bluuebunny/crossref_metadata_2025 huggingface dataset:
Bottlenecks in space weather model validation: Where do we stand and how do we move forward?
Authors: Reiss Martin , Muglach Karin , Perri Barbara , Mullinix Richard , Wiegand Chiu
Published: February 2023

The rate at which we develop and update solar and heliospheric models has outpaced the rate at which we build our data and validation infrastructure. As a consequence, we end up with a bottleneck in advancing heliospheric modeling. The validation practices that rely only on selected events and time intervals, the usage of individually developed metrics, and a slow iterative process between developers and end-users all contribute to this bottleneck. These validation practices make a complete assessment of the "state-of-the-art" in space weather modeling difficult or even impossible. Here we present the activities of the Ambient Solar Wind Validation Team embedded in the COSPAR ISWAT initiative. Our mission is to provide the science community with an assessment of the state-of-the-art in solar wind modeling at Earth and other planetary environments. To this end, we are developing an open online platform hosted at NASA's CCMC for validating large-scale solar wind models by comparing their solutions with measurements from space explorers. The new online platform will allow the space weather community to test the quality of state-of-the-art solar wind models with unified metrics providing an unbiased assessment of progress over time. In this contribution, we will give a status update on our team effort, showcase the first version of the online platform, and outline future perspectives.
Following the temporal and spatial variability of atmospheric 14CO2 across Switzerland to estimate source contributions to the national CO2 emissions.
Authors: Geissbühler Dylan , Laemmel Thomas , Gautschi Philip , Wacker Lukas , Szidat Sönke
Published: February 2023

Perturbations to the natural carbon cycle due to anthropogenic and induced natural emissions of carbon dioxide (CO2) into the atmosphere are strongly linked with the current trend of global climate change. Efforts aiming at measuring amounts of CO2 emitted by different ecosystems and industrial activities have been increasing in the past years, in order to gather information about necessary mitigations efforts towards reduced future emissions.Radiocarbon (14C) measurements of atmospheric CO2 are unique in their capabilities to provide information on carbon sources and transport. The radiocarbon method allows an apportionment between "modern" sources, with 14CO2 signatures close to the global atmospheric average and fossil-fuel derived sources which are 14C-depleted. The capability to determine the fraction of fossil CO2 in atmospheric samples provides insight on the contribution of different emissions to the current rise in atmospheric CO2 concentration. When associated with meteorological data and atmospheric dispersion models, radiocarbon data can be used to identify fossil-fuel emissions patterns from a local to a regional scale, across time.The Radiocarbon Inventories of Switzerland (RICH) project aims to build the first database and model of the distribution and cycling of 14C at a national scale and across the atmosphere, soils, rivers and lakes of the country. The project presented here (RICH-Air) will serve to construct complementary monitoring and snapshots approaches of atmospheric 14CO2 measurement in this larger scope. For the monitoring aspect, air masses passing over Switzerland are collected and measured every two weeks at three tall tower sites situated over the populated Swiss plateau and one background site (Jungfraujoch). As for the snapshots, we focus on three industrial point sources (two cement plants, and a combined refinery-cement site) and use an Upwind-Downwind approach to have emissions and background samples at each site. As a complementary method, tree leaf samples will also be collected close to sites of interest, to have more temporally-integrated data.First results show that the seasonality has a huge influence on the monitoring of the 14CO2 signature, with a decrease in the winter months, due to limited atmospheric mixing, and accumulation of ground emissions. For the industrial hotspots, plume catching was shown to be challenging, even though an increased signal of a few ppm was generally visible.
Chemical munitions in the Baltic Sea – growing evidence of environmental impact
Authors: Bełdowski Jacek , Jakacki Jaromir , Vanninen Paula , Lehtonen Kari , Brenner Matthias , Fabisiak Jacek , Popiel Stanisław , Czub Michał , Nawała Jakub , Dziedzic Daniel
Published: February 2023

Over 38000 tons of chemical munitions were dumped in the Baltic Sea after World War II. They rest on the bottom of the Gotland and Bornholm Deeps. Studies performed between 2011 and 2019 show that those munitions are largely corroded, and chemical warfare agents (CWA) are released to the environment. Biomarker studies indicate, that they adversely affect marine biota from the dumpsites. Hydrodynamic models suggest that they can be transported with currents to adjacent areas. CWAs are transformed in the environment producing a variety of different degradation products, some of them characterized by higher toxicity than the parent compounds. An effort was undertaken to summarize the studies performed in three EU Interreg and one NATO SPS projects focusing on this problem.
Simulation of the Ca emission at Mercury and comparison with the observations by PHEBUS/BepiColombo during the first two flybys
Authors: Chaufray Jean-Yves , Leblanc François , Robidel Rozenn , Quémerais Eric , Koutroumpa Dimitra
Published: February 2023

Due to the lack of a thick atmosphere, the surface of Mercury is regularly bombarded by micrometeoroids at a rate depending on the position of Mercury around the Sun. One consequence of these impacts is an alteration of its surface (space weathering) and the ejection of its material around Mercury forming a tenuous exosphere. Even if the detail on the origin of the exospheric atomic calcium, observed systematically by MESSENGER is not fully understood, it is mostly associated to such impacts. In order to interpret the MESSENGER observations, we have recently developed a time dependent 3D model of the Ca exosphere of Mercury and successfully reproduced the seasonal variations observed by MESSENGER at dawn during its orbital phase. In this presentation, we will compare the simulated brightness from this model with the observations performed by PHEBUS onboard BepiColombo during the first two flybys of Mercury and discuss the differences.
The electrification of the Almadén mercury mine: causes and consequences.
Authors: Jurado Merchan Raquel Maria , Higueras Pablo , Tejero Jose
Published: February 2023

The Almadén mercury mine, located in Ciudad Real province, South-Central Spain, has been the World’s largest producer of this element worldwide. During its continuous activity of 2000 years, it has provided some one third of the total human production of this element. Many different technologies have been used to perform the mining exploitation of this singular mine, of underground typology, and centred in a complex cinnabar (HgS) orebody, with some 650 m. depth and some 500 m. length.Mercury is an element which importance for mankind has been diverse in different moments of history: Romans considered its ore, cinnabar, a critical resource, producing the important red stain; Arabs were highly interested on the alchemy concerns affecting this unique liquid metal; during the conquest of America, the discovery of the possibilities of amalgamation in silver recovery produced an intense traffic of this element from Europe to the new discovered continent; during the early 20th century, the use of Hg fulminate in ammunition also made of this element an important war resource. However, the catastrophic Hg-related poisoning in Minamata (Japan) and Iraq caused the acute decline of the importance of this element, due to the high toxicity of most of its compounds.In this work we present the results of a heritage-based research of a critical historic moment of the mine exploitation, concerning the transformation of a technically obsolete mining facility in a mine equipped with the latest advances that the use of electrical energy allowed. Besides, this research has allowed to cover an important documentary gap, concerning a period of time that had not been addressed in any previous research work.
Strengthened East Asian winter monsoon associated with insolation and Arctic sea ice since the middle Holocene
Authors: Zhou Peng , Shi Zhengguo , Li Xinzhou
Published: February 2023

The East Asian winter monsoon (EAWM) is one of the most important Asian climate systems, with a huge influence on social, agricultural productivity, and economic development. Sub-orbital-scale variations of the East Asian winter monsoon (EAWM) since the mid-Holocene and its associated mechanisms, however, are still not fully understood. Based on a high-resolution transient simulation, here we present a continuous climate evolution of EAWM in response to orbital forcing. Similar to the record proxy, the simulated EAWM variations exhibit a strengthening trend since the mid-Holocene, especially in the spring. Following the orbitally-induced decay of Northern Hemisphere summer insolation during the Holocene, growing Arctic Sea ice persists into winter and increases the latitudinal temperature gradient between low- and high latitudes, which lead to the strengthening of wintertime EAWM. While the intensified springtime EAWM can be attributed to the enhanced temperature gradient caused by solar insolation at different latitudes, rather than local insolation. Our results indicate that insolation forcing and Arctic Sea ice have played a key role in driving Holocene EAWM changes by enhancing temperature gradient between low and high latitudes.
Dynamics in mountain SNOW water resources by MODEs of climate variability assessed from satellite observations
Authors: Jans Jonas-Frederik , Beernaert Ezra , Lievens Hans , Verhoest Niko
Published: February 2023

Satellite information concerning the snow water equivalent (SWE) stored in the world’s mountain ranges is still lacking. This observation gap hinders the accurate estimation of total seasonal water storage in snow. Therefore, the SNOW-MODE project aims to address this gap by improving and developing two satellite retrieval methods to estimate SWE. Firstly, a recently developed empirical change detection algorithm for SWE retrieval from Sentinel-1 (S1) backscatter observations will be thoroughly analyzed and, if possible, improved. Secondly, a snow (Bic-DMRT), soil (Oh) and vegetation (WCM) radiative transfer model (RTM) will be coupled and inverted to estimate SWE using S1 radar backscatter observations and auxiliary snow, soil and vegetation properties. This method will be applied at the point- and grid-scale. The point-scale approach will make use of detailed in-situ measurements and novel tower-mounted radar measurements for RTM development and validation of the retrievals, whereas the grid-scale approach will utilize data generated from a land surface and a snow model. The inclusion of the grid-scale approach allows to investigate whether spatial patterns in SWE can be accurately represented by the S1 retrievals.
Subsequently, both S1 retrieval methods (i.e., change detection and RTM) will be compared over several mountain regions in the Northern Hemisphere (High-Mountain Asia and European and western United States mountains) to assess their uncertainties, validity conditions and main strengths as well as shortcomings. Furthermore, a physics-based snow model (e.g., SnowClim) will also be utilized to simulate snow depth and SWE on a daily basis. To improve the simulation results, the meteorological forcings will be downscaled to a resolution of 500 meter. Further improvements will be aspired by assimilating the mountainous snow depth retrievals (either from the RTM or change detection method) into the snow model. Finally, the generated SWE dataset will be related to modes of climate variability and will be translated into basin-scale water resources availability for society. 
Digitizing the Carrington 1859 storm: magnetogram records from Greenwich and Kew observatories
Authors: Florczak Ewelina , Beggan Ciaran , Clarke Ellen
Published: February 2023

Dedicated scientific measurements of the strength and direction of the Earth's field began at Greenwich and Kew observatories in London, UK, in the middle of the 19th century. Using advanced techniques for the time, light-sensitive photographic paper and light-levered reflections from magnetized needles allowed continuous analogue magnetograms to be recorded. By good fortune, both observatories were in full operation during the so-called Carrington storm in late August/early September 1859 providing as complete a record as possible. Based on digital images of the magnetograms and information from the observatory yearbooks and scientific papers scaling the measurements to SI units is possible at minute-mean cadence. However, due to the magnitude of the storm, periods of the greatest magnetic field variation are lost as the traces moved off-page. We present the most complete digitized magnetic records to date of the ten-day period from 25th August to 5th September 1859 encompassing the Carrington storm and its precursor on the 28th August.
Laboratory experiments and numerical modeling of wave transformations on a complex reef platform
Authors: Su Shih-Feng , Wu Wei-Hsuan , Chen Deng-Hong , Weng Wen-Kai
Published: February 2023

        Low-lying and small-scale coral reef islands are considered extremely vulnerable to the impacts of strong storms. Wave erosion is expected to destabilize reef islands and reduce them uninhabitable on the coast. Reef island morphodynamics have found to be dominated by nearshore wave hydrodynamics on reef platforms. Due to interactions between incident waves and reef morphology, wave characteristics on reefs are highly dependent on reef size, shape and island position, especially for the scale between O(100m) and O(1000m). In this study, laboratory experiments and numerical modeling are used to investigate wave transformation on a reef platform with a complex morphology. A prototype 1:100 three-dimensional reef island and platform were constructed on a wave basin of 50-m in length, 50-m in width and 1.0-m in depth, and nine wave gauges installed on the reef platform to observe water surface elevation under high-energy wave events from three incident directions. A numerical model XBeach is employed to compute short-period waves, long-period infragravity waves, wave setup and currents. Parameters in the wave-breaking dissipation formulation are calibrated against experimental data. Due to a varying of reef slopes surround the reef platform, the optimal breaking parametric values would be disparity between one- and two-dimensional simulations. The ideal values are decided by the model performance in two-dimensional simulation for wave and current fields. Long-period infragravity waves interlaced through refraction and diffraction on the complex localized reef morphology are further examined if the multiple mechanisms can drive shoreline amplification of long waves. The wave characteristics would provide critical indicators for accurate assessments of island shoreline change and better resolve the coast vulnerability.
Finite-amplitude modeling of estuarine sand dunes
Authors: van der Sande Wessel , Roos Pieter , Gerkema Theo , Hulscher Suzanne
Published: February 2023

Estuarine sand dunes are primary bedforms existing in many sandy estuaries. They generally have lengths between those of river dunes (tens of meters) and marine sand waves (on the order of hundred meters). Estuaries are known for their complex flow patterns, arising from a mix of riverine and tidal flow, bringing in freshwater from land and salt water from the sea. Two particular flow patterns arising from the interaction between salt- and freshwater are the gravitational circulation and the strain-induced circulation, induced by a longitudinal and a vertical salinity gradient, respectively. Recent research was directed to understanding the influence of these flow patterns on estuarine sand dunes through a linear morphodynamic model ([1], [2]). Linear stability models are capable of capturing initial growth from a flat bed, and yield the system’s preferred bedform length and migration rate.Here, we build upon the linear modeling approach with a nonlinear morphodynamic model capturing both the subsequent bedform development towards equilibrium, and the effect of dunes on the flow as they develop. The model domain has spatially periodic boundary conditions and a rigid lid at the surface; the hydrodynamic module is non-hydrostatic and is solved with a k-omega turbulence closure. Furthermore, we include bed-load sediment transport with a formulation that contains a slope term. Results show the height, length, shape and migration rate of dunes in an estuarine environment, and reveal the flow- and turbulence patterns over these bedforms. Furthermore, we show the deceleration of the flow with development of dunes, and thus quantify the effect of dunes on flow resistance.[1]          Van der Sande, W. M., Roos, P. C., Gerkema, T., & Hulscher, S. J. M. H. (2021). Gravitational circulation as driver of upstream migration of estuarine sand dunes. Geophysical Research Letters, 48(14). DOI: 10.1029/2021GL093337[2]          Van der Sande, W. M., Roos, P. C., Gerkema, T., & Hulscher, S. J. M. H. (in press).  Shorter estuarine dunes and upstream migration due to intratidal variations in stratification. Estuarine, Coastal and Shelf Science. DOI: 10.1016/j.ecss.2023.108216 
Trace metals in the topsoil of Kandahar region, Afghanistan and their associated health and ecological risk
Authors: Monib Abdul Wahid , Yadav Sudesh
Published: February 2023

In urban regions, surface dust and topsoil can be used as indicators of metal pollution. Numerous studies have been conducted in different locations throughout the world to assess metal pollution and associated environmental and human health risks, but none have been conducted in Afghanistan's Kandahar region. The purpose of this study is to examine the environmental and health risks of metal concentrations (As, Cd, Co, Cr, Cu, Ni, Pb, V, and Zn) in topsoil samples of sampling site. The average metal concentrations in the topsoil slightly exceeded their corresponding background values in Upper Continental Crust (UCC). Top soil samples showed low contamination for Cd, Co, Cr, Cu, Ni, Pb, V, Zn and considerable to very high contamination for As. Pollution load indices (PLI) demonstrated that all sampling sites are at a high load of metal pollution (PLI >1) indicating deterioration of soil quality.  According to Geo-accumulation Index (Igeo), topsoil samples fall under uncontaminated category for Co, Cr, Cu, Ni, Pb, V, Zn and moderately to heavily contaminated for Cd and heavily to extremely contaminated for As. Ecological risk values suggested that study area had low risk for Co, Cr, Cu, Ni, Pb, V, Zn while considerable to high risk for Cd and high to very high risk for As. According to the health risk assessment, ingestion is the major pathway for non-carcinogenic risk and children are at more risk as compared to adults. Fall outs of high ammunition usage, wear and tear of heavy duty vehicles and fossil fuel consumption seems to be responsible for the high levels of metals in topsoil of Kandahar region. More such studies need to be conducted with more spatial coverage to identify contaminated areas and subsequent remediation to safeguard human health and ecosystem.
Interferometric Synthetic Aperture Radar (InSAR)-based measurements of displacements due to geomorphologic changes in northern mining environments – testing and validating InSAR in open pit and tailings of Pyhäsalmi Mine, Finland
Authors: Kotavaara Ossi , Domenech Guillem , Mingot Sandra , Joutsenvaara Jari , Puputti Julia , Nieto Yll Daniel , Acero Zarina , Ala-Hulkko Terhi
Published: February 2023

Monitoring the stability of mine structures, such as tailing ponds and open-pits, is crucial for ensuring the safety of personnel on-site and for preventing environmental accidents. This must be done, not only during the active operation of a mine, but also during possible reuse phases, and even after closure. Currently, monitoring the structural stability of the mining area relies heavily on manually conducted RTK-GNSS-based measurements of established control points. While this is a precise and relatively simple technique, it does pose a limit to how many control points can feasibly be monitored, as using tens or even hundreds of control points is time-intensive and laborious. Consequently, monitoring larger areas and areas requiring frequent measuring can be challenging. A remote monitoring option would also remove the element of danger that comes from having to reach control points in possibly unstable areas. InSAR appears to be an alternative for measuring terrain displacements in large, mining areas. Some limitations remain, as terrain coverage and weather conditions in northern latitudes can hinder InSAR analysis.  The Callio Lab research centre at the Pyhäsalmi mine in Finland has been chosen as a test site for InSAR measurements conducted during the EU H2020-funded GoldenEye project. InSAR is used to measure terrain displacement as a result of geomorphologic changes during the summer and autumn of 2022. Additionally, InSAR analysis will be carried out using a network of corner reflectors during winter 2023. InSAR measurements will be evaluated and compared to drone imagery-based photogrammetric Digital Elevation Models (DEM) and field observations. Supplementary RTK-GNSS measurements are planned to be used to control the stability of selected control points. Results will provide valuable insight about InSAR usability for long-term monitoring in northern latitudes in mine environments, as well as, knowledge related to weather and terrain conditions required for obtaining reliable InSAR. Results will also touch on the main challenges faced when using InSAR in such an environment. This work has been supported by project Earth observation and Earth GNSS data acquisition and processing platform for safe, sustainable and cost-efficient mining operations (Goldeneye) ID: 869398, Horizon 2020.
Impact of forest site preparation on soil functions in a temperate alluvial forest
Authors: Behringer Max , Katzensteiner Klaus
Published: February 2023

Alluvial forests in the temperate zone of Europe are frequently changing drastically in their hydrological regime, vegetation composition and structure, and disturbance dynamics. Causes are river regulations, historic land use, recent forest management, and introduced species such as Solidago canadensis agg. or the pathogenic fungus Hymenoscyphus fraxineus causing ash dieback. Climate change increases the scale of these changes. As a result, like in the present case study, pre-mature stands dominated by Pica abies or Fraxinus excelsior have to be clearcut. In order to achieve a tree species composition which is adapted to the altered site conditions and still economically desirable, tree planting in a larger scale is inevitable. To control competing vegetation (e.g., Solidago, Clematis, Rubus…), site preparation (mulching and tilling of planting strips) was deemed to be necessary but is discussed controversially. Effects of site preparation on indicators for soil functions were compared for the two dominating soil types, Fluvisols and Rendzic Leptosols, using a chronosequence approach. The following key results were obtained: (1) Soil type has a significant effect upon most indicators. (2) Areas treated ≥5 years ago have a significantly higher bulk density (and thus, despite partly decreased C-concentration, higher C-stocks) in the 20 cm topsoil indicating compaction. (3) Tilling strips significantly impact anecic earthworm abundance (+) compared to areas only mulched. (4) Effects of site preparation on organic C concentration (-), C/N-ratio (-), ratio of microbial to organic carbon (+), abundance of anecic earthworms (+) and hydraulic conductivity estimated from pedotransfer functions (-) were mainly significant for Rendzic Leptosols. This may reflect the mobilization of accumulated forest floor, which was present in mature spruce stands on Rendzic Leptosols but not on Fluvisols. (5) The ground vegetation shows an expected response to clearing (increased cover of light demanding species including Solidago canadensis agg.). Effects of site preparation could not be separated from clearing effects. (6) Nitrate concentrations in seepage are below drinking water standards and show no clear treatment effect, though highest values were found in declining spruce stands on Leptosols.
The role of sediments in the mechanics of the subduction plate interface – Chugach accretionary prism Alaska
Authors: Akker Ismay Vénice , Behr Whitney M. , Morales Luiz F.G. , Braden Zoe
Published: February 2023

The subduction interface is a shear zone that defines the boundary between two convergent tectonic plates, the subducting slab and its overriding upper plate. The rheological and seismic behavior of the plate interface is a function of interacting physicochemical processes such as metamorphic grade and mineral dehydration reactions. Here we study the role of initial oceanic crustal composition in controlling these low-grade (prehnite-pumpellyite facies) conditions, and investigating the potential links between composition, deformational styles and modes of fault slip along subduction megathrusts. Our study area is located on the Kenai Peninsula in southern Alaska where the Jurassic-Cretaceous Chugach accretionary complex is preserved. This complex comprises underplated slices of basaltic oceanic crust and sedimentary material. We compare two field sites at similar metamorphic temperatures that each represent an interface shear zone: a basalt dominated section and a sediment-rich section. Raman spectroscopy to determine graphite crystallinity and deformation temperatures, combined with detrital zircon dating (U-Pb) are examined as function of structural depth and provide constraints on the metamorphic conditions and timing of underplating, and the peak temperature reached in underplated slices. Observations from field work and drone imaging shows that the sediment-rich interface shear zone includes a chert-argillite mélange zone of up to 15-m thick. Within this mélange, greywacke blocks occur and are surrounded by brittle-deformed and heavily veined basalt and/or greywacke slabs. The basalt dominated section includes several localized duplex faults. The fault planes are much narrower fault surfaces (< 5 cm thicknesses) and are decorated by highly orientated laths of chlorite. Microstructural observations will allow us to decipher the microphysical deformation mechanisms. Comparing the deformation structures and mechanisms at these two sites provides new insights into the compositional control on the rheology of the subduction interface.
Concept and validation of a Meteosat based dataset for Surface Radiative Balance
Authors: Bourgeois Quentin , Tetzlaff Anke , Stöckli Reto , Christen Nicolas , Viju John , Moutier William , Clerbaux Nicolas , Gellens-Meulenberghs Françoise , Trentmann Jörg , Trigo Isabel
Published: February 2023

During the Third Continuous Development and Operations Phase (CDOP-3) of EUMETSAT, the Satellite Application Facility (SAF) on Climate Monitoring (CM SAF) extends its product portfolio with a Thematic Climate Data Record (TCDR) of Regional Land Fluxes based on two sensors of the Meteosat suite of geostationary satellites: the Meteosat Visible and InfraRed Imager (MVIRI) and the Spinning Enhanced Visible and InfraRed Imager (SEVIRI). The Regional Land Fluxes TCDR will provide various parameters depicting the surface states and radiation fluxes, including the Surface Radiative Balance (SRB), the Cloud Fractional Cover (CFC), the Land Surface Temperature (LST), the Evapotranspiration (ET) and the Latent (LE) and Sensible (H) Heat Fluxes. The TCDR is achieved by consolidating and unifying previously separated developments in CM SAF, LSA SAF and the EUMETSAT Secretariat, and running them in a joint retrieval using the Meteosat Fundamental Climate Data Record. This unique concept ensures consistency among the TCDR parameters.We focus here on the SRB product of the Regional Land Flux TCDR. All components of the SRB - including the Surface Incoming Solar radiation (SIS, or solar irradiance), the Surface Albedo (SAL), the Surface Outgoing Longwave radiation (SOL) and the Surface Downward Longwave radiation (SDL) - are jointly retrieved using the CM SAF software “GeoSatClim” over the period 1983-2020. The SRB data record covers area up to 65°N/S and 65°W/E. The TCDR consists in hourly, daily and monthly means with a spatial resolution of 0.05 degree.In this presentation, we show the detailed concept of the SRB algorithm. The SRB product and its single components are validated with BSRN, GEBA, ASRB and SwissMetNet ground based stations and they are compared with other global SRB products such as ERA5-Land, ISCCP-FH and CLARA. Overall, the SRB monthly mean absolute bias reaches the target accuracy of 15 W.m-2, and the SRB stability falls below the requirement of 2 W/m2/decade.
Recurrence of drought events over Iberia under present and future climate conditions
Authors: Moemken Julia , Koerner Benjamin , Ehmele Florian , Feldmann Hendrik , Pinto Joaquim G.
Published: February 2023

Seasonal droughts are a common feature of the Iberian climate. They can have severe socioeconomic and ecological impacts – especially, when recurring in consecutive years. We investigate the recurrence of extreme drought events in the Iberian Peninsula (IP) for the past decades and in regional climate change projections. With this aim, we introduce and apply a new set of indices: the Recurrent Dry Year Index (RDYI) and the Consecutive Drought Year (CDY) Index. For the present climate, different gridded observational and reanalysis datasets at several spatial resolutions (10 to 25 km) are used. To analyse the potential impacts of climate change, we apply the indices to a large EURO-CORDEX multi-model ensemble with 12 km horizontal resolution consisting of 25 different global-to-regional model (GCM-RCM) chains for the historical period and future periods along the RCP8.5 scenario. Results show that the IP is regularly affected by extreme droughts under present climate conditions, with roughly three individual events per decade. Especially the southern and central parts of IP are exposed to recurrent events, which last between two and six years. Under different global warming levels (GWLs), results reveal a general tendency towards more severe drought conditions. Moreover, recurrent drought events are projected to occur more frequent and last longer (up to 14 years). While the ensemble mean responses are only moderate for a GWL of +2°C (compared to the pre-industrial average), recurrent drought conditions are strongly enhanced for the +3°C GWL. The climate change signals are robust for most of IP and the considered recurrent drought indices, with a larger model agreement for the +3°C GWL. For both present and future climate conditions, results show some sensitivity on the choice of index and dataset. We conclude that the new indices are suitable for the detection and evaluation of recurrent drought events under present and future climate conditions. With ongoing climate change, the Iberian Peninsula faces an increased risk of recurrent drought events. If global warming should exceed the +3°C threshold, the majority of models projects an almost permanent state of drought – with severe consequences for the Iberian population and ecosystems.
The role of soil-forming processes and changes in land cover in the storage and stabilization of soil organic carbon - preliminary results from the Carpathians (Southern Poland)
Authors: Musielok Łukasz , Stolarczyk Mateusz , Rudnik Anna , Buczek Krzysztof
Published: February 2023

The sequestration of carbon in the form of organic compounds in the soil is considered one of the main strategies for mitigating climate change. Mountain ecosystems have a great potential to store soil organic carbon (SOC) due to relatively lower temperatures and higher precipitation, which slow down the rate of organic matter decomposition. However, mountains are also regions particularly vulnerable to changes caused by direct and indirect human activity, in particular climate change and land cover change. All these changes have an impact on soil properties and thus on SOC stocks and their stability. One of the changes that has been particularly evident in mountainous regions in recent decades is the rapid succession of forests over grasslands, due to the land abandonment and the effects of global warming. In addition, the soil cover of mountainous regions is characterized by a large natural diversity of soil-forming processes, which is reflected in differences in the SOC sequestration potential. Thus, the aim of this research was to determine the effect of different soil-forming processes compared to different land cover on SOC stock and SOC stability. The SOC stock was measured in soils subjected to various soil-forming processes (podzolization, brunification, peat accumulation) and with different land cover (ancient forests, succession forests, meadows) in three similar study areas in the Carpathians (S Poland). The highest SOC stocks in the first 30 cm of soil were found in ancient forests (between 4.2 kg m-1 and 8.8 kg m-1) and the lowest in meadows dominated by tall-grass communities (1.3–2.0 kg m-1). The SOC stock was significantly higher in Podzols than in Cambisols and Histosols; however, most of the soils subjected to podzolization were found in forests. In addition, in mineral soils with contrasting pedogenic pathways (Podzols and Cambisols) soil organic matter fractionation was carried out. The preliminary results indicate that Podzols are characterized by much higher SOC content outside water-stable aggregates and in light fractions (particulate organic matter), which suggests relatively a weaker stability of organic matter in this type of soils than in Cambisols.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 952327 (HES-GEO) and has been supported by a grant from the Priority Research Area Antropocene (Young Labs) under the Strategic Programme Excellence Initiative at Jagiellonian University.
Effects of mesoscale turbulence on the wind-driven circulation in a closed basin with topography
Authors: Zavala Sanson Luis
Published: February 2023

This work addresses the effects of time-dependent, mesoscale turbulence on the wind-driven ocean circulation in a closed basin with variable topography. The main results concern the so-called Neptune effect, which involves the generation of persistent flows correlated with topography, but in this case, such currents are formed in the presence of a continuous, stochastic forcing. Numerical simulations of a single-layer fluid with sloping bottom topography near the boundaries are performed. The forcing is a suitable combination of a steady, basin-scale wind that generates the classical western-intensified anticyclonic gyre, plus a shorter, time-dependent forcing that injects energy at a narrow range of scales. Two contrasting situations are considered. First, in the absence of large-scale forcing, the turbulence generates a cyclonic flow that follows the geostrophic contours around the basin. This configuration corresponds to the most probable state equivalent to that expected in statistical equilibrium. Second, the resulting mean circulation is studied when the large and small-scale forcing terms are considered together. The main consequence is the alteration of the anticyclonic gyre due to the turbulent-induced cyclonic circulation. This result implies that large-scale, semi-steady circulations might be altered according to the turbulence characteristics.
Dyke-sill propagation in glacial-volcanotectonic regimes: The case study of Stardalur laccolith, SW Iceland
Authors: Drymoni Kyriaki , Tibaldi Alessandro , Pasquaré Mariotto Federico , Bonali Fabio Luca
Published: February 2023

Dykes (Mode I extension fractures) supply magma from deep reservoirs to the surface and subject to their propagation paths, they can sometimes reach the surface and feed volcanic eruptions. Most of the times they mechanically stall in the heterogeneous crust or deflect through pre-existing fractures forming sills. Although several studies have explored dyking in heterogeneous regimes, the conditions under which dykes propagate in glacial-volcanotectonic regimes remain unclear.Here, we coupled field observations with FEM numerical modelling using the software COMSOL Multiphysics (v5.6) to explore the mechanical and geometrical conditions that promote (or not), dyke-sill propagation in glacial-tectonic conditions. We used as a field example the Stardalur cone sheet-laccolith system, located in the Esja peninsula proximal to the western rift zone. The laccolith is composed of several vertical dykes that bend into sills and form a unique stacked sill ‘flower structure’. We modelled a heterogeneous crustal segment composed of lavas (top) and hyaloclastites (bottom). We then studied the emplacement of a dyke with varied overpressure values (Po = 1-10 MPa) and regional extension (Fe = 0.5-3 MPa) loading conditions at the lava/hyaloclastite contact. In the second stage, we added an ice cap as a body load to explore dyking subject to unloading due to glacier thickness variations (0-1 km).Our results have shown that the presence of the ice cap can affect the dyke-sill propagation and the spatial accumulation of tensile and shear stresses below the cap. The observed field structure in non-glacial regimes has been formed either due to the mechanical contrast (Young’s modulus) of the studied contact, a compressional regime due to pre-existing dyking or faulting, or finally, high overpressure values (Po  ≥ 5 MPa). Instead, in a glacial regime, the local extensional stress field below the ice cap encourages the formation of the laccolith when the ice cap becomes thinner (lower vertical loads). Our models can be applied to universal volcanoes related to glacier thickness variation and sill emplacement.
Thermal maturity and depositional conditions in the Orava part of Central Carpathian Palaeogene Basin
Authors: Marynowski Leszek , Staneczek Dorota , Więcław Dariusz
Published: February 2023

Central Carpathian Palaeogene Basin (CCPB) is a wedge-top basin that opened in the Central Western Carpathians in Lower Palaeogene. Orava sub-basin (OSB), located in N-Slovakia, comprises the NW remnants of CCPB. Based on previous studies (Środoń et al., 2006), OSB is the least mature part of CCPB. Yet, the estimated palaeotemperatures are relatively high and reach 95-100oC. Obtained results based on biomarkers study show differences in thermal maturity depending on the location of sampling sites and lithostratigraphy. Generally, maturation increases from N to S and Biely Potok (Upper Oligocene) to Huty Fm (Lower Oligocene). The occurrence of ββ-hopanes, hopenes, oleanenes, and low values of 22S/(22S+22R) homohopane ratio (~0.4), as well as 20S/(20S+20R) sterane ratio (~ 0.1 - 0.2), suggests low thermal maturity of organic matter in N and NE part of OSB. On the contrary, the S part is characterized by relatively high values of 22S/(22S+22R) ratio (>0.5), the 20S/(20S+20R) ratio (>0.4) and lack of unsaturated compounds, indicating that these units have reached the oil window stage. Rock-Eval analysis reveals the dominance of III-type kerogen in both Lower and Upper Oligocene due to terrestrial organic matter input. Biomarkers of terrestrial origin were detected in all samples including both angiosperm and gymnosperm affinity. Moreover, in less mature samples perylene is present as one of the major compound. This compound is interpreted as derived from soil and/or wood degrading fungi (Marynowski et al., 2013). In the Lower Oligocene, dysoxic to euxinic depositional environments are prevalent, which is manifested by the occurrence of isorenieratane and its derivatives, as well as small (<5µm) pyrite framboid diameters in many samples. However, a change of sedimentary conditions to oxic/dysoxic was found in Upper Oligocene samples. The results show larger framboid diameters (>5µm), a lack of isorenieratane and homohopanes with more than 33 carbon atoms in the molecule. In summary, sedimentary conditions in the Oligocene of CCPB changed from predominantly anaerobic to aerobic, with increased input of terrestrial organic matter. This work was supported by the National Science Centre, Poland (grant 2018/31/B/ST10/00284 to LM). Środoń, J., Kotarba, M., Biroń, A., Such, P., Clauer, N., Wojtowicz, A., 2006. Diagenetic history opf the Podhale-Orava Basin and the underlying Tatra sedimentary structural units (Western Carpathians): evidence from XRD and K-Ar of illite-smectite. Clay Miner. 41, 751–774.Marynowski, L., Smolarek, J., Bechtel, A., Philippe, M., Kurkiewicz, S., Simoneit, B.R.T. 2013. Perylene as an indicator of conifer fossil wood degradation by wood-degrading fungi. Org. Geochem. 59, 143–151.
Revealing the statistics of extreme stratospheric sudden warming events hidden in short weather forecast data
Authors: Gerber Edwin , Finkel Justin , Abbot Dorian , Weare Jonathon
Published: February 2023

Climate change will be felt primarily through changes in extreme weather: intense storms, precipitation events, and temperature anomalies.  Extreme events in the stratosphere, namely Sudden Stratospheric Warmings (SSWs), are known to impact surface weather extremes, driving an equatorward shift of the storm tracks and associated jet streams.  Efforts to quantify potential changes in SSWs in response to anthropogenic forcing, both their frequency and their surface impact, however, have been hampered by the large uncertainty in the observational record.  The problem becomes more acute for the most extreme SSWs, which are known to have a stronger surface impact. A once-in-a-century event takes, on average, 100 years of observations or simulation time to appear just once.  This is far beyond the typical integration length of our most accurate weather models, which provide the best representation of stratosphere-troposphere coupling, so the task is often left to cheaper, but less accurate, low-resolution or statistical models.  One reduces the sampling error (aleatoric uncertainty) at the expense of increased model error (epistemic uncertainty).In this work, we propose methods to extract climatological information from subseasonal forecast ensembles.  Despite being short in duration, weather forecast ensembles are produced multiple times a week, collectively, adding up to thousands of years of data.  Using ensemble hindcasts produced by the European Center for Medium-range Weather Forecasting (ECMWF) archived in the subseasonal-to-seasonal (S2S) database, we compute multi-centennial return times of extreme SSW events. Consistent results are found between alternative methods, including basic counting strategies and Markov state modeling. By combining different trajectories together in a statistically rigorous way, we obtain estimates of SSW frequencies and their seasonal distributions that are consistent with reanalysis-derived estimates for moderately rare events, but can be extended to events of unprecedented severity that have not yet been observed historically. The same methods hold potential for assessing extreme events throughout the climate system, beyond the example of stratospheric extremes presented here, and could be adopted in the context of climate change integrations to quantify the impact of anthropogenic forcing on extreme weather.
Different approaches in determining global geodetic parameters from SLR data - a simulation study
Authors: Najder Joanna , Sośnica Krzysztof , Strugarek Dariusz , Zajdel Radosław
Published: February 2023

Satellite laser ranging (SLR) is currently one of the four space geodetic techniques that provide a relevant contribution to the International Terrestrial Reference Frame (ITRF) realization as well as to the determination of global geodetic parameters including the low-degree harmonics of the Earth's gravity potential. ITRF realizations are mostly based on the observations to the two LAGEOS and two Etalon satellites, however, the impact of observations to Etalon satellites is marginal when compared to LAGEOS. Currently under consideration is an extension of the ITRF solution to include the LAser RElativity Satellite (LARES) and LARES-2 developed by the Italian Space Agency ASI and launched on July 13, 2022. The contribution of other satellites with retroreflectors is still being investigated.This study aims to verify various approaches to estimating geodetic parameters depending on the number of determined empirical once-per-revolution parameters for satellite orbits and different approaches of parametrization for the Earth rotation parameters (ERP), including piecewise linear and piecewise constant parametrization. We analyze six parametrizations, where three of them are proposed in this study and the other three are used by research centers, such as the Center for Space Research (CSR), the International GNSS Service (IGS), and the International Laser Ranging System (ILRS). For IGS and ILRS, these are the approaches used in determining the ERPs based on GNSS and SLR data, respectively. To the constellation of geodetic satellites such as LAGEOS-1/-2, Etalon-1/-2, and LARES-1/-2, we add hypothetical SLR satellites such as LARES-3/-4 and LARES-5/-6 which supplement the current constellation in the simulation study. We check whether satellite parameters, such as satellite altitudes and inclination angles affect individual global geodetic parameters when using different approaches to ERP parameterization and the set of estimated empirical orbit parameters.The obtained results show that the value of the obtained formal errors may depend not only on the choice of the estimated geodetic parameters but also on the number of satellites or satellite orbit parameters involved in the calculations.