bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of orientation of marine magnetometers by means of modelled local field variations derived from spherical elementary current systems
Authors: Hölz Sebastian , Johnsen Magnar Gullikstad , Franz Gesa , Córdoba Ramírez Fernando , Cairns Graeme , Nedimovic Mladen , Jegen Marion , Berndt Christian , Elger Judith , Maselli Vittorio
Published: February 2023

In the marine environment, active and passive electromagnetic (EM) measurements are used to derive information about the conductivity structure beneath the seafloor. While the conductivity is mostly determined by the conductive seawater contained in the pore space or fractures, anomalies may occur in the presence of more resistive (e.g. hydrocarbons, free gas, gas hydrates, freshened water) or conductive materials (e.g. massive sulfides, brines). For the correct interpretation of EM data it is important to know the measurement geometry, including the orientations of receivers. From an experimental standpoint, this can be challenging because stations are often deployed free falling, thus, ending up in arbitrary orientations on the seafloor. The orientations are frequently derived from electronic compass measurements or magnetometers which record all components of the magnetic field. However, these measurements may be distorted by magnetic parts on stations (e.g. batteries), biased by local inhomogeneities in the local field or difficult to perform if no reliable reference data from a nearby observatory is available.A possible remedy for such problems may come from space physics. Given a grid of stationary magnetometer stations, surrounding the area of interest but at relatively large distances, the method of spherical elementary current systems (SECS) (Amm & Viljanen, 1999, Earth, Plants and Space) can be used to reconstruct equivalent ionospheric currents and their resulting time variations of the magnetic field at any point within the grid. The method is especially suitable to be applied at northern latitudes, where fairly dense magnetometer networks such as IMAGE and CARISMA exist, and where the magnitude of geomagnetic disturbances from ionospheric currents is significant.We have successfully applied the method to three marine EM data sets, one offshore Iceland, one in the arctic section of the North Atlantic (Loki's Castle) and one off the Canadian coast (Prince Edward Island). The SECS method qualitatively reproduces the magnetic variation as observed by the seafloor stations. Here we investigate the results from the above mentioned EM data sets, and discuss the applicability, accuracy and constraints of the SECS method for EM data calibrations. Furthermore, we illuminate the possibility for using SECS as an interpolation tool for other applications at remote offshore locations, such as measurement while drilling (MWD) operations.
Investigating oceanic sources of methane and their influence on ambient concentrations in polar regions.
Authors: Workman Evelyn , Jones Anna , Fisher Rebecca , France James , Linse Katrin , Yang Ming-Xi , Bell Tom , Dong Yuanxu
Published: February 2023

Atmospheric methane (CH4) is a potent greenhouse gas with natural and anthropogenic sources. Concentrations have been significantly increasing over the past few decades, which poses a problem for future climate change goals. The contribution of oceans to the global atmospheric CH4 cycle is largely uncertain. It is accepted that oceans act as a small net source of atmospheric CH4. As the polar regions are warming faster than the global average, it is important that we can better quantify CH4 emissions from the polar oceans. In this study, we combine various forms of shipborne data (ambient atmospheric methane concentrations, sea-air CH4 fluxes and isotopic composition of atmospheric CH4) taken during cruises in the Arctic and Southern Oceans to present a more complete picture of atmospheric CH4 above polar oceans, including addressing the question of how much the oceanic component is contributing towards the atmospheric budget in these regions. Measurements  were made around the Barents Sea and Greenland Sea in the Arctic, and in the Atlantic sector of the Southern Ocean, including the Scotia Sea.Sea-air CH4 fluxes are measured using the eddy covariance method; indeed, this the first study to use this technique to directly measure how much CH4 is released from the ocean into the atmosphere in both the Southern and Arctic Oceans. Atmospheric CH4 measurements are then investigated in order to understand the impact that CH4 released from the ocean has on the atmospheric burden. We also measure the isotopic composition of CH4 (δ2H and δ13C) in air samples taken onboard polar cruises, to understand the sources of atmospheric CH4 above these oceans. The isotope measurements can indicate if the CH4 comes from a biogenic or thermogenic source, which can help determine if anthropogenic or natural processes are behind the production.We investigate the potential sources of CH4 released by the polar ocean by looking at areas of known seabed CH4 seepages, investigating phytoplankton abundance, and investigating the isotopic composition of atmospheric CH4 in areas of elevated CH4. We find that the region of the Arctic Ocean investigated in this study is a slight atmospheric CH4 source in boreal summer, while the region of the Southern Ocean investigated is a CH4 source in areas of shallower water/continental shelves and a CH4 sink in region of open ocean, in austral summer. This finding is consistent with previous studies that have detected seabed CH4 emission. Seabed CH4 seepage at shallower depths is more likely to penetrate the sea-air interface, while CH4 produced at the seabed at deeper depths gets oxidised as it travels through the water column, making it less likely to reach the surface . We also find evidence of localised “hot spots” of methane emission which will be described. 
The impact of Amazon deforestation on rain system using a storm-resolving global climate model
Authors: Yoon Arim
Published: February 2023

Previous studies with coarse-resolution global climate models (GCMs) have widely shown that extensive deforestation in the Amazon leads to a reduction in precipitation, with a potential irremediable loss of the rainforest past a critical threshold. However, precipitation in the Amazon region is of convective nature and thus has to be parameterized in coarse-resolution GCMs, limiting confidence in the results of such studies. To bypass this limitation, this study aims to investigate the impact of Amazon deforestation on precipitation in global climate simulations that can explicitly represent convection. The simulations are conducted with the ICON-Sapphire atmosphere-only model configuration run with a grid spacing of 5 km for two years. To understand the impacts of Amazon deforestation, we compare the results of a complete deforestation simulation with a control simulation. Results show no significant change in precipitation during the wet season and a slight decrease of precipitation during the dry season in the deforested simulation. Precipitation decreases due to decreased evapotranspiration are compensated by enhanced moisture convergence.
Analyses of Heatwaves in Observational and Modelled Data for Africa
Authors: Ziegler Katrin , Abel Daniel , Weber Torsten , König Lorenz , Paeth Heiko
Published: February 2023

The WASCAL WRAP2.0 project LANDSURF aims to calculate and compare different climatological and agrometeorological indices to support stakeholders and farmers in adapting to climate change and its impact in Africa.This study, which was conducted in the framework of LANDSURF, focuses on the number and duration of heatwaves as rising temperature and resulting heat were found to limit crop yield and thus lower food security in different African regions. We calculated the heat wave duration index (HWDI) for reanalysis data, three regional climate models (RCMs) (REMO2015, RegCM4-7, and CCLM5-0-15) from CORDEX CORE, and their respective forcing data to validate the models over a historical climatological period (1981-2010) and investigate the change of the HWDI for three climatologies of the near-, mid-, and long-term future until 2100 using the two Representative Concentration Pathways (RCPs) 2.6 and 8.5.
Modelling rainfall interarrival times and rainfall depths at daily scale
Authors: Ferraris Stefano , Agnese Carmelo , Martini Tommaso , Di Nardo Elvira , Baiamonte Giorgio
Published: February 2023

Analysis of daily rainfall data, and subsequent modelling of some derived variables concerning rainfall, is fundamental in different areas such as agricultural, ecological, and engineering disciplines. A way of studying the alternance of consecutive rainy days (wet spells) and no-rainy days (dry spells) is through the interarrival time (IT), which is the time elapsed between two consecutives rainy days. If we suppose that IT observations are independent and identically distributed (i.i.d.), ITs are usually modelled through a renewal processes. The simplest renewal process is the Bernoulli process with ITs geometrically distributed. The need to suppose a non-constant probability of rain brings to more sophisticated models. Previous works [Agnese et al. (2014), Baiamonte et al. (2019)] have successfully proposed the three-parameter family of the Hurwitz-Lerch-Zeta distribution (HLZD), which represents a forward step with respect to other commonly used IT distributions. In [Agnese et al. (2022)], a second successfully reached goal was to show that the HLZD is also suitable to model the rainfall depth, h. In literature, rainfall depths are more frequently treated as continuous, despite sometimes these models fail to account for the time discreteness of the sampled process. Indeed, daily rainfall depth measurements are usually carried out by automatic-counting how many times a small bucket corresponding to 0.2 mm is filled. Due to the abundance of ties in the data, the variable depth h is well suited to be considered discrete. We present results involving data never considered in literature and consisting of measures sampled along 60-70 years at 7 different stations. These stations represent different climates from the rainfall characteristics point of view and let us to infer about the great handiness of the HLZD within rainfall modelling. Current research is addressed to modelling further rainfall variables related to IT and h, such as wet and dry spells, and the cumulative rainfall depth in a wet spell. Furthermore, given the remarkable performance of the HLZD family of distributions in the univariate modelling, we aim at modelling the dependence structure between IT and h, exploiting possibly new methodological advances in the subject, such as discrete copulas.
 
References

Agnese, G. Baiamonte, E. Di Nardo, S. Ferraris, and T. Martini (2022). Modelling the frequency of interarrival times and rainfall depths with the Poisson Hurwitz-Lerch zeta distribution. Fractal and Fractional, 6(9).
Agnese, G. Baiamonte, and C. Cammalleri (2014). Modelling the occurrence of rainy daysunder a typical Mediterranean climate. Advances in Water Resources, 64:62–76.
G. Baiamonte, L. Mercalli, D. C. Berro, C. Agnese, and S. Ferraris (2019). Modelling the frequency distribution of inter-arrival times from daily precipitation time-series in north-west Italy. Hydrology Research, 50(1):339–357.
Standing Column Wells: A transformative opportunity to provide heating to buildings in dense urban areas.
Authors: Pasquier Philippe
Published: February 2023

Ground-coupled heat pump systems can help reducing energy consumption and electrical peak power demand while contributing to reduce greenhouse gas emissions. A key element of these systems is the ground heat exchanger that links the mechanical equipments to the underground geological materials. Although most ground heat exchangers are composed of closed-loop wells, standing column wells (SCW) represent a transformative opportunity in dense urban areas where aquifer productivity is limited. Based on a decade of research conducted in the area of Montreal in Canada, this conference will illustrate the potential of SCWs, present the preliminary results of two demonstration projects, discuss the impact of hydrogeological and hydrogeochemichal conditions on system design and discuss some recent advances related to field testing and modeling of SCWs. The challenges that remain to be overcome will also be discussed.
Unraveling the unknowns of global tropical cyclone risk in the future
Authors: Meiler Simona , Emanuel Kerry , Bresch David N.
Published: February 2023

Tropical cyclones (TCs) are among the most devastating natural hazards putting populations and assets at risk. This risk is expected to increase further in a warming climate and with socio-economic development. It is, therefore, of great importance and the aim of our study to assess the drivers and uncertainties of global TC risk in the future. We use a large set of synthetic TCs downscaled from various general circulation models (GCMs) and different warming scenarios of the CMIP6 generation to simulate TC activity at the middle and end of this century. In parallel, we derive economic growth factors from different Shared Socioeconomic Pathways (SSPs) to approximate socio-economic development. We combine these future representations of hazard and exposure data with vulnerability functions to estimate the TC risk increase in the future, using an open-source probabilistic impact model (CLIMADA). Furthermore, we perform a systematic uncertainty and sensitivity analysis to understand which of the model input factors contribute most to the uncertainty in the future TC risk increase. First, we find a non-linear effect between climate change and socio-economic development that drives the total future risk. Second, we show that the choice of GCM affects the output uncertainty most among all varied input factors. However, we note that exposure and vulnerability data are notoriously sparse and that advances in future TC risk assessment also depend on a better representation of these components. Ultimately, unraveling these unknowns of global TC risk in the future may help focus future research efforts and enables better-informed adaptation decisions and mitigation strategies.
Synthesis, homogenisation and regionalisation of inland water greenhouse gas budget estimates for the RECCAP2 initiative
Authors: Lauerwald Ronny , Allen George H. , Deemer Bridget R. , Liu Shaoda , Maavara Taylor , Raymond Pete , Alcott Lewis , Bastviken David , Hastie Adam , Holgerson Meredith A. , Johnson Matthew S. , Lehner Bernhard , Lin Peirong , Marzadri Alessandra , Ran Lishan , Tian Hanqin , Yang Xiao , Yao Yuanzhi , Regnier Pierre
Published: February 2023

Inland waters are important sources of the greenhouse gasses (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) to the atmosphere. While a growing number of global estimates of inland water GHG emissions exists, the integration of inland waters into regional GHG budgets is often hampered by the lack of adequate geo-spatial datasets. Moreover, existing estimates diverge substantially, in part due to persisting uncertainties related to the size and distribution of effective inland water surface areas.  In the framework of the 2nd phase of the REgional Carbon Cycle Assessment and Processes (RECCAP-2) initiative, we synthesize existing estimates of GHG emissions from streams, rivers, lakes and reservoirs, and homogenize them with regard to underlying global maps of inland water surface areas and the effects of seasonal ice cover. We then produce estimates of inland water GHG emissions for 10 extensive land regions that are used for the regional land budgets of RECCAP2. According to our synthesis, global inland waters emit 5.6 (3.5-9.1) Pg CO2 yr-1, 101 (83-135) Tg CH4 yr-1 and 326 (254-592) Gg N2O yr-1. South American rivers contribute about one third of global inland water CO2 emissions. North-American and Russian lakes contribute together one third of global inland water CH4 emissions. Finally, North America alone contributes one fourth of global inland water N2O emissions.The global inland water emissions sum up to a global warming potential (GWP) of an equivalent emission of 13.6 (10.0-20.3) and 8.3 (5.8-12.7) Pg CO2 yr-1 at a 20- and 100-year horizon, respectively. At 100-year horizon, the contribution of CO2 dominates the GWP of global inland water GHG emissions, with rivers being the largest emitters. At the 20-year horizon, on the contrary, lakes and rivers are equally important emitters, and the contributions of CH4 to the GWP of inland water GHG emissions even exceed those of CO2. Contributions of N2O to the GWP appear to be less significant at both time horizons. Normalized to the area of the RECCAP-2 land regions, South America and South East Asia show the highest inland water emission rates in terms of GWP, dominated by riverine CO2 emissions.
Tracking ecological health status of a tropical coastal ocean- applicability of benthic foraminifera coenosis
Authors: Mandal Arkaprava , Bhadury Punyasloke
Published: February 2023

Coastal oceans offer multifaceted ecosystem level services and represent a key part to achieve UN SDG Goals including SDG14. The northeast coastal Bay of Bengal (BoB) in South Asia is interspersed with several coastal biotopes influenced by the Ganga-Brahmaputra-Meghna delta among others and contribute immensely to sustainable blue economy. The Sundarbans mangrove, world’s largest continuous mangrove, a UNESCO World Heritage Site and a RAMSAR site along with long intertidal zones represent characteristic features of this region. These sites are increasingly reeling from numerous anthropogenic stressors and the scales of anthropogenic disturbances were characterized through benthic foraminifera coenosis over three seasons along with robust measurement of organic carbon in sediment as well as integrating new technologies such as eDNA approach. The studied sites showed overwhelming abundance of calcareous taxa Ammonia spp. and Quinqueloculina spp. as well as low taxon level diversity. There was notable high abundance of dead and degraded tests indicating potential taphonomic alterations that indicated changes influenced by lowering of porewater oxygen content, N:P stoichiometry and possible changes in freshwater flow. The values of total organic carbon of sediment exhibited wide variability and the strong influence of anthropogenic forcings in closer proximity to human influences. There was resulting evidence of anaerobic degradation of sediment organic matter resulting in changes in sediment pH and taphonomic alteration of benthic foraminifera tests. The eDNA based high-throughput sequencing exhibited signs of low diversity of benthic foraminifera and signals influenced by anthropogenic stressors such as forms of nitrogen. The study based on spatio-temporal mosaics of mapping of coastal health of northeast coastal BoB indicates increasing human pressure will have long-term effects on SDG Goal 14 and beyond.
Coastal aquifer, shoreline and shallow marine sediment permeability on a global scale
Authors: Tschaikowski Jarrid , Moosdorf Nils
Published: February 2023

The world's coast is an important interface of global hydrogeology. It mediates the flow of groundwater to the oceans and the supply of fresh groundwater that much of the coastal population relies on for drinking water. The coast connects also fresh groundwater and marine seawater. For a better understanding of the global water cycle, the interaction between freshwater and seawater along the more than 2 million kilometers of global coast needs to be studied more intensively. For this, knowledge of coastal permeability is paramount.The global coastal permeability map (GCPM) aims to represent the coastal permeability of the world's coast in 1-kilometer segments. The GCPM divides coastal permeability into three distinct views: Permeability of the landward aquifer, the shoreline, and the shallow marine sediments. Extensive GIS-based work was conducted to merge several recent global datasets which represent attributes indicating permeability with the shoreline.  Using the multiple features of these datasets, the coastline was then classified into permeability configurations.The GCPM provides an important and useful baseline data set for local to regional coastal hydrogeology and especially for global coastal hydrogeology. Possible uses include serving as an input parameter for coastal boundary conditions for global models that integrate sea-land interactions, as a parameter for submarine groundwater discharge calculations, and as an aid in identifying areas of increased saltwater intrusion hazard. Also, pooling coastal parameters from the individual datasets will increase accessibility and allow opportunities for broader analyses. Differentiating between costal aquifer, shoreline, and shallow marine permeability will make the GCPM valuable to a broader field of coastal science and applications, as well as influence the way coastal permeability is viewed in the future.
Concentration and chemical bonding conditions of metal(loid)s in mining contaminated subaquatic sediments of the Hüttenteich near Berthelsdorf, Saxony, Germany
Authors: Hartmann Clemens , Scheytt Traugott
Published: February 2023

Significant amounts of sediments are stored in natural lakes and dams. In the Erzgebirge, Germany, these sediments were eroded from surrounding areas and are often contaminated by metal(loid)s. This leads to a potential risk for water quality. The sediments themselves reduce the water storage capacity of these reservoirs. Decreasing capacities of landfills necessitate comprehensive treatment and recycling strategies to reduce the solid concentrations of the main contaminants (As, Pb, Cd, Cu, Zn). The aim of the study was to determine the spatial and fractional distribution of concentration and chemical bonding conditions of these metal(loid)s in the sediments of the investigation area to derive effective treatment technologies. For this, the total solid concentration, and the leaching behaviour of the metal(loid)s have to be determined. Therefore, representative samples were studied under reducing conditions using ‘aqua regia digestions’, sequential extractions with the fine grained fraction (≤ 0.063 mm), and elution tests with precipitation water and ultrapure water. The results show that pH, grain size and metal(loid) concentrations of the eluate and the solid depend on catchment areas, flow conditions, deposition conditions within the dam, and sediment depth. Maximal solid concentrations were detected between 30 cm and 60 cm sediment depth. There is no significant difference in solid concentration of the metal(loid)s between the fine grained fraction and the coarse grained fraction (> 0.063 mm, ≤ 2 mm). The main contaminants are bound in different proportions to non-residual compounds, thus less to silicates. The dissolved concentrations of the metal(loid)s, determined by the elution tests with the two solvents considered, do not differ significantly from each other. The study shows that mobilization may be an effective treatment option for these subaquatic sediments, but its evaluation requires further investigation.
Estimating Freshwater Lens Volume based on Island Circularity
Authors: Thissen Lena , Greskowiak Janek , Massmann Gudrun
Published: February 2023

Freshwater lenses (FWLs) are an important source of drinking water on many islands in the world. Thus, it is important to study their volumes. Many case studies have already been carried out on real world islands to approximate the FWL volume of the respective islands. Also, generic studies on FWLs exist that consider idealised island shapes such as circular or strip islands. However, to the authors’ knowledge there is no study so far that describes the general relationship between the island’s shape and the freshwater volume of its lens. Here we show that there is a relationship between these two quantities. In our approach, we characterized the shape of the islands using a circularity parameter; the volume was approximated using this shape and a simple numerical steady-state Ghyben-Herzberg approach. While we found a strong relationship between island shape and FWL volume, the relationship between the island shape and the depth of the FWL was less clear. The findings of this study can help to estimate the FWL volume on islands for which there are no case studies available.
Successful treatment of PFAS-contaminated soils on large scale: practical experience with soil washing.
Authors: Faigle Dr. Benjamin , Edel Dr. Hans-Georg , Volz Bernhard
Published: February 2023

The method of soil washing is currently the only economically feasible cleaning method for PFAS-contaminated soils on large scale.A total of about 430,000 t of soil contaminated with PFAS and HCs was washed from August 2018 to October 2021 at the site of a former refinery in Bavaria. The cleaned soil could then be refilled at site-specific costs of about EUR 50 per ton. Since September 2022, Züblin Umwelttechnik GmbH has been operating another soil washing plant in Northern Germany, which was specially designed to treat soils contaminated with PFAS. Several hundred thousand tons of sandy soil with around 10% fines will be washed and refilled on site in the next years.Data obtained from these two large-scale remediation projects are presented. The technical concept and challenges to treat 1,000 to 3,000 t of material per day are discussed, along with regulatory obstacles and the boundary conditions to process these quantities while limiting the emissions. A special focus lies on the heterogeneous nature of input material, with varying contaminant load, soil quality and soil structure as well as affiliated contaminants. In both attempts, the washing water is circulated in a closed water cycle, therefore elaborate treatment of sludge and polluted water is required.One of the critical issues in soil washing is to optimise the washing process so that the washing liquid serves as the predominant contaminant sink. In this way, steady washing results are achieved, and all output fractions can be successfully processed while water consumption is kept to a minimum.The complex nature of the contaminant itself, the multitude of singular PFAS substances and precursors, further complicate operation and controlling. Progress shows that soil washing can even be a viable tool to treat the fine fraction, and various strategies in different treatment steps have been tested on multiple scales, including several washing agents.Since after treatment, the washed soils can be safely reused on site, large emissions from transportation and properly disposing the PFAS-materials is avoided while increasingly limited landfill space is maintained.Future research is required for expanding the applicability of the method to highly challenging materials such as high fines and/or high organic content. Further projects for washing of PFAS contaminated soils in Europe are already in the planning stage.
Mosses as biofilters for ditch methane emissions from forestry drained peatlands
Authors: Larmola Tuula , Rissanen Antti J. , Ojanen Paavo , Stenberg Leena , Kohl Lukas , Mäkipää Raisa
Published: February 2023

In drained peatland forests, drainage ditches cover ca. 3% of the area, but contribute to up to 100% of methane (CH4) emission. The drained peat soils, in contrast, can act as a CH4 sink especially under efficient drainage. Therefore, emissions from ditches will impact whether drained peatland is a net CH4 sink or source. The net CH4 flux is likely to be impacted by the conditions in the ditches such as the extent and type of plant cover and the time since drainage. In order to provide more accurate ditch CH4 emission factors for national greenhouse gas (GHG) inventory, we examined the fluxes and the underlying CH4 cycling processes in a nutrient rich peatland forest in Ränskälänkorpi, Southern Finland during May-October 2021. We compared the ecosystem-atmosphere CH4 fluxes and their δ13C values from moss dominated and open water ditches. We determined CH4 and CO2 mixing ratios and their δ13C values in water and in sediment by gas chromatography and cavity ring-down spectroscopy (Picarro G2201-i), respectively. We also assessed the role of CH4 as a carbon source for Sphagnum mosses growing in ditches by analyzing δ13C values in submerged and partly submerged Sphagnum using elemental analysis - isotope ratio mass spectrometry. We found that mean seasonal CH4 emissions from moss dominated ditches were 90% lower than from open water surfaces. In this dry summer, moss-dominated ditches were occasionally net sinks of atmospheric CH4. These results can be explained by CH4 consuming microbes inhabiting surface water, moss layer or sediment below the moss layer and using CH4 as a source of carbon and energy. Isotopic mass balance calculations accounting for the measured δ13C values of Sphagnum moss, dissolved CO2 and CH4 as well as fractionation against 13C during (mass-transfer-limited) moss CO2 fixation indicated that 10-28% of carbon in ditch Sphagnum mosses potentially originated from oxidized CH4. Ditch network maintenance, including removing mosses, is likely to decrease along with changing peatland forest management, e.g., continuous cover forestry. Our results suggest that ditches overgrown by mosses have potential to reduce CH4 emissions from drained peatland forests and could serve as an additional GHG mitigation measure to management practices that maintain a continuous forest cover, attenuate the changes in water table level and thus reduce CH4 emissions from peat soils. 
First results on global hybrid-Vlasov magnetospheric simulations with a coupled ionosphere
Authors: Pfau-Kempf Yann , Ganse Urs , Papadakis Konstantinos , Alho Markku , Battarbee Markus , Cozzani Giulia , Dubart Maxime , George Harriet , Gordeev Evgeniy , Grandin Maxime , Horaites Konstantinos , Kotipalo Leo , Suni Jonas , Tarvus Vertti , Tesema Fasil , Turc Lucile , Zaitsev Ivan , Zhou Hongyang , Palmroth Minna
Published: February 2023

Vlasiator, the global hybrid-Vlasov model of the terrestrial magnetosphere, now features a coupled ionosphere model replacing the previous, perfectly conducting inner boundary. Following a well-established approach, densities, temperatures and field-aligned currents are mapped along the geomagnetic dipole field down to an ionospheric grid. Height-integrated Hall and Pedersen conductivities are computed using a model atmospheric profile based on the NRLMSIS model in order to solve for the ionospheric potential. Its gradient is then mapped back to the hybrid-Vlasov simulation domain, yielding an electric field and a resulting EXB drift affecting the plasma at the boundary.We present an overview of this new coupled ionosphere module as well as highlights from the first large-scale magnetospheric simulation runs performed with it. In particular, we compare the global behaviour of the magnetosphere under steady southward interplanetary magnetic field driving using the perfectly conducting or coupled ionosphere boundary models.
Investigating the environmental implications of biogas production pathways using life cycle impact assessment model to support regional energy transitions
Authors: Kalu Amarachi
Published: February 2023

The regional energy transition requires a growing share of alternative technologies powered by biomass sources,for which not all their environmental impacts have been fully understood yet. The UN and the sustainabledevelopment goal (SDG’s) seven encourage a cleaner, safer and modern energy production for all to upholdenvironmental and climatic protection. This case study aims to apply the Life Cycle Assessment (LCA) modelingtool such as the openLCA in assessing wholly (from up to downstream) the environmental, socio-economic andengineering perspectives of energy transitions.The Purpose is to analyze the environmental impacts of maize silage production for biogas production in supportof clean and affordable energy. This means, analyzing the supply chain activities from upstream to the downstreamto obtain the impacts on ecosystem and its services. The objectives of this research are to (a) explore differentbioenergy emission and climate change related problems while finding the tradeoffs across various impacts whenmaize silage is used as feedstock. (b) To discover current natural gas production technology pathways in Alberta,the oil exploration province of Canada and compare them with biogas production impactsThe Method applied is the Eco-indicator 99, E, E method, used in analyzing life cycle impact assessment worst-case scenario of products or services, while comparing the effects with the TRACI & ReCipe methods across board. It provides robust quantitative estimates of GHG emissions, eutrophication, climate impacts, health and land-use impacts of maize silage production for biogas on a regional scale.From the study’s scientific findings, relevant information on the interconnectedness of bioenergy environmentalimpact is generated, which are also useful/applicable for Canada and globally. The result found that the use of highnitrogen fertilizer (above 120 kg/h) contributes to high eutrophication potentials and drying of the maize silagehas high climate change potentials which proves that biogas production from maize silage is not completely cleanbut can be improvedIn conclusion. It concludes that biogas systems can decarbonize regional fossil energy grids, drying of the silagebe carried out in summer with biogas and natural gas mix, and supports the moderate use of farm chemicals tocreate a balance between bioenergy development and environmental prosperity. the project is significant becauseit comprehensively states the need for reduction of excessive emission of greenhousegases, land conversion, and nutrient delivery through biogas production and other energy transition activities thathave the potential to increase global warming, damage water and land resources in Alberta which is scarcely available.KEYWORDS: Energy transition, Environmental impacts, Life cycle impact assessment, Openlca Eco indicator99, biogas production, Sustainable Environmental.
Multidecadal change in natural carbon dynamics at the interface between Atlantic and Southern Ocean
Authors: Delaigue Louise , Sulpis Olivier , Reichart Gert-Jan , Humphreys Matthew P.
Published: February 2023

Although global marine anthropogenic CO2 inventories have typically highlighted the North Atlantic as being the main feature of interest, southern hemisphere processes also play a key role in the changing marine carbon cycle. The South Subtropical Convergence (SSTC) in the South Atlantic, where low-macronutrient subtropical gyre waters intersect high-macronutrient Antarctic Circumpolar Current waters, is a key location for studying key processes such as the effects of climate change on the biological carbon pump. Here, we present a time series consisting of marine carbonate chemistry measurements from recent expeditions and global marine observations (GLODAPv2.2022 and BGC-ARGO) at 40°S in the Atlantic Ocean. We calculate the rates of change in dissolved inorganic carbon (DIC) and other related variables and use these to disentangle the apparent drivers of DIC change both natural (carbonate pump, Ccarb and soft tissue pump, Csoft) and anthropogenic (Canth). An increase in DIC is observed throughout the water column. The relative contribution of the Csoft and Canth components to the DIC change varies, however, significantly depending on whether we use nutrients or dissolved oxygen in the analysis. We discuss the causes of this discrepancy, using a water mass analysis to investigate the effect of water mass composition shifts in formation regions, and exploring the impact of reduced oxygenation and increased remineralization in the Southern Ocean, aiming to understand which tracer more accurately represents the changing carbon pump.
Ice Sheet Speed-dating: Using Expert Elicitation to identify “good” simulations of the LGM North American Ice Sheets
Authors: Gandy Niall , Ives Gemma , Rivers Gwyneth , Astfalck Lachlan
Published: February 2023

After running a large ensemble of palaeo ice sheet model runs, it is common to either rank the simulations or determine which simulations are an acceptable match to observations and which are ruled out. This task requires human judgement, which is usually left only to the authors of the research. Tools have been developed to compare ice sheet simulations to empirical reconstructions numerically, but even this approach requires some human input on values for match thresholds.An alternative is to use expert elicitation to identify “good” ice sheet simulations. Expert elicitation normally captures expert’s beliefs in the form of a probability distribution; for something as complicated as ice sheet geometry this is much too arduous a task. Instead, we propose to elicit binary classifications of “good” and “bad” and find descriptions of plausible ice sheets through probabilistic inverse modelling. Experts can consider empirical ice sheet reconstructions, but also “soft-knowledge” about the sectors of the ice sheet it is most important to match, margin shapes considered to be glaciologically plausible, and an idea of the reasonable best-reconstruction a model will be able to provide. By seeking the input of many experts, it is possible to both lighten the task load of determining the quality of 100-1000s of simulations, and gain a wisdom of the crowd benefit to the results. Just like any other method of ranking ice sheet simulations, this method requires human judgement; in this case more explicitly than usual.We are seeking expert input to rank an existing ensemble of North American Ice Sheet simulations. By asking experts at EGU 2023 to spend 3-5 minutes sorting simulations using an online interface we will build up an average community view on which LGM North American Ice Sheet simulations are “good”. This will provide a community resource to compare future ice sheet simulations against that is a justifiable representation of academic expert knowledge, adding to the current arsenal of model-data intercomparison tools.
Effects of the 2018 European heatwave and drought on coastal biogeochemistry in the German Bight
Authors: Kaiser David , Voynova Yoana , Brix Holger
Published: February 2023

In 2018, Europe experienced an unprecedented heatwave and drought, especially in central and northern Europe, which caused decreased terrestrial production and ecosystem health. The effects on the marine environment are yet unclear. Here we investigate the biogeochemical response to the event in the German Bight of the North Sea. Using time series data from FerryBoxes, research cruises, monitoring programs and remote sensing we compare conditions in 2018 to climatological values. We hypothesize that (1) the heatwave caused unusual warming of surface waters, (2) the drought reduced river discharge and nutrient loads to the coast, and (3) the combined effects altered coastal biogeochemistry and productivity. During 2018, both water discharge and nutrient loads from rivers discharging into the German Bight were extremely low from March onward. Throughout the study domain, water temperature was unusually low in March 2018, but extremely high in May 2018, representing the fastest spring warming on record. This extreme warming period saw concurrent unusually high peaks in chlorophyll a, dissolved oxygen and pH values, consistent with the development of a strong spring bloom. It appears that productivity was unusually strong in near-shore regions, while offshore it was unusually low in 2018. The drought related low discharge limited nutrient supply from the rivers, but likely enhanced near-shore water residence time, where a burst of effective nutrient utilization during the spring depleted nutrients available for transport off shore. There, the heatwave related rapid surface water warming resulted in the establishment of a stable thermal water column stratification, hindering vertical nutrient supply to the surface layer during the summer.
Evaluating the seasonal non-stationarity in the Wei River Basin
Authors: Yuan Xin , O'Loughlin Fiachra
Published: February 2023

Due to the impact of changing climate and human activities on hydrology, non-stationary research is becoming more popular. In the Wei River Basin, which is the largest tributary of the Yellow River, non-stationary has been studied for decades and has found non-stationary signals in discharge and precipitation records. However, these studies have mainly focused on the annual time series and ignored the seasonal signal.In this study, to investigate the non-stationarity more comprehensively, two non-stationary tests have been applied including the Mann-Kendall test and the Heuristic segmentation algorithm. These tests were applied to runoff time series from 12 catchments and catchment averaged precipitation and temperature time series derived from 114 meteorological stations. Like other studies, our results, show that on the annual timescale, non-stationary signals (multiple change points and decreasing trends) are found in the runoff time series on most catchments along the mainstem, while the runoff time series of the Beiluo catchment does not show any non-stationarity signal. However, our results show that there is clearly a seasonal difference with change points occurring at contrasting times. Among all time series, about 40% show only single nonstationary signals (trend or change point), while the remainder exhibit multiple signals indicating the importance of using multiple tests. While the results show that non-stationary signals exist in all time series, further work is needed to quantify if or to what level are meteorological variables the driver of non-stationary signals in the runoff time series.  
Transitioning: the role of disturbances on instigating cross-overs of vegetation zones (a biome perspective)
Authors: Ekberzade Bikem , Yetemen Omer , Sen Omer Lutfi , Dalfes H. Nuzhet
Published: February 2023

This study considers the potential shift of biomes due to simulated changes in climatic drivers up until the end of this century, and how these changes effect the frequency of disturbances which in turn may affect the ranges of vegetation life zones. The study area is mainly the Anatolian Peninsula and its immediate surroundings, a unique location harboring high species diversity and high rates of endemism. Forcing a global to regional dynamic vegetation model with five Global Circulation Model contributions to Coupled Model Intercomparison Project (CMIP6, bias-corrected with ERA5-Land), we looked not only at the changes in the distribution and composition of key forest taxa, but the range shifts of vegetation formations from a biome perspective (classified per The International Geosphere–Biosphere Programme’s nomenclature) focusing on transition zones. Our results simulated a potential increase in the ranges of all 4 woody biomes: forest, transitional woodland, woody grassland and shrubland, with a potential retreat in grasslands. This shift is continuous throughout the simulation period of 1961-2099, with the Central Anatolian grasslands being taken over by tree taxa – comprised mostly of pines and oaks – even for the historical simulation period (1961-2021), but more significantly towards the end of the century. From a biome perspective, the increase in forest biomass and the retreat in grasslands is somewhat contrary to expectations that dryland mechanisms will become more common even in mesic environments as climate change progresses, however in line when we look at the overall picture from a taxon-specific perspective, as species that make up the composition of the simulated woody grasslands in Central Anatolia are mainly drought resistant taxa. One potential reason behind this woody plant encroachment may be the changes in fire frequency and intensity in the absence of anthropogenic interference. Our ongoing research is focusing on this curious pattern as we further analyze this phenomenon with more detailed climate input data with different time windows and with a special focus on disturbances.
Satellite-based dry-wet seasonal changes of OCS surface budgets over the Amazon rainforests
Authors: Tan Lin , Li King-Fai , Jiang Xun , Kuai Le , Liang Danie
Published: February 2023

Carbonyl sulfide (OCS) is the most dominant sulfur-containing species in the atmosphere and is an important tracer of the terrestrial gross primary productivity as it is involved only in photosynthesis. Biomass burning and terrestrial uptakes by plants and soil is the primary terrestrial source and sink of OCS, respectively.  The Amazon basin alone accounts for 10% of the global biomass burning emission and 33% of the global plant/soil uptake. However, both terms are sensitive to water stress, heat stress, and the associated wildfires in the dry seasons. Here, we estimate the dry-wet seasonal difference of the terrestrial OCS budget over the Amazon region by constraining the NCAR MOZART4 chemistry-transport model with the mid-tropospheric OCS abundances retrieved from NASA’s Thermal Emission Spectrometer (TES) measurements during 2004 and 2012.  Our perturbative calculations show that biomass-burning emissions that are predominant in the south rim of the Amazon have more influence on the mid-tropospheric OCS over the southeast subtropical Amazon. In comparison, the plant/soil uptakes that are predominant in the tropical Amazon have more influence over the northwest tropical Amazon.  This dipole spatial pattern helps distinguish the mid-tropospheric OCS seasonal variability due to biomass-burning emissions and plant/soil uptakes.
Using MPAS model to forecast the Convectively Induced Turbulence
Authors: Chen Haoming , Shi Xiaoming , Leung Chiristy Yan-yu , Cheung Ping , Chan St
Published: February 2023

Convectively induced turbulence (CIT) is a serious aviation hazard and it is challenging to forecast the CIT in the region near convection. Previous studies used reginal model with high resolution or global model with low resolution and selected empirical indices to diagnose the turbulence. In this study, we used The Model for Prediction Across Scales (MPAS) to simulate some cases of CIT reported near Hong Kong. MPAS allows us to use convection-permitting resolution in the interested area while including the global-large scale circulation with coarser resolutions in other regions. The eddy dissipation rate (EDR) is computed to diagnose the potential occurrence of CIT. We compared three methods for calculating EDR from the resolved flow in the MPAS, the first one based on second order structure function, the second one based on Scale-Similarity in Large Eddy Simulation (LES) and the third is Near Cloud Turbulence (NCT) diagnostics by using Convective Gravity Wave Drag. Comparing with the NOAA Graphical Turbulence Guidance (GTG) product and flight data suggests that computing EDR with Scale-Similarity is more effective and accurate than second order structure function and NCT diagnostics. Resolution is also an important factor in forecast, we tested the method in mesh with different resolutions but similar distributions, the results from low resolution simulations can generate a useful turbulence pattern forecast, but the intensity is weak, highlighting the value of high resolution simulations that can resolve convection. We evaluated the sensitivity to several model physics and numeric options in simulations. Those variations can change the EDR prediction by influencing the intensity and the life cycle of the convection. No particular scheme produces systematically more intense turbulence than others, suggesting varying model physics captures some stochasticity of convection. Compared with flight records of EDR along the flight routes, MPAS could produce in three out of five cases showing maximum EDR is close to the observed intensity of turbulence (EDR>0.4). However, in the other two cases, the results are not satisfactory mainly because of significant location biases of the predicted convection. We also add initial condition perturbation-based large ensemble in one case and find it possible to improve the prediction of the failed cases by influencing the position of the convection. Further work should be conducted to prioritize the ensemble members since only a few members can capture the turbulence and doing the average will erase them easily.