bluuebunny/crossref_metadata_2025 huggingface dataset:
Effective Science Communication for Climate Change Adaptation on Regional Scale – Regional Climate Information Platforms: A Case Study in Oberland (Upper Bavaria – Germany)
Authors: Koc Gamze , Lorenz Christof , Feldmann David , Böker Brian
Published: March 2024

Climate change poses a significant threat to communities on regional scale as well as worldwide, and the urgency for adaptation is particularly crucial for small- and medium-sized communities and cities. However, a pervasive knowledge gap exists in these regions, hindering their ability to adapt effectively. The lack of accessible and tailored climate information and services exacerbates the vulnerability of these communities. Therefore, this study focuses on addressing this knowledge gap and developing effective science communication strategies, emphasizing the regional scale through the implementation of Regional Climate Information Platforms.The chosen case study location, Oberland (Upper Bavaria, Germany), is characterized by complex terrain, encompassing Alpine and Pre-Alpine regions, with three distinct climate zones in close proximity. The diverse topography of Oberland presents unique challenges, as climate change impacts may manifest differently across the region, particularly for hydro-meteorological extremes. Moreover, the region heavily depends on tourism, making it economically susceptible to changing climate conditions and increasing extreme events, such as extreme precipitation, flooding, summer heatwaves and decreasing snowfall affecting tourism activities (e.g. skiing, hiking, climbing, etc.).Thus, the study aims to follow a comprehensive workflow, starting with the collection of climate data, followed by bias correction and regionalization for Oberland. High-resolution rainfall statistics will be developed and integrated into hydrodynamic simulations and cluster analyses of flood triggering mechanisms. The outcome will be the creation of risk maps for hydro-meteorological extremes, providing crucial information for stakeholders and decision-makers. Finally, these risk maps will be then incorporated into the digital decision support system, Platform Oberland within the KARE (Klimawandelanpassung auf regionaler Ebene) Project.In addition to the scientific aspects, the study emphasizes the importance of stakeholder interaction and co-design in the development of Platform Oberland. The collaboration between scientists and stakeholders ensures that the information generated is relevant and usable for decision-making. With this study, it is also aimed to identify "best-practice" approaches for transferring scientific workflows and results into actionable climate-related measures for small- and medium-sized communities.This case study in Oberland could serve as a regional model for effective science communication and adaptation strategies at the regional level for hydro-meteorological extremes, offering insights into the development of climate indicators and the integration of scientific findings into practical, community-centered climate adaptation.
Detecting Linear Kinematic Features in Arctic Sea Ice in a Warmer World Using High Resolution Model Output
Authors: Gärtner Jan
Published: March 2024

The polar sea ice cover exhibits narrow bands of increased deformation, resulting in the formation of leads and pressure ridges. They are referred to as linear kinematic features (LKFs). They are important features of the sea ice field as they directly influence the heat and momentum exchange between ocean and atmosphere. By doing so, they influence the development of not only the sea ice cover but also the ocean and the local climate. Conversely, LKFs are also influenced by climate changes as the sea ice cover will be affected by changes in atmospheric and ocean temperature. In this work, the LKFs in the Arctic sea ice cover in current climate are compared to those in a warmer world. An LKF detection and tracking algorithm will be used to create a climate change signal. For this, the number of LKFs as well as their lifetimes are taken into account. The data analyzed in this work is created by the ocean-sea ice model FESOM. As LKFs are highly localized features, using a high spatial resolution is crucial. The resolution used in the analyzed runs is 1km. They span over five years starting at 2010, 2050, and 2090.
Fog controls biological cycling of soil phosphorus in the Coastal Cordillera of the Atacama Desert
Authors: Sun Xiaolei , Amelung Wulf , Klumpp Erwin , Walk Janek , Mörchen Ramona , Böhm Christoph , May Simon Matthias , Tamburini Federica , Bol Roland
Published: March 2024

Soils in hyper-arid climates, such as the Chilean Atacama Desert, show indications of past and present forms of life despite extreme water limitations. We hypothesize that fog plays a key role in sustaining life. In particular, we assume that fog water is incorporated into soil nutrient cycles, with the inland limit of fog penetration corresponding to the threshold for biological cycling of soil phosphorus (P). We collected topsoil samples (0‒10 cm) from each of 54 subsites, including sites in direct adjacency (< 10 cm) and in 1 m distance to plants, along an aridity gradient across the Coastal Cordillera. Satellite-based fog detection revealed that Pacific fog penetrates up to 10 km inland, while inland sites at 10‒23 km from the coast rely solely on sporadic rainfall for water supply. To assess biological P cycling we performed sequential P fractionation and determined oxygen isotope of HCl-extractable inorganic P (δ18OHCl-Pi). Total P (Pt) concentration exponentially increased from 336 mg kg-1 to a maximum of 1021 mg kg-1 in inland areas ≥ 10 km. With increasing distance from the coast, soil δ18OHCl-Pi values declined exponentially from 16.6‰ to a constant 9.9‰ for locations ≥ 10 km inland. Biological cycling of HCl-Pi near the coast reached a maximum of 76‒100%, which could only be explained by the fact that fog water predominately drives biological P cycling. In inland regions, with minimal rainfall (< 5 mm) as single water source, only 24±14% of HCl-Pi was biologically cycled. We conclude that biological P cycling in the hyper-arid Atacama Desert is not exclusively but mainly mediated by fog, which thus controls apatite dissolution rates and related occurrence and spread of microbial life in this extreme environment.
Permian-Triassic CO2 before, during and after the mass extinction
Authors: Jurikova Hana , Whiteford Ross , Garbelli Claudio , Wang Wenquian , Shi Guang Rong , Shen Shuzhong , Angiolini Lucia , Rae James
Published: March 2024

The study of mass extinctions is invaluable for understanding the effects of extreme environmental change on the different components of the Earth system and their responses and implications. Growing interest in extinctions, combined with new field evidence and analytical breakthroughs over recent years, has enabled us to zoom into individual events, construct their high-resolution chronologies and proxy records and start untangling their cause mechanisms from consequences. This is fundamental to progressing our knowledge, however, how far can we zoom in without overlooking the wider context? To what extent does the prior background climate state influence the outcome and magnitude of an extinction? For example, how would our understanding of the Permian-Triassic mass extinction change if we were to find the late Permian had low or high background CO2? And what was CO2’s fate in its aftermath? We present a new multi-million-year boron isotope-derived record of ocean pH and atmospheric CO2 spanning the Permian-Triassic, which allows us to establish the climate conditions before and after the mass extinction, as well as during the eruption of the Siberian Traps Large Igneous Province (LIPs) considered the ultimate cause (i.e. the trigger) of the extinction. We discuss the implications of our new CO2 record, and more broadly reflect on the role of background climate as a generalizable component of extinctions.
The hydrogen isotope composition of nocturnal sucrose does not reflect the 2H-depletion of remobilized leaf starch
Authors: Holloway-Philips Meisha , Wacker Anina , Nelson Daniel B. , Tcherkez Guillaume , Lehmann Marco , Kahmen Ansgar
Published: March 2024

The hydrogen isotope composition (δ2H) of cellulose is inherently linked to that of sucrose synthesised in leaves. During the daytime, sucrose is synthesised from photosynthetic products, and at night, from remobilised starch. From theory, the δ2H of starch should be 2H-depleted relative to triose-phosphates generated during photosynthesis. Consequently, sucrose δ2H values should diurnally vary so that on a flux-weighted basis, cellulose δ2H values could provide a sensitive proxy for the partitioning of photoassimilates between sucrose and starch. However, this hypothesis is yet to be tested.We made diel measurements of sucrose and starch δ2H in three species – Vicia faba (bean), Raphanus sativus (radish), and Helianthus annuus (sunflower) differing in their sucrose/starch dynamics. Plants were grown under controlled environment conditions to minimise variation in leaf water δ2H and physiology, so that changes in sucrose δ2H could be attributed to day/night shifts in photoassmiliates vs transitory starch used for sucrose synthesis. We confirmed that transitory starch in leaves was 2H-depleted compared with sucrose, on average by around 100 ‰. However, whilst there were species-specific trends in daytime sucrose δ2H, surprisingly, there was no significant day-night difference in the three species. Several explanations are discussed for the lack of day/night variation in the δ2H of sucrose, including the signal being subsequently overwritten in the cytosolic processing of sugars or masked by 2H-enrichment at other positions to counteract the 2H-depleted starch signature. We qualify the latter possibility with a simplified steady-state isotopic model.
Improved Spatial Autocorrelation Method for Dispersion Imaging of Ambient Seismic Noise
Authors: Xi Chaoqiang , Liu Ya , Zhang Hao
Published: March 2024

The determination of shear (S) wave velocities within near-surface earth layers holds paramount significance in the realms of hazard assessment and geotechnical applications. In the fields of geophysics and civil engineering, ambient noise surface wave methods have garnered considerable attention due to their effectiveness in determining shear wave velocities within near-surface layers, particularly in densely populated urban areas. The spatial autocorrelation (SPAC) method, introduced in 1957 for the analysis of ambient noise dispersion, has maintained enduring relevance and widespread utilization within the realm of engineering geophysics in recent years[Aki 1957; Hayashi et al.,2022].However, the dispersion energy generated using the SPAC (Spatial Autocorrelation) method is susceptible to contamination, especially at high frequencies, resulting from the occurrence of 'crossed' artifacts[Cheng et al.,2023]. The presence of these 'crossed' artifacts leads to the intersection and distortion of dispersion energy within the frequency–velocity domain[Xi et al.,2021]. These artifacts emerge from the simultaneous fitting of both inward and outward propagating cylindrical wavefields, encapsulated within the Bessel function. To mitigate the impact of these artifacts, we advocate for the exclusive fitting of the outward propagating cylindrical wavefield. To achieve this, a combination of the spatial autocorrelation coefficient and its Hilbert transform is employed, facilitating the construction of the outward propagating cylindrical wavefield.In our proposed improved SPAC method, we replace the Bessel function with the Hankel function for fitting the constructed outward propagating cylindrical wave. Both synthetic and real-world field examples substantiate the efficacy of the proposed method in enhancing the accuracy of surface wave multimode dispersion measurements. This modification not only eliminates the 'crossed' artifacts but also underscores the robustness of our approach in refining the precision of dispersion analysis, particularly in scenarios involving complex wavefields and varying geological conditions.Aki, K., 1957. Space and time spectra of stationary stochastic waves, with special reference to microtremors. Bulletin of the Earthquake Research Institute, 35(3), 415–456.Cheng F, Xia J, Xi C. Artifacts in High-Frequency Passive Surface Wave Dispersion Imaging: Toward the Linear Receiver Array. Surveys in Geophysics, 2023: 1-31.Hayashi K, Asten M W, Stephenson W J, et al. Microtremor array method using spatial autocorrelation analysis of Rayleigh-wave data. Journal of Seismology, 2022, 26(4): 601-627.Xi C, Xia J, Mi B, et al. Modified frequency–Bessel transform method for dispersion imaging of Rayleigh waves from ambient seismic noise. Geophysical Journal International, 2021, 225(2): 1271-1280.
Contribution of SeismoCitizen Raspberry Shake dense network in monitoring induced seismicity in northern Alsace (France)
Authors: Turlure Mathieu , Grunberg Marc , Engels Fabien , Jund Hélène , Schlupp Antoine , Schmittbuhl Jean
Published: March 2024

PrESENCE ANR project (2022-2025) focuses on seismic hazards induced by deep geothermal operations in northern Alsace, France, and their associated societal perception. Seismological observations are obtained using a large number of low cost internet-connected equipment (Raspberry Shake seismic station and associated open access data). The breakthrough strategy of the project relies on the deployment of the stations in residences or administrative buildings of non-seismologist volunteer citizens or authorities. The aim is to use those stations to densify the french permanent seismic network, and to improve the detection and location of seismic events, in particularly small ones. Our presentation will be focused on the Soultz-sous-Forêts and Rittershoffen areas (northern Alsace, France), which are sites of deep geothermal operations.  The topology of the seismological network was determined by the location of permanent stations, from Epos-France permanent network (4) and public stations belonging to geothermal operators (2), the number of low-cost stations (35) to be deployed in the region, the location of deep geothermal power plants (Soultz and Rittershoffen) and the location of volunteer citizen hosts. Volunteer citizens were selected initially by word of mouth, then by a call for applications (through social networks, flyers, local newspapers). Twenty-one stations are currently (end of 2023) hosted in the area. About ten additional stations are planned to be deployed early 2024 in the area. Based on our past experience in deploying similar networks in other contexts and regions (Mayotte, Vosges massif, Mulhouse, etc.), we have consolidated the installation of these stations to ensure reliable data acquisition and, in particular, to achieve better data completeness (acquisition directly at the station using the Seedlink protocol via a VPN, hardware watchdog). We use Ansible (an open source IT automation platform) to facilitate the deployment of Raspberry Shake stations configuration and management tasks, ensuring rapid and consistent production deployment. The workflow for building the seismicity catalog benefits from our advances in the use of new artificial intelligence tools, such as PhaseNet, a deep learning automatic picking method, as well as in the development of a deep learning method for discrimination between earthquakes, quarry blasts and explosions. Our tests over the year 2023 show that even if the stations are installed in urban areas (and therefore in a noisy environment), the network is able to automatically detect and locate many small induced earthquakes, including around 250 with a high level of confidence, compared with the ten detected or so by the standard procedure of BCSF-Renass, the French National Observation Service.
Contribution of blowing snow sublimation to the surface mass balance of Antarctica
Authors: Gadde Srinidhi , van de Berg Willem Jan
Published: March 2024

Blowing snow transport is an essential polar boundary layer process and constitutes the major ablation term in the Antarctic ice sheet's surface mass balance (SMB). Here, we present an update to the blowing snow model in the Regional Atmospheric Climate Model (RACMO), version 2.3p3, to include the effect of blowing snow sublimation and transport in the prognostic equations for temperature and water vapour. Updates rectify the numerical artefacts in the modelled blowing snow flux variation with wind speed. Updates include the replacement of uniformly distributed ice particle radius, which limited the maximum ice particle radius to ≤ 50 μm, with an exponentially increasing ice particle radius distribution to include all the relevant range of radii between 2 to 300 μm without any additional computational overhead. We compare the model results against the observations from site D47 in Adèlie Land, East Antarctica. These updates correct the numerical artefacts observed in the previous model results, and RACMO successfully predicts the power-law variation of the blowing snow transport flux with wind speed. Updates also improve the prediction of the magnitude of the blowing snow fluxes. In addition, at site D47, we obtain an average blowing snow layer depth of 230±116 μm, which falls within the range of values obtained from satellite observations. A qualitative comparison of the simulated blowing snow frequency from RACMO with CALIPSO satellite observations shows that the simulated frequency matches well with the satellite product. Compared to the previous model version for the period 2000–2010, the contribution of integrated blowing snow sublimation is increased by 30%, with a yearly average of 176±4 Gt yr-1. The increase amounts to 1.2% reduction in the integrated SMB of the Antarctic ice sheet. The updates also introduce changes in the climatology of blowing snow in Antarctica. Specifically, we observe significant changes in the sublimation of interior regions of the escarpment zone of Antarctica.
Creating a holistic view on the situation of historic parks and gardens
Authors: Moßgraber Jürgen , Hellmund Tobias , Reuter Jürgen , Kotova Lola , Matheja Katharina
Published: March 2024

Extreme weather events due to climate change not only affect nature, but can also impact historical buildings, collections, and historic parks and gardens. Assessing the extent to which cultural heritage is threatened by such weather and climate events is an interdisciplinary task that requires the collaboration of experts from heritage preservation and restoration, climate research, natural and engineering sciences, social and economic sciences, landscape architecture, informatics, and more.Due to this complexity and the abundance of available information, modern IT tools are crucial in explaining the condition of cultural heritage sites to decision-makers and providing insights into future developments. To get a better understanding of the situation of historic parks and gardens, a knowledge platform can offer map-based visualization of data. The biggest challenge in developing such a platform was the integration and processing of relevant data. Due to the interdisciplinary nature of the field and the heterogeneity of the data, it was designed to be able to flexibly integrate and process various types of data. For example, the platform incorporates:- (Live) sensor data,- Severe weather risk maps,- Climate projections and models,- Expert knowledge incl. tree cadasters,- Image and video materials, and- Unstructured documentsThis integration aims to provide users with a comprehensive view of their properties.As part of the project, soil moisture sensors were deployed in Sanssouci Park in Potsdam Germany to monitor soil moisture levels over an extended period of time. These sensors allow for the measurement of soil moisture and temperature at a depth of one meter. A total of 10 sensors were placed at representative locations to provide insights into the irrigation needs of the property. The sensors transmit their data using LoRaWAN (Long Range Wide Area Network), a wireless communication technology that can reliably transmit smaller amounts of data over long distances with low energy consumption. Given the vastness of the Sanssouci Park case study, this approach is suitable as it allows the sensors to be placed in relevant locations without having to consider technical constraints.The collected data is stored using a FROST server, which is an open-source software project that enables the capture of time series data, including their metadata. The FROST server implements the SensorThings API, a standard of the Open Geospatial Consortium, which aims to standardize the description of sensor data and simplify their reuse. For the visualization of the captured sensor data, a map view has been developed that allows for the positioning of the sensors and the display of their measured data.
Modelling approach to account for competitive sorption of PFAS in MODFLOW-based solute transport simulations
Authors: Fagerlund Fritjof , Johnson Mason , Earon Robert
Published: March 2024

Per- and polyfluoroalkyl substances (PFAS) are extremely persistent contaminants that constitute an increasing problem for drinking water resources worldwide. Modelling tools to predict the subsurface transport of PFAS are important both for risk assessment and for design and evaluation of in-situ PFAS stabilization using activated carbon (AC) or other sorbent amendments. At highly contaminated hotspots, such as fire-fighting training sites, a mixture of many PFAS are typically present in the contaminated groundwater. The different PFAS can interact in the sorption process and e.g. compete for sorption sites, which may affect both the risks associated with PFAS transport and the efficacy of remediation strategies such as sorbent amendments.The aim of this study was to develop a user-friendly modelling approach to account for competitive sorption of PFAS in a solute transport package that can be applied in combination with groundwater flow modelling with MODFLOW, and to illustrate the effect of competition on the transport of different PFAS for a field site scenario. A competitive sorption model for PFAS was implemented in MODFLOW/MT3DMS and can be run in combination with a graphical user interface for MODFLOW such as GMS. The new model is aimed for practical applications of site modelling and PFAS risk assessment when competition effects may be important. Modelling of a field site scenario based on a fire-fighting training site at a Swedish airport illustrates that competitive sorption affects the transport of PFAS in the groundwater and can provide valuable site-specific insight for remediation efforts.
Identification of system-specific observation errors for SLR and VLBI telescopes at GOW
Authors: Zeitlhöfler Julian , Bloßfeld Mathis , Neidhardt Alexander , Eckl Johann
Published: March 2024

The observations of the four space-geodetic techniques (GNSS, SLR, VLBI, DORIS) are used for the computation of the International Terrestrial Reference Frame (ITRF) and for the realisation of its geodetic datum as well as (except VLBI) for the precise orbit determination of Earth-observing satellites. The ITRF itself is fundamental for a broad variety of scientific and societal applications such as Earth monitoring and positioning, relevant for satellite companies, logistics, and finally new techniques like autonomous driving. However, all four techniques still suffer from unknown systematic measurement or modelling errors which makes the estimation of bias parameters inevitable.The Geodetic Observatory Wettzell (GOW), Germany, with its unique and ideal test environment comprising multiple GNSS antennas, three VLBI antennas, two SLR telescopes, a DORIS beacon, and numerous other sensor systems provides the opportunity to systematically identify, quantify, understand, and compensate system-specific measurement errors. The installation of a so-called common target (CT) in 2017 and the realisation of a common clock (CC) enables a profound analysis of space-geodetic measurements. The CT is connected to the clocks of the space-geodetic techniques via delay-compensated fibre links which allows so-called ‘closure in time’ experiments.Within the recently established DFG research unit ‘Clock Metrology: Time as a New Variable in Geodesy’, one project at DGFI-TUM focuses on the investigation of time-related and technique-specific errors using ‘closure in time’ experiments at the GOW. Therefore, completed experiments involving the CT are analysed and enhanced experiments will be planned and conducted. With the aid of the CC, the source of present measurement discrepancies will be investigated and resolved. We present the current state of our work with the main focus on the analysis of VLBI and SLR observations of the two SLR and three VLBI systems at GOW.
Down-scaling and bias correction of precipitation with generative machine learning models 
Authors: Aich Michael , Pan Baoxiang , Hess Philipp , Bathiany Sebastian , Huang Yu , Boers Niklas
Published: March 2024

Earth system models (ESMs) are crucial for understanding and predicting the behaviour of the Earth’s climate system. Understanding and accurately simulating precipitation is particularly important for assessing the impacts of climate change, predicting extreme weather events, and developing sustainable strategies to manage water resources and mitigate associated risks. However, earth system models are prone to large precipitation biases because the relevant processes occur on a large range of scales and involve substantial uncertainties. In this work, we aim to correct such model biases by training generative machine learning models that map between model data and observational data. We address the challenge that the datasets are not paired, meaning that there is no sample-related ground truth to compare the model output to, due to the chaotic nature of geophysical flows. This challenge renders many machine learning approach unsuitable, and also implies a lack of performance metrics.
Our main contribution is the construction of a proxy variable that overcomes this problem and allows for supervised training and evaluation of a bias correction model. We show that a generative model is then able to correct spatial patterns and remove statistical biases in the South American domain. The approach successfully preserves large scale structures in the climate model fields while correcting small scale biases in the model data’s spatio-temporal structure and frequency distribution.
Airborne and ground measurements for vertical profiling of secondary ice production during ice pellet 
Authors: Lachapelle Mathieu , Bala Kenny , Nguyen Cuong , Bliankinshtein Natalia , Ranjbar Keyvan , Girouard Margaux , M. Thériault Julie , Minder Justin , Kingsmill David , French Jeffrey , Wolde Mengistu , Nichman Leonid
Published: March 2024

Predicting the accurate type of precipitation during winter storms is crucial for the implementation of mitigation measures such as aircraft deicing in commercial aviation or the spreading of salt and abrasives on roads. For this reason, a better understanding of the microphysical processes leading to winter precipitation types is essential. During freezing rain events, secondary ice produced by the freezing of supercooled raindrops via the fragmentation of freezing drops (FFD) process can initiate a chain reaction, potentially transitioning freezing rain into ice pellets. However, including this process in numerical weather prediction models is challenging due to the uncertainty in the efficiency of this mechanism. To bridge this gap, this study aims to evaluate the efficiency of the FFD process during ice pellet precipitation using measurements collected onboard the NRC Convair-580 research aircraft during the WINTRE-MIX field campaign, in February 2022. Specifically, measurements from two missed-approaches conducted in the Saint Lawrence Valley, Quebec, Canada during an ice pellet storm are analyzed. These missed-approaches provide unique datasets collected above, within, and below the ice pellet freezing altitude using in-situ and remote sensing instruments. In the region characterized by completely frozen ice pellets, a bi-modal particle size distribution, indicative of secondary ice production, was measured. Observations from imaging and optical-array probes suggest that particles smaller than 200 µm in diameter were, likely, non-spherical ice crystals, whereas the particle size mode with the larger diameters was associated with ice pellets. The observations of fractured ice pellets and ice pellets with bulges and spicules on most large particles suggested the occurrence of the FFD process. Subsequently, the measured number concentration of small ice particles, which was of the order of 500 L-1, was compared with the number concentration of ice particles simulated through existing parametrizations of secondary ice production. This analysis  will be valuable for selecting the most accurate FFD process parametrization to use for freezing rain and ice pellets simulation. 
Growth is not just about wood : investigating the link between ecosystem carbon uptake and net primary productivity in three European forests
Authors: Delpierre Nicolas , Limousin Jean-Marc , Berveiller Daniel , Morfin Alexandre , Vincent Gaëlle , Kempf Jean , Ourcival Jean-Marc , Cuntz Matthias , Joetzjer Emilie , Courtois Pascal , Cailleret Maxime
Published: March 2024

A body of work published over the past two decades shows that there is a partial decoupling between the fixation of carbon by photosynthesis and the formation of wood in forests. Years of high photosynthesis are not necessarily accompanied by large wood production. In this contribution, we explore the link between photosynthesis, estimated using eddy covariance fluxes and the productivity of the various forest compartments (leaves, wood, fruit, roots) measured over 12 to 21 years on three forest sites in France belonging to the European ICOS network (two temperate sites, one oak forest and one beech forest, and one Mediterranean oak forest). Annual wood productivity was not significantly correlated with carbon fixation, neither GPP nor NEP, at any of the three sites. On the other hand, annual above-ground net primary productivity was significantly correlated with GPP at all sites and with NEP at two of the three sites, i.e. the Mediterranean and the temperate oak forests. In these oak forests, years of high productivity are masting years, supporting the hypothesis that reproduction is limited by the availability of recent photo-assimilates. These results remind us that wood growth is not necessarily representative of tree productivity, and invites us to investigate the causes of the inter-annual variability of carbon allocation to the different organs and tissues of trees.
Changes in the causal effect networks of single and compound extreme hot and dry events in Central Europe
Authors: Di Capua Giorgia , Tian Yinglin , Giaquinto Domenico , Claassen Judith , Ali Javed , Li Hao , De Michele Carlo
Published: March 2024

Hot and dry extreme events in Europe have become more frequent and pose serious threats to human health, agriculture, infrastructure, and ecology. Single and compound hot and dry extremes in Europe have been attributed to synoptic atmospheric circulation variations and land-atmosphere interactions. However, the exact causal pathways and their strength, as well as their historical trends, have not been quantified. An accurate understanding of the mechanisms behind these land-atmosphere extremes is crucial to improving S2S forecasts and implementing appropriate adaptation measures. Here, we use the Peter and Clark momentary conditional independence (PCMCI) based Causal Effect Networks (CENs) to detect and quantify dynamic and thermodynamic causal precursors of extremely high 2m temperature (T2m) and extremely low soil water deficit and surplus (WSD) in central Europe (CEU).Our analysis reveals that the single hot events are driven mainly by anomalous atmospheric patterns and soil water deficiency, while single dry events are mainly driven by the soil moisture memory, and anomalous atmospheric patterns, and only marginally by temperature changes. The atmospheric circulation patterns preceding both single hot and dry events show a high-pressure system over central Europe, with a low-pressure system over the Atlantic Ocean, and partly explain the occurrence of the compound events. This atmospheric pattern is also linked to an anomalous zonal cold-warm-cold SST pattern over the Atlantic Ocean and a warmer eastern Pacific Ocean.The identified causal links vary with temperature and humidity conditions, that is, the impact of soil moisture memory on the WSD variation is sensitive to T2m and WSD, while the influence of soil moisture condition on T2m changes is strengthened by reduced WSD. Moreover, during compound hot and dry extremes, the effect of reduced soil moisture on temperature is significantly higher than during single events, reaching twice the magnitude under moderate conditions. When historical trends are analyzed, we show that the impact of dry soil on temperature is amplified by 42% (46%) for single (compound) extremes during 1979-2020, while the influence of atmospheric drivers on soil moisture is intensified by 28% (43%).This work emphasizes (i) the intensification of the strength of the thermodynamic causal pathways for warmer and dryer CEU over time and (ii) the stress on the varying forcing strength of the drivers, which can lead to non-linear variations of weather stressors under climate changes and thus add extra challenges to extreme adaptations.  
3D crustal shear wave velocity structure in northeast India from joint inversion of receiver function and Rayleigh wave group velocity
Authors: Anand Aakash , Borah Kajaljyoti , Mandal Sourav , Bora Dipok
Published: March 2024

In this study, we computed the Rayleigh wave group velocity tomography of northeast India (NEI) to a higher resolution of 2°×2° for a 15 to 80-second period. The group velocity dispersion obtained from the tomography was inverted using two ways – (a) inversion for every 0.2 degree of the study area to estimate the 3-D shear wave velocity, which overcome the constraint of sparse seismic station coverage in a few segments of the study region,(b) Joint Inversion of the computed dispersion with the  Receiver Function from 22 stations spread across NEI, covering all major geological features, to deduce the shear wave velocity structure. Moho geometry showed significant variation in the region, with IBR (~ 43–62 km) and Himalaya (~ 40–53  km) showing deeper Moho; Assam Valley (~ 33–38 km), Shillong Plateau (~ 30–32 km) and Bengal Basin (~ 37 km) being comparatively shallower. Moho beneath Shillong Plateau is found to be the shallowest (~ 30 km). For stations, TAWA, RUPA, ITAN, and TZR significant back azimuthal variation in shear wave velocity structure is observed. The average crustal shear wave velocity Vs beneath Shillong Plateau (Vs ~ 3.16-3.27 km/s) and Assam Valley (Vs~3.14-3.35 km/s) is found to be lower than the average crustal Vs (~3.75 km/s) beneath the Indian shield. Shillong Plateau and proximal Assam Valley stations showed low uppermost mantle shear wave velocity (Vsn ~ 4.0-4.1 km/s), which might be attributed to factors such as rock composition, grain geometry, higher temperature or the presence of partial melt.The eastern segment of the Assam Valley is not in conformity with the western segment, as evident from the DIBR station at the eastern edge of Assam Valley which doesn’t show this decreased Vsn.Thus indicating prima facia towards different geodynamics along the eastern and western segment of the Assam valley, which might be attributed to the role played by the uplifted, uncompensated Shillong Plateau and/or the Kopli Fault. Relatively higher Vsn (~ 4.2-4.6 km/s) observed beneath the IBR stations can be associated with the deeper moho (~ 43–62 km). Thus the improvised Moho geometry, crustal velocities structure, Vsn could be crucial in understanding the geodynamics of the region and could provide better constraint on the quantification of seismic hazards in the region.
Compression of meteorological reanalysis data files and their application to Lagrangian transport simulations 
Authors: Khosrawi Farahnaz , Hoffmann Lars
Published: March 2024

Computer performance has increased immensely in recent years, but the ability to store data has hardly increased at all. The current version of meteorological reanalysis data ERA5 provided by the European Centre of Medium-Range Weather Forecasts (ECMWF) has increased by a factor of ∼80 compared to its predecessor ERA-Interim. This presents scientists with major challenges, especially if data covering several decades is to be stored on local computer systems. Accordingly, many compression methods have been developed in recent years with which data can be stored either lossless or lossy. Here we test three of these methods two lossy compression methods ZFP and Layer Packing (PCK) and the lossless compressor ZStandard (ZSTD) and investigate how the use of compressed data affects the results of Lagrangian air parcel trajectory calculations with the Lagrangian model for Massive-Parallel Trajectory Calculations (MPTRAC). We analysed 10-day forward trajectories that were globally distributed over the free troposphere and stratosphere. The largest transport deviations were derived when using ZFP with the largest compression. Using a less strong compression we could reduce the transport deviation and still derive a significant compression. Since ZSTD is a lossless compressor, we derive no transport deviations at all when using these compressed files, but do not loose much disk space using this compressor (reduction of ∼20%). The best result concerning compression efficiency and transport deviations is derived with the layer packing method PCK. The data is compressed by about 50%, but transport deviations do not exceed 40 km in the free troposphere and are even lower in the upper troposphere and stratosphere. Thus, our study shows that the PCK compression method would be valuable for application in atmospheric sciences and that with compression of meteorological reanalyses data files we can overcome the challenges of high demand of disk space from these data sets.
Biosphere changes during the Carnian-Norian in Tasmania: A new perspective from PAH analysis from the Paleo Antarctic Circle.
Authors: Ghoshal Indodeep , Al Suwaidi Aisha , P Fox Calum , Naohiko Ohkouchi , Nanako O Ogawa , Hisami Suga
Published: March 2024

 The Carnian–Norian, Late Triassic was a period of major global climatic change, often associated with a transition from arid to more humid conditions that began with the Carnian Pluvial Episode (CPE). This transition to wetter conditions is often linked to the emplacement of the Wrangellia Large Igneous Province (LIP), ~233 Mya in northern Panthalassa. Here, we present new organic geochemical data (molecular fossils) combined with organic carbon isotopes and elemental data from sediments of the Bicheno 3A core. These sediments represent fluvial deposits of the Upper Parmeener Supergroup, a freshwater sequence from eastern Tasmania. They offer a unique opportunity to examine the impact of this major climate transition at high latitudes in the paleo-southern polar circle. During the Late Triassic Tasmania was located at a latitude of -69°S, a position today occupied by the frozen continent of Antarctica. Sediment samples from the BIC 3A core were processed and then analyzed in a gas chromatography (GC: Agilent 7890A System) for n-alkane and Polycyclic Aromatic Hydrocarbon (PAH) compounds. They were detected using a GC/mass spectrometry (Agilent 5975C Triple-Axis Detector.) Preliminary results from this study show an increase in soil erosion through the core based on higher concentrations of dibenzofuran and dibenzothiophene. A rise in retene concentrations during a similar time interval suggests an increased influx of terrestrial inputs further supporting enhanced hydrological conditions through the Late Triassic. Concentrations of an aggregate of PAHs spanning 3 to 7 rings associated with biomass burning also increase during a similar interval, suggesting increased wildfire activity, possibly driven by a shift to more humid conditions. When comparing the higher molecular weight PAHs (5- to 7-ringed PAHs) to the lower molecular weight PAHs (3-ring PAHs), a higher burning intensity and temperature towards the upper section of the core is observed since higher temperature wildfires produce PAHs with higher molecular weights. This upper section also shows indications of localized fire. Parameters including that of fluoranthene/ (fluoranthene + pyrene) and 1- and 2-methylphenanthrene/phenanthrene used to determine the origin of PAHs support that the PAHs from this sediment are of pyrogenic origin. This PAH profile from Tasmania represents a unique continuous record of climate change in high latitude Southern Hemisphere through the Carnian Pluvial Episode into the Norian, highlighting the complex interplay between fire and intensified rainfall in the Triassic paleo-Antarctic, as well as the major climatic and ecosystem changes experienced during this period.
Microplastics from surgical masks: A piggy-back ride for sulfamethoxazole in the sea
Authors: Joseph Anuja , Biswas Bishwatma , Goel Sudha
Published: March 2024

Microplastics can act as carriers for several organic pollutants like poly aromatic hydrocarbons, pesticides, polychlorinated biphenyls, and other persistent pharmaceutical pollutants. It is important to be noted that pharmaceuticals are bio-active substances, structurally modified to induce pharmacological changes in living organisms. These pharmaceuticals pose a threat to the ecosystem and the organisms living in it when not treated effectively. Antibiotic residues may enter the aquatic environment through effluents from sewage treatment plants, application in aquaculture, and other riverine inputs. The transport of one such antibiotic, Sulfamethoxazole (SMX), with the aid of microplastics was investigated in this study.Surgical masks are made up of polypropylene fibers and they tend to degrade faster in the air as compared to sea-water when exposed to sunlight. Surgical masks are used for medical and personal care purposes and are often disposed of irresponsibly. In this study, the sorption mechanism of SMX onto the mask fibers was observed. The optimum adsorption capacity was analyzed for the microplastics. The effects of pH, salinity, microplastic dose, and SMX concentration were observed. Kinetic models were used to identify the sorption behavior and mechanism. The sorption pattern was then fitted onto linear and Freundlich isotherms. The van Der Waal interactions were probably responsible for the interaction between SMX (hydrophilic) and microplastics (hydrophobic). The results indicate that the microplastics can adsorb up to 15 % of the SMX concentration, when in seawater. The adsorption and desorption of SMX aided by the microplastics from the surgical masks can be interpreted into a transport model for SMX. Thus, this study confirms that aged microplastics when left near the seashore, gradually enter the aquatic ecosystem and act as carriers for pharmaceuticals like SMX. The ability of microplastics to desorb a certain amount of adsorbed contaminant can lead to major health concerns, as the organisms may consume the same, causing complications to health.
Comparison of inversions of global methane emissions using TM5-MP/4DVAR with TROPOMI measurements
Authors: Parraguez Cerda Santiago , Nüß Johann Rasmus , Daskalakis Nikos , Schneising Oliver , Buchwitz Michael , Vrekoussis Mihalis , Kanakidou Maria
Published: March 2024

Methane (CH4) is an important greenhouse gas (GHG), contributing about ~23% (0.62 W m-2) of the additional radiative forcing on the troposphere due to its increased concentrations compared to pre-industrial levels. Mainly, anthropogenic sources of CH4 are agriculture, livestock farming, fossil fuels and biomass burning. Further, natural sources are primarily wetlands, while minor ones are oceans, termites, wild animals and permafrost. There are persistent uncertainties regarding the sources of CH4 due to limited knowledge of the processes underlying them, leading to inconsistencies between top-down and bottom-up estimates. It is relevant to reduce these uncertainties and accurately assess CH4 emissions as it is meaningful for atmospheric modelling, climate change estimations, and policy making. Higher resolution and lower uncertainty data can benefit assimilation systems, thus increasing confidence in estimates of emission sources.This work aims to assimilate high-resolution data from satellite observations and measurements obtained from surface stations to optimize global methane emission fields. We evaluate differences resulting from the assimilation of satellite observations at varying resolutions. Additionally, we compare different setups of the assimilation framework, using varied combinations of satellite and surface measurements, to assess potential discrepancies in the resulting emissions. The modelling framework is based on the TM5-MP (massive parallel) atmospheric chemistry-transport model, utilizing its adjoint in a four-dimensional (4DVAR) data assimilation system. Our study aims to constrain global CH4 emissions first at a spatial resolution of 3° × 2° (longitude × latitude) for 2018 and then increase the resolution to 1° × 1°. The tropospheric CH4 mixing ratio product slated for assimilation is acquired by the TROPOMI instrument onboard the satellite Sentinel 5-P, and retrieved using the weighting function modified differential optical absorption spectroscopy (WFMD-IUP) algorithm. This product offers enhanced coverage, especially over higher latitudes, and reduced uncertainty compared to the operational product. Conversely, near-surface CH4 measurements are obtained from stations within the global NOAA network. Preliminary results suggest a relevant role of both the resolution of the satellite instrument and the type of data assimilated regarding convergence and final results.