bluuebunny/crossref_metadata_2025 huggingface dataset:
Behavior of Flare-associated Suprathermal Ions at Coronal Mass Ejections observed with Solar Orbiter at 0.5 AU
Authors: Janitzek Nils , Moraleda Mario , Walsh Andrew , Mason Glenn , Gomez-Herrero Raúl , Kollhoff Alexander , Pacheco Daniel , Barcynski Krzysztof , Rodríguez-García Laura , Musset Sophie , Hayes Laura , Zouganelis Ioannis , Ho George , Wimmer-Schweingruber Robert , Rodríguez-Pacheco Javier
Published: February 2023

Flare-associated particles from so-called impulsive events might be efficiently reaccelerated in gradual Solar Energetic Particle (SEP) events which are typically related to coronal mass ejections (CMEs). The existence and characteristics of such a flare-associated seed population might play a key role for understanding the high variability in particle intensity under comparable CME speeds and solar wind conditions. Understanding this variability will improve predictions of large gradual SEP events that cause a severe risk for satellite and even ground-based infrastructure. We analyze a sequence of impulsive and subsequent gradual events that occurred between 5 and 11 March 2022 and were measured in-situ with Solar Orbiter at a close distance of 0.5 AU to the Sun. We study in detail the behavior of suprathermal ions during the events and relate it to the ambient solar wind plasma properties and remote-sensing observations of the respective flares and CMEs observed from SOHO, SDO, and Solar Orbiter. We find in particular a strong local enhancement of suprathermal flare-associated ions that are trapped for several hours between two ICME structures and provide therefore a natural reservoir of seed particles that can be efficiently further accelerated in ambient compression regions or occurring shocks on their way out to 1 AU. 
On the control of small-scale heterogeneity and (spatially variable) diffusion on mixing-limited reactions in unsaturated soils
Authors: Vincent Henri Christopher , Diamantopoulos Efstathios
Published: February 2023

Soils are characterized by structural components on multiple spatial scales, originating from soil formation processes, soil-plant interactions, microbial activity and management operations. This leads to local heterogeneities for almost all measurements of physical, chemical and biological state variables. This includes the diffusion process, which is known to be affected by the tortuosity, and therefore the water content. Also, biochemical reactions in soils appear to be highly variable in space and time. Yet, the identification of the main controlling factors of the dynamic of reaction rates in unsaturated porous media remain partial.Studying biochemical reaction in real-world soil-plant-atmosphere systems is highly challenging since the true underlying structures can never be absolutely known. For this, it is appealing to employ synthetic experiments. In this study, we consider a simple A+B à C reaction and investigate the potential impact of small-scale heterogeneity, infiltration fluxes and diffusion on apparent reaction rates in a series of synthetic soils geostatistically described by the Miller-Miller theory. Reactive transport is solved using the random-walk particle-tracking approach to properly account for dispersion and mixing conditions.Results indicates a synergetic control of the intensity of soil heterogeneity, the Peclet number and the spatial variability of the (tortuosity-dependent) diffusion coefficient on mixing conditions, which has a great impact on effective reaction rates and on the formation of hot-spots and hot-moments. The initial location of the reactants appears to also condition the mixing state of the system and, therefore, the dynamic of reactions. We illustrate then the high complexity of reactive systems in unsaturated soils, which makes the use of average macroscopic reaction rates (as in most agriculture, environmental and geoengineering models) at least questionable.
Tall tower measurements with laser isotope spectrometry to investigate urban CO2 emissions in Vienna
Authors: Meeran Kathiravan , Matthews Bradley , Leitner Simon , Sanden Hans , Chen Jia , Watzinger Andrea
Published: February 2023

Cities contribute significantly to global carbon dioxide (CO2) emissions, and it is important to understand and accurately measure these emissions in order to effectively mitigate climate change. Current methods for estimating emissions, such as emission inventories, can be very uncertain at the scale of individual cities. Measurement methods that involve analyzing local atmospheric CO2 levels and the respective stable carbon isotopic composition of CO2 can provide additional, independent information on local emissions, particularly in terms of source contributions from combustion of different fossil fuels and natural respiration. As part of the Vienna Urban Carbon Laboratory (VUCL), a cavity-ring-down laser isotope spectrometer (G2201-i, Picarro Inc., USA) has been operating on a radio tower in Vienna’s city centre since May 2022 to measure atmospheric mixing ratios of CO2 and stable carbon isotopic composition of CO2 (δ13C) 144 m above the surface.The overall objective here is to establish an analysis framework to best utilize these measurements in combination with tall-tower eddy covariance measurements for the identification and quantification of local CO2 emission emitters in Vienna. Initial analysis of the half-hourly CO2 concentrations and fluxes between May and Dec 2022 show that a night-time increase of measured CO2 concentrations are followed by an early morning peak, due to a nocturnal build-up of surface-level CO2 that is followed by an upward flush of CO2 in the morning. The δ13C of CO2 (based on keeling plot analysis) suggests that fluxes from natural respiration are dominant over the night. In the afternoon, the δ13C of CO2 sources decreases, which may be due to an increased contribution from sources with isotopically depleted CO2, such as traffic emissions and small-scale stationary methane combustion. We also observed higher concentrations CO2 that are isotopically depleted, during the summer when winds came from the area southeast of the tower, which has more industrial and refinery activity. In addition to these initial results from keeling plot analysis, our presentation will also include results from the ongoing winter measurements, where we expect to see indications of enhanced methane combustion for space heating. Furthermore, results from ongoing tests of other analysis methods for identifying emitting sources (e.g., application of the miller trans model method, analysis of the data at higher temporal resolutions) will be presented.
Impact of land use change on local climate: regional climate model sensitivity experiments & scenarios within a multi-model set-up over Belgium
Authors: Ghilain Nicolas , Fettweis Xavier , Doutreloup Sebastien , Van Schaeybroek Bert , Bajkovic Josip , Hamdi Rafiq , Termonia Piet
Published: February 2023

Testing the sensitivity of regional climate models to the land cover/use changes in temperate regions is a preliminary step in the quantification of the respective contributions from human induced land surface changes and greenhouse gases emissions over Europe. Recently, the LUCAS-FPS (https://ms.hereon.de/cordex_fps_lucas/) initiative from Euro-CORDEX(https://www.euro-cordex.net/) has proposed a common framework and a time varying land cover database (Hoffmann et al., 2022) to build an ensemble of models responding to land use scenarios for the 21st century and ultimately to sort out the signal emerging from the impact of land use changes over Europe. In the meantime, coordinated experiments have been tested at higher resolution over Belgium for national and regional climate services. The present contribution focuses on the plans of coordinated experiments over Belgium (and Europe) with two regional climate models -MAR (Fettweis et al, 2013) and ALARO (Termonia et al, 2018)- :

i) the methodological aspects developed to make the simulations comparable and more in line with Euro-Cordex & LUCAS-FPS requirements ,

ii) the first results from the simulations over these domains by focusing on the changes in key climate variables for the historical past period used for verification and for a scenario of strong land cover change.

 

Fettweis, X., Franco, B., Tedesco, M., van Angelen, J. H., Lenaerts, J. T. M., van den Broeke, M. R., and Gallée, H.: Estimating the Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR, The Cryosphere, 7, 469–489, https://doi.org/10.5194/tc-7-469-2013, 2013.

 

Hoffmann, P., Reinhart, V., Rechid, D. (2021) LUCAS LUC historical land use and land cover change dataset (Version 1.0). World Data Center for Climate (WDCC) at DKRZ.

 

Termonia, P., Fischer, C., Bazile, E., Bouyssel, F., Brožková, R., Bénard, P., Bochenek, B., Degrauwe, D., Derková, M., El Khatib, R., Hamdi, R., Mašek, J., Pottier, P., Pristov, N., Seity, Y., Smolíková, P., Španiel, O., Tudor, M., Wang, Y., Wittmann, C., and Joly, A.: The ALADIN System and its canonical model configurations AROME CY41T1 and ALARO CY40T1, Geosci. Model Dev., 11, 257–281, https://doi.org/10.5194/gmd-11-257-2018, 2018.
Non-Henrian behavior of hydrogen between plagioclase and silicate melt
Authors: Xu Yongjiang , Lin Yanhao , Westrenen Wim
Published: February 2023

Hydrogen reported in lunar plagioclase (one of nominally anhydrous minerals) was used to quantify the water concentration of the late stage of Lunar Magma Ocean (LMO) based on an oft-cited fixed value of partitioning coefficient between plagioclase and silicate melt. However, the partitioning coefficient of hydrogen between plagioclase and silicate melt has been poorly constrained, especially at the lunar conditions. We conducted a series of water-bearing experiments to determine plagioclase-melt partition coefficients of hydrogen under the late stage of LMO conditions. The water concentrations of plagioclase and coexisting melt were analyzed using Fourier Transform Infrared Spectroscopy. Our new results show that the partitioning behavior of hydrogen between plagioclase and melt does not obey a classical Henry’s law at the water concentration in melt lowering than ~0.7 wt.%, and that the hydrogen partition coefficients do systematically increase with decreasing the water concentrations of the coexisting silicate melt, consistent with the re-evaluating all of the previous data of hydrogen partitioning coefficients between plagioclase and silicate melt. This indicates that the water concentration of silicate melt plays a dominant role in controlling hydrogen partitioning between plagioclase and coexisting silicate melt. This finding suggests that hydrogen partitioning between nominally anhydrous minerals and silicate melt could be far more complicated than previously thoughts, and indicates that it should be in caution when using plagioclase as a watermeter.
Ice sheet-ocean coupling in an Earth System Model
Authors: Asay-Davis Xylar , Begeman Carolyn , Engwirda Darren , Han Holly , Hoffman Matthew , Price Stephen
Published: February 2023

We present our approach to coupling an ocean component (MPAS-Ocean, Model for Prediction Across Scales-Ocean) to an ice sheet component (MALI, MPAS-Albany Land Ice) within an Earth System Model (E3SM, the Energy Exascale Earth System Model) developed by the US Department of Energy.  First, we present an extrapolation technique, similar to the ISMIP6 (Ice Sheet Modeling for CMIP6) protocol, that can be used in the absence of evolving grounding lines in the ocean component.  This technique, while crude, can be used in both Greenland fjords and ice-shelf cavities as a stop-gap in situations where the ocean component cannot capture the topographic evolution (e.g. because the ocean grid is too coarse or full coupling has not yet been completed).  Second, we demonstrate progress on a fully conservative wetting-and-drying technique using the idealized MISOMIP1 (Marine Ice Sheet-Ocean Intercomparison Project, phase 1) experiments within E3SM.
Applying single- and multi-site weather generators for the estimation of extreme floods in the Austrian Alps
Authors: Ehrendorfer Caroline , Herrnegger Mathew
Published: February 2023

The length and quality of observed discharge data is frequently insufficient to derive robust extreme discharge values, which are crucial for water management planning for the present and future climates. Using long timeseries of synthetic weather data generated by stochastic weather generators (SWGs) as input to rainfall-runoff models to derive extreme discharge peaks could be of value for basins with missing or short observation timeseries. While multi-site generators preserve spatial correlation between stations, their complexity also limits them in other ways, such as implementing only simple parametric distributions that don’t adequately represent tails of distributions and extreme events. Single-site generators offer more complex parametric distributions, but don’t preserve correlation between stations, making them unsuitable for distributed hydrological modeling. In the context of hydrological modeling with emphasis on extremes, the question arises if the lumped output of a multi-site generator outperforms a single-site generator in combination with a lumped hydrological model, or if the advantages of a heavy-tailed distribution can outweigh the averaging across a heterogenous catchment. This work examines the transfer of synthetic weather data into runoff extremes in the alpine watershed of the Austrian Ybbs River by driving the rainfall runoff model COSERO with meteorological timeseries from the single- and multi-site SWGs WeaGETS and MulGETS. A GEV distribution was fit to each timeseries of annual runoff maxima to derive events with return periods of 30, 100 and 300 years. The single-site generators and their superior parametric distribution functions did not outweigh the averaging effect, and hydrological simulations were greatly biased, significantly underestimating flood peaks. However, also the results of the flood frequency analysis using multi-site synthetic data underestimated the results using observed data for all return periods by at least 30 %. The findings show that the application of single- and multi-site SWGs to estimate runoff extremes may not be applicable and must be critically reviewed.
Drivers and controls of greenhouse gas dynamics in subarctic, alpine catchments
Authors: Popp Andrea L. , Valiente Parra Nicolas , Aalstad Kristoffer , Trier Kjær Sigrid , Pirk Norbert , Eiler Alexander , Dörsch Peter , Hessen Dag Olav , Tallaksen Lena Merete
Published: February 2023

Headwater catchments are known to substantially contribute to global carbon and nitrogen cycles through transport, storage, and direct emissions of greenhouse gases (GHGs). Despite extensive research on GHG dynamics in headwater systems, their drivers and controls remain elusive, particularly in cold region environments that are undergoing rapid transformations. Cryospheric changes, such as alterations in snowpack mass, are known to be strongly coupled with the hydrological cycle. However, we have limited insight into the nexus between snow cover changes, source water contributions (e.g., groundwater and glacial meltwater) to surface waters and associated biogeochemical cycling. To better understand the hydrological and biogeochemical changes in cold regions, we obtained field- and satellite-derived data from two sub-arctic catchments (one glaciated, one non-glaciated) in the north-western part of the Hardangervidda mountain plateau (South Central Norway). With this work, we aim to obtain an improved understanding of the impact of snow cover on GHGs dynamics in high-latitude, alpine catchments. During late summers in 2020 and 2021, we analysed various water sources including streams, lakes, groundwater, snow and ice for environmental tracers (major ions, stable water isotopes, radon-222) and GHGs  (CO2, CH4 and N2O). The combination of environmental tracer data with a Bayesian end-member mixing model allowed us to partition water source contributions to streams and lakes. To estimate snow cover anomalies between 2020 and 2021 compared to a five-year mean, we retrieved fractional snow cover durations (FSCDs) from 2016 to 2021 by applying a spectral unmixing algorithm to merged Sentinel-2 and Landsat 8 imagery over Finse. According to the satellite-derived data, 2020 was exceptionally snow-rich, while 2021 was a normal year. Our results indicate that GHG saturations distinctively differ among different water sources (e.g., lakes and streams), of which most are supersaturated. Thus, surface waters act as net sources for GHGs to the atmosphere, at least for the time windows of our sampling campaigns. Gas saturations distinctively differed between the glaciated and the non-glaciated catchments as well as between snow-rich and normal snow conditions. Groundwater is the most CO2 and CH4 supersaturated water source. However, groundwater only marginally contributed to surface waters and is thus not a major driver of GHGs emissions. Consequently, we hypothesise that snow cover, glacial meltwater, and resulting differences in subsurface water routing control GHGs dynamics at our study site. These findings provide new insights into the linkage between snow cover and the associated different hydrologic conditions and GHGs dynamics in high-latitude and alpine inland waters. 
A new framework for drought definition, identification, and preparedness
Authors: Lima Alencar Pedro Henrique , Paton Eva Nora
Published: February 2023

Climate change has led to new forms of extreme that until recently were not a topic of concern for the scientific community and general society. Terms such as flash droughts, megadrought, and anthropogenic droughts, among others, entered our vocabulary only recently, in the past decade or so. However, such categorizations are unclear and only come after the fact and with a considerable delay between impacts and definition, hindering preparedness potential. By the current projections and actions regarding climate change, one can only assume that extreme events of different magnitudes, multiple drivers and extensive impacts will keep surprising us. We propose in this work a novel frame to define extreme events. The aim is to allow their identification and increase preparedness against their impacts. The premise is to invert the pyramid of priorities and (1) in collaboration with stakeholders, policymakers and society, assess the potential impacts, defining different levels of “damage”. (2) From the identified levels of impact, use historical data, modelling, and projections to assess frequencies and drivers. Finally, (3) define the thresholds and patterns that lead to such impacts, supporting informed mitigation action and forecast. We present two examples of the application of this methodology regarding crop production in Germany. First, we identify what dry spell duration, thresholds, and seasonality are critical to crop yield. In the second, we identify the flashiness and intensity of flash droughts that lead to increasing crop losses, besides environmental drives to such events. This approach provides better results in identifying and defining such events. It also equips scientists with more didactic and direct measures of extreme events, facilitating communication and empowering action.
Hazard assessment of the potential outburst flood of the Ikhnach Lakes, Uzbekistan
Authors: Umirzakov Gulomjon , Semakova Eleonora , Junsaliev Dilmurad , Sabitov Timur , Mamirov Halimjon , Cicoira Alessandro
Published: February 2023

Glacier lakes outburst floods (GLOFs) study in the Central Asian region is a very important task in terms of global warming and glacier shrinking. It is expected that ongoing climate changes will lead to an increase in the magnitude and frequency of glacial hazards with profound implications for risks. The appearance and expansion of naturally-dammed lakes in the mountain regions of Uzbekistan poses a threat to downstream communities through the potential for sudden drainage.In this study, we considered a possible flood from failures of natural dams of the two well-known Ikhnach lakes located in the Pskem River basin at an altitude of 2400 m. We simulated the GLOF using the RAMMS: DebrisFlow software. In our scenario the potential debris flow from the Ikhnach Lakes can reach a constructed dam of the Pskem new reservoir located at the altitude of 1020 m. The total length of the analyzed flow path is 34 km. It is known that accurate and up-to-date digital elevation models (DEMs) are important tools for studying mountain hazards. We used such global DEMs as input as ALOS PALSAR, and TanDEM-X DEMs. According to the simulation results of possible floods from the Ikhnach lakes in the Debris Flow module of the software, the following results were obtained: (i) the time of the flood to reach the hydropower station (HPP) area - 14800±700 sec ~ 4.11 hours; (ii) maximum water discharge of flood water at the HPP area – 410±20 m3 s-1; (iii) height of the flood in the HPP area - 1.2 m.The obtained results show that there is no potential disastrous effect of the possible flood from the lakes to the residential area as the lowest settlement along the river bed is located considerably higher than flood risk area. However, possible floods in the lakes potentially can reach and have an effect on day to day dam operation of newly constructed Pskem HPP and its engineering infrastructures. Therefore, flood parameters modeled in the RAMMS can be useful information for designing flood damage prevention structures and reservoir operation.
Landslide mechanisms unraveled by RFID monitoring with a Machine Learning approach
Authors: Charléty Arthur , Le Breton Mathieu , Larose Eric , Baillet Laurent
Published: February 2023

 Radio-Frequency Identification (RFID) shows great potential for earth-sciences applications [1], notably in landslide surface monitoring at high spatio-temporal resolution [2] with meteorological robustness [3]. Ten 865MHz RFID tags were deployed on part of a landslide (Harmalière) and continuously monitored for 12 months by a station composed of 4 reader antennas. 2D relative localization was performed using a Phase-of-Arrival approach [4,5], and compared with optical reference measurements.    The spatio-temporal accuracy of the method allowed for a thorough exploration of the landslides mechanisms during a 6-months period of activity. Laplacian clustering was applied to the RFID data and groups of tags with coherent behavior were identified, allowing a fine description of the kinematic motion of the landslide blocks and various mass transfer mechanisms. Each identified block can be monitored individually.         Different deformation zones were highlighted on the monitored zone. The surface movement was initiated by the topmost blocks, transferring after several weeks to the bottom of the monitored zone. This opens the way to building a landslide mechanical model in order to interpret the acquired data.    RFID landslide monitoring allows dense observation of ground surface movements at a centimeter scale and with sub-hourly time precision, and new results bring a finer understanding the the landslides inner mechanisms. References :[1] M. Le Breton, F. Liébault, L. Baillet, A. Charléty, E. Larose, and S. Tedjini,“Dense and long-term monitoring of earth surface processes with passiverfid—a review,” Earth-Science Reviews, p. 104225, 2022.[2] M. Le Breton, L. Baillet, E. Larose, E. Rey, P. Benech, D. Jongmans, F. Guy-oton, and M. Jaboyedoff, “Passive radio-frequency identification ranging, adense and weather-robust technique for landslide displacement monitoring,”Engineering geology, vol. 250, pp. 1–10, 2019.[3] M. Le Breton, L. Baillet, E. Larose, E. Rey, P. Benech, D. Jongmans, andF. Guyoton, “Outdoor uhf rfid: Phase stabilization for real-world appli-cations,” IEEE Journal of Radio Frequency Identification, vol. 1, no. 4,pp. 279–290, 2017[4] A. Charléty, M. Le Breton, E. Larose, and L. Baillet, “2d phase-based rfid lo-calization for on-site landslide monitoring,” Remote Sensing, vol. 14, no. 15,p. 3577, 2022. [5] P. V. Nikitin, R. Martinez, S. Ramamurthy, H. Leland, G. Spiess, andK. Rao, “Phase based spatial identification of uhf rfid tags,” in 2010 IEEEInternational Conference on RFID (IEEE RFID 2010), pp. 102–109, IEEE,2
Aufeis in High Mountain Asia: Evidence from two endorheic basins (Tso Moriri and Pangong Tso)
Authors: Brombierstäudl Dagmar , Schmitt Tobias , Schmidt Susanne , Nüsser Marcus
Published: February 2023

Aufeis is a common phenomenon in permafrost and cold regions of the Northern Hemisphere that develops during winter by successive water overflow and freezing on ice-covered surfaces. Most studies on the occurrence and hydrological importance of aufeis focus on North America and Siberia, while research in High Mountain Asia is still in an early phase. However, its widespread occurrence in the Upper Indus Basin, especially in the cold-arid regions of the Trans-Himalaya and the Tibetan Plateau indicates a need for comprehensive analysis.Two endorheic basins, located at an elevation above 4500 m a.s.l. were selected for an in depth study: Pangong Tso and Tso Moriri covering an area of ~33500 km² and 2350 km², respectively. Based on a time-series analysis of Landsat and Sentinel-2 data for the period 2008–2021, aufeis fields were mapped and their spatial occurrence and temporal patterns were characterized. Derived parameters include the number, maximum area, and topographical parameters, such as elevation and slope. In addition, high altitude wetland areas were classified for both basins in order to explore potential interactions between hydrology and vegetation cover.More than 1000 aufeis fields covering an area of 88 km² were detected in the Pangong basin. The largest individual aufeis field reached an area of 14 km². The size increases from south to north towards the Tibetan plateau. 50 % are located at an elevational range from 4800 and 5000 m a.s.l.. In the Tso Moriri basin 27 aufeis fields covering a maximum area of 9 km² spreading over an elevational range from 4600 up to 5000 m a.s.l. were detected. Here, the largest individual aufeis spreads over 1.7 km². The accumulation of aufeis fields starts with regular overflow of water between November until April, while aufeis is usually completely melted by the end of July. However, in the Pangong basin 28 aufeis fields remain until the onset of the next accumulation cycle. All of them are located in elevations above 5000 m a.s.l.. In contrast to the Pangong basin, aufeis fields in the Tso Moriri basin are mostly found in close proximity to wetlands, on areas with frequent aufeis accumulation vegetation is almost completely absent. Potential water sources for overflow events are often located close or within the wetland areas, suggesting close hydrological interactions. The study contributes to an improved understanding of aufeis development and distribution in cold-arid environments and will help further comprehensive cryosphere studies in High Mountain Asia and beyond.
Air pollution in Rotterdam: urban vs. port contributions and the role of neighborhood design
Authors: Fry Juliane , Ooms Pascale , Vermeulen Roel , Kerckhoffs Jules
Published: February 2023

The Ruisdael Rotterdam campaign in August - September, 2021 featured a comprehensive suite of air pollutant, greenhouse gas, and meteorological data collection across the city and port of Rotterdam, Netherlands. We will present data from the Utrecht University Air Quality car mobile platform, which was deployed for >80 hours of sampling across the region, measuring particulate matter (PM1, PM2.5 and PM10), ultrafine particulate matter count (UFP), black carbon (BC), carbon dioxide (CO2), and nitrogen dioxide (NO2). We analyze this data with particular focus on the relative contribution of urban and port emissions to air pollution levels across the city, and on the role of neighborhood design in determining street-level concentrations of pollutants.
Regime-oriented causal model evaluation of Atlantic-Pacific teleconnections in CMIP
Authors: Karmouche Soufiane , Galytska Evgenia , Runge Jakob , Meehl Gerald , Phillips Adam , Weigel Katja , Eyring Veronika
Published: February 2023

Regime-oriented causal model evaluation of Atlantic-Pacific teleconnections in CMIP6Abstract:The Pacific Decadal Variability (PDV) and the Atlantic Multidecadal Variability (AMV) are two important modes of long-term internal variability that significantly impact the climate system and its spatio-temporal changes. In this study, we use a regime-oriented causal discovery method (Karmouche et al, 2022) to examine the changing interactions between the PDV and AMV. The results of this analysis are used to evaluate the ability of models participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6) to represent the observed changing interactions between the PDV, AMV, and their extra-tropical teleconnections.Applying the regime-oriented causal discovery method to reanalysis time series revealed that the interactions between AMV and PDV differ from one regime to the other. The results also show that there are both direct and indirect connections between the Atlantic and Pacific oceans, which are established through various teleconnection patterns.In order to evaluate the ability of climate models to represent these observed interactions, we applied the same regime-oriented causal discovery method to the CMIP6 Large Ensemble historical simulations. We show that several models performed well in simulating the observed causal patterns when AMV and PDV are "out-of-phase", and that the two models with the largest number of members generally outperformed other models in simulating observed causal patterns during longer regimes. This work shows how causal discovery on LEs complements the available diagnostics and statistics metrics of climate variability to provide a powerful tool for climate model evaluation.Karmouche, S., Galytska, E., Runge, J., Meehl, G. A., Phillips, A. S., Weigel, K., and Eyring, V.: Regime-oriented causal model evaluation of Atlantic-Pacific teleconnections in CMIP6, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2022-1013, 2022.
An industry framework to estimate changes in hurricanes wind risk due to climate change
Authors: Joffrain Mathis
Published: February 2023

Since the early 90s, natural catastrophe models have been mainly used by the re/insurance industry for pricing and risk management purposes.These rely on a catalogue of plausible yet so far unseen events called the “stochastic events catalogue”. For each of these events a loss and a frequency is calculated leading to an industry standard output called YLT (Year Loss Table).Based on the YLT, insurers can calculate a wide range of risk measures such as the Value at Risk or the annual average loss. They also can modify the YLT to incorporate impacts by Climate Change. This poster sets out to:(i) Explain the concept of Year Loss Table (YLT)(ii) Show the derivation of key risk measures.(iii) Describe how the YLT can be modified to take into account the impacts by climate change, with a focus on the North Atlantic hurricane wind risk.(iv) Present the results obtained by the approach in (iv).
The anisotropy of internal tide generation: Global estimates for the M2 tide and implications for tidally driven mixing parameterizations
Authors: Pollmann Friederike , Nycander Jonas , Eden Carsten , Olbers Dirk
Published: February 2023

Energetically consistent parameterizations of small-scale turbulent mixing rely on internal gravity wave energetics. A crucial ingredient is the generation of internal waves by the interaction of the barotropic tide with rough seafloor topography. Owing to the orientation of topographic obstacles and the directionality of barotropic tidal currents, this process is inherently anisotropic, but so far, this dependence on horizontal direction was not taken into account in global estimates of internal tide generation. We present the global application of a new method based on linear theory that resolves the horizontal direction of the internal tide generation, showing the substantial anisotropy of this process. How this in turn affects vertical mixing and the ocean state is evaluated with the aid of the internal gravity wave model IDEMIX, a backbone of energetically consistent parameterizations of wave-induced mixing.
Identifying late spring frost impacts on European beech near its upper elevational limit using climatic and dendrochronology data
Authors: Martínez-Sancho Elisabeth , Baumgarten Frederik , Reim Joanna , Gessler Arthur , Vitasse Yann
Published: February 2023

Global warming has considerably advanced the start of the growing season of temperate trees. However, the rate of this phenological change does not necessarily track the changes in the date of the last spring frost, also induced by climate change, which may result in a higher risk of false spring. When a late spring frost (LSF) occurs during tree leaf emergence, it can lead to complete tree defoliation. Although the impacts of LSFs are rarely fatal for a tree, it is essential to identify those years to understand its effect on tree performance and vitality.Here we aimed at identifying the years with potential frost damages, i.e., when frost have occurred around the time of leaf emergence of European beech (Fagus sylvatica L.) growing at two different elevations (1,065 and 1,365 m asl) at the Weissenstein (Swiss Jura mountains). We calibrated several phenological models using the Phenology Modeling Platform gathering various models considering forcing temperatures only or with a combination of chilling and photoperiod using high-resolution climate datasets and available phenological observations from a nearby station conducted from 2005 to 2022 (9 km away from our study sites, 1,120 m asl). The analyses are ongoing and will be compared to dendrochronology data collected from the same sites and be used to disentangle the pure effect of LSF from drought impacts on beech growth. Further investigations should be conducted on this aspect as the frequency and severity of extreme droughts are expected to increase while spring onset will continue to advance under a warmer climate, potentially increasing the risk of frost damage.
Biomass Burning Contributes Less to Remote Tropospheric Ozone than Human Activity, Indicated by a Deep Learning Approach
Authors: Ma Chaoqun , Cheng Yafang , Su Hang
Published: February 2023

Tropospheric ozone (O3) is a key greenhouse gas and pollutant that is receiving increasing attention globally.  While there are many sources of tropospheric O3, precursors from human activity (Anthro) and open biomass burning (BB) are the only ones that can be controlled. As such, it is crucial for policymakers to understand the relative contributions of the two. However, determining the contribution of O3 can be challenging as it cannot be directly observed. It must be calculated by chemical transportation model (CTM) simulation which could be biased for unreal emission inventory, or estimated by real observations that assumes too simple chemical and transportation processes.In this paper, we propose a solution by developing a deep learning (DL) model that combines both CTM simulations and observations. The DL model is able to learn a generalized relationship between unobservable O3 contribution from Anthro or BB sectors and observable mixing ratio of tracers simulated by CTM with full chemistry and transportation processes. The DL model then, when applied to observed tracers, could avoid the bias from model to provide an accurate estimation of the contributions in reality.Our results indicate the contribution from BB to tropospheric remote ozone mixing ratio is no larger than that from Anthro emission from a global perspective, even when uncertainties are deliberately tuned to bias BB. Therefore, the reduction of anthropogenic emissions should be the top priority for controlling global background O3 levels, at least for the time period of 2016-2018 studied.
Application of historical cadastral maps and high resolution airborne LiDAR topography to distinguish anthropogenic from natural karst landforms: case study of karst dolines
Authors: Breg Valjavec Mateja , Ciglič Rok , Geršič Matjaž , Čonč Špela
Published: February 2023

Dolines are concave circular karst landforms that are clearly presented by topography data (topographic maps), especially on high-resolution LiDAR digital terrain models (DTM). In the karst landscape, man has reshaped natural dolines through centuries by collecting rocks and soil to increase the flat area of tillable (cultivated) land at the bottom of the doline. By this human-induced process, the natural doline was reshaped into a cultivated doline. Cultivated dolines have a rich historical legacy of use for local agricultural production, high geomorphological value for geodiversity and present an important habitat supporting biodiversity. They are an element of agro-karstic landscape (paysage agro-karstiques) and are distinctive of Mediterranean karst landscapes like Dinaric karst, Central massive, Apulia etc. Most of the cultivated dolines have been recently abandoned, and covered by forest, thus the human impact is not evident anymore so clearly.In most studies on natural characteristics and processes in dolines, there is no distinct separation between natural and cultivated dolines and no consideration of past agricultural land use. Thus, the main goal of this study/presentation is to provide a geoinformatics methodology to separate cultivated dolines from natural dolines based on differences in micro-topography by using recent very high-resolution LiDAR topography data and historical cadastral maps (19th century).Using visualized LiDAR DTM the most evident morphometric differences between the natural and cultivated doline landforms were recognized. Cultivated dolines were characterized by (1) a circular concave landform with a flat bottom (2) the presence of anthropogenic elements, such as circular stonewalls at the upper doline edge, which provides evidence of stone-removal from the doline slopes (smooth surface). Additionally, in the 19th-century cadastral maps, only individual dolines with important land use were marked as special lots. Given the rural character of the landscape during that time, the only land use recorded in the concentric lots of the dolines was agricultural use (arable fields, gardens, meadows, and pastures). As a result, the number, location and surface coverage of cultivated dolines were precisely defined for classical karst regions in SW Slovenia. Based on Lidar data, bowl-shaped cultivated dolines with flat bottoms were separated from non-cultivated funnel-shaped dolines. 
Marine primary productivity and redox conditions during the Permian-Triassic transition
Authors: Müller Johann , Sun Yadong , Yang Fen , Regelous Marcel , Fantasia Alicia , Joachimski Michael
Published: February 2023

The end-Permian mass extinction occurred during an interval of extreme global warming caused by enormous greenhouse gas emissions from Siberian Traps volcanism. A common concomitant effect of global warming is ocean deoxygenation which can be observed in geological and modern times. In the case of the end-Permian mass extinction, marine anoxia has long been postulated as one of the key killing mechanisms. However, causes for the Permian-Triassic (P-T) deoxygenation are under debate. Two frequently invoked scenarios are eutrophication and ocean stagnation.We present geochemical data from two P-T carbonate sections across the Paleotethys Ocean. Productivity-related proxies (reactive P, TOC and trace elements) indicate high organic matter and P export to the sediments during the late Permian. A decrease in all these proxies during the C. yini conodont Zone suggests a decline of marine primary productivity at the study sites, approximately 30 kyr prior to the main marine extinction interval. Moreover, C/P ratios document a switch from intense P-recycling to efficient P-burial. Above the C. yini conodont Zone, Ce-anomalies (measured on the carbonate fraction of our samples) shift from negative to positive revealing deoxygenation of the local water columns.Our proxy data imply that low productivity coincided with anoxic conditions at the study sites, hence not supporting a eutrophication scenario as a cause for the intensification of anoxia. Instead, we argue that ocean stagnation caused a stably stratified water column with reduced mixing, upwelling, overturning and ventilation. Regenerated P was trapped in the deeper, aphotic zones of the stagnant Paleotethys Ocean and was not available for photosynthesis.We suggest that those settings of the Paleotethys Ocean represented by our study sections (deep slope and distal carbonate ramp) were characterized by high productivity and well-ventilated conditions during the relatively cool late Permian. Prior to the marine extinction interval, conditions switched to a low-productivity-anoxic state which persisted into the Early Triassic. This productivity collapse likely resulted in food shortage for higher trophic levels further stressing heterotrophic organisms before and during the extinction event.
The occurrence of dichlorodiphenyltrichloroethanes (DDT) and its metabolites in Chinese forest soils: Implications for sources and environmental processes
Authors: Qu Chengkai , Wang Ruiqi , Sun Wen
Published: February 2023

Dichlorodiphenyltrichloroethane (DDT) and its metabolites are highly toxic and pose chronic effects to the biosphere. As a natural storage pool, forests have great potential to capture them from the atmosphere and migrate them to the forest soil, which, in turn, influences the safety of the forest ecological environment. In this study, a systematical survey of DDT and its metabolites has been carried out to measure their spatial variations in Chinese forest soils. The main objectives of this study were to (1) investigate the levels, distribution and sources of DDT and its metabolites, and further estimate their mass inventories in Chinese forest soils, (2) explore the impact of soil properties on their distribution, and (III) assess the ecological and health risks of DDT and its metabolites. The research results were as follows. The average concentration of ΣDDTs reached up to 9.75 ng/g, and p,p’-DDT is the main component. Significant difference in the concentration of ΣDDTs was observed between the southeast and northwest regions (p<0.01), which may be related to multiple factors such as pesticide use, rainfall and altitude. The forest soil quality inventory is about 0.58×103 tons, which is lighter than that of domestic farmland soil. 56.1% of soil samples were less than the low value of risk assessment (ERL). The concentration of ΣDDTs in the East and middle is higher than that in the West, and the high value is mainly distributed in the coastal areas. DDTs were mainly from the input of the mixed source composed of industrial DDT and dicofol, of which at least 97% came from industrial DDT and up to 4% from dicofol. ΣDDTs was only positively correlated with precipitation and population density (p<0.05). The degradation of DDT in soil occured from primary stage to high stage. The possible degradation pathways involved in DDTs entering forest soil were preliminarily deduced. Firstly, the surrounding pollution sources volatilize DDTs from soils to the atmosphere through secondary emission. In this process, DDT was continuously transformed into DDE through photodecomposition. The atmosphere rich in DDTs were transported to the forest area and then into the forest surface soil through atmospheric dry and wet deposition. Then, DDT transported continuously accumulated and degraded in forest soil. In the alternation of anaerobic and aerobic process, the main degradation pathways are DDT→DDD→DDMU, DDT→dicofol+DBP, DDT→DDE→DDMU, DDMU→DDNU.
Violent land terrain alterations and their impacts on water management; Case study: North Euboea
Authors: Dimitriadis Panayiotis , Kougia Matina , Sargentis G.-Fivos , Iliopoulou Theano , Mamasis Nikos , Koutsoyiannis Demetris
Published: February 2023

North Euboea is a place with high topographic relief, covered mostly by wild forests, with a lot of small rivers receiving high amounts of rainfall. After 2017 a severe disease started to eliminate plane trees (Platanus orientalis), which were growing on the riverbanks stabilizing the flow of water. One more dramatic event which severely impacted North Euboea was the wildfire that occurred in August 2021 and burnt 52,900 ha. Both events drastically changed the land terrain, causing various impacts on the area’s watersheds. In this vein, we try to investigate the changes in the water flow and inspect the combined effects of these landscape alterations on water management. 
Towards a better understanding of fine PM sources: online and offline datasets combination in a single PMF
Authors: Via Marta , Yus-Díez Jesús , Canonaco Francesco , Petit Jean-Eudes , Hopke Philip , Reche Cristina , Pandolfi Marco , Ivančič Matic , Rigler Martin , Querol Xavier , Alastuey Andrés , Minguillón María Cruz
Published: February 2023

Source apportionment (SA) techniques allow matching the measured ambient pollutants with their potential source origin. Hence, they are a powerful tool for assessing air pollution mitigation strategies. The Positive Matrix factorization (PMF) model is one of the most widely used SA approaches, and its multi-time resolution add-on (MTR-PMF), which enables mixing different instrument data in their original time resolution, is the focus of this study.Co-located one-year measurements of non-refractory submicronic particulate matter (NR-PM1), black carbon (BC) and metals, obtained respectively, by a Q-ACSM (Aerodyne Research Inc.), an Aethalometer (Aerosol d.o.o.) and offline fine PM samples collected on quartz-fibre filters, were combined in a single PMF in two different resolutions (30 minutes for the NR-PM1 and BC, and 24h every 4 days for the offline samples). The multi-time resolution PMF (MTR-PMF) was run varying both the time resolution (averaging the dataset) and the uncertainty weightings of both datasets in order to assess the impact of these variations on the model output. The resolution assessment revealed that averaging the high-resolution data was disadvantageous in terms of model residuals and environmental feasibility. Regarding uncertainty weightings, overweighting the uncertainties of the 24-h dataset dividing them by two provided the most optimal scaled residuals adjustment.The MTR-PMF was run with the optimised time resolution and uncertainty weightings retrieving eight PM1 sources: ammonium sulphate (AS) + heavy oil combustion (24%), ammonium nitrate (AN) and ammonium chloride (15%), fresh SOA (15%), traffic (14%), biomass burning (11%), aged SOA + mineral dust (8%), urban mix (7%) and cooking-like organic aerosol + industry (6%). The MTR-PMF technique allowed the identification of two more sources respect a dataset containing the same species at a 24h time resolution (base case) and four more respect to the conventional offline and PMF, proving that the combination of both high and low time resolution data through MTR-PMF is significantly beneficial for SA. This is especially true for those sources which have been disentangled with respect to the conventional and base case PMFs. 