ability to detect ground subsidence in vegetated and rural areas. In addition, it resolves persistent scatterers with low spatial density by recognising and collecting data from partially correlated scatterers, or PSs. We observed subsidence in the study area from 2017 to 2022, omitting the monsoon months (June to September), using publicly available Sentinel-1 data from the ESA (European Space Agency). Consequently, we discovered that the LOS velocity varies between -7.4 and +5.3 mm/year, as reported by ascending datasets, and between -8.7 and +6.1 mm/year, as reported by descending datasets. Along with a scope of comparative study of the results obtained from DGPS and PS-InSAR, the rate of subsidence in the old underground mining region reveals that some densely populated areas are at risk.
Artificial chemical weathering of basaltic rock under the earth surface conditions of the present and the Proterozoic era
Authors: Kobayashi Shoichi , Takahashi Yukiko , Naohara Jun
Published: February 2023

In order to compare the mineral chemical effects of acid rain on surface materials under the present oxygen level and the early Proterozoic or late Archean low oxygen (before the GOE) environmental conditions, artificial chemical weathering experiments using an improved Soxhlet extraction apparatus were conducted for basalt, which had already been covered on the early earth’s surface. Some dozens of polished basalt plates put in the extraction chamber were reacted to HCI, H2S04 and HN03 solutions at pH 4, and CO2 saturated water, and distilled water at 50℃ for a different period of time up to 950 days in an open system. In the experiment under the low oxygen condition (5×10⁻⁴ PAL), the whole extraction apparatus was placed in the acrylic glove box, and oxygen was removed by the deoxidizer, and it was carried out in the nitrogen gas flow. The basalt was composed mainly of olivine as a phenocryst, and plagioclase, clinopyroxene, ilmenite and glass as a groundmass. The extracted sample solutions were collected, and analyzed using ICP-MS. Morphological, chemistry and altered product of each mineral surface were studied by SEM, EPMA, XRD and microscopy techniques.Under both the low oxygen before the GOE and the present oxygen concentration conditions, SEM images showed remarkable dissolution of olivine surface by the H2SO4, HNO3 and HCl solutions. The (Mg + Fe)/Si on the olivine surface and (Na + Ca + K)/ (Al + Si) on the plagioclase surface decreased significantly with increasing experimental period. In chemistry of the extracted solutions, molar ratios of many elements such as Mg, K and Zn tend to be high in the three acidic solutions at pH 4, and low by the CO2 saturated water and distilled water. The molar ratio is calculated by dividing the cumulative total mole of each extracted element by the mole of individual element in the unaltered basaltic rock. The ratios of Fe, Mg, Ni, Zn and Co near 70 pm in ionic radius are high, and reflect the dissolution from the octahedral coordination of olivine. The ratios of Ca, Na, Sm, Ce, La and Sr near 110 pm are high, and reflect the dissolution from the cavities within the framework of plagioclase. Under the low oxygen condition, major elements such as Fe and Mn, and minor ones such as Zn tend to dissolve easily in all extraction solutions. Ce and Eu in REE, and Nb, Ti, Y and Zr in HFS elements are soluble in pH 4 HCl and H2SO4, CO2 saturated water and distilled water under the low oxygen condition. The results suggest that easily extracted elements under the low-oxygen condition of the early Proterozoic or late Archean influenced the evolution of continental crust, land and ocean, and may have contributed to the formation of the early Earth's surface environment.
A theoretical review of the air-ground coupling of 1D elastic media
Authors: Xu Zongbo , Lognonné Philippe
Published: February 2023

The air-ground coupling is the conversion of the atmospheric pressure perturbation to the ground motion. This coupling includes the pressure static loading and the acoustic-to-seismic conversion. Studying this coupling can aid investigating the shallow subsurface using the pressure drops and monitoring explosive sources in the atmosphere (like meteorites). However, the theory link of the possible coupling scenarios is missing for 1D elastic media. We demonstrate that by utilizing the compliance, the ratio between the ground motion and the atmospheric pressure perturbation on the ground surface, we can analytically model the coupling scenarios: the static loading, the air-coupled Rayleigh wave, leaky mode, and the acoustic-to-body-wave conversion.
Different approaches to model temporary hydrological regimes in a Mediterranean karst basin using the SWAT model.
Authors: Centanni Marco , Ricci Giovanni Francesco , De Girolamo Anna Maria , Gentile Francesco
Published: February 2023

In the Mediterranean Region basins are characterized by a specific hydrological regime that generally includes periods of absence of flow and flash flood events. Lithological and geological features are factors that greatly affect the flow regime. In this work, the Soil and Water Assessment Tool (SWAT) model was applied to simulate the Canale d'Aiedda (Apulia, Italy) flow regime, a Mediterranean temporary karst river basin with limited data availability. Different basin delineations and model parameterizations were adopted that include: (i) cut-off of karst areas in GIS (Configuration A); (ii) setting up the basin including the karst areas (Configuration B) and (iii) parameterizing, in the calibration process, the Crack Flow function in the karst sub-basins (Configuration C). The model performed satisfactorily for daily streamflow for configurations B and C and good for A. A better simulated large floods. C was the best solution for monthly flow from May to July. Regarding the water balance, C showed higher surface runoff values and lower total water yield values than A and B. The Crack flow function proved to be a valid option to improve the simulation of hydrological processes in karst areas. Several factors, such as the final aim of the study, data availability, and basin characteristics should be considered in selecting the best model configuration.
Characterisation of Quaternary scarps in the Baix Ebre Basin (NE Spain) and analysis of their potential seismogenic origin
Authors: Ollé-López Marc , García-Mayordomo Julián , Masana Eulàlia
Published: February 2023

The Baix Ebre Basin (BEB), located in the NE of Spain, is a passive margin where different systems of normal faults exist, oriented NNE-SSW, oblique-to-parallel to the coast. Those intraplate faults are considered slow faults, with slip rates around 0,2 mm/yr. However, their active status has been proved by different studies during last years. Close to this area, the main fault in which paleoseismic studies have demonstrated a seismogenic behaviour is the El Camp Fault (ECF), located towards the NE of the BEB. It has been studied in detail due to its remarkably geomorphological expression and due to its proximity to the Vandellós nuclear power plant. Recently, thanks to higher resolution Digital Elevation Models (DEM) of the terrain, some morphological scarps affecting Quaternary alluvial fans have also been detected along the BEB, from Pla de Sant Jordi Basin (NE of the BEB) until La Sènia (SW of the BEB). Those scarps are oriented in the same direction as the ECF, suggesting a possibly tectonic origin related to the same stress field. In this case, they would have to be considered as the ECF propagation to the south, which could imply a big impact on the seismic hazard of the entire region. Nevertheless, other possible origins for these topographic scarps should be explored, as a possible paleo-coast line or some kind of karstic or gravitational processes. With this aim, it has been planned a detailed geomorphological analysis to identify and characterise all the possible scarps along the BEB and to locate the suitable places for field detailed studies and a geophysical survey. In this geophysical study, it is planned to use different techniques (GPR, electric tomography and magnetotellurics) in order to explore its combined use and to analyse the subsoil structure from shallow to depth. In case of demonstrating its tectonic origin, firstly, it is planned to carry out a paleoseismological study (to determine their seismological history) and, secondly, to analyse their contribution into the seismic hazard models of the region. In this work, we present the first preliminary results of our ongoing research.
Assessment of the impact of the forest fire pollutants on vegetation and crop health in Northeast India
Authors: Sankar Mira Shivani , Singh Alka , Subbanna Nagesh K , Maretto Raian V
Published: February 2023

Wildfires are increasing tremendously in Northeast India mostly due to anthropogenic intervention. Indian states are prone to high-intensity fire events resulting in long-term impact on the forest ecosystem such as changes in the vegetation pattern and life cycle of species, decrease in certain species population, and quality of vegetation. Also, forest fires are known to influence the air pollution rate, and the pollutants generated through forest fire are way more complex when compared with urban air pollutants as the composition of forest fire pollutants (FFP) depend on the type of vegetation in the region. Additionally, volatile organic compounds (VOC’s), soot, ozone and black carbon which are few of the products from forest fire has the ability to travel far away from the source fire affecting different ecosystem at various ways and intensity.As FFP can cause a decline in local, regional and global terrestrial productivity, a deep learning model will be useful in understanding and assessing the impact on vegetation health. Consequently, it is necessary to model the effects of the forest fires, so that their effects in both nearby and far off areas is understood.  In order to accomplish this, we employ Bi-directional Long Short-Term Memory (BiLSTM). The advantages of using a LSTM model are its ability to learn from Spatio-temporal series of data, avoid vanishing and exploding gradient problem, while being tractable to train. The inputs consist of concentrations of, aerosol, carbon monoxide, ozone, black carbon density, evapotranspiration, leaf area index, soil moisture, temperature and relative humidity obtained from MERRA – 2, MODIS and Sentinel – 5P satellite datasets accessed using google earth engine portal. Utilizing these datasets, the normalized vegetation index can be predicted. Standard techniques (mean squared error, root mean squared error, mean absolute error and mean absolute percentage error) are employed to determine the performance of the algorithm.Keywords: forest fire, pollutants, BiLSTM, google earth engine, deep learning
Water level fluctuation induced variation of sulfamethazine biogeochemical behavior and expression of resistance genes in the hyporheic zone: A case study of Chaobai river, China
Authors: Zhu Siyu , Zhang Linus , Niu Jianzhi , Ma Weifang
Published: February 2023

It is well known that the intensive biogeochemical activity in hyporheic zone of groundwater and antibiotic contaminated river water induced the pollution diffusion and variation of biogeochemical transformation. However, the complex interaction process caused by water level fluctuation is difficult to accurately depict on a larger, catchment scale. Therefore, a loosely coupled HYDRUS-3D/GMS was established in Chaobai river basin to simulate the sulfamethazine (SMZ) pollution interaction process caused by river and groundwater level fluctuation. The upward fluctuation of river water level increased the migration of SMZ from surface water to the hyporheic zone soil and groundwater with the rate of 3.04 m/(y·m), which accelerated the pollution diffusion. Moreover, the rise of river water level reduced DO and ORP in hyporheic zone, which induced the biochemical transformation of SMZ from aerobic to anoxic and anaerobic, thus reduced 25% decomposition rate and increasing 7 times expression of resistance genes. The expression of ARGs sul1, sul2, sul3 were positively correlated with the SMZ concentration with coefficient of 0.9954, 0.9856, 0.9689. The biogeochemical behavior of SMZ was completely opposite when the river water level fell back in the dry season compared with that of water level rising, which contributed to the decomposition of accumulative antibiotics in the hyporheic zone. However, the upward fluctuation of groundwater table led to the secondary release of 20% SMZ accumulated in hyporheic zone soil and the reverse interaction of river water pollution, which induced increase in the abundance of resistant bacteria, thereby enhancing the expression intensity of ARGs. In addition, the accumulation and diffusion of SMZ were also closely related to soil physicochemical properties (P<0.01 to BET; P<0.001 to TOC) and microbial community structure during the interaction between groundwater and surface water in hyporheic zone. The accumulation of SMZ increased the ecological risk and induced the variation of microbial community structure and relative abundance. The enrichment of these antibiotic degrading genera, Hyphomicrobium, Thermomonas and Comamondaceae, improve the degradation of antibiotics and enhanced the expression of resistance genes sul1 and sul2, which increased the risk of drug resistance of superbacteria. This study provided a new approach to predict the variation of SMZ biogeochemical behavior and expression of resistance genes in the hyporheic zone due to water level fluctuation, which can effectively improve removal technologies and the drinking safety of groundwater.
Regularization Approach to Tidal Analysis
Authors: Ciesielski Adam , Forbriger Thomas , Zürn Walter , Rietbrock Andreas
Published: February 2023

Since the times of Doodson it has been established that a record of length T is required to resolve tidal harmonics with a frequency separation 1/T. This rule, known as Rayleigh criterion, does not consider the actual resolution provided by the signal-to-noise ratio of the data. Available tidal analysis software, like Eterna, seek gravimetric parameters for a priori defined groups (sums) of harmonics that are assumed otherwise indistinguishable. The residual between the predicted tidal signal for groups and the recording is minimized with simple least squares (LS) fit.We developed the new software, RATA, that abandons the concept of groups, so each tidal harmonic present in the catalogue receives its set of tidal parameters that are free to vary. The resulting ill-conditioned matrix is stabilized by Tikhonov regularization (ridge regression) in the LS objective function. To validate the results, we used the moving window analysis (MWA) technique for a priori groups, with the resulting local response model as the a priori model. Compared to the standard approach, which used the Wahr-Dehant-Zschau elastic analysis model, we clearly see that bias and beating patterns are significantly smaller or almost vanish. Hence, the local response model can capture the apparent temporal variations by appropriate tidal parameters within the MWA groups.While the most information in each group is carried by the tidal wave with the largest amplitude, influence of other harmonics must be properly considered in estimated amplitudes and phases. Therefore, if amplification factor or phase from any other large amplitude harmonic in the group is significantly different from the expectation, the grouping parametrization might lead to an inaccurate (biased) estimate of tidal parameters. The trade-off parameter between data residuals and the model difference to the reference model is chosen at the corner of the misfit curve, indicating expected level of noise in the data. The resulting model parameters indicate “data-driven” groups to be inferred from significant harmonics in the inversion. To demonstrate the method and how it may be used to reveal system properties hidden by wave grouping, we analyzed 11.5 years gravity recordings from the superconducting gravimeter SG056 at the BFO (Black Forest Observatory, Schiltach). As a result, we distinguished 61 significant groups of harmonics for the local tidal response model, with no clear evidence that more groups are resolvable. Some of them highly violate Rayleigh criterion.
Rainwater harvesting potential: the Turin case for an analysis at the urban scale
Authors: Carollo Matteo , Butera Ilaria , Revelli Roberto
Published: February 2023

The population growth and its concentration within cities, on the one hand lead to an increment of water demand and on the other hand affect the urban water cycle with frequent urban flood events associated to rain extreme events. New approaches to the water management are currently being developed where a role is assigned to rain water harvesting (RWH). RWH provides water for non-potable uses (private and public, indoor and outdoor), reducing water consumption. Moreover, RWH allows to partially retain water on site, reducing the probability of failures of the sewerage system during heavy rain events.These positive effects are easily evaluable at a building scale when well-known behavioral models are used, while the evaluation becomes often more complex at an urban scale, due to the lack of characteristics and demographic data about all the buildings in the city. In our work, we consider RWH impact at the urban scale, by means of the representative building concept.We focus on several hypothetical retrofitting scenarios for the residential buildings of Turin (Italy): 1) domestic use of rainwater (e.g., toilet flushing and the washing machine), where buildings are independent of each other, and 2) two public uses of rainwater (the irrigation of public green areas and street washing), for which we have hypothesized that the rainwater collection takes place at a district scale. We estimate a reduction of 42% in the non-potable water consumption for domestic use (values vary across the municipal districts from 29% to 62%, according to the characteristics of the buildings), while for irrigation and street washing, that require a lower amount of water, about 80% of the water can be provided by RWH. The highest reduction of the flow peak conveyed to the sewerage system during extreme storms is reached in the domestic use scenario (about 60%, quite constant across the city), while for public uses the retention capacity is very low.Finally, our estimations based on historical rainfall series are examined against different climate change scenarios. 
A stalagmite-based multiproxy reconstruction of local environmental changes in the 20th century from Normandy, France
Authors: Bejarano Arias Ingrid , Nehme Carole , Breitenbach Sebastian F.M. , Meyer Hanno , Modestou Sevasti , Pons-Branchu Edwige , Mouralis Damase
Published: February 2023

Speleothems are increasingly widely studied globally, but some regions remain poorly covered, including NW France. The cave-quarry of Caumont, located in Normandy develops in chalk limestone and contains speleothem formations from different time intervals. Chalk was extracted from this quarry for building stone since Roman times well into the 20th century. We collected several stalagmites from one of the excavated chambers with the aim to investigate their sensitivity to environmental signals. Of particular interest is stalagmite CCB-1 which was deposited over the last century and likely holds highly detailed climatic signals. We have tested whether stalagmite CCB-1 records hydrological or thermal seasonality, and if atmospheric circulation patterns can be reconstructed from this sample. To establish modern baselines we monitored temperature, drip rate, drip water isotopes, and collected modern carbonate precipitates between November 2019 and July 2021. The monitoring revealed that in-cave conditions are very stable all year round (Tcave air= 10.4 ±0.3°C; δ18Odrip and δDdrip change is ~0.1‰ and <0.8‰ respectively). Modern calcite samples fall mostly on the Coplen (2007) equilibrium regression line, suggesting that modern precipitation occurs near isotope equilibrium. From sample CCB-1 we obtained three U/Th dates, counted 114 growth laminae and analysed 750 samples for stable isotope composition. The age model was constrained with laminae counting, historical inscriptions, and grey value based annual growth counting measurements and provides an annually resolved record for the last 114 years (1905 to 2019). The δ18O and δ13C signals from CCB-1 were compared with surface climatic parameters including precipitation, temperature, and the standardised precipitation evapotranspiration index (SPEI) for the last century. While δ18O of carbonate is influenced by surface temperature and the original isotopic composition in precipitation, the δ13C signal is governed by effective moisture supply and prior carbonate precipitation. Our reconstruction analysis reveals a significant change in the isotope record after ca. 1960. This change is best seen when comparing the δ13C time series with the SPEI and might be related to increasingly drier local conditions. A trend to stronger local evapotranspiration in recent decades is most likely linked to an increasing lack of effective rainfall. 
Boreal Summer Intraseasonal oscillation convective initiations in S2S models
Authors: Simon Daniel , Joseph Mani Neena
Published: February 2023

Boreal summer Intraseasonal Oscillation (BSISO), with its 20–90 day periodicity characterised by northward propagation over the northern Indian Ocean and eastward propagation over the equatorial region, acts as a major source of predictability in the intraseasonal time scale. Predicting the initiation of BSISO over the equatorial Indian Ocean is of vital importance in the prediction of BSISO's northward advancement over the ISM domain. This study tries to investigate where we stand in terms of predicting the BSISO initiation and propagation, making use of the reforecasts available from the different operational forecasting centres part of the Sub-Seasonal-to-Seasonal (S2S) prediction project. The BSISO convective initiations over the Equatorial Indian Ocean are objectively identified using OLR MJO Index(OMI), and the ability of the models to simulate the initiation and propagation of BSISO is assessed. The BSISO propagation skill, quantified in 9 S2S models, ranges from 11 to 29 days, while the BSISO initiation skill, quantified in 4 out of 9 models, ranges from 11 to 16 days, which is systematically lower compared to the skill of the BSISO non-initiation stages. Two major regions of BSISO initiation were identified, one over the Western Equatorial Indian Ocean and another over the Eastern equatorial Indian Ocean. Over these identified initiation regions, observation show a buildup (reduction) of lower tropospheric moisture before (after) the BSISO initiation. Out of the 9 models considered, few capture either the buildup or reduction, while the majority of the models show biases in capturing the moisture buildup and reduction. Previous studies have emphasised the role of background moisture in the propagation of BSISO. The relationship between the background moisture gradient over the ISM domain and the BSISO propagation prediction skill is examined in the S2S models and a positive relationship is found.
The hunter-gatherers of Abra del Toro rock shelter, northwestern Argentina, suffered the effects of the large 4.2 ka Cerro Blanco eruption
Authors: Fernandez-Turiel Jose-Luis , Carbonelli Juan Pablo , Belotti López de Medina Carlos
Published: February 2023

There is a dearth of information regarding prehistoric foraging societies from the intermontane longitudinal valleys of the South-Central Andes. Due to the intense anthropization of the landscape or the scarce research efforts on prehistoric populations of hunter-gatherers in the intermontane valleys of the Andes, occupation sites have been found on very few occasions. However, new perspectives in the Abra del Toro rock shelter in the Yocavil Valley (Catamarca province, Argentina) have opened up from recent and ongoing excavations. This rock shelter is the first archaeological case in which it is possible to analyze the relationship between a large-scale natural catastrophe and the prehistoric populations living in the Andean intermontane valleys of the southern Central Andes. This rock shelter's stratigraphy and archaeological remains contain the record of interactions between human communities and volcanism. The stratigraphic record of the rock shelter shows a 1-m-thick volcanic ash deposit formed by aeolian transport from primary outer ashfall deposits. Geomorphological and sedimentological context, texture, glass and mineral content, whole-rock chemical composition, and radiocarbon dating prove that the tephra was derived from the 4.2 ka BP eruption of the Cerro Blanco Volcanic Complex in southern Puna (NW Argentina). This volcanic eruption is the largest documented in the world in the last five thousand years and covered the surroundings of the archaeological site with an ash layer of approximately 1 meter thick. The stratigraphic sequence of the Abra del Toro rock shelter allows us to hypothesize that there were three main occupational moments: two hunter-gatherer moments, separated by the record of the large volcanic eruption, and a subsequent agro-pottery period (Carbonelli et al. 2022. J. Archaeol. Sci. Rep. 45, 103629). The rock shelter after the eruption remained in the memory of the hunter-gatherer groups. Good visibility, accessibility, and proximity to water were attributes of this space that made it possible for it to be re-occupied after the eruptive event. Our next objective is to reconstruct, using proxy analysis, how the paleoenvironment was in the intermontane valleys before and after the eruption. The evidence of this Mid-Holocene catastrophic volcanic event in the Abra del Toro rock shelter opens the possibility of knowing its impact on the contemporary hunter-gatherer community and drawing conclusions for similar future volcanic crises.This work was supported by the National Scientific and Technical Research Council (Grant PIP 112-201301-00178), the University of Buenos Aires (Grant UBACyt 20020170100318BA) (University of Buenos Aires), the National Agency for the Promotion of Research, Technological Development and Innovation (Grant 2019-01229) and the QUECA Project (MINECO, Grant CGL2011-23307).
Simulating wet front evolution along a sinuous riverbank to understand impact of bank slope on hyporheic flow and transport
Authors: Li Yiming , Wen Zhang , Krause Stefan , Schneidewind Uwe
Published: February 2023

Hyporheic exchange flow (HEF) is one important driver determining the spatial and temporal evolution of the biochemical characteristics predominant in the hyporheic zone (HZ) of rivers. As such, better understanding of HEF patterns will allow us to improve our quantitative estimates of the biochemical reaction potential in the HZ and the wider river corridor. While HEF has been found to be impacted by riverbank morphology (including sinuosity and bank slope) past studies have specifically neglect the effect of bank slope in combination with river sinuosity. Here we simulate and assess the impact of bank slope on the spatial extent of the HZ of a meandering river and on the evolution of HEF and residence times (RT) into the alluvial aquifer under varying aquifer transmissivity conditions. We use a 2-D numerical finite element model set up in COMSOL and implement variations in lateral bank slope by using a deformed geometry method (DGM) to simulate the wet front evolution into the alluvial aquifer during a dynamic flood event. Different scenarios were run for varying combinations of bank slope angle and aquifer transmissivity.           Our results show that the impact of bank slope on HEF and wet front evolution was more pronounced in aquifers with lower transmissivity. Furthermore, the impact of bank slope can lead to both shorter and longer residence time of river water in the alluvial aquifer, depending on whether HEF is infiltrating a point bar or cut bank. Aquifers with high transmissivity were more impacted by bank slope during the flood event, whereas aquifers with lower transmissivity were less impacted by bank slope during the flood event but while this impact lasted much longer into the post-flood-event phase. Overall, our study shows that river sinuosity and bank slope should be considered when assessing HEF and RT in river corridors.
Discharge Estimation for Different Bed Slope Conditions Using Entropy-Based Concept: An Experimental Investigation
Authors: Singh Gurpinder , Khosa Rakesh
Published: February 2023

In hydraulic engineering, river discharge estimation is an important requirement for managing and planning the channel flow. Discharge measurements are of utmost importance for the purposes such as water availability analysis, reservoir operation, flood forecasting, designing of hydraulic structures, etc. In the discharge estimation process, the spatial velocity distribution in the transverse cross-section at the desired location of measurement is required. In traditional approaches such as Prandtl-Von Karman logarithmic law and power law, the velocity is employed deterministically, making its utility easier and providing accurate results for the wide channels only. In contrast, Shannon’s information entropy concept, which evaluates random variables probabilistically, is used in hydrology to determine entropy-based velocity distributions. In this approach, the velocity distributions obtained depends on a parameter called as entropy parameter, which is considered to be a fundamental measure of information about the channel characteristics such as channel bed slope and roughness. It provided better results for both the clear water and sediment-laden flow as compared to the former. In the present study, experiments for discharge estimation were performed on the experimental flume to collect the velocity data at different channel bed slope conditions to demonstrate the accuracy of the entropy-based concept. To prove the truthfulness of the entropy-based concept, the results were compared with the ones obtained from the classical method (velocity area method). Both the approaches have their respective advantages and limitations. Therefore, error analysis was necessary to check the efficiency and accuracy of the entropy-based model, which was performed by comparing the percentage error between the observed and computed discharge values. The final results revealed that the entropy model was a quick and accurate technique for discharge estimation as absolute percentage errors were less than 5% and the 95th percentile was 3%.
Shear wave velocity variation across the South Almora Thrust, Kumaon Himalaya using Joint Inversion of Horizontal-to-Vertical Spectral Ratio (HVSR) and Dispersion curve
Authors: Pandey Mohit , Joshi Anand , Sharma Saurabh , Singh Jyoti
Published: February 2023

The Horizontal-to-Vertical Spectral Ratio (HVSR) method and Multi-Channel Analysis of Surface Waves (MASW) method are commonly used as a joint fit technique to retrieve the 1-D shear wave velocity. The Kumaon Himalaya consists of major thrusts like MFT, MBT, SAT, NAT and MCT, from South to North) and other tectonic features. These geological structures are observed in the form of lineaments on the surface. In the present study, 2-D section of shallow shear wave velocity structure has been estimated along the transect crossing South Almora Thrust (SAT) in the Kumaon Himalaya to study the variation of shear wave velocity across the thrust. In the present work, the ambient noise survey and Multi-Channel Analysis of Surface Wave (MASW) survey has been conducted along the road profile crossing the South Almora Thrust (SAT) at equally spaced stations of 3 Km. The 1-D shear wave velocity has been used to prepare the 2-D section of shear wave velocity. The lineaments in this division have been identified by the variation in the two dimensional shear wave velocity section prepared from the so obtained 1-D shear wave velocity in this profile. The study shows that there is a good correlation between variation of shear wave velocity in the region and major tectonic features of the area. The geological sections in this area has been compared with the obtained 2D structure which give a fair amount of idea about dip of SAT in this area.
Assessing vulnerability and risk to livelihoods in river deltas socio-ecological systems: alignment of the GDRI with global frameworks’ indicators
Authors: Cremin Emilie , Banerjee Sumana , Murshed Sonia , O'Connor Jack , Hong Hua Hieu , Van Huynh Da , Vo Thanh Son , Thi Van Le Hue , Mashfiqus Salehin , Sebesvari Zita , Large Andy , Renaud Fabrice
Published: February 2023

Disasters have significant impacts on the progress towards achieving the Sustainable Development Goals (SDGs). However, the interlinkage between sustainable development and disaster risk reduction is not considered enough in risk assessment tools. A greater alignment with global frameworks would ease the monitoring while increasing the capacity to address data availability issues for indicator-based assessments.To bridge this gap, we use the Global Delta Risk Index (GDRI), which is composed of multiple components to assess risks to livelihoods: hazards, vulnerability, and exposure of social-ecological systems. The modular library of indicators of the GDRI has been further aligned with the Sustainable Development Goals (SDG) and the Sendai Framework for Disaster and Risk Reduction (SFDRR). To improve the accuracy of the risk assessment, the list of indicators has been weighted and scored through consultation with stakeholders.This research presents the initial results of a multi-hazard risk assessment that encompasses SDG and SFDRR indicators in three Asian river deltas: Ganges-Brahmaputra-Meghna, Mekong and Red River. This work aims at better informing risk management and supporting delta-level interventions to influence progress towards sustainability and resilience of river deltas.
A spatiotemporal indicator-based method to assess the drought and heat risks for urban green infrastructure
Authors: Shehayeb Raghid , Ortlepp Regine , Schanze Jochen
Published: February 2023

Given the significance of urban green infrastructure (UGI) and their ecosystem services (ES) towards urban climate resilience and sustainable development, a practical method to assess the drought and heat risks for UGI is needed for understanding the risks, selecting reduction alternatives and protecting the benefits of UGI. Hence, this study develops a spatiotemporal indicator-based method, based on a conceptual drought and heat risk assessment framework, which supports decision makers in analyzing and evaluating risks under changing conditions, and selecting risk-reduction alternatives. The UGI types of parks, creeks, and lakes are selected as representative UGI for this study for developing the assessment method. Subsequently, endpoints as variables of the biophysical risk system are derived considering the processes of drought and heat hazards, exposed UGI entities, ecosystem functions and ES. The biophysical endpoints such as biota, soil-water dynamics, and UGI’s cultural uses, are then translated into information with descriptors explaining their vulnerability aspects following a multi-layer approach and interpreted over three dimensions of provisioning, regulating, and cultural. The multi-layer approach states that the layers of descriptors are accompanied with layers of indicators as a mean to operationalize these characteristics. A two-stage literature review is applied to identify vulnerability indicators for the defined descriptors, whereas a lane-based approach is followed to interrelate these indicators based on their qualities we refer to as attributes. Using the attributes of the drought and heat hazards, the vulnerability indicators are linked with the hazards to derive risk indicators. By introducing these vulnerability and risk indicators, we pave the road for the analysis and evaluation of compound risks to support the decision makers in planning and managing UGI and protecting their ES under these risks. 
Spatiotemporal Variation in Low Frequency Earthquake Recurrence Along the San Andreas Fault
Authors: Allen Jessica , Wang Ting
Published: February 2023

    Episodic tremor sequences comprised of overlapping low frequency earthquakes (LFEs) occur frequently along the San Andreas Fault. Accompanying slow slip activity has been detected from Global Navigation Satellite System (GNSS) data, confirming occurrence of the episodic tremor and slip (ETS) phenomenon here.            The characteristics of slow slip events (SSEs) impede comprehensive detection, making it challenging to study their occurrence patterns. We utilise extensive LFE data from a long running high resolution seismic network to gain insights into this more frequent and easily detectable aspect of the ETS process, with the aim to have a detailed understanding of the occurrence patterns and properties of LFEs. This will strengthen methods for the detection and modelling of SSEs.        Hidden Markov models were used to study the occurrence patterns of LFE events. Based on these models, LFE events along the San Andreas Fault can be classified into different states. Each state is a proxy for changes in the generating mechanisms that give rise to LFE events, with potential contributors including pore pressure and fault stress. We use the classification to illustrate a detailed picture of temporal changes in LFE activity - including the effects of events such as the 2004 Parkfield earthquake, and to highlight the diverse behaviours displayed across generating locations.     The evolution of LFE activity over space and time gives additional insights into how slow slip may propagate. We use clustering methods to reveal patterns in the migration of activity between spatially distinct generating locations, and identify locations with similar characteristics that are likely influenced by the same generating circumstances.              
Simulation of water-induced seismic waveforms in glaciers through hydrodynamic modelling
Authors: Magyar Jared , Reading Anya M. , Turner Ross J. , Cook Sue
Published: February 2023

This work aims to contribute to progress in the detection of hidden or transient hydrological events. Passive seismic methods offer high temporal resolution and the ability to monitor seismic sources hidden from direct view, making it an ideal candidate to complement other in-situ and satellite methods in these cases. The dynamics of a glacier can be greatly affected by its hydrological system, whether this be through water mediated ice fracturing, or the influence the water has on friction at the ice-bed interface. Effective detection of moving meltwater is therefore of great interest for anticipating future glacier changes and sensitivities.To effectively infer any hidden process from the observed seismic waveforms, we require a physically rigorous modelling framework. Our work therefore combines hydrodynamic models depicting meltwater flow with seismic wave propagation methods to produce synthetic seismograms. The hydrodynamic model of choice is smoothed particle hydrodynamics (SPH). This is a full, three-dimensional computational fluid dynamics method, meaning we can make minimal assumptions on the exact seismogenic mechanism prior to simulation. SPH has the capacity to capture a broad range of signal-generating processes that may prove to be of interest for modelling meltwater flow, such as fluid-solid impact events, free-surface behaviour (e.g., wave breaks), and some forms of turbulence. Beyond the modelling of complex flow, SPH also allows a simple implementation of arbitrarily shaped solid boundaries and the computation of force of the water on these boundaries; a necessary output for waveform simulation.We propose a correspondence between different types of meltwater flow and the attributes of the waveforms they produce, as a step towards better detection and characterisation of hidden and short-lived events. Across a diverse set of model geometries and flow types, we anticipate the collection of synthetically generated signals will be useful for categorising archived and real-time signals according to a mechanistic process using unsupervised machine learning methods in ongoing work.