bluuebunny/crossref_metadata_2025 huggingface dataset:
Dieback events of Scots pines caused by lack of rain in mid and late summer
Authors: Hunziker Stefan , Begert Michael , Scherrer Simon C. , Rigling Andreas , Gessler Arthur
Published: February 2023

Same as other parts of Europe, the inner-Alpine Swiss Rhône valley has been increasingly affected by Scots pine (Pinus sylvestris L.) dieback events since the 1990s. Such events were not confined to years of extreme heat and drought across Switzerland and Europe such as 2003 or 2018, and the severity and frequency of sudden tree mortality varied on relatively small spatial scales. Which are the relevant parameters that changed in time and which factors triggered these dieback events?We found that sudden mortality events occurred exclusively after periods of below average precipitation between July and September. During this time of the year, soil moisture regularly drops to a minimum while the atmospheric water demand is high. Further factors such as insect infestation or spring frost may increase the magnitude of tree mortality, but they were neither a required contributor nor were they found to trigger dieback events. Consequently, the region with lowest summer precipitation within the Swiss Rhône valley outlines the area most affected by Scots pine dieback.However, the amount and frequency of the highly variable summer precipitation did not decrease since the 1980s, but the atmospheric water demand in spring and summer increased continuously. As a result of the higher water loss to the atmosphere, the period of low soil moisture has been prolongated and intensified. Therefore, Scots pines have become more dependent on (temporary) water stress relief by precipitation events during mid and late summer.Many Scots pine died (most likely due to hydraulic failure) within months following severe summer water stress. The effects of such periods appeared faster on tree crown defoliation (i.e., the proportion of needles that should be present on a tree, but which have been lost) than on mortality, as some trees died only after a year or two. We found that these Scots pines exceeded a defoliation threshold of about 75 % and were unable to recover. In such strongly defoliated trees, stress-related metabolites increase in needles, but get depleted in roots, indicating that mortality is linked to belowground carbon starvation negatively affecting functions central for tree survival.
Source apportionment of fine aerosol at a rural background site in Central Europe based on seasonal distributions of dicarboxylic acids, sugars and related compounds
Authors: Vodička Petr , Kawamura Kimitaka , Deshmukh Dhananjay K. , Pokorná Petra , Schwarz Jaroslav , Ždímal Vladimír
Published: February 2023

Water-soluble dicarboxylic acids (hereafter diacids) and sugars are an important part of the atmospheric water-soluble organic aerosol. Here, we studied diacids and other compounds in fine aerosol particles (PM1) collected at a rural background site National Atmospheric Observatory Košetice (NAOK), Czech Republic, Central Europe. Aerosol samples were collected every second day for 24 h from September 2013 to August 2014 (n=146). Based on receptor modeling (PMF), we identified PM1 organic compounds that are more typical to anthropogenic and to biogenic sources. We have apportioned two anthropogenic sources especially evident during the heating season from mid-October to mid-April: (i) biomass burning (BB) (main contribution of levoglucosan and methylsuccinic, maleic, methylmaleic and azelaic acids) and (ii) fossil fuel combustion (FF) (represented by phthalic, terephthalic and ketomalonic acids). Furthermore, we identified two sources of biogenic aerosols: (iii) summer factor was largely characterized by compounds with three and seven carbons (malonic, 4-ketopimelic, oxoheptanoic, methylmalonic acids) while (iv) spring biogenic factor was characterized mostly by primary sugars, normal chain diacids and their precursors (oxalic, malonic, succinic, glutaric, ketomalonic, 4-oxobutanoic and 5-oxopentanoic acids). Last but not least, we distinguished (v) background factor mainly represented by less oxidized diacids precursors such as glyoxal, methylglyoxal, glyoxylic and pyruvic acids, but also by aromatic diacids, which may originate from traffic emissions; a stable and year-round source.Acknowledgement: This conference contribution was supported by the Ministry of Education, Youth and Sports of the Czech Republic under the project ACTRIS-CZ-LM2018122, by the Czech Science Foundation grant No. 20–08304J and by the Japan Society for the Promotion of Science (JSPS) through Grant-in-Aid No. 24221001. We appreciate the financial support of JSPS fellowship to P. Vodička (P16760) in Japan.Reference: Vodička, P., Kawamura, K., Deshmukh, D.K., Pokorná, P., Schwarz, J., Ždímal, V.: Anthropogenic and biogenic tracers of fine aerosol based on seasonal distributions of dicarboxylic acids, sugars and related compounds at a rural background site in Central Europe, Atmos. Environ., submitted, 2023.
Convection-Permitting Future Climate Simulation Based on SSP3-7.0 Scenario Over the Black Sea Basin
Authors: Kelebek Mehmet Baris , Önol Barış
Published: February 2023

The regional climate models are recently run at grid spacings of 4 km or less, so-called the convection-permitting scale, over different regions of the world. The previous studies highlighted the added value of the convection-permitting simulations, especially in representing the daily and sub-daily precipitation over complex topography. The Black Sea Basin, including the coastal areas of the Black Sea and a broad part of the Anatolian Peninsula, is one of the climate change hot-spots with its complex topographical features and where strong air-sea interactions occur. Previously, this region has become a subject of regional climate modelling studies at horizontal resolutions on the order of 10 km. In this study, we performed a decade-long convection-permitting climate simulation at 3 km horizontal resolution between 2061-2070 based on the SSP3-7.0 greenhouse gas emission scenario over the Black Sea Basin. To this end, we downscaled the last generation CMIP6 MPI-ESM1.2-HR outputs by using the WRF model. The results indicate that the daily 2m mean, minimum, and maximum air temperatures increase in the spring, summer, and autumn by about 3°C compared to the 2005-2014 reference period over the study area. Nevertheless, the increase in the cloud cover suppresses the warming in the winter. In terms of precipitation, the total precipitation amount decreases in spring and summer over the Black Sea Basin. On the other hand, the total precipitation amount increases significantly by about 3 mm/day in winter over the Eastern Black Sea region due to the positive change in evaporation of around 15%. The maximum daily precipitation amount reaches 350 mm over the northeast of Turkey and over the Caucasus. The intensification of the daily precipitation is most pronounced in the coastal subregions of the Black Sea Basin. Furthermore, the results highlight the intensification of sub-daily precipitation in these regions. In particular, the afternoon precipitation increases in autumn over the coastal regions of Turkey.
East Siberian glaciers have contracted over the last two glacial cycles
Authors: Nørgaard Jesper , Margold Martin , D. Jansen John , Kurbanov Redzhep , Szuman-Kalita Izabela , Lund Andersen Jane , Olsen Jesper , Faurschou Knudsen Mads , Corbett Lee , Bierman Paul
Published: February 2023

Satellite-based maps of glacial landforms reveal that the mountain landscapes of northeast Eurasia contain over one million km2 of glaciated terrain. Previous work has speculated on the existence of large ice masses during the Last Glacial Maximum (LGM) and the preceding cold phases, but the lack of age constraints means that little is known about the timing of past glaciations across this vast region.With an aim to gain a better understanding of the glacial history of this region, we collected samples for cosmogenic 10Be exposure dating of boulder erratics and moraines in the mountains of eastern Siberia. Here, we present the first results from two sites, both within the Chersky Range: (1) Malyk Sen, which contains a succession of three end moraines in a foreland setting; and (2) Ust-Nera, which features boulder erratics and glacial bedrock pavement exposed in a previously glaciated valley. At Malyk Sen, the relative positions and corresponding ages of the three moraines indicate progressive contraction of maximum glacier extent since termination of the Marine Isotope Stage (MIS) 6, with the innermost moraine dated to the LGM. Our preliminary results from Ust-Nera suggest exposure ages from glacially-transported boulders and bedrock pavement that are significantly older than the LGM. Both sites indicate limited extents of mountain glaciation during the LGM in eastern Siberia. And while the glacial chronology of our study does not extend beyond MIS 6, mapping of the surrounding areas indicates that even more expansive glaciers existed further back in time.Our findings confirm the trend of successively smaller glacial extent maxima’s in continental Eurasia towards the LGM, with at least one ice advance during MIS 5-3 larger than the LGM advance. This trend could to be linked to extreme continental settings such as in Eurasia and westernmost America, as it contrasts with larger parts of the Northern Hemisphere glaciations where Late Pleistocene maxima were reached during LGM.
Response of the Indian monsoon to a warming Indian ocean
Authors: Goswami Bidyut Bikash
Published: February 2023

The Indian summer monsoon rainfall (ISMR) has been declining since the middle of the last century. However, recently (since about 2002) it is reported to have revived. For these observed changes in the ISMR, several explanations have been reported. Among these explanations, the warming of the Indian Ocean is considered a major one. However, we still do not fully understand the response of the atmosphere to this warming. Here we report that warming in the Indian Ocean (focusing on the eastern side of it where the sea surface temperatures are climatologically very warm) drives atmospheric responses that oppose Indian summer monsoon circulation and reduces ISMR. 
The seasonal cycle of atmospheric CO2 in South America over the last ten years seen by GOSAT
Authors: Artelt Lukas , Metz Eva-Marie , Vardag Sanam , Basu Sourish , Butz André
Published: February 2023

The number of in-situ CO2 measurements in the Southern Hemisphere is very limited. This leads to large uncertainties in estimates of regional carbon fluxes by in-situ based inverse models. Satellite-based CO2 measurements, on the other hand, are available in the Southern Hemisphere with a dense spatial coverage. By evaluating these, the regional carbon cycle can be studied in more detail and the results of carbon cycle models can be validated against the satellite data.Here, we present a comparison of atmospheric CO2 data provided by the Greenhouse gases Observing SATellite (GOSAT) and in-situ based inverse models for South America from 2009 to 2019. The seasonal cycle of atmospheric CO2 concentrations measured by the GOSAT satellite shows differences in both,amplitude and timing, compared to in-situ based atmospheric inversions. To determine the reason forthese discrepancies, we use the TM5-4DVar atmospheric inversion model assimilating GOSAT satellite data to obtain GOSAT based land-surface fluxes. This allows us to identify sub-regions responsible for the differences. In order to gain a deeper understanding of the underlying processes, we also analyse various climate parameters, fire emission data, and vegetation proxies (for example Solar Induced Fluorescence, SIF). By doing so, we aim at improving our understanding of the mechanisms that influence the seasonal carbon cycle in South America.
Porewater-derived nutrient biogeochemistry in a saltmarsh-fringed estuary under intensive human activity
Authors: Zhu Peiyuan , Chen Xiaogang , Zhan Yan , Chen Xinyu , Li Ling
Published: February 2023

Saltmarshes in estuaries with intensive human activity regulate coastal nutrient biogeochemistry, however, limited studies have quantified porewater-derived nutrient fluxes and identified the implication on coastal nutrients cycling. Here, we hypothesize that porewater-derived nutrient fluxes may contribute to coastal water quality issues. Spatial investigation was conducted in a saltmarsh-fringed estuary with multi-species saltmarshes. Based on a radon mass balance model, porewater-derived fluxes of nitrogen (including total nitrogen, nitrate, nitrite, and ammonium), phosphorus (total phosphorus and orthophosphate) and silicate were estimated. While nitrate was absorbed by saltmarshes, ammonium was export from porewater to surface water. Nitrate flux was supposed to provide nitrogen for saltmarsh species and ammonium flux was considered as the production of organic nitrogen mineralization. Furthermore, obvious inorganic phosphorus sink and silicate source were observed in the saltmarsh. According to nutrient fluxes and related N/P ratio, porewater-derived nitrogen and phosphorus fluxes can significantly mitigate the eutrophication in nearby water body.
Precipitation of CaCO3 through induced mixing and its impact on solute breakthrough
Authors: Gonzalez-Subiabre Guido , Fernàndez-Garcia Daniel , Trabucchi Michela , Reales-Nuñez Daniela
Published: February 2023

Calcium carbonates precipitation plays an important role in several geological, biogeochemical and engineered processes. It has been extensively studied for its application in remediation of contaminated groundwater, enhancing oil and gas recovery, improving geological carbon storage, reducing leakage in tunnel buildings and also to understand dissolution processes in coastal karst aquifers. Most of these works are based on theoretical formulations,  numerical simulations or batch/column experiments and little experimental evidence under transport conditions are reported in the literature. In this work through mixing-induce precipitation experiments we propose the visualization and characterization of the dynamic of precipitation processes focused on the understanding of its influence in solute breakthrough. We performed the experiments in a transparent horizontal cell flow made of plexiglass with 26 x 20 x 1 cm dimensions. The tank was disposed horizontally and filled with glass beads of 2 millimeter. The flow-cell was initially saturated with double-deionized water. In the experimental investigation, two different chemical solutions containing 0,1 M CaCl2 and 0,1 M NaCO3 were injected in two separate inlet ports. Color tracer tests consisted on fluorescein were injected before and after the precipitation experiment with the objective of visualizing and quantifying the impact of precipitation in solute transport. We evaluated the effectiveness of the standard solute transport equation to represent precipitation processes and developed new mechanistic transport models.
Applying statistical downscaling to CMIP6 projections of precipitation for South America: Analysis of pre and post-processed simulations
Authors: de Souza Ferreira Glauber Willian , Simões Reboita Michelle , Martins Ribeiro João Gabriel
Published: February 2023

Global Climate Models (GCMs) are fundamental for simulating future climate conditions. However, such tools have limitations like their coarse resolution, systematic biases, and considerable uncertainties and spread among the projections generated by different models. Thus, raw outputs from GCMs are insufficient for regional-scale studies, which can be solved using downscaling techniques. These methods are particularly relevant for South America (SA), given the continent's climate regimes and topographic complexity. Moreover, critical socio-economic activities developed in SA, such as rainfed agriculture and hydroelectric power generation, are highly dependent on climate conditions and susceptible to extreme events, which can lead to intense droughts or floods depending on the region. Given the background, this study aims to analyze the performance of the statistical downscaling technique Quantile Delta Mapping (QDM) applied to precipitation projections simulated by an ensemble composed of eight GCMs from the Coupled Model Intercomparison Project Phase 6 (CMIP6) for SA. In this manner, we evaluate both the original precipitation projections from the GCMs, and after applying the QDM statistical downscaling technique. Daily precipitation data from the Climate Prediction Center (CPC), with a horizontal resolution of 0.5°, and from the Multi-Source Weighted-Ensemble Precipitation version 2 (MSWEPV2), with a horizontal resolution of 0.1°, are used as a reference, so the final resolution of the GCMs (and the ensemble) projections after the QDM technique application is the same from the different validation databases. Preliminary results with CPC indicate a satisfactory performance of the technique on precipitation simulations over SA. The authors thank the CAPES, the R&D Program regulated by ANEEL, and the companies Engie Brasil Energia and Energética Estreito for their financial support.
Pleistocene climatic variability in eastern Africa influenced hominin evolution: the 620,000-year climate record from Chew Bahir
Authors: Foerster Verena , Asrat Asfawossen , Bronk Ramsey Christopher , Brown Erik T. , Deino Alan , Grove Matthew , Hahn Annette , Junginger Annett , Kaboth-Bahr Stephanie , Lane Christine S. , Opitz Stephan , Noren Anders , Roberts Helen M. , Tiedemann Ralph , Vogelsang Ralf , Vidal Céline M. , Cohen Andrew S. , Lamb Henry F. , Schaebitz Frank , Trauth Martin H.
Published: February 2023

As a contribution towards a regional environmental context of human-climate interactions, the ICDP co-funded Chew Bahir Drilling Project, a part of the HSPDP (Hominin Sites and Paleolakes Drilling Project), recovered ~280-m long cores of sedimentary strata through continental scientific drilling in southern Ethiopia. The fluvio-lacustrine coring locality in the Chew Bahir basin is situated near key archaeological and paleoanthropological sites, such as the Omo-Kibish where the Omo 1 and 2 Homo sapiens fossils were recovered.Here we present the 620,000-year environmental record from Chew Bahir that provides an extraordinary opportunity to examine the potential influence of climate variability on hominin evolution, cultural innovation and dispersal during the Middle to Late Pleistocene. The near-continuous Chew Bahir record documents 13 environmental episodes that differ in length and character, potentially inducing habitat changes influencing hominin biological and cultural transformation. We infer that long-lasting and relatively stable humid conditions from ~620,000–275,000 years BP (Episodes 1–6) were interrupted by several abrupt and extreme hydroclimatic oscillations. This phase coincided with the appearance of high anatomical diversity in hominin groups. During Episodes 7–9 (~275,000–60,000 years BP), a pronounced pattern of climatic cyclicity was paralleled by the gradual transition from Acheulean to Middle Stone Age technologies, the emergence of H. sapiens in eastern Africa, and a key phase of human social and cultural innovation. Episodes 10–12 (~60,000–10,000 years BP), marked by high-frequency climate oscillations, is contemporaneous with the global dispersal of H. sapiens, facilitated by continued technological innovation and the alignment of humid pulses between eastern Africa and the eastern Mediterranean.Prospectively, the Chew Bahir record represents a crucial component for the Middle and Late Pleistocene in the ongoing efforts of the scientific community (future and upcoming ICDP-funded projects) to address questions in Africa  across four topical core areas: paleoclimate, paleoenvironment, basin evolution, and modern lake systems.
Influence of reservoir on propagation from meteorological to hydrological drought for Tapi river basin
Authors: Pachore Akshay , Agrawal Nirav , Rakhmonov Komiljon , Mujumdar Sanskriti , Umirzakov Gulomjon , Remesan Renji
Published: February 2023

Meteorological drought generally gets propagated into agricultural and hydrological drought. Hydrological drought is characterized by reduced streamflow in the river regime. Due to the interconnection between different drought types, it is important to analyze the drought propagation time. Propagation from meteorological to hydrological drought is of prime concern, as hydrological drought is having immediate consequences on industry, agriculture, and the water supply system. In the present study propagation time from meteorological to hydrological drought was studied using the spearman rank correlation coefficient for the Tapi river basin of India having semi-arid climatic conditions.  Spearman rank correlation was calculated between lagged values of the standardized precipitation index (SPI-1,2,3,4,5,6,7,8,9,10,11,12), and monthly standardized streamflow index (SSI-1). Drought propagation under the influence of the Ukai reservoir was analyzed for Sarangkheda and Ghala gauging stations. Sarangkheda station is in the upstream of the Ukai reservoir whereas, Ghala station is in the downstream. Results indicated that there is a clear influence of reservoir on propagation time from meteorological to hydrological drought. The highest correlation for the Sarangkheda station was observed for SPI-5 and SSI-1, whereas, for the Ghala station, it is for SPI-12 and SSI-1. Propagation time has significantly increased for reservoir-influenced gauging station as compared to gauging station in the natural catchment. The present study is important as information on propagation time under the influence of a reservoir can be useful to the water resource manager, stakeholders, and policymakers for doing the required preparation and taking necessary measures.
A vine copula-based approach for constructing nonparametric synthetic design flood hydrographs
Authors: Liová Anna , Výleta Roman , Hlavčová Kamila , Kohnová Silvia , Bacigál Tomáš , Szolgay Ján
Published: February 2023

Reliable flood risk management needs to correctly estimate and design the size of volumes in reservoirs, spillways of dams and flood levees. To design secure and well-serving hydraulic structures, we often need to use design flood hydrographs that allow a sufficient description of the impacts of flood events in many cases.In this study, a methodology is proposed based on using both empirical and statistical approaches for constructing nonparametric synthetic design flood hydrographs. It is based on flood hydrographs that are observed in the hourly discharge time series, in which is respected the dependence among the peaks, volumes and duration of a set of observed seasonal flood hydrographs. The method consists of seasonality analysis of floods, sampling of seasonal flood hydrographs, normalization of the hydrographs into flood fragments, dependence modelling of peaks, volumes and durations using the vine copulas, rescaling of hydrograph fragments with the appropriate design flood into synthetic design hydrographs and determining the joint conditional return period of the flood volume and the duration conditioned on the flood peak for each synthetic hydrograph.By that, the designer is furnished with a set of design flood hydrographs, which have diverse shapes, volumes, and durations for a selected design discharge with a known joint conditional return period of the volumes and durations for flood risk analysis.  The method was tested and carried out on gauged discharge data from the Horné Orešany reservoir in the watershed of the Parná river in Slovakia. Using flood regionalization approaches can be this method also applicable to ungauged catchments. Acknowledgements:This study was supported by PhD student project SYLUETI.  The study was also supported by the Slovak Research and Development Agency under Contract No. APVV-20-0374.
Defining the Anthropocene for the greatest good as an Event-based Renaissance
Authors: Koster Emlyn
Published: February 2023

Paul Crutzen’s concept of the Anthropocene in Nature in 2002 stressed that “a daunting task [lay] ahead for scientists and engineers to guide society towards environmentally sustainable management” and that “this will require appropriate human behaviour at all scales”. The proposal by the Anthropocene Working Group of the International Commission on Stratigraphy’s Subcommission on Quaternary Stratigraphy for an ‘Anthropocene Epoch’ with an isochronous mid-20th century start has been recently challenged by another group of researchers. Mindful of the diachronous impacts of human evolution, they favor a much longer and still ongoing ‘Anthropocene Event’.In sync with IUGS goals to promote public understanding of the Earth and contribute to international policy decisions, the Anthropocene debate offers an unprecedented opportunity for the geoscience profession to become proactively relevant to the UN’s next-step vision for Planet Earth. Arguably, its 2015-2030 agenda of 17 Sustainable Development Goals each focused on a facet of society and the environment needs a more holistic successor with realistic thinking about sustainability, “one of the most overused and ill-defined words in conversations about the environment” in the view of Andrew Revkin at Columbia University’s Earth Institute. Ideally, the UN’s successor plan would be aligned with the interdependent subsystems of the Earth-Human System and propelled by transdisciplinary involvement of the sciences and humanities.Echoing an observation by Stanley Finney and Lucy Edwards in GSA Today in 2016 that the terms Anthropocene and Renaissance have similar characteristics as “richly documented, revolutionary human activities”, an ‘Anthropocene Renaissance’ would highlight the need for greater harmony among and between environmental and societal movements. In this vision, the past-framed ‘Anthropocene Event’ underpins the future-framed ‘Anthropocene Renaissance’ as a boldly integrated effort to ‘protect our planet’, one of twelve commitments made by world leaders in 2020 at the UN’s 75th Anniversary Meeting. In a profile of the Anthropocene debate in The New York Times on 18 December 2022, the conclusion featured my interview: “I always saw it not as an internal geological undertaking but rather one that could be greatly beneficial to the world at large”. The UN’s ‘Summit of the Future: Multilateral Solutions for a Better Tomorrow’ will take place in New York City on 22-23 September 2024.    
A global model for estimating fuel consumption and fire carbon emissions at 500-m spatial resolution
Authors: van Wees Dave , van der Werf Guido R. , Randerson James T. , Rogers Brendan M. , Chen Yang , Veraverbeke Sander , Giglio Louis , Morton Douglas C.
Published: February 2023

Fires constitute a key source of emissions of greenhouse gasses and aerosols. Fire emissions can be quantified using models, and these estimates are influenced by the spatial resolution of the model and its input data. Here we present a novel global model based on the Global Fire Emissions Database (GFED) modelling framework for the estimation of fuel consumption and fire carbon emissions at a spatial resolution of 500 m. The model was primarily based on observation-derived data products from MODIS, reanalysis data for meteorology, and an updated field measurement synthesis database for constraining fuel load and fuel consumption. Compared to coarser models, typically with a resolution of 0.25°, the 500-m spatial resolution allowed for increased spatially resolved emissions and a better representation of local-scale variability in fire types. The model includes a separate module for the calculation of emissions from fire-related forest loss, using 30-m Landsat-based forest loss data. We estimated annual carbon emissions of 2.1 Pg C yr-1, of which around 24% was from fire-related forest loss. Fuel consumption was on average a factor 10 higher in case of fire-related forest loss compared to fires without forest loss. Up to now, emission estimates from our new model are based on MODIS burned area with a 500-m resolution, leading to global emissions similar to GFED4s. However, novel high-resolution burned area datasets based on the Landsat and Sentinel-2 missions reveal substantially more global burned area. Our 500-m global fire model provides a suitable framework for converting these burned area products to emissions, with the prospect of substantially higher global emissions.
An exploration of volcanic controls on glacier velocity
Authors: Mallalieu Joseph , Barr Iestyn , Martin Michael , Symeonakis Elias , Edwards Benjamin , Spagnolo Matteo , Mullen Donal
Published: February 2023

Approximately 17% of the Earth’s 1,413 Holocene volcanoes are glacier covered or possess at least one glacier within a radius of 5 km. Glacier-volcano interactions are therefore relatively common, yet our understanding of these interactions is hindered by a sparsity of observations and a lack of quantitative data. Furthermore, glaciovolcanicanism has been implicated in a number of particularly deadly and costly volcanic eruptions in recent decades. Documenting and quantifying the impacts of glacier-volcano interactions is therefore increasingly needed to both accurately forecast the future dynamics of volcanic glaciers and mitigate associated glaciovolcanic hazards.Encouragingly, recent research has shown that optical satellite imagery can be used to detect volcanic impacts on glacier surface morphology, such as the development of ice cauldrons and widespread crevassing. However, to date the capacity of volcanic activity to influence glacier velocities and wider glacier geometry remains relatively unexplored. Here, we present a comparative study of volcanic and non-volcanic glacier velocities and geometries. We apply descriptive and multivariate statistical analyses to a broad range of glacial, volcanic and climate records in order to: i) compare volcanic and non-volcanic glacier parameters globally for the year 2017/18, and ii) investigate relationships between volcano properties and volcanic glacier characteristics.Our final dataset comprises ~2,700 volcanic glaciers and ~210,000 non-volcanic glaciers. We reveal that volcanic glaciers typically exhibit greater and more variable velocities than their non-volcanic counterparts, with an average median velocity of 18.09 ma‑1 versus 7.94 ma-1 for non-volcanic glaciers. We also find that volcanic glaciers are typically larger, longer and thicker than non-volcanic glaciers, and are more likely to be situated at lower elevations, on more gentle slopes in warmer, wetter climates than their non-volcanic counterparts. However, when controlling for these differences in glacier geometry, situation and climate, we find that the greater velocities observed for volcanic glaciers remain statistically significant. Relationships between volcano properties and volcanic glacier characteristics tentatively indicate that volcano type and tectonic setting may also act as controls on volcanic glacier velocities, and that the greatest volcanic glacier velocities are typically found in glaciers situated closest to volcanoes.The enhanced velocities documented here, particularly for glaciers most proximal to volcanoes, are hypothesised to be a consequence of locally increased geothermal heat inputs. Consequently, we contend that the velocities of volcanic glaciers may be a valuable proxy for volcanic activity and, with further investigation, may provide considerable potential for monitoring and forecasting volcanic activity, and for improving the mitigation of glaciovolcanic hazards.
Understanding impact of Rainfall Intensity Distribution and Climatology on Recharge and Baseflow in tropical Hard-rock Aquifers of South India
Authors: Goswami Shubham , Sekhar Muddu
Published: February 2023

Processes controlling surface-groundwater interaction in terms of recharge and baseflow have been a topic of pursuit in the hydrological research community. The groundwater recharge and baseflow in hard-rock aquifers is significantly impacted by rainfall pattern, aquifer characteristics, weathering/soil condition, topography, land use and land cover. Analysis of the recharge and baseflow process in tropical semi-arid hard-rock aquifer regions of southern India is crucial due to heavily tailed monsoon system prevailing in the region, heterogeneity of aquifers in terms of fractures and lineaments and presence of several man-made irrigation tanks along with the drainage network. Process uncertainties in groundwater recharge simulation due to impact of climate change on vegetation and resulting changes in evapotranspiration can significantly impact groundwater projections. Poor representation of diffused and focused recharge pathways and inadequacy in capturing the feedback among climate, land use and groundwater systems are other factors introducing uncertainties. Finally, the gaps in long-term observational data make it challenging to assess the impact of climate change. A taluk scale study conducted in Karnataka State of India indicated a significant correlation between the rainfall intensity distribution and climatology on groundwater recharge in Hard-rock aquifers. The current study targets to add a baseflow component represented by a 2D groundwater model and extend the previous study to a larger scale. The primary objectives of the study are to estimate the long-term groundwater recharge and baseflow trends and evaluate their association with rainfall and climatological variability. As the projected climate scenarios reflect higher frequency of high-intensity rainfall, it becomes essential to evaluate the impacts of varying rainfall patterns on the surface-subsurface processes.
Effects of water on the brittle to ductile transition of sandstones
Authors: Lazari Francesco , Violay Marie , Begue Florence
Published: February 2023

Geothermal energy is one of the renewable energy sources that can help mitigate climate change. Rocks are elasto-plastic materials at low pressure and temperature, and the deformation is accommodated along localized shear bands (brittle behavior); at high pressure and temperature rocks are elasto-visco-plastic and the deformation is homogeneous (ductile behavior); the transition between the two behaviors is called the brittle to ductile transition (BDT). Rocks capable of hosting geothermal fluids hot enough for electricity production (above 100°C) might be at or beyond the BDT.The importance of the BDT of rocks stems from the fact that the largest earthquakes occur there, and it corresponds to a major decrease in the permeability of the crust. In the literature, the mechanical properties of rocks across the BDT are relatively well known, though only lately the effect of the presence of fluids and their chemical composition has been investigated by few research groups. However, certain fluid compositions might lead to mineral dissolution, precipitation, weakening and alteration, which in turn affect the mechanical properties of rocks.To investigate the effect of water, fluid chemistry and alteration, triaxial experiments on a porous silicate sandstone (Adamswiller sandstone) with and without water at 100°C were done, to understand in detail the effect of water on deformation. To assess the evolution of the mechanical properties, complex electrical conductivity, permeability and ultrasonic seismic velocity were monitored in situ to fully describe the rock properties across the BDT.The experiments resulted in a complete characterization of the failure and yield envelopes of Adamswiller sandstone across the BDT, together with the electrical conductivity, permeability and ultrasonic seismic velocities. The presence of water lowers both the peak stress and yield stress. Electrical conductivity decreases beyond the BDT due to porosity reduction, following the reduction of permeability.
Collision-sticking rates of acid-base clusters in the gas phase determined from atomistic simulation and a novel analytical interacting hard-sphere model
Authors: Reischl Bernhard , Yang Huan , Neefjes Ivo , Tikkanen Valtteri , Kubečka Jakub , Kurtén Theo , Vehkamäki Hanna
Published: February 2023

Kinetics of collision-sticking processes between vapor molecules and clusters of low volatile compounds govern the initial steps of atmospheric new particle formation. Conventional non-interacting hard-sphere models underestimate the collision rate by neglecting long-range attractive forces, and the commonly adopted assumption that every collision leads to the formation of a stable cluster (unit mass accommodation coefficient) is questionable for small clusters, especially at elevated temperatures. Here, we present a generally applicable analytical interacting hard-sphere model for evaluating collision rates between molecules and clusters, accounting for long-range attractive forces. In the model, the collision cross section is calculated based on an effective molecule-cluster potential, derived using Hamaker’s approach. Applied to collisions of sulfuric acid or dimethylamine with neutral bisulphate-dimethylammonium clusters composed of 1-32 dimers, our new model predicts collision rates 2-3 times higher than the non-interacting model for small clusters, while decaying asymptotically to the non-interacting limit as cluster size increases, in excellent agreement with a collision rate theory-atomistic molecular dynamics simulation approach. Additionally, we calculated sticking rates and mass accommodation coefficients (MAC) using atomistic molecular dynamics collision simulations. For sulfuric acid, unit MAC is observed for collisions with all cluster sizes at temperatures between 200 K and 400 K. For dimethylamine, we find that MACs decrease with increasing temperature and decreasing cluster size. At low temperatures, the unit MAC assumption is generally valid, but at elevated temperatures MACs can drop below 0.2 for small clusters.
Early Triassic super-greenhouse climate driven by vegetation collapse
Authors: Xu Zhen , Yu Jianxin , Yin Hongfu , Merdith Andrew , Hilton Jason , Allen Bethany , Gurung Khushboo , Wignall Paul , Dunhill Alexander , Shen Jun , Schwartzman David , Goddéris Yves , Donnadieu Yannick , Wang Yuxuan , Zhang Yinggang , Poulton Simon , Mills Benjamin
Published: February 2023

The Permian–Triassic Mass Extinction (PTME), life’s most severe crisis1, has been attributed to intense global warming triggered by CO2 emissions from Large Igneous Province volcanism2–8. It remains unclear, however, why super-greenhouse conditions persisted for around five million years after the volcanic episode, when Earth system feedbacks should have returned temperatures to pre-extinction levels within a few hundred thousand years8. Here we reconstruct spatio-temporal maps of plant productivity through the Permian–Triassic and undertake climate-biogeochemical modelling to investigate the unusual longevity and intensity of warming. Our reconstructions show that terrestrial vegetation collapse during the PTME, especially in tropical regions, resulted in an Earth system with low levels of organic carbon sequestration and chemical weathering, leading to limited drawdown of greenhouse gases and protracted period of extremely high surface temperatures.
Evolution from continental rifting to passive margin in northeast Arabia; evidence from exploration wells in the United Arab Emirates
Authors: Jabir Mohammed , Ali Mohammed
Published: February 2023

The continental lithosphere stretches and ultimately splits during extension resulting in rifted margins that may transform into passive margins depending on their mechanical and thermal state. The heating and thinning of the continental lithosphere during the rifting process causes contemporaneous subsidence that accumulates syn-rift deposits. The extension of the lithosphere plays a critical role in plate dynamics as it occurs both in oceans and continents. The passive margin of northeast Arabia provides a unique geodynamic system for the full development of a continental rift into a mature passive margin. Here, this margin is buried under 5-7-kilometer-thick foreland basin sequences. The basement beneath the passive margin sequences has not been imaged by seismic nor sampled by deepest exploration wells. Therefore, the evolution remains enigmatic due to the lack of resolving data and the deep burial cover. This signifies the need for a powerful innovative approach to characterize the lithospheric stretching that occurred and its ever-since evolution. Here we integrate seismic reflection profiles and 3D seismic volumes, with compiled biostratigraphic data from 260 exploration wells to remove the sediment and water loads effect to acquire terms due to tectonic mechanisms. Seismic stratigraphy loosely identifies the top of the passive margin sequences based on the seismic reflection configurations, reflector geometry, and reflection termination. The bottom of these rifted sequences however cannot be determined. Additionally, the structural configuration of the rifting that occurred was severely obscured by the Ophiolite emplacement in the Late Cretaceous and the collision along the Zagros suture in the Miocene. As result, the faults were highly inverted negatively due to the emplacement of significant orogenic loads and crustal shortening. On the basis of backstripping, we suggest the occurrence of at least two phases of continental rifting during the Permian-Jurassic time spanning combined age of ~147 Ma. The initial phase commenced in the Early Permian (ca. 272 Ma) and is linked to the initial Tethys opening. The final rifting phase took place in the Late Jurassic (ca. 160 Ma) and is associated with the culmination of the continental break-up of Gondwana. The anomalous tectonic subsidence coupled is related to the heating and thinning that caused the thermal contraction of the crust. A uniform depth extension model implies that the lithosphere was thinned to 88% during the initial rifting and by 1% during the final rifting based on modeled stretching factors of 1.13 to 1.27 and 1.11 to 1.17, respectively. Spatial modeling of the stretching factors yielded critical insight into the lithospheric and crustal necking that occurred in the area. The identified evolution of northeast Arabia’s passive margin and its implications contributes to efforts in determining the hydrocarbon prospectivity of deep plays in the area.
Pluvial flood depth mapping in urban areas using data fusion
Authors: Schröter Kai , Steinhausen Max , Salgmann Lars , Müller Henning , Huszti Levente , Drews Martin
Published: February 2023

Inundations of urban areas induced by extreme rainfall are an increasingly important driver of loss and damage. With climate change, locally heavy precipitation will occur more frequently and with greater intensity. For efficiently reducing flood impacts and informing precautionary measures rapid and reliable information on affected areas is essential. Increasing amounts of data are available from a growing diversity of sensors and data sources. The Increasing volume and velocity of data are auspicious but require improved capabilities of extracting and integrating knowledge from this wide variety of data. Using recent pluvial flood events in Budapest (Hungary), Dresden (Germany), and Braunschweig (Germany) we investigate whether the combination of data from multiple sources (remote sensing, simulation models, online media, VGI) provides more reliable and more accurate inundation depths maps to better inform the assessment and management of pluvial floods. We combine data with geospatial analysis methods and fuse the different datasets using statistical and ML-based approaches. The results indicate that the combined data sources help to close gaps in individual data sources. Further, we note a compensatory effect, which results in more reliable and accurate inundation maps.
Supervised Learning for Automatic Source Type Discrimination of Seismic Events in Sweden
Authors: Eggertsson Gunnar , Lund Björn , Schmidt Peter , Roth Michael
Published: February 2023

Distinguishing small earthquakes from man-made blasts at construction sites, in quarries and in mines is a non-trivial task during automatic event analysis and thus typically requires manual revision. We have developed station-specific classification models capable of both accurately assigning source type to seismic events in Sweden and filtering out spurious events from an automatic event catalogue. Our method divides all three components of the seismic records for each event into four non-overlapping time windows, corresponding to P-phase, P-coda, S-phase and S-coda, and computes the Root-Mean-Square (RMS) amplitude in each window. This process is repeated for a total of twenty narrow frequency bands. The resulting array of amplitudes is passed as inputs to fully connected Artificial Neural Network classifiers which attempt to filter out spurious events before distinguishing between natural earthquakes, industrial blasts and mining-induced events. The distinction includes e.g. distinguishing mining blasts from mining induced events, shallow earthquakes from blasts and differentiating between different types of mining induced events. The classifiers are trained on labelled seismic records dating from 2010 to 2021. They are already in use at the Swedish National Seismic Network where they serve as an aid to the routine manual analysis and as a tool for directly assigning preliminary source type to events in an automatic event catalogue. Initial results are promising and suggest that the method can accurately distinguish between different types of seismic events registered in Sweden and filter out the majority of spurious events.
A stochastic MPC framework for the control of pumping stations in polder systems with regard for uncertainty in inflow and hourly electricity prices
Authors: van der Heijden Ties , van de Giesen Nick , Palensky Peter , Abraham Edo
Published: February 2023

The Netherlands is a low-lying country situated in the Rhine-Meuse delta. A significant portion of the Netherlands is located below sea level, making the proper management of local and national waterways essential. Polders are used to manage groundwater levels, drain excess rainwater, and store water during times of drought. These polders often have pumping stations that pump water into drainage canals, like the Noordzeekanaal-Amsterdam-Rijnkanaal (NZK-ARK), which receives water from the Rhine river and four local water authorities and connects to the North Sea at IJmuiden through a pumping station and a series of undershot gates.The operators of the NZK-ARK utilize Model Predictive Control (MPC) to schedule the discharge of water through the gates and pumps. The combination of the pump and gate discharge allows the NZK-ARK to discharge excess water to the North Sea when the sea water level is both higher and lower than the water level in the canal. However, traditional MPC can lead to suboptimal schedules when uncertainty is introduced, resulting from, for example, incoming discharge, fluctuating electricity prices, and the availability of renewable energy. Stochastic MPC allows for the consideration of uncertainty in decision-making, optimizing control actions based on a range of potential scenarios. In the future, the objectives for the control system of the gates and pumps may become more complex and may need to take into account factors like renewable energy availability and electricity prices. Ensuring the effective and efficient management of water in the Netherlands is critical, and the use of polders for water storage and control of groundwater tables, and techniques like MPC and stochastic MPC play important roles in achieving this goal.In this study, we present a framework that combines probabilistic forecasting, scenario generation and reduction, and stochastic MPC to minimize energy costs associated with pumping at the NZK-ARK. This framework is based on probabilistic forecasts of electricity prices and incoming discharge and is specifically designed for use at the NZK-ARK. By considering the uncertainty present in electricity prices and incoming discharge, our framework allows for the optimization of control actions through the use of stochastic MPC. The ultimate goal of this approach is to reduce energy costs at the NZK-ARK by effectively managing the discharge of water through the pumps and gates while complying with local constraints.