bluuebunny/crossref_metadata_2025 huggingface dataset:
The response of field-aligned and horizontal ionospheric currents to HSS/SIR driven storms and comparison to ICME driven storms
Authors: Pedersen Marcus , Vanhamäki Heikki , Aikio Anita
Published: February 2023

The time delay from an interplanetary driver arriving at the magnetopause to the response in the ionospheric and field-aligned currents (FAC) has never been quantified separately for different types of storm drivers. The development and evolution of the total FAC during storms driven by high speed streams and associated stream interaction regions (HSS/SIR) are different compared to these driven by the sheath and magnetic clouds of interplanetary coronal mass ejections (ICME), as shown in Pedersen et al. (2021, 2022). The main differences are that the FACs in HSS/SIR storms maximize earlier in the storm main phase and are less intense than during ICME storms. Likewise, differences in response times is possible. The delay time for HSS/SIR driven storms is investigated using cross correlation analysis between the total FAC and SME index and the Newell coupling function (NCF), and is compared to sheath and MC driven storms. It is found that the total FAC and SME index lag the NCF by 40 ± 10 min during storms driven by HSS/SIR and sheaths, and by 60 ± 10 min for MCs. Additionally, the total FAC best correlate with the NCF when using solar wind data averaged over the preceding 60 min for sheath, 100 min for HSS/SIR and 120 min for MC driven storms.
Towards sub-daily satellite-based interception loss estimates
Authors: Tronquo Emma , Zhong Feng , Verhoest Niko E.C. , Miralles Diego G.
Published: February 2023

Terrestrial evaporation (E) plays a crucial role in the Earth system, acting as a link between the water and carbon cycles and playing a major role at the complex interplay between land and atmosphere. Therefore, accurate monitoring of E and its different components is crucial. However, since E cannot be observed directly from satellite sensors, current E retrieval algorithms are largely indirect and satellite-based E estimates remain highly uncertain, especially in what respects to the partitioning of evaporation into its different components. In particular interception loss (Ei), the volume of precipitation captured by plant surfaces and evaporated back into the atmosphere without reaching the ground, remains one of the most uncertain components in the global water balance. Moreover, current existing E datasets only deliver daily satellite-based Ei estimates, being unable to resolve precipitation event scales.  The research presented here is focused on estimating Ei on a sub-daily scale. To do so, the Global Land Evaporation Amsterdam Model (GLEAM; Miralles et al., 2011) is used. GLEAM is an E model that simulates the different components (transpiration, soil evaporation, interception loss) using satellite data, including microwave observations of surface soil moisture and vegetation optical depth (VOD). We adapted GLEAM to function at sub-daily resolution, by (1) relying on sub-daily satellite-based forcing data and (2) extending the recent interception model presented by Zhong et al. (2022) by following a Rutter approach (Rutter et al., 1975) to make it applicable at sub-daily scales. This interception model calculates a running balance in time of rainfall, throughfall, evaporation and changes in canopy storage, whereby Ei is the evaporation from the wet canopy. The model is driven by satellite-observed vegetation dynamics, potential evaporation and precipitation. The sub-daily Ei estimates are compared to existing daily estimates and diurnal cycles are analyzed, and this at different spatial scales.References:Miralles, D. G., Holmes, T. R. H., De Jeu, R. A. M., Gash, J. H., Meesters, A. G. C. A., & Dolman, A. J. (2011). Global land-surface evaporation estimated from satellite-based observations. Hydrology & Earth System Sciences, 15, 453–469. Rutter, A. J., Morton, A. J., & Robins, P. C. (1975). A predictive model of rainfall interception in forests. II. Generalization of the model and comparison with observations in some coniferous and hardwood stands. Journal of Applied Ecology, 12, 367–380.Zhong, F., Jiang, S., van Dijk, A. I. J. M., Ren, L., Schellekens, J., & Miralles, D. G. (2022). Revisiting large-scale interception patterns constrained by a synthesis of global experimental data. Hydrology & Earth System Sciences, 26, 5647–5667. 
Nationwide groundwater recharge evaluation for a sustainable water withdrawal over Italy
Authors: Rossi Mauro , Donnini Marco , Beddini Giulio
Published: February 2023

Groundwater recharge (GR) is the amount of water that infiltrates into the soil recharging aquifers. For Italy, we applied a water balance method for estimating GR, along with other balance components, using gratis/libre open access data and open source software. The results were compared with the data available from the literature on Central Italy, to validate the model and to investigate the variation in the GR, while considering different lithologies. The comparison of the GR results with anthropogenic water withdrawals enabled the evaluation of sustainable water use in Italy. The results show that in Italy the annual averaged GR is ~110 × 109 m3. This estimate may vary for specific years; in 1992 and 2015, the GR exceeded the value by 3% and 27%, respectively. According to these and related estimations, the 1981–2010 average groundwater withdrawals for civil, industrial and agricultural use were estimated to be ~14% of the averaged GR for the same period. In 1992, the withdrawals for the mineral water industry was about 0.01% of the GR and that for civil use was ~10% in 2015. In this study, we observed significant differences in the GR at the regional level, mostly influenced by the precipitation distribution and elevation. The proposed approach can provide quantitative data in line with the Goal 6 (Targets 6.4 and 6.5) of the 2030 Agenda for Sustainable Development of United Nations (https://sdgs.un.org).
Determining the best functional form of reservoir operating policies to maximize the value of integrating seasonal streamflow forecasts into reservoir operations in the Colorado River Basin
Authors: Singh Samarth , Quinn Julianne , Wiens Nathan , Smith Rebecca
Published: February 2023

Droughts are among the most severe natural disasters, but are difficult to prepare for because of their slowonset. In absence of effective drought early warning systems and response plans, water users oftencontinue to pursue short-term economic gains that ultimately come at the expense of longer-termeconomic and ecological sustainability. Fortunately, seasonal forecasts have shown promise for informingadaptive water management policies that can reduce these impacts. One avenue of adaptation is throughreservoir operations, where seasonal streamflow forecasts can enable hedging of releases to favor morefrequent but less impactful water shortages over more devastating impacts down the line. This can beachieved by optimizing reservoir operating policies that define how much water to release from a networkof reservoirs as a function of these seasonal forecasts. However, the best functional form for such policiesis an open research question.The goal of this project is to compare alternative formulations of reservoir operating policies conditionalon seasonal climate forecasts to see which is most effective in reducing economic and ecological droughtimpacts. We investigate this question in the Colorado River Basin (CRB). Commonly termed the“lifeblood of the West,” the Colorado River provides irrigation water for over 5.5 million acres ofagricultural land, drinking water for more than 40 million people, and over 4000 MW of installedhydropower capacity. Yet managing this system is becoming increasingly challenging due to ongoingclimatic and anthropogenic drought conditions that jeopardize water security and endanger the river’secological health. To improve water security in the basin, this project aims to optimize reservoir operatingpolicies in Lake Mead, Lake Powell, and three upstream reservoirs by coupling a RiverWare reservoirmodel of the CRB with Borg, a multi-objective optimization algorithm, to reduce the frequency andseverity of water shortages to the Upper Colorado River Basin (UCRB), Lower Colorado River Basin(LCRB), and Mexico. In this study, we explore different ways of incorporating seasonal forecasts of theinflows to these five reservoirs into their operating policies considering different functional forms of theoperating policies using a model-free, closed loop optimal control method called Direct Policy Search(DPS). Specifically, we compare using logistic and Gaussian Radial Basis Functions (RBFs) for thereservoir rules. Our work illustrates the value of integrating streamflow forecasts into reservoir operatingrules for drought management, while also providing insights into how to formulate the policies tomaximize that value.
Statical prediction system of the typhoon intensity using Numerical Weather Prediction model for correction
Authors: Bae Jeong-Ho , Lee Jung-Rim , Won Seong-Hee , Ham Dong-Ju
Published: February 2023

The accuracy of tropical cyclone (TC) forecasts from NWP models have been improved especially for the track. Relatively, TC intensity forecasts still include huge uncertainties though the dynamics, physics processes, and resolutions of NWP systems become higher in both horizontal and vertical. For this reason, many operational centers and academia for TC forecasts implemented statistical prediction systems and Artificial Intelligence (AI) algorithms based on long-term dynamic model forecasts for better predictions of typhoon intensity.The National Hurricane Center (NHC) developed the Statistical Hurricane Intensity Prediction Scheme (SHIPS) which is a statistical model based on NWP forecasts (parameters from atmosphere and ocean). Also, infrared imagery from geostationary satellite is used as predictors for the regression. SHIPS is implemented for the North Atlantic and East Pacific regions. Otherwise, the Joint Typhoon Warning Center (JTWC) implemented this model for the Northwest Pacific region. Also, Korea Meteorological Administration (KMA) and Japan Meteorological Administration (JMA) developed the statistical based typhoon prediction systems (called STIPS and TIFS, respectively). However, the accuracy of these systems is not stable because it is not easy to define the tendency of NWP forecasts for TC intensity. The National Typhoon Center of KMA developed a new statistical model (Statistical Prediction Intensity of Korea mEteorological administrator, SPIKE) for typhoon intensity prediction based on ECMWF forecast. While the ECMWF Integrated Forecast System (IFS) has an excellent performance in forecasting track of typhoons, the intensity tends to be underestimated compared to typhoons analysis information. SPIKE is basically developed as a multi-linear regression model, and its predictors are extracted from the IFS forecast. The average prediction error of typhoon intensity of SPIKE in 2022 decreased by about 30% compared to the ECMWF forecasts. However, there was still a limitation, especially for cases of rapid intensification (RI). More studies to reflect real-time intensity, cloud development, center location, and prediction errors of the model are conducted. Then, the second multi-linear regression model to account for these parameters is developed. Finally, an additional improvement of about 30% was achieved. Also, the performance for RI cases developing more than 35 knots within 24 hours was greatly improved. 
Diversity and patterns of fracture-exposed alteration features in thick recharge-area regolith
Authors: Lehmann Robert , Eshvara Arachchige Dinusha , Aehnelt Michaela , Totsche Kai Uwe
Published: February 2023

Typically thick aeration zones of topographic groundwater recharge areas are hardly investigated parts of subsurface ecosystems and the subsurface water/matter cycles (Lehmann and Totsche 2020). In fractured bedrock settings, here, mineral surfaces and assemblages, exposed to major flow-paths, can largely differ from the bulk rock-forming compositions. Representing highly diverse and likely important reaction spaces for subsurface matter cycling and groundwater quality, yet, their compositional and morphological diversity, their provided habitat structure and endolithic dwellers, and their matter sources and dynamics are scarcely known. In drill core samples of Triassic limestone-mudstone alternations from the Hainich Critical Zone Exploratory (Collaborative Research Center AquaDiva), we characterized and classified alteration features across regolith down to the phreatic zone. Besides analysis of fracture/pore fillings and rock matrices by digital microscopy, SEM(-EDX), among others, we investigated possible controlling factors like lithofacies associations, depth, water saturation, groundwater flow patterns and oxicity. Generally, strong weathering features with up to 1 mm thick fillings and up to several centimeters thick zones of alteration in rock of the aeration zone contrast with minor features in the phreatic zone. In the limestones and mudstones, major classes of fracture surface coatings, are taken by secondary Fe-oxides and/or clay laminae. Our results highlight the typical presence of diverse and likely dynamic reaction spaces, providing highly diverse microbial habitats. We suggest to carefully consider and explore the diversity and dynamics of mineral fractures surfaces of the aeration zone, and their contributions to element cycling and groundwater quality evolution. References:Lehmann, R., Totsche, K. U. (2020). Multi-directional flow dynamics shape groundwater quality in sloping bedrock strata. Journal of Hydrology 580. https://doi.org/10.1016/j.jhydrol.2019.12429
Predictable patterns within the kelp forest can indirectly create temporary spatial refugia for ocean acidification
Authors: Bednarsek Nina , Pelletier Greg , Beck Marcus , Feely Richard , Siegrist Zach , Kiefer Dale , Davis Joth , Peabody Betsy
Published: February 2023

Seaweeds are gaining recognition as a significant CO2 sink with a role in active mitigation andclimate change adaptation, and specifically so in the application of an innovative coastal CO2 removal belt, effectively utilizing seaweed habitats to mitigate the adverse effects of ocean acidification (OA). However, assessing OA modification strength requires an understanding of the multiple parameters’ potential buffering effects, especially in highly dynamic systems. Exactly how kelp might generate more favorable conditions for marine calcifiers, has not been taken into account in previous studies to date. We studied the effects of sugar kelp (Saccharina latissima) on an experimental farm at the north end of Hood Canal, Washington—a low retentive coastal system. This study can serve as a natural analogue for many coastal bay habitats where prevailing physical forcing drives chemical changes. In this field mesocosm study, pelagic and benthic calcifiers were exposed with or without the kelp’s putatively protective proximity at locations in the middle, on the edge, and outside the kelp array. Model outputs were used to identify dominating factors in spatial and temporal kelp dynamics, while wavelet spectrum analyses helped in understanding predictability patterns. We linked these results to biological assessments, including biomineralization, growth and subcellular energetics responses of the examined species. We found our studied kelp array system did not modify carbonate chemistry parameters, but changed pH autocorrelation patterns towards higher predictability that was more favorable for marine calcifiers. Kelp also improved habitat provisioning through kelp-derived particulate organic resource utilization. Because of this, the co-culture of bivalves and seaweed can protect the calcifiers from negative effects of projected near-future OA. However, our study shows that a complex combination of physical, chemical and biological processes determines the efficiency of the kelp farms for creating more favorable habitats with respect to OA. Future macrophyte studies should focus significantly on the importance of predictability patterns, which can additionally improve the conditions for marine calcifiers as well as ecosystem services, with important implications for the aquaculture industry.  
Benchmark of multiple non-invasive electrodes for a relevant use in urban environments
Authors: Debouny Tom , Caterina David , Nguyen Frédéric
Published: February 2023

Over time, urbanized areas have undergone continuous development and growth as they adapt to the changing needs of their residents. This has often involved the construction of new buildings, roads, and infrastructures, as well as the renovation and expansion of existing structures. Subsurface characterization is thus a crucial aspect of urban development, as it is essential for the planning, construction and monitoring of new or existing infrastructures. Urbanized environments may be challenging for conventional subsurface characterization methods such as drilling or excavation due to difficulty of access or the presence of buried networks that are not always properly mapped. Geophysical methods can be seen as an interesting alternative to these traditional characterization approaches but require to be adapted to work properly in such environment. This led to the development of the urban geophysics discipline.Among the different geophysical methods available, Electrical resistivity tomography (ERT) appears as a useful and robust tool for studying subsurface materials and structures in urban environments. It has already been used to investigate underground utilities such as tunnels, cellars, pipes, tank storages and building foundations as well as natural structures. While ERT minimizes site disturbance, the use of fully non-invasive electrodes is sometimes required for the preservation of investigated sites. The best example remains the investigation of archeological structures. For that purpose, a diversity of non-invasive electrodes such as flat electrodes, bentonite mud or conductive gel has already been used overtime for different purposes but showed different outcomes in terms of contact resistance, measurement uncertainty, durability or signal to noise ratio. To our knowledge, few systematic comparison has been done between the different types of non-invasive electrodes and their impact in terms of imaging/monitoring in specific conditions for urban applications.The present study proposes an assessment of the use of different non-conventional electrodes on various surfaces often encountered in urban environments at controlled lab-scale. The tested electrodes can be divided into two main categories, the electrolytic and the weight electrodes. The analysis focuses on contact resistance, electrical current transmission, noise measurements, strength and stability of the signal over time. The ease and time of deployment are also taken into account for future uses in larger scale fieldworks. Based on preliminary results, the electrodes based on electrolytic contact demonstrate better performances in highly resistive environments, where a better grounding resistance can globally be achieved compared to weight-based electrodes. However, their implementation are more fastidious slowing the acquisition.
Summer Net Community Production in the northern Chukchi Sea: Comparison between 2017 and 202
Authors: Hahm Doshik , Kwon Soyeon , Lee Inhee , Park Keyhong , Cho Kyoung-Ho , Jung Jinyoung , Park Taewook , Lee Youngju , Jeon Chanhyung , Seo Seongbong
Published: February 2023

The Arctic Ocean experiences warming-induced processes, such as the decrease in sea-ice extent and freshening of the surface layer. While these processes have the potential to alter primary production and carbon export to the deep layer, the changes that will likely occur in them  are still poorly understood. To assess the potential changes in net community production (NCP), a measure of biological carbon export to the deep layer, in response to climate change, we observed the O2/Ar at the surface of the northern Chukchi Sea in the summers of 2017 and 2020. The NCP estimates derived from O2/Ar measurements were largely in the range of 1 -- 11 mmol O2 m-2 d-1 in the northern Chukchi and Beaufort Seas, close to the lower bounds of the values in the global oceans. The average NCP of 1.5 ± 1.7 mmol O2 m-2 d-1 in 2020 was substantially lower than 7.1 ± 7.4  mmol O2 m-2 d-1  in 2017, with the most pronounced decrease occurring in the ice-free region of the northern Chukchi Sea; the NCP of the ice-free region in 2020 was only 12% of that in 2017. The decrease in 2020 was accompanied by a lower salinity of >2, which resulted in shallower mixed layer depths and stronger stratification. We speculated that the anomalously low pressure near the east Russian coast and the lack of strong winds contributed to the strong stratification in 2020. With a continuing decrease in the extent of sea ice, the northern Chukchi Sea will likely experience earlier phytoplankton blooms and nitrate exhaustion. Unless winds blow strong enough to break the stratification, the biological carbon export in late summer is likely to remain weak.  
Estimating water balance components of Pinus brutia and Cupressus sempervirens trees with observational tree sapflow and soil moisture data
Authors: Djuma Hakan , Bruggeman Adriana , Eliades Marinos , Sofokleous Ioannis , Zoumides Christos , Siakou Melpomeni
Published: February 2023

In the coming decades, the Mediterranean region is expected to be one of the areas most affected by climate change as models project a reduction in precipitation. It remains a question if some of the Mediterranean forests will be able to adapt and survive. Pinus brutia (pine) and Cupressus sempervirens (cypress) are two important forestry species in the Mediterranean region. Although they are both coniferous, they can have different strategies to cope with water stress. The objective of this study is to estimate water balance components of pine and cypress trees with observational tree sapflow and soil moisture data. The study site is located in Athalassa Forest Park, in Cyprus. The site has a surface area of 10 ha with an average slope of 4%. Average annual rainfall is 315 mm with a mean daily minimum temperature of 5° C during January and a mean daily maximum temperature of 37° C during August. The site was converted in 2011 from rainfed agriculture to a mixed forest by planting seedlings of different tree and shrub species. Hourly observations of sapflow (cm3) and volumetric soil moisture (%) from two pine and two cypress trees and surrounding soil were used for this study. Soil moisture sensors were installed under the tree canopy (0.4 to 0.9 m from the tree trunk), at the edge of the canopy (1.3 to 2.2 m from the tree trunk) and in the open area (midpoint between neighboring tree trunks, 2.6 to 3.5 m from the tree trunk). The sensors were installed at two opposite sides of each tree trunk, in the direction of the neighboring trees. Sensor depths were 10 cm, 30 cm and 50 cm, reaching a total of 60 sensors. Daily water balance calculations were made for the period 06/11/2020 to 29/06/2022 (20 months), in which total rainfall was 581 mm. The extent of the tree root zone area was estimated for different sets of assumptions. For a root zone depth of 60 cm and a root zone area radius of 2.2 m, transpiration amounted to 33.2% of the precipitation for one of the two cypress trees and 40.9% for the other tree, with losses (interception, soil evaporation and drainage) of 60.3% and 53.6% and soil moisture changes of 6.5% and 5.5%, respectively. The pine tree observations indicated a smaller root zone area. For a root zone depth of 60 cm and a radius of 1.7 m, the transpiration of the two pine trees amounted to 30.4% and 48.0% of the precipitation, losses were 60.6% and 50.7% and soil moisture changes were 9.0% and 1.3%. The effect of the different assumptions on the water balance components will be presented.This research has received financial support from the PRIMA (2018 Call) SWATCH Project and the Water JPI (Joint Call 2018) FLUXMED Project, both funded by the Republic of Cyprus through the Cyprus Research and Innovation Foundation. The PRIMA programme is supported by Horizon 2020, the European Union's Framework Program for Research and Innovation.
Root water uptake in relation to plant transpiration
Authors: van Dusschoten Dagmar , Pflugfelder Daniel , Kochs Johannes
Published: February 2023

Typically, root water uptake (RWU or Utot) is said to be driven by transpiration (Tr). It is however more accurate to state that transpiration causes a reduction in leaf water content that reduces the leaf water potential such that a water potential gradient builds up between leafs and soil water, such that water can be extracted from the soil. For herbaceous plants, the amount of water that is hereby lost is typically assumed to be negligible so the plant can be treated as a resistive system. In how far this is true is open to discussion as quantifying shoot water changes is not easily feasible, especially when the soil-root system is drying out. A balance cannot observe water moving between the soil and the shoot and shoots have empty spaces such that 3D cameras provide an incomplete picture. Shoot weight determination requires that the amount of soil water is independently assessed to discriminate between the two pools of water. This can be achieved when a balance is combined with a Soil Water Profiler (SWaP) on the same soil-plant system. The precision of the SWaP is comparable to that of an expensive balance (<10mg for a 6kg system).Here we performed experiments with the SWaP – balance combination under modulated light with progressive soil dehydration for sunflower and faba bean (N=4). Our data shows that transpiration precedes Utot by about 5 to 10 mins under wet conditions (pF~2) and Utot can exceed Tr by up to 20%. Gradually, with decreasing soil water content we find that Utot becomes smaller than Tr and at the same time the delay between Tr and Utot increases. For pF>3.5 most of the transpired water stems from the shoot, not from root water uptake, indicating that Tr is a poor proxy for RWU for pot experiments where soil is drying at a rate of ~5% per day at well watered conditions. This is very important for calculations of root conductance during drying scenarios. We found significant differences between sunflower sensitivity to soil drying as compared to faba beans that are somewhat more sensitive. We also present data that shows that the delay between Tr and local water uptake is rather dependent on depth and not so much dependent on local pF, which is typically lower for shallow sections of the pot. This may potentially be explained by loss of root water when Tr increases with light, analogous to shoot water losses.The combination of the SWaP and gravimetric methods opens up a new way of looking at root water uptake as driven by transpiration and shoot water loss dynamics as it provides hitherto inaccessible information about these processes.
Towards realizing the EU 2050 Zero Pollution Vision for Nitrogen Export
Authors: Kumar Rohini , V. Nguyen Tam , J. Sarrazin Fanny , Ebeling Pia , Schmidt Christian , Beusen Arthur , Bouwman Lex , H. Fleckenstein Jan , Attinger Sabine , Musolff Andreas
Published: February 2023

The European Union has adopted an ambitious long-term, zero pollution vision for 2050  aiming for EU’s  “air, water and soil pollution to be reduced to levels no longer considered harmful to health and natural ecosystems …” [1]. However, the extent to which such a goal can be realistically realized for legacy contaminants like nitrogen (N) is not yet properly understood. Herein, we provide a comprehensive assessment of nitrogen retention and export across the European landscapes to receiving waterbodies using a suite of climate, hydrology, and future socioeconomic scenarios. We establish a chain of hydroclimate and nitrogen export scenarios, comprising climate simulations from global climate models (CMIP) under different emission pathways (RCPs) and shared socioeconomic pathways (SSPs) to force a coupled hydrology and water quality model (mHM-N [2]) that characterizes the N retention and export dynamics over the period 1971-2070. SSPs consider balancing options for agricultural land management and technical innovations, taking into account future food, economic growth, and environmental demands; and provide N input trajectories from both diffuse (agricultural) and point (wastewater) sources. Our analysis shows a higher degree of improvement with substantially lower N levels in all European surface water bodies by the 2050s, compared to current levels (2010s). Eastern European rivers may benefit from technological improvements by reducing point source inputs, while in the Western European region, lower N levels can be noticed due to a reduction in diffuse N inputs. Despite these improvements, there are areas of concern where some European water bodies may still suffer from N levels exceeding critical thresholds (e.g., 2-3 mg N/l) in 2050. This may be related to continued N exports that slowly deplete legacy storages (e.g., soil and groundwater). Overall, this requires more proactive measures, particularly aiming at reducing N inputs while harvesting/utilizing and attenuating the built-up storage, to achieve the zero-pollution goal.References[1] https://environment.ec.europa.eu/strategy/zero-pollution-action-plan_en[2] https://doi.org/10.1029/2008WR007327; https://doi.org/10.1029/2022GL100278
The effect of early diagenesis on magnetic mineralogy and quality of paleomagnetic recording in marine sediments: case study from the NE Mediterranean shelf
Authors: Zemach Yakar , Shaar Ron , Sivan Orit , Herut Barak , Katz Oded , Hyams-Kaphzan Orit , Roberts Andrew
Published: February 2023

Magnetic properties of marine sediments are dictated not only by the detrital mineralogy, but also by diagenetic processes that can start instantaneously after deposition and may proceed for a long time as sediments are buried. Early diagenesis encompass a range of biochemical reactions associated with bacterial respirations. These may include oxidation at the water sediment interface, iron reduction, sulfate reduction, and anaerobic oxidation of methane (AOM) if methane is present. To investigate the link between diagenesis, sedimentary magnetic properties and quality of paleomagnetic recording, we collected eight 6m-long piston-cores from the Holocene Eastern Mediterranean continental shelf in four locations. Two locations are characterized by high concentration of methane and detectable sulfate-methane transition zone (SMTZ) at depth of 1-4 m. In the other two locations, organoclastic sulfate reduction is dominant throughout the entire cores. Sedimentation rates in this region range between 1 - 5 mm/year. In all cores, concentrations of sulfate, methane and ferrous iron were measured from the pore water. The geochemical data were compared to the mineral magnetic profile that include a range of parameters calculated from IRM, ARM, low- and high- field susceptibility, hysteresis, and FORCs. Paleomagnetic time-series of declination and inclination were obtained from demagnetization experiments carried out in 2 cm resolution. Age models were constructed from radiocarbon dating of carefully collected foraminifera. The results show a consistent link between the diagenetic zones and the magnetic mineralogy: Increase of magnetic properties in the shallow ferruginous zone, decay of magnetic parameters in the sulfate reduction zones,  rapid decrease at the SMTZ and stabilization at the methanogenic zone. XHR-SEM analysis show multiple generations of greigite and pyrite framboids at all depths and unaltered detrital titanomagnetites. We find that except a short time interval below the SMTZ of one core, the paleomagnetic directions in these sediments do not represent the expected directions of the geomagnetic field. We conclude that continuous organoclastic sulfate reduction in marine sediments might have a profound effect on the quality of paleomagnetic recording, but AOM at the SMTZ may help stabilize the magnetic phase. 
Multi-spacecraft observations of near-relativistic electron events at different radial distances
Authors: Kollhoff Alexander , Berger Lars , Brüdern Maximilian , Dresing Nina , Eldrum Sandra , Fleth Sebastian , Gómez-Herrero Raúl , Heber Bernd , Kühl Patrik , Pacheco Daniel , Rodríguez-García Laura , Rodríguez-Pacheco Javier , Wimmer-Schweingruber Robert F. , Xu Zigong
Published: February 2023

With the launch of Solar Orbiter (SolO) on Feb. 10th 2020, a new era of multi-spacecraft solar energetic particles (SEP) observations has started. The unique orbit of the mission allows the observation of SEP events close to the Sun (<0.28 au), which can occasionally be compared to corresponding observations made by other spacecraft at 1au. Such multi-spacecraft observations of the same event at different radial distances provide an excellent opportunity to study the radial evolution of SEP events.In this study, we identify SEP events for which SolO and either Wind or STEREO-A had a small longitudinal separation (<15°) between their magnetic foot-points at the Sun. For all SEP events that satisfy our selection criteria we determine the onset times and rise times as well as peak fluxes and peak values of the first-order anisotropy for electrons in the energy range from ∼50−85 keV. We compare the event parameters observed at the different spacecraft regarding their radial changes. In our sample we find strong event-to-event variations in the radial dependency of all derived event parameters. For the majority of events, the peak flux and the maximum value of the first-order anisotropy decrease with increasing radial distance to the Sun, while the rise time increases with radial distance in the majority of events. The derived onset delays observed between two spacecraft were found to be too long to be explained by ideal Parker spirals in multiple events.We present an overview of the most interesting observations and discuss the wide variability in the radial dependency of the event parameters analysed in this study.
CASPER: A Space Mission Concept to Investigate Transient Luminous Events and Terrestrial Gamma Ray Flashes
Authors: Maurer Manuel , Byrne Louí , Falk-Petersen Ulrik , Hamdoun Ali , Hénaff Gwendal , Huber Kilian , Ilas Andreea , Reisinger Nadja , Sinjan Jonas , Suarez Crisel , Szilágy-Sándor András , Tarvus Vertti , Tsindis Marialinda , Vaganov Mikhail
Published: February 2023

As part of the Alpbach Summer School, a collaboration between FFG, ESA and ISSI, a team of students developed the F-class CASPER mission concept to investigate Transient Luminous Events (TLEs) and Terrestrial Gamma Ray Flashes (TGFs). These lightning-related plasma phenomena, first detected on Earth in 1989, typically occur in the mesosphere at an altitude between 50-100 km. The UVS instrument onboard the JUNO mission detected several similar events on Jupiter, and they are expected to also occur on other planets.The CASPER mission consists of two identical spacecraft, each of which will be equipped with three cameras in different wavelengths and four high speed sensors, the latter will function as triggers to start the data acquisition of higher resolution images. A system chosen to combat the transient characteristic of the events (lifetime < 300 ms). While three sensors will be taking measurements of photons, one will quantify the electron flux in order to constrain the role of TLEs and TGFs in the global electric circuit.The second great area of interest is the vertical structure of TLEs as well as their global distribution and occurrence rates. To achieve this, data will be captured using a two-satellite train in a sun-synchronous low earth orbit. The orbit is inclined at 98° and the satellites are phased at an angle of 5.2° to observe these events from two points of view simultaneously. The operational mission lifetime is five years, with a possible extension.
Thermodynamic Approach to Assessing Ecosystem Integrity of Gwangneung Old-Growth Forest Biosphere Reserve in Korea
Authors: Kim Joon , Yang Hyunyoung , Kang Minseok , Chun Jung-Hwa
Published: February 2023

Biodiversity and integrity are the key indicators representing ecosystem’s state. Much attention has been given to the former while less to the latter. This is because (1) the definition of integrity is ambiguous, (2) theoretical framework is lacking for quantitative assessment, and (3) observation data for quantification and validation are in paucity. The review of literature funnels down the definition of integrity to twofold perspectives: normative and thermodynamic. Accordingly, we define integrity as a state of ecosystem whose structure and function self-organize to an extent comparable to its reference state. Here, system’s self-organization can be expressed holistically based on non-equilibrium thermodynamics by quantifying the system’s thermodynamic entropy balance. We have tested this definition and the theoretical framework to assess the integrity of Gwangneung old-growth forest in Korea (GDK), which has been designated as one of the UNESCO’s Biosphere Reserves since 2010. Long-term observation (from 2005 to 2020) of energy, matter (water vapor and carbon dioxide) and information flows in and out of GDK were divided into the reference period (2006-2010) and the test period (2011-2020). These dataset emcompasses a wide range of environmental conditions and disturbances to examine ecosystem response and adaptability. GDK's self-organization was estimated in terms of entropy production (σ) and entropy transfer (J). Also, using information-theoretic approach, the behaviors of σ and J were analyzed in terms of the balance between informational emergence (flexibility) and self-organization (order, thus related to resilience). These results were compared and scrutinized by associating with the analyses of (1) linear cause and effect relationships between key variables representing ecosystem structure and function (e.g., energy capture, energy dissipation, biomass production, respiration, biodiversity) and (2) transfer entropy-based dynamic process network (of subsystems at various spatio-temporal scales, feedback types/loops and delay). Granting the necessity of further test and improvement, we argue that thermodynamic and information-theoretic frameworks are complementary and shed a light to development of more holistic and operational indicators for ecosystem integrity such as maximum complexity and antifragility.
An analysis of daily ice coverage changes for the Yenisei River from 2002 to 202
Authors: Qiu Yubao , Zhang Yixiao , Li Yang , Leppäranta Matti , Liang Wenshan , Jiang Zhengxin , Cheng Bin
Published: February 2023

Since the beginning of the 20th century, the surface air temperature in the Arctic has increased more than three times faster than the global average. River ice is an important component of the terrestrial cryosphere, which is very sensitive to air temperature. The Yenisei River originates from the Sayan Mountains in Mongolia and is the largest watersheds drained by Arctic Ocean, which covers latitudes from 46°N to 73°N. The changes of river ice for Yenisei River provides reflect the response of great rivers in the high latitudes of the Northern Hemisphere to climate change. In this study, the daily river ice coverage in the Yenisei River was firstly estimated with a grid of resolution at , derived from the Moderated Resolution Imaging Spectroradiometer (MODIS) daily observations for the period 2002-2021. The classical Normalized-Difference Snow Index (NDSI) algorithm was employed to extract the ice cover; a cloud removal and filtering method were used to reduce errors caused by cloud contamination and the polar night influence. The validation with dependence to the Landsat data showed that an overall accuracy was achieved by 86%. By applying the Theil–Sen nonparametric statistical slope method and the Mann–Kendall test to the results, it was found that the river ice coverage shows a decreasing trend. Over the past 20-year period, 82.8% of the Yenisei River Basin experienced a decreasing ice coverage, of which 21.9% is significant at the 0.05 level of significance. A correlation analysis indicated that the winter river ice coverage is driven by the mean winter air temperature () and that the ice coverage shows a strong latitude dependence (). River ice coverage is highly sensitive to the air temperature in the south part of the Yenisei basin, where the latitudes are low and the altitudes are high. It was also found that, during the winter, the accumulated negative temperature correlates with river ice coverage similarly with the average temperature (). In Lake Baikal, the largest freshwater lake in the Yenisei basin, apart from air temperature the distribution characteristics of ice coverage was most probably affected by heat inflows from streams, dynamics and water depth.
Impacts of climate change on hydrological extremes and hydropower production in tropical Africa: catchments of Lake Malawi and the Shire River in Malawi
Authors: Bronstert Axel , Mtilatila Lucy , Vormoor Klaus
Published: February 2023

The study investigates the sensitivity of water resources, droughts and hydropower generation to climate change in the Lake Malawi and Shire River basins, covering three different aspects:Analysis of the variability and trends of meteorological and hydrological droughts based on observational data from 1970 to 2013;
Drought analysis for future conditions and investigation of potential changes in water balance and various drought indicators;
Hydrological simulation and sensitivity analysis of the Lake Malawi water balance and water level, as well as its discharge and associated hydropower generation in the Shire River.
The key findings of these analyses are:Between 1970 and 2013, meteorological droughts have increased in intensity and duration. This can be attributed to a decrease in precipitation and an increase in temperatures and evaporation.
The hydrological system of Lake Malawi reacts to meteorological droughts with a time lag (up to 24 months), so that hydrological droughts can be predicted up to 10 months in advance by meteorological drought parameters. Hydrological droughts are characterized by water levels below 474.1 m asl in Lake Malawi.
Despite all the differences and uncertainties in climate projections, they agree that meteorological droughts will continue to increase in the future, in the form of increasing drought intensities DI (+25% to +50% for 2021-2050 and +131% to +388% for 2071-2100) and increasing drought months DM (3-5 and 7-8 more drought months per year, respectively).
The water level in Lake Malawi, as a residual of the catchment water balance, is very sensitive to changes in precipitation and evaporation. Outflow from the lake is a direct function of lake water level, and the combination of projected precipitation decline and temperature increase ultimately leads to significantly reduced flow in the Shire River and a decline in annual hydropower production of between 1% and 2.5% (2021-2050) and 5% and 24% (2071-2100). Sometimes, individual projections even suggest that the outflow from Lake Malawi would temporarily dry up and the power supply in the country would be interrupted.
It is shown that failure to meet the 1.5°C global temperature increase target will have a severe impact on droughts and water resources in Malawi. This in turn has implications for hydropower production, as a result of which the achievement of most of the Sustainable Development Goals (SDGs) will be at risk.
Advances in the determination of a global unified reference frame for physical heights
Authors: Sanchez Laura , Huang Jianliang , Barzaghi Riccardo , Vergos Georgios S.
Published: February 2023

Measuring, studying, and understanding global change effects demand unified geodetic reference frames with (i) an order of accuracy higher than the magnitude of the effects to be observed, (ii) consistency and reliability worldwide, and (iii) long-term stability. The development of the International Terrestrial Reference System (ITRS) and its realisation, the International Terrestrial Reference Frame (ITRF), enable the precise description of the Earth’s geometry by means of geocentric Cartesian coordinates with an accuracy at the cm-level and with global consistency. An equivalent high-precise global height reference system that provides the basis for the consistent determination of gravity field-related coordinates worldwide, in particular geopotential differences or physical heights, is missing. Without a conventional global height system, most countries rely on local height systems, which have been implemented individually, applying in general non-standardised and non-uniform procedures. It is proven that their combination in a global frame presents discrepancies at the metre level. Therefore, a core objective of the international geodetic community is to establish an international standard for the precise determination of physical heights. This standard is known as the International Height Reference System (IHRS). Its realisation has been a main topic of research during the last years. Recent achievements concentrate on (1) compiling detailed standards, conventions, and guidelines for the IHRS realisation, (2) evaluating computational approaches for the consistent determination of potential differences, and (3) designing an operational infrastructure that ensures the maintenance and long-term stability of the IHRS and its realization. This contribution summarises advances and current challenges in the establishment, realization and sustainability of the IHRS.
Stress field analysis from induced earthquakes caused by deep fluid injection: the 2013 St. Gallen (Switzerland) seismic sequence.
Authors: Massa Bruno , Adinolfi Guido Maria , Convertito Vincenzo , De Matteis Raffaella
Published: February 2023

The city of St. Gallen is located in the Molasse Basin of northeast Switzerland. Mesozoic units of the substratum are affected by a fault system hosting a hydrothermal reservoir. In 2013 a deep geothermal drilling project started in an area close to the city. During a phase of reservoir stimulation, a sequence of more than 340 earthquakes was induced with a maximum magnitude ML 3.5. Stress inversion of seismological datasets became an essential tool to retrieve the stress field of active tectonics areas. With this aim, a dataset of the best constrained Fault Plane Solutions (FPSs) was processed in order to qualitatively retrieve stress-fields active in the investigated volume. FPSs were obtained by jointly inverting the long-period spectral-level P/S ratios and the P-wave polarities following a Bayesian approach (BISTROP). Data were preliminarily processed by the Multiple Inverse Method to evaluate the possible dataset heterogeneity and separate homogeneous FPS populations. The resulting dataset was then processed using the Bayesian Right Trihedra Method (BRTM). Considering that hypocentral depths range between 4.1 and 4.6 km b.s.l., in order to emphasize depth-related stresses, we performed a first step of raw stress inversion procedure splitting the data into five subsets, grouping events located inside 100-m depth ranges. Once the presence of stress variations with depth has been excluded, the second step of fine stress inversion procedure was performed on the entire dataset. The stress-inversion procedure highlights an active stress field dominated by a well-constrained NE low-plunging σ3 and a corresponding NW low-plunging σ1. The corresponding Bishop ratio confirms the stability of the retrieved attitudes. Results are in good accordance with the regional stress field derived from regional natural seismicity. Additionally, the retrieved, dominant, stress field is coherent with the regional tectonic setting.This research has been supported by PRIN-2017 MATISSE project (No. 20177EPPN2).