bluuebunny/crossref_metadata_2025 huggingface dataset:
Causal drivers of central Amazon precipitation variability during austral summer
Authors: Henningsen Emily , Di Capua Giorgia , Donner Reik V.
Published: February 2023

The South American monsoon system is one key component of the regional climate of South America, and its interannual as well as intraseasonal variability is of great relevance for water availability over vast parts of the continent. To further develop advanced prediction systems for hydro-meteorological conditions, a better understanding of the underlying atmospheric as well as coupled ocean-atmosphere and land-atmosphere processes governing the intraseasonal variations of rainfall is of paramount importance. In this work, we focus on rainfall variability over the central Amazon basin (CAB) as a particularly vulnerable region during the peak season of the monsoon (December to February). In order to identify causal precursors of CAB rainfall variability and their mutual causal interdependence structure, we employ a causal discovery tool called Peter and Clark Momentary Conditional Information (PCMCI) algorithm to monthly average sea surface temperature (SST), mean sea level pressure (MSLP) and precipitation fields from reanalysis data sets for two different time periods, 1950-2020 and 1979-2020. As a first step, anomaly maps and correlation maps are used to identify potential candidate drivers of the precipitation variability in the CAB at lead times of up to three months. The causal effect networks resulting from the subsequent application of the PCMCI algorithm unveil the causal dependencies of different climate phenomena with CAB rainfall variability during austral summer, confirming previous results based on standard correlation analyses and allowing for a quantitative assessment of the different effects. Among others, we find that SST changes in the tropical Pacific Nino1+2 region close to the South American west coast have a causal effect on CAB precipitation, with lower SSTs promoting more rainfall with a lag of one to two months. Notably, we do not find any similar statistically significant causal impact of SST variations in the Nino3.4 region in the central tropical Pacific, which is commonly most closely associated with the El Niño Southern Oscillation. Additionally, the obtained causal effect networks demonstrate that the Southern Annular Mode (SAM) causally influences the Amundsen Sea Low (ASL), which in turn causally affects the CAB rainfall. Both links are negative, i.e. a positive SAM mode leads to a deeper ASL with a lag of one month, and a deeper ASL supports higher precipitation in central Amazonia with a lag of three months. Finally, SST variability in the tropical North Atlantic as well the Madden-Julian Oscillation do not show a significant causal relationship with CAB rainfall. Our obtained findings are qualitatively consistent among the two different time periods. However, when analyzing data starting only after 1979, some links increase in strength while generally less causal links show up in the networks.
Groundwater flow system as determined by multi-tracer approach in Tokyo Metropolitan area, Japan
Authors: Tsujimura Maki , Nagano Kosuke , Sato Keisuke , Suzuki Taiga , Asakura Hiroko
Published: February 2023

We performed an intensive monitoring and sampling of groundwater in Tokyo Metropolitan area to investigate the groundwater flow system from upland to lowland areas. We took 83 groundwater samples at 39 locations, 25 stream water samples, 7 spring water samples from August 2018 through June 2021. We also observed the spatial distribution of hydraulic head in the groundwater. The stable isotopic composition of oxygen 18 and deuterium, SF6 concentration, and solute ions concentrations were determined on all water samples.The SF6 age of groundwater in the upland area ranges from a few years to 40 years, whereas that in the lowland area ranges from 40 years to more than 80 years. The solute concentrations are characterized by Ca-HCO3 type in the upland, whereas that is categorized in Na-HCO3 or Na-Cl type. In addition, d18O of the groundwater in the upland ranges from -10.4 per mil to -8.8 per mil, whereas that in the lowland ranges from -9 per mil to -8 per mil.The hydraulic head distribution shows that the unconfined groundwater flows from west to east directions in parallel with the topographical surface, and the confined groundwater flows from south-west toward north-east directions in parallel with the bedrock surface topography.The results show that the groundwater flows from west toward east directions across the border of the upland and the lowland, and it flows across the boundary of the aquifers, meaning the unconfined groundwater recharges the confined groundwater in an area where a certain amount of unconfined groundwater is pumped up.
Simulation of extreme precipitation events over south-west France: the role of large-scale atmospheric circulation and atmospheric rivers
Authors: Shahi Namendra Kumar , Zolina Olga , Gulev Sergey K. , Gavrikov Alexander , Jomaa Fatima
Published: February 2023

South-western France has witnessed some of the most devastating extreme precipitation events that eventually lead to record-breaking severe flash flooding in the region and cause losses to human lives, urban transportation, agriculture, and infrastructure. In this study, two cases of deadly flash floods that occurred/reported in the Aude watershed in south-western France during 12-13 November 1999 and 14-15 October 2018 are studied using the WRF4.3.1 model simulations, with a particular emphasis on the model ability to capture these heavy precipitation events. We performed two simulations one with parameterized convection and one without the use of convection parameterizations for each case at gray-zone resolution (~9 km horizontal grid spacing) using the ERA5 reanalysis as the lateral boundary condition. In addition, attempts have been made to investigate the role of large-scale atmospheric circulation and atmospheric rivers in the production of these heavy precipitation events. The results from model simulations are compared quantitatively with available observations and reanalysis and found that the simulations at ~9 km gray-zone resolution capture the observed spatio-temporal distribution of precipitation characteristics during both extreme cases. The added value of gray-zone resolution simulations over driving coarse-scale ERA5 reanalysis datasets is observed in the representation of the precipitation characteristics. It has also been observed that the model simulation without the use of convection parameterization yields a reasonable and realistic representation of the precipitation characteristics during both extreme cases, and this suggests that at this “gray-zone” resolution the organized mesoscale convective systems/processes can be resolved explicitly by the model dynamics. The contribution of the large-scale atmospheric circulation and the atmospheric river (i.e., moisture transport) in the production of these flood events has also been observed.
Project FOCI - Non-CO2 Forcers and Their Climate, Weather, Air Quality and Health Impacts
Authors: Halenka Tomas , Sokhi Ranjeet , Baklanov Alexander
Published: February 2023

While overall global warming with the causes and global processes connected to well-mixed CO2, and its impacts on global to continental scales are well understood with a high level of confidence, there are knowledge gaps concerning the impact of many other non-CO2radiative forcers leading to low confidence in the conclusions. This relates mainly to specific anthropogenic and natural precursor emissions of short-lived GHGs and aerosols and their precursors. These gaps and uncertainties also exist in their subsequent effects on atmospheric chemistry and climate, through direct emissions dependent on changes in e.g., agriculture production and technologies based on scenarios for future development as well as feedback of global warming on emissions, e.g., permafrost thaw. In addition to the atmospheric radiative forcing (gaseous or aerosols), albedo changes connected to land use and land cover can play a role, depending on the adaptation or mitigation measures included in different scenarios.
The main goal of the EC Horizon Europe project FOCI (from the call HORIZON-CL5-2021-D1-01-0 Improved understanding of greenhouse gas fluxes and radiative forcers, including carbon dioxide removal technologies), is to assess the impact of key radiative forcers, where and how they arise, the processes of their impact on the climate system, to find and test an efficient implementation of these processes into global Earth System Models and into Regional Climate Models, eventually coupled with CTMs, and finally to use the tools developed to investigate mitigation and/or adaptation policies incorporated in selected scenarios of future development targeted at Europe and other regions of the world. We will develop new regionally tuned scenarios based on improved emissions to assess the effects of non-CO2 forcers. Mutual interactions of the results and climate services producers and other end-users will provide feedback for the specific scenarios preparation and potential application to support the decision-making, including climate policy.
The Diurnal Cycle of the Cloud Radiative Effect of Deep Convective Clouds over Africa from a Lagrangian Perspective
Authors: Jones William , Stengel Martin , Stier Philip
Published: February 2023

Tropical deep connective clouds (DCCs) have large top of atmosphere (ToA) cloud radiative effects (CREs) in both the shortwave (SW) and longwave (LW), which both have average magnitudes of greater than 100 Wm-2. Due to the opposite sign of the two components, the overall ToA CRE is generally assumed to average to approximately 0 Wm-2. Although there are a number of mechanisms that contribute to this balance, the fact that the daytime only SW CRE balances with the LW CRE indicates that the diurnal lifecycle of DCCs is a key component of this balance. Understanding how the diurnal cycle of DCCs influences their CRE is vital for understanding how any changes in their diurnal cycle of these clouds may influence the climate. A year-long dataset of retrieved cloud properties and derived broadband radiative fluxes has been produced by the ESA Cloud CCI project using temporally highly resolved satellite observations. Using a novel method, we are able to detect and track both isolated DCCs and large, mesoscale convective systems (MCSs) over their entire lifecycle. We explicitly retrieve the cloud properties and CREs of DCCs over Africa, and how these properties change over the lifecycle of approximately 100,000 observed clouds. We find that the mean anvil SW CRE greatly varies depending on the initiation time of day and the lifetime of the DCC, whereas the LW CRE is consistent throughout the diurnal cycle and varies primarily with cloud top temperature. As a result of our study we can confirm that the mean observed ToA CRE of all DCCs (integrated over area and lifetime) is indeed approximately 0 Wm-2, but very few DCCs individually have mean CREs near this value. Instead, we find that DCCs occurring during the daytime have a large cooling effect, and those at nighttime have a warming effect, resulting in a bimodal distribution. While MCSs make the largest contribution to the overall effect due to their large areas and lifetimes, because they tend to exist during both nighttime and daytime the overall magnitude of their ToA CREs tend to be smaller than those of isolated DCCs. As a result, factors which influence the diurnal cycle of deep convection – such as changes in CAPE generation or convective inhibition – may have a more important influence on the properties of isolated DCCs rather than larger MCSs.
Searching for the most extreme temperature events in recent history
Authors: Cattiaux Julien , Ribes Aurélien
Published: February 2023

Because they are rare, extreme weather events inevitably attract public and scientific attention. The most unusual events are regularly documented as part of routine climate monitoring by meteorological services, and put into the perspective of climate change by attribution studies through quantities such as a probability ratio. However, it is often recognized that (i) the selection of studied events is geographically uneven, and (ii) the definition of a given event, in particular its spatio-temporal scale, is subjective, which may impact the results.In previous work, we proposed an objective method of event definition, consisting in the automatic selection of the spatio-temporal window maximizing the event rarity. Importantly, we showed that maximizing the event rarity does not bias attribution statements, in the sense that it does not systematically maximize (or minimize) the probability ratio. Here we present how this method can be used to compare several events occurring on different years, seasons, regions, etc. Our objective research procedure works both over time, which can be useful for routine climate monitoring, and over space, which can resolve the geographical selection bias of attribution studies. Ultimately, we provide a selection of the most extreme hot and cold events that have occurred worldwide in the recent past, among which are iconic heat waves such as that seen in 2021 in Canada or 2003 in Europe.
Kinetic Alfvén waves from hybrid-Vlasov simulations
Authors: Zhou Hongyang , Turc Lucile , Cozzani Guilia , Zaitsev Ivan , Pfau-Kempf Yann , Horaites Konstantinos , Kebede Fasil , Battarbee Markus , Alho Markku , Grandin Maxime , Gordeev Evgenii , Tarvus Vertti , Dubart Maxime , Suni Jonas , Papadakis Konstantinos , Ganse Urs , Palmroth Minna
Published: February 2023

Kinetic Alfvén wave (KAW) is the kinetic extension of shear Alfvén wave (SAW) where the perpendicular wavelength with respect to the magnetic field becomes comparable to the ion scale. It has been suggested theoretically that mode conversion from incident compressional waves to KAWs at the magnetopause leads to the plasma transport. Existence of KAWs has been identified from in-situ observations and shown to be closely related to the Hall field from magnetic reconnection. In this study, we investigate the properties of KAWs using the hybrid-Vlasov model Vlasiator. Local runs of tangential discontinuities with parameters relevant to Earth’s magnetopause are performed to look at the mode conversion from fast waves to Alfvén waves. Signatures of KAWs are identified from both local and global simulations, which provide insights into the nonlinear plasma transport process in the magnetosphere.
Investigating Potential Risk of Thermal Hazards Along Race Routes of Taipei Marathon By Mobile Monitoring and Quantitative Analysis
Authors: Lin Cheng-En , Chien Shiuh-Shen , Juang Jehn-Yih
Published: February 2023

In the recent years, the long-distance endurance running races, such as half-marathon or marathon, are becoming much more popular in Taiwan. However, due to the frequent hot and humid weather in this low-latitude country, runners in these races usually face the risk of thermal hazards. In order to analyze the heat stress for the runners in such environment, the main objectives of this study are to characterize the thermal environment in road race events and to quantify the risk of thermal hazard for athletes.This study chose the route of half-marathon of Taipei Marathon, a World Athletics Elite Label race, as the research object.  The necessary environmental parameters for risk of thermal hazards along the route were collected by means of mobile monitoring, and the heat stress on the route was evaluated through the Heat Strain Decision Aid model (HSDA) and the thermal index, Wet Bulb Globe Temperature (WBGT). To quantify the impact of heat stress on different groups from beginner to elite runners, the spatiotemporal variations of WBGT and body core temperature along the route were further estimated. The results from this study could help the race organizer to identify the high-risk areas during the race planning and help the participants to understand the potential risk of heat stress in the race.
About the use of near-surface seismic data to better constrain hydrogeological models
Authors: Bodet Ludovic , Dangeard Marine , Sanchez Gonzalez Ramon , Gesret Alexandrine , Rivière Agnès
Published: February 2023

Over the past decade, we have done our best to develop alternative methods to image the heterogeneities of the critical zone, describe the dynamics of its hydrosystems, and add seismic techniques to the hydrogeophysics toolbox. With the growth of long-term observation infrastructures in this field, the geophysical tools recently developed by the community tend to be viewed as state-of-the-art geophysical characterization methods mainly deployed to augment observatory and network databases. A major problem is that geophysical results are mostly just sets of parameters, in other words "models", deduced from sparse data sets and poorly posed problems. They certainly cannot be considered as data by observatories. In order to better transport information from the data into models that could be safely exploited by non-geophysicists, we need to: increase the extent and throughput of our surveys; optimize our acquisition configurations with respect to the target of interest; greatly increase our spatial and temporal sampling capabilities; automate our tedious processing workflows; and improve, if not completely revise, our inversion tools. We illustrate this last point with examples from the field. They show how a thorough interpretation of geophysical models can provide valuable prior information on the distribution of hydrofacies and calibrate the hydrogeological modeling domain. In addition, we raise the question of the propagation of uncertainty from the geophysical data to the hydrogeological model and suggest the use of alternative petrophysics to better interpret the data collected in the partially saturated zone.
How inlet tubing material affects the response time of water vapor concentration measurements
Authors: Miltner Markus , Stoltmann Tim , Kerstel Erik
Published: February 2023

Measurements involving water in the vapor phase have to deal with the stickiness of the H2O molecule: The associated adsorption and desorption processes can increase the response time of these measurements significantly. To achieve short response times in scientific instrument design, hydrophobic surface materials are used to reduce surface interactions in the tubing that guides the sample towards the analyzer. The study presented here focuses on the effects of the tubing material choice, length, humidity level, gas flow rate, and temperature on the observed response time. We use an Optical Feedback Cavity Enhanced Absorption Spectrometer (OFCEAS) designed for stable water isotope measurements at low water concentration (< 1000 ppm), which we connect to two bottles containing humidified synthetic air of different water concentration using 6.6-m tubing of different materials and surface treatments. Other parameters that are varied are the flow rate and the temperature of the tubing. With proper selection of tubing material and surface treatment, the contribution from the tubing to the overall response time for low water concentration isotopic measurements can be sufficiently suppressed for it to be neglected.
FAIR Notebooks: opportunities and challenges for the geoscience community
Authors: Coca-Castro Alejandro , Fouilloux Anne , Hosking J. Scott , community Environmental Data Science Book
Published: February 2023

Making assets in scientific research Findable, Accessible, Interoperable and Reusable (FAIR) is still overwhelming for many scientists. When considered as an afterthought, FAIR research is indeed challenging, and we argue that its implementation is by far much easier when considered at an early stage and focusing on improving the researchers' day to day work practices. One key aspect is to bundle all the research artefacts in a FAIR Research Object (RO) using RoHub (https://reliance.rohub.org/), a Research Object management platform that enables researchers to collaboratively manage, share and preserve their research work (data, software, workflows, models, presentations, videos, articles, etc.). RoHub implements the full RO model and paradigm: resources associated to a particular research work are aggregated into a single FAIR digital object, and metadata relevant for understanding and interpreting the content is represented as semantic metadata that are user and machine readable. This approach provides the technical basis for implementing FAIR executable notebooks: the data and the computational environment can be “linked” to one or several FAIR notebooks that can then be executed via EGI Binder Service with scalable compute and storage capabilities. However, the need for defining clear practises for writing and publishing FAIR notebooks that can be reused to build upon new research has quickly arised. This is where a community of practice is required. The Environmental Data Science Book (or EDS Book) is a pan-european community-driven resource hosted on GitHub and powered by Jupyter Book. EDS Book provides practical guidelines and templates that help to translate research outputs into curated, interactive, shareable and reproducible executable notebooks. The quality of the FAIR notebooks is ensured by a collaborative and transparent reviewing process supported by GitHub related technologies. This approach provides immediate benefits for those who adopt it and can feed fruitful discussions to better define a reward system that would benefit Science and scientific communities. All the resources needed for understanding and executing the notebook are gathered into an executable Research Object in RoHub. To date, the community has successfully published ten FAIR notebooks covering a wide range of topics in environmental data science. The notebooks consume open-source python libraries e.g. intake, iris, xarray, hvplot for fetching, processing and interactively visualising environmental research.  While these notebooks are currently python-based, EDS Book supports other programming languages such as R and Julia, and we are aiming at engaging with computational notebooks communities alike towards improving the research practices in environmental science.
Understanding drought indicator-to-impact relationships to improve drought monitoring and early warning: Thailand as a case study
Authors: Tanguy Maliko , Barker Lucy , Eastman Michael , Ekkawatpanit Chaiwat , Goodwin Daniel , Hannaford Jamie , Holman Ian , Magee Eugene , Pardthaisong Liwa , Parry Simon , Rey Dolores , Visessri Supattra
Published: February 2023

Thailand has already been experiencing an increase in severity and duration of its droughts as a consequence of the changing climate. Developing a reliable drought monitoring and early warning system (DMEWS) is an integral part of strengthening a country’s resilience to droughts. However, for DMEWS to be useful for stakeholders, the indicators they monitor should be translatable to potential drought impacts on the ground and, ideally, inform mitigating actions. Here, we analyse these drought indicator-to-impact relationships in Thailand, using a novel combination of correlation analysis and random forest modelling. In the correlation analysis, we study the link between meteorological drought indicators and high-resolution remote sensing vegetation indices used as proxies for general crop health and forest growth. Our analysis shows that these links vary greatly depending on land use (cropland vs. forest), season (wet vs. dry) and region (north vs. south). The random forest models built to estimate regional crop productivity provided a more in-depth analysis of the crop- and region-specific value of different drought indicators. The results highlighted seasonal patterns of drought vulnerability for individual crops, usually linked to their growing season, although the effect was somewhat masked in irrigated regions (North). This new high-resolution knowledge of crop- and region-specific indicator-to-impact links can be used as the basis of targeted mitigation actions in an improved DMEWS in Thailand. In addition, the framework developed here can be applied elsewhere in the Southeast Asia region, as well as other drought-vulnerable areas internationally, in particular those that are data sparse.  
Towards FAIR hydrological modeling with HydroMT
Authors: Boisgontier Hélène , Eilander Dirk , Bouaziz Laurène , Buitink Joost , Couasnon Anaïs , de Goede Roel , Hegnauer Mark , Leijnse Tim , van Verseveld Willem
Published: February 2023

Hydrological models are crucial to understand water systems and perform impact assessment studies. However, these models require a lot of accurate data, especially if the model is spatially distributed. However, sufficiently accurate datasets while available, for example from earth-observations, need to be converted into model-specific, sometimes idiosyncratic, file formats. Therefore, hydrological models require various steps to process raw input data to model data which, if done manually, makes the process time consuming and hard to reproduce. Hence, there is a clear need for automated model instance setup for increased transparency and reproducibility in hydrological modeling. HydroMT (Hydro Model Tools) is an open-source Python package (https://github.com/Deltares/hydromt) that aims to make the process of building hydrological model instances and analyzing their results automated and reproducible. Compared to many other packages for automated model instance setup, HydroMT is data- and model-agnostic, meaning that data sources can easily be interchanged without additional coding and the generic model interface can be used for different model software. This makes it possible to reuse workflows to prepare input from different datasets or for different model software that require the same parameter (e.g. Manning roughness derived from land use maps) and thereby supporting controlled model intercomparison and sensitivity experiments.  In this contribution we show the application of HydroMT for flood hazard modeling using the distributed hydrological Wflow model and the reduced-physics hydrodynamic SFINCS model, both open-source models. We use HydroMT to setup a controlled and reproducible model experiment. We test the sensitivity of both models to various data sources used- and assumptions taken in the model instance building process and compare the skill to simulate peak discharge. Using this application, we discuss the merits and limitations of HydroMT and next steps toward FAIR hydrological modeling.
Numerical simulations of the effects of astronomical forcing on nutrient supply and oxygen levels during the Devonian
Authors: Sablon Loïc , Goddéris Yves , Da Silva Anne-Christine , Crucifix Michel
Published: February 2023

Declining oxygen levels in the ocean since the middle of the 20th century have been linked to increasing temperatures, CO2 concentrations, and nutrient inputs. In the geological past, numerous oceanic anoxic events have occurred under similar conditions. These events, during which dissolved oxygen in the ocean drop to potentially harmful levels, can have serious consequences for marine life and can also alter the geochemistry of the ocean.Specifically, we focus here on the Devonian (419 and 359 Ma), a warmer-than-present geological period. The sixty million years Devonian stage was the theatre of at least 29 identified anoxic events (Becker et al., 2020), marked most of the time by the deposition of black shales, associated with carbon isotopic excursion. It is understood that concurrent trends in CO2 and silicate weathering during the Devonian period have generated a context prone to ocean anoxia. On the other hand, there is growing evidence that their periodic recurrences in sedimentary records may have been influenced by astronomical forcing, such as changes in Earth's axis rotation and orbit geometry (De Vleeschouwer et al., 2017; Da Silva et al. 2020)In the umbrella project WarmAnoxia, we combine climate models and geological observations to explore and test proposals linking astronomical forcing to Devonian anoxia. Through this presentation, we focus specifically on the hypothesis that astronomical forcing influenced precipitation and temperature patterns in a way that significantly modified soil weathering dynamics, with enough effects on nutrient fluxes toward the ocean to promote oceanic anoxia.To test this proposal, we performed 81 experiments with the global atmosphere-slab model HadSM3. Experiments have been designed to span the range of astronomical forcing and CO2 concentrations experienced during the Devonian. The output was used to calibrate an emulator. With the latter, we estimate the transient evolutions of temperature and precipitation over 5 million-year periods, for which we assumed both simplified and realistic astronomical forcing scenarios. In turn, these transient evolutions force the GEOCLIM model (Maffre et al. 2022), which simulates soil dynamics, estimates nutrient fluxes from the continents to the oceans, and the response on the oceanic chemistry and atmospheric oxygen levels.References:Da Silva A. et al., (2020), Scientific Reports, 10 (12940) doi:10.1038/s41598-020-69097-6; Maffre P. et al., (2022) American Journal of Science, (322) 461–492, doi:10.2475/03.2022.02; Becker R.T. et al. (2020), The Geological Time scale, 10.1016/B978-0-12-824360-2.00022-X
Depositional processes, particulate organic carbon contents and origin across the Helgoland Mud Area, SE German Bight.
Authors: Müller Daniel , Liu Bo , Geibert Walter , Miramontes García Elda , Taubner Hei­di , Holtappels Moritz , Henkel Susann , Volz Jessica , Kasten Sabine
Published: February 2023

Fine-grained coastal and marine sediments represent the largest permanent sink for carbon on our planet. They harbor large stocks of particulate organic carbon (POC) derived from marine plankton, land plants and coastal vegetation that build POC via photosynthesis and in this way take up CO2 from the atmosphere. The Helgoland Mud Area (HMA) represents the main depocenter for fine-grained and organic-rich sediments in the German Bight, North Sea. It covers a seafloor area of approximately 500 km2 off the island of Helgoland with a sediment thickness of up to 21 m and water depths between 11 and 27 m. In order to be able to quantify the long-term storage of carbon and its turnover during mineralization in the sediments of the HMA, we reconstruct sedimentation rates for the past decades and determine POC contents and origin. These results on the natural POC dynamics in the HMA are fundamental in order to understand how on-going anthropogenic activities (e.g., bottom trawling, dredging, offshore infrastructure) may affect the POC storage capacity of the HMA. Complementing existing estimates of sedimentation rates, we have determined 210Pbxs and 137Cs activities from the upper ~ 30 cm of the sediments in a high spatial and vertical resolution across the HMA. Based on this new dataset, we establish age models and describe the variation of depositional conditions across the HMA. The source of POC is determined by using the pore-water dissolved inorganic carbon concentrations (DIC) and respective stable carbon isotopic compositions with Keeling and Miller-Tans plot analysis as well as thermal gravimetric analysis (TGA). Published sedimentation rates for the HMA range from 0.5 to 11 mm yr-1 with strong lateral variations. The highest rates have been reported for the NW and central HMA. Our first results on sedimentation rates show ~ 2 mm yr-1 for these high accumulation areas within the HMA. POC contents in these areas are at ~ 1 wt% throughout the upper ~ 30 cm of the sediments. The source isotopic composition of POC ranges from -2.6 to -28.2 ‰ throughout the study area and needs to be complemented by on-going TGA analyses in order to reliably determine the origin of the POC. Once these analyses are completed, we aim to better understand the sources of organic carbon in this depocenter and to assess how the variation in depositional processes controls the mineralization and long-term burial of POC in the sediments of the HMA.
Ten years of groundwater temperature monitoring at a residential neighborhood under intensive shallow geothermal energy use – insights and lessons learned
Authors: Vienken Thomas
Published: February 2023

In 2013 we started a spatial and temporal high-resolution groundwater temperature monitoring campaign at a residential neighborhood under intensive shallow geothermal energy use in the western outskirts of the city of Cologne, Germany. The monitoring was conducted with the aim to identify effects of the intensive thermal use upon groundwater temperatures. Although individual systems sizes in the neighborhood are small, the installed 47 borehole heat exchanger systems sum up to a total borehole heat exchanger length of 11,009 m within a confined area of 0,12 km2 to satisfy, together with three open systems, a total heat demand of 506 kW.With almost ten years of groundwater temperature monitoring we created a valuable data set. Our results show a reduction of overall groundwater temperatures when comparing upstream and downstream groundwater temperatures during the first years of geothermal operation as an effect of the intensive use of shallow geothermal energy for heating and warm water provision. However, monitoring results depend on the measurement location in our study and it is known that urban subsurface and groundwater temperatures are influenced by several factors. In this contribution, the monitoring concept, results as well as pitfalls of the monitoring campaign are illustrated on our way to untangle urban groundwater temperature changes as a response to the intensive shallow geothermal energy use.
Development of a Python Framework (pyRadman) for QPE using radar and CML data at DWD
Authors: Wenzel Malte , Vogel Christian , Graf Maximilian , Winterrath Tanja , Chwala Christian
Published: February 2023

The daily life of everybody is affected by weather, especially by precipitation events. Climate projections indicate that the number and intensity of heavy rain events could increase in future. Therefore, the interest to improve QPE has increased rapidly, particularly for assurances, public infrastructure and flood risk management.Currently, the QPE is calculated by using the RADOLAN algorithm of Deutscher Wetterdienst. This algorithm combines the data of 17 weather radars and roughly 1,200 rain gauges in Germany by adjusting the radar reflectivity to the precipitation amount measured at the ground. The adjustment process is done every 10 minutes using the hourly total of radar and rain gauge data. Due to the rain gauge data delivery the adjustment process is delayed by 25 minutes. For this reason, short convective precipitation events can only be observed insufficiently.   Therefore, the RADOLAN algorithm has to be adapted to improve the QPE based on shorter data accumulation time and contemporary data delivery. One approach is to use almost real-time available data from the telecommunication network. Rainfall leads to attenuation of the signal level of commercial microwave links (CMLs). The path integral of the attenuation along one sender-receiver pair can be related to a certain precipitation amount. Germany is covered by several thousands (~130,000 in total) of CMLs, which can potentially be used to quantify rainfall events. Especially in urban areas the density of CMLs exceeds the density of meteorological networks rain gauges clearly. Therefore, it becomes possible to observe convective extreme weather events with higher temporal and spatial resolution.Within the project HoWa-PRO, the Deutscher Wetterdienst (DWD) collaborates with University of Augsburg, Karlsruhe Institute of Technology in Garmisch-Partenkirchen, and Ericsson. One of the first tasks is to set up a continuous data flow from Ericsson to DWD. To investigate different combinations of data sources and adjustment intervals, a fast, flexible and expandable software framework for combining and processing this data has to be developed.      We present first results of QPE after adjustment using different combinations of data e.g. CML+radar data and gauge+radar data. These results were analyzed and compared to show the potential of using opportunistic data from CMLs for radar adjustment.
Influence of waves on the three-dimensional distribution of plastic in the ocean
Authors: Huck Thierry , Bajon Raphaël , Grima Nicolas , Maes Christophe , Blanke Bruno , Richon Camille , Couvelard Xavier
Published: February 2023

The world's oceans are confronted with plastic pollution, 80% of which is of terrestrial origin, flowing mainly from the mismanaged waste of coastal populations and to a less extent, from river discharge. To study the fate of this pollution, we follow the trajectories of neutral plastic particles released continuously in numerical ocean simulations with two realistic source scenarios defined according to poorly managed waste from coastal populations and river discharge. The trajectories are three-dimensional and calculated for a period of 24 years by the Ariane Lagrangian tool from ocean currents simulated by a ¼° global ocean general circulation model (NEMO). The important particularity of the present model is that it is coupled with the WaveWatch III (WW3) wave model and consequently represents the Stokes drift in a consistent manner. The results are compared to trajectories calculated with an uncoupled NEMO simulation in which the Stokes drift is simply not considered. The results show that microplastics (as neutral particles) accumulate at the surface in the subtropical convergence zones of the Ekman transport before penetrating to depth and being strongly dispersed around 200 to 300 m depth over 40 degrees of latitude. At the end of the simulation, about 5.3% of the microplastics remains at the surface in these convergence zones and near the emission regions for the wave-coupled model, whereas only 2% remains for the uncoupled model. Our results indicate that waves may increase the retention of neutral plastic particles at the surface by a factor of two to three because of the upward vertical velocities induced by the divergence of Stokes transport in the surface layers. Plastic surface concentrations are maximal in the North Pacific and Indian Ocean basins. This result is due to the large discharge fluxes surrounding these basins of the northern hemisphere. The Mediterranean Sea exhibits also highly concentrations in microplastics due to high coastal population densities. This work shows the strong influence of waves (and Stokes drift) on the transport of plastic particles in the oceans, both on the retention of particles at the surface, the importance and location of convergence zones, and on the dispersion of neutral plastics at depth.
Generalised Ohm’s Law in the Magnetosheath: How do plasma conditions impact turbulent electric fields?
Authors: Lewis Harry , Stawarz Julia , Franci Luca , Matteini Lorenzo , Klein Kristopher , Salem Chadi
Published: February 2023

Turbulence is a complex phenomenon whereby fluctuation energy is transferred between different scale sizes as a result of nonlinear interactions. Electromagnetic turbulence is ubiquitous within space plasmas, wherein it is associated with numerous nonlinear interactions. The dynamics of the magnetic field, which are widely studied in turbulence theory, are intimately linked to the electric field, which controls the exchange of energy between the magnetic field and the particles. Magnetospheric Multiscale (MMS) provides the unique opportunity to decompose electric field dynamics into contributions from different linear and nonlinear processes. The evolution of the electric field is described by generalised Ohm’s law, which breaks down the dynamics into components arising from different physical effects. Using high-resolution multipoint measurements, we compute the MHD, Hall and Electron Pressure terms of generalised Ohm’s law for 60 turbulent magnetosheath intervals. These terms, which have varying contributions to the dynamics as a function of scale, arise as a result of different physical effects related to a range of underlying turbulent phenomena. We examine how two characteristics of the turbulent electric field spectra depend on plasma conditions: the transition scale between MHD and Hall dominance (the ‘Hall scale’, kHall) and the relative amplitude of Hall and Electron Pressure contributions. Motivated by dimensional analysis arguments which appeal to characteristics of the plasma and the turbulence that can be quantified in a number of ways by MMS, we demonstrate the necessary refinements required to reproduce measured values. The scalar isotropic kinetic Alfven wave prediction for the ratio of Electron Pressure to Hall terms as a function of plasma beta is not consistent with measurements. We observe that the MHD and Hall terms are dominated by either nonlinear or linear dynamics, depending on the interval, while the Electron Pressure term is dominated by linear components only. Our work shows how contributions to turbulent dynamics change in different plasma conditions, which may provide insight into other turbulent plasma environments.  
Postglacial strike-slip faulting within the Skjálfandi Bay, N-Iceland
Authors: Brandsdóttir Bryndís , Detrick Robert , Driscoll Neal , Karson Jeffrey , Guðmundsson Gunnar
Published: February 2023

The Tjörnes Fracture Zone (TFZ) is a complex transform fault zone linking the Northern Volcanic Zone (NVZ) on land Iceland, with the offshore Kolbeinsey Ridge. The TFZ is roughly 150 km long (E-W) by 50-75 km wide (N-S) incorporating three major N-S trending pull-apart basins bounded by a complex array of normal and oblique-slip faults. The Skjálfandi Bay is the southern extension of the central basin. Seismicity within the Skjálfandi Bay is mostly confined to its western margin and the Húsavík-Flatey fault system (HFFS) across the southern part of the bay, extending eastwards into the NVZ and westwards into the westernmost basin. The main strands of the HFFS can be traced offshore across the Skjálfandi Bay in both CHIRP and multibeam data, as two WNW-trending, south-facing fault scarps. Several smaller WNW-trending faults are located sub-parallel of the main HFFS, many of which are delineated by pockmarks on the seafloor. Pockmark lineaments in northeastern Skjálfandi are elongated NE-SW, and WNW-ESE in the western part of the bay. The NE-SW pockmarks appear to be aligned along sediment covered marginal faults of the Skjálfandi basin whereas the northwestern pockmark field seems to be linked to WNW-ESE –trending strike-slip faults with little or no vertical displacement. The inferred pattern of WNW-ESE strike-slip faults and NE-SW basin-bounding faults matches results from adjacent areas of the Tjörnes Peninsula and Flateyjarskagi. Paleoearthquake records can be derived from high‐resolution seismic reflection profiles of active fault-growth sequences where long-term rate of sedimentation exceeds the rate of vertical fault displacement. Dense profiles across strike-slip faults within Skjálfandi exhibit vertical slip of up to 15 m during several earthquake sequences during the last ~12000 years.
Do oceanic observations (still) matter in initializing decadal climate predictions over the North Atlantic ocean?
Authors: Brune Sebastian , Koul Vimal , Baehr Johanna
Published: February 2023

Earth system models are now regularly being used in inter-annual to decadal climate prediction. Such prediction systems based on CMIP5-generation Earth system models had demonstrated an overall positive impact of initialization, i.e. deriving initial conditions of retrospective forecasts from a separate data assimilation experiment, on decadal prediction skill. This view is now being increasingly challenged in the context of improvements both in CMIP6-generation Earth system models and CMIP6-evaluation of external forcing as well as in the context of ongoing transient climate change. In this study we re-evaluate the impact of atmospheric and oceanic initialization on decadal prediction skill of North Atlantic upper ocean heat content (0-700m) in a CMIP6-generation decadal prediction system based on the Max Planck Institute Earth system model (MPI-ESM). We compare the impact of initial conditions derived through full-field atmospheric nudging with those derived through an additional assimilation of observed oceanic temperature and salinity profiles using an ensemble Kalman filter. Our experiments suggest that assimilation of observed oceanic temperature and salinity profiles into the model reduces the warm bias in the subpolar North Atlantic heat content, and improves the modelled variability of the Atlantic meridional overturning circulation and ocean heat transport. These improvements enable a proper initialization of model variables which leads to an improved decadal prediction of surface temperatures. Our results reveal an important role of subsurface oceanic observations in decadal prediction of surface temperatures in the subpolar North Atlantic even in CMIP6-generation decadal prediction system.
Spatial and temporal variations of thermal contrast in the planetary boundary layer
Authors: Di Gioacchino Tommaso , Clarisse Lieven , Van Damme Martin , Coheur Pierre
Published: February 2023

Short-lived atmospheric pollutants mainly reside in the planetary boundary layer (PBL). In recent years, the sensitivity of high-resolution infrared sounders to the PBL has been amply demonstrated, most notably through observations of local emission sources of sulphur dioxide (SO2), carbon monoxide (CO) and ammonia (NH3). However, sensitivity of infrared sounders to the PBL varies strongly as a function of thermal contrast (TC), the temperature difference between the Earth’s skin temperature and the temperature of the atmosphere. Enhanced contrast, typically seen during daytime when the surface is typically (much) warmer than the air, provides favourable measurement conditions. At night, TC is smaller, and can even become negative, providing again favourable measurement conditions. More generally speaking, TC is highly variable in both time (inter and intraday) and space. Up to now, no study has provided insight in the global statistical behaviour of the TC or answered the question when and where thermal infrared sounders experience optimal measurement conditions.Here we combine the Copernicus Global Land Services land surface temperature (LST) dataset, derived from geostationary satellite measurements, with air temperatures from the ERA5 reanalysis dataset to obtain a global TC dataset at high temporal (1 hour) and high spatial (31 km) resolution. TC is analysed at two different altitudes, the standard meteorological height of 2 meters, and at half the boundary layer height. In addition to the ERA5-based dataset, we also present an additional TC dataset obtained with data from a global constellation of meteorological stations.We analyse and present statistics on the dependence of TC as function of time of the day, time of the year and land cover.  These provide constraints on the time windows and boundary conditions (e.g., land cover type) for which the sensitivity of the TIR instruments is best. It also allows optimal planning of overpass times for future infrared satellite sounders or the organization of aerial measurement campaigns for near-surface pollutants. Finally, this unique dataset can be used to statistically assess the measurement sensitivity of infrared sounders.