bluuebunny/crossref_metadata_2025 huggingface dataset:
Along-strike fault geometry controls damage zone parameters: the case of the Kornos-Aghios Ioannis Extensional Fault (Lemnos Island, NE Greece)
Authors: Berio Luigi Riccardo , Balsamo Fabrizio , Pizzati Mattia , Storti Fabrizio , Curzi Manuel , Viola Giulio
Published: February 2023

The study of fault damage zones is key to the understanding of fault-related fluid flow in the upper crust with many applications, including groundwater and hydrocarbon exploration, and underground storage of CO2 and H. Many studies reveal that a relationship exists between fault damage zone width and net fault displacement. Despite this positive relationship, several factors such as the tectonic setting, the depth of deformation, the deformation mechanisms, and the evolving mechanical properties of fault rocks affect damage zone characteristics (e.g., width, asymmetry, fracture attitude, deformation intensity). Furthermore, recent studies show that the overall along-strike fault geometry may play a pivotal role in controlling damage zone characteristics. In particular, areas such as tip regions, linkage sectors, relay ramps and step-overs can be characterised by fault damage zone parameters markedly different from sectors away from these structural complexities. In this contribution, we present new structural data of fault damage zone parameters acquired along the 8 km long extensional Kornos-Aghios Ioannis Fault (KAIF) on Lemnos Island, North Aegean Sea, Greece. The KAIF deforms lower Miocene effusive and hypabyssal magmatic rocks and middle Eocene to lower Miocene turbidites. Deformed rock volumes along the KAIF are locally strongly altered by hydrothermal fluids (e.g., hydrothermal silicification). We provide a detailed characterization of the KAIF in terms of 2D fault geometry (mapped at 1:1000 scale) and kinematics and we present a characterization of fault damage zone parameters, including frequency and attitude of subsidiary fault-related fractures, in different fault sectors. The acquired data allowed us to define the boundaries of fault damage zones in the different sectors and to discuss the differences in terms of fracture attributes in linking- and tip-damage zones compared to damage zones away from these structural complexities. Our results show that fault damage zones in linkage and tip sectors are wider and that fault-related fractures are more clustered around several subsidiary faults with centimetre- to metre-offsets. Also, secondary fractures in linkage and tip sectors are less systematically oriented, thus increasing fracture network connectivity and, consequently, facilitating fluid mobility in structurally complex fault sectors.
Stranding of early cyprinid life stages: effects of artificial flow down-ramping on Barbus barbus L. and Chondrostoma nasus L. under experimental conditions
Authors: Führer Simon , Hayes Daniel S. , Hasler Thomas , Graf David R. M. , Stoisser Felix , Fauchery Elora , Coudrais Anna , Olejarz Antonin , Mameri Daniel , Schmutz Stefan , Auer Stefan
Published: February 2023

Artificial sub-daily flow fluctuations caused by peak-operating hydropower plants are considered one of the most significant impacts on riverine ecosystems downstream of dams. These rivers have, therefore, been subject to numerous studies in recent decades. However, cyprinid fish, in contrast to salmonids, have hardly been addressed in hydropeaking studies yet, and extensive knowledge gaps remain. Therefore, our experimental study aims to assess the effects of rapid flow reductions on the early life stages of two European cyprinid indicator species, the common barbel (Barbus barbus L.) and the common nase (Chondrostoma nasus L.).We conducted mesocosm experiments (2.25×2 m) under semi-natural conditions at an outdoor experimental facility (http://hydropeaking.boku.ac.at), simulating different hydropeaking scenarios with varying down-ramping rates during day and night. At each trial, 100 fish from one species (body length <20 mm) were stocked at peak flow (80 L.s-1). After an acclimation time (15 min.), the flow rate was reduced with variable ramping rates (0.3–1.8 cm.min-1) to constant low flow conditions (10 L.s-1). As a response parameter, larval stranding on a gently sloped shoreline mimicking typical nursery habitats was quantified during day and night.The results reveal distinct diurnal patterns for both species, with increased stranding rates at night for all experimental scenarios. In addition, the data indicate differences between the tested down-ramping rates and show interaction effects between both parameters. The difference between species may result from water temperature and ecological factors. The study outcomes will benefit the ongoing discussion on species-specific hydropeaking mitigation by providing first insights on the direct effects of artificial flow down-ramping on early life stages of cyprinid fish.
Exploring the Socio-Cultural Compatibility of Green Infrastructures in Built Heritage Contexts: A Case Study in Antwerp (Belgium)
Authors: Kale Eda , De Groeve Marie , De Kock Tim
Published: February 2023

Built heritage, which gives identity to the urban fabric and fosters the collective memory of the community, is at risk of deterioration due to climate stressors. These stressors result from rapid urbanisation, covering surfaces with hard materials, and a disconnection from nature.Today, nature-based solutions have become a growing trend as a way to reconnect with nature and mitigate the impact of climate change. Green infrastructures (GI), in particular, offer numerous environmental and social benefits, especially in dense urban areas, including improved air quality, reduced heat island effect, increased biodiversity and improved stormwater management, and stress-reducing and restorative effects on individuals.Although built heritage sites form an important part of the urban fabric, they are often excluded from this green transition due to the risk of invasive species damaging historic buildings' structural and aesthetic integrity. Therefore, there is a lack of research analysing rigorously designed examples of GI in a historical context.This study aims to narrow the focus to the sociocultural perception and acceptance of GI in a historical context. We will analyse spatial-perceptual patterns and socio-cultural motivations behind the deliberate use of GI in this context, using biophilic design principles and architectural perception theories as frameworks. Using GIS monitoring as a methodology, we will map and collect inventory data on real-life examples of GI applied to historical buildings in Belgium-Antwerp. The goal is to understand the correlations between spatial-perceptual factors and the use of GI in built heritage contexts.
Analysis of snow avalanche simulation results in a thalweg-following coordinate system
Authors: Dick Oscar , Tonnel Matthias , Wirbel Anna , Oesterle Felix , Fischer Jan-Thomas , Neuhauser Michael
Published: February 2023

The thickness integrated dense flow avalanche simulation module com1DFA of the open source framework AvaFrame is used for snow avalanche simulations with application in hazard mapping for different mountainous areas. In order to further increase the information value gained from the avalanche simulation results in a global coordinate system, we introduce a thalweg following coordinate system. It allows us to quantitatively compare simulation scenarios and results of different modelling approaches in a new way. It helps to bridge the gap between the modules operating in three-dimensional terrain (com1DFA) versus two-dimensional along the avalanche path, such as the well-known alpha-beta model implemented in module com2AB. One essential step of the analysis procedures (analysis modules in AvaFrame) is the avalanche thalweg generation itself. The thalweg depends on the main flow direction, a property of the avalanche event which is strongly influenced by the terrain the avalanche flow will encounter. So far, the main flow direction is usually derived from observations or avalanche simulations, and the thalweg is generated manually. However, the reproducibility of this method raises an issue, and manually identifying the avalanche thalweg for every slope is unnecessarily time-consuming. In this work, we use com1DFA simulations in three dimensional terrain. We automatically generate the two-dimensional avalanche thalweg by extracting the centre of mass coordinates at every time step. Projecting the simulation results into this thalweg following coordinate system, we can derive the position of the avalanche front and the local travel angles, from which scalar measures like runout length and runout angle are determined. We combine temporal and spatial information by introducing the thalweg-time and thalweg-altitude diagrams. These offer a different perspective on the simulation results and, at a glance, provide information on the evolution of spatio-temporal flow variables (thickness, velocity) along the avalanche thalweg in a single plot. Additionally, by using a numerical particle-grid method, we can evaluate simulation outputs at a particle level and relate them to the whole avalanche flow. Another advantage of the analysis tools operating in the thalweg coordinate system is the possibility to compare simulation results with field measurements. For example, we present in-flow particle sensors trajectories and corresponding velocities recorded during field experiments to evaluate com1DFA simulation results and thereby help to improve the dense flow module. For different avalanche simulations, we show how these analysis modules provide a new way to summarize the complex spatio-temporal flow variables evolution in three dimensional terrain in a more intuitive two dimensional illustration along the automatically generated thalweg.
Assessment of water status in almond trees using optical indices at high and medium spatial resolution
Authors: Carpintero Elisabet , Moldero David , Zarco-Tejada Pablo , González-Dugo Victoria
Published: February 2023

The almond tree is one of Spain’s most widespread woody crops, with an annual growth rate of 4% of cultivated area. In recent years, management practices focused on the intensification of plantations to increase almond production have led to higher irrigation requirements in regions with recurrent water scarcity. In this context, an accurate assessment of canopy water stress is key to successfully apply deficit irrigation strategies. They are critical to optimize water resources without causing severe yield reductions. The usefulness of the Crop Water Stress Index (CWSI) for monitoring transpiration and water status in almond trees has been successfully demonstrated, which uses thermal information acquired remotely at very high spatial resolution to target individual tree crowns. However, canopy temperature in open vegetation orchards is currently limited to sensors installed in manned or unmanned aerial vehicles, which could significantly increase production costs in commercial fields.This work aims to evaluate the ability of a set of optical indices applied to airborne hyperspectral imagery to assess the water status of an almond tree orchard located in Southern Spain during the 2018 campaign. The field was subjected to different deficit irrigation treatments: fully irrigated, moderately stressed and severely stressed. The analysis has been carried out at different spatial scales to explore the effects of pixel size in detecting water stress situations in an attempt to extrapolate the methodology to Sentinel-2 satellite imagery at medium resolution.The indices were compared with stem water potential measurements collected in randomly selected trees within areas with deficit irrigation treatments. The results support the potential of the shortwave infrared-based indices, Normalized Difference Water Index (NDWI) and Moisture Stress Index (MSI) to monitor the water stress of this complex crop with open canopy structure when thermal data are not available at sufficient spatial resolution.
Non-stationary flood frequency analysis: case study in the Po river basin
Authors: Cafiero Luigi , Mazzoglio Paola , Monforte Irene , Claps Pierluigi , Viglione Alberto , Laio Francesco
Published: February 2023

Traditional regionalization methods allow estimating hydrological variables in stationary conditions: in the context of climate change new techniques are sought, which take into account the non-stationarity of climate variables. As part of a project in collaboration between universities and the Po basin authority, different approaches including regionalization procedures are used to characterize the hydrological extremes in the Po River basin. In particular, we use the Spatially Smooth Regional Estimation method, which is based on multiregressive estimation of L-moments that do not require the definition of homogeneous regions. The regression models are based on morpho-climatic descriptors including climate variables such as the mean annual precipitation, and the coefficients of a model for the  IDF  curves. By analyzing the multi-year variability of the climatic variables in each basin, with this work we aim at: (i) comparing the trends of the climatic variables and the trend of discharges associated with different return periods, (ii) analyzing the sensitivity of the regression equations to changes in time of these variables. Moreover, we compare the rainfall and flood quantiles for each sub-basin, to evaluate the percentage change of the standardised flood discharge for the percentage change in extreme rainfall. This approach allows us to investigate the effects of rainfall mechanisms and catchment characteristics on flood probabilities in the Po River basin.
On the correlation between electron density and temperature in the topside ionosphere through Swarm satellites data
Authors: Pignalberi Alessio , Giannattasio Fabio , Pezzopane Michael , Coco Igino , Alberti Tommaso
Published: February 2023

Electron density (Ne) and electron temperature (Te) observations collected by Langmuir Probes (LPs) on board the European Space Agency’s Swarm satellites are used to characterise the Ne−Te correlation in the topside ionosphere. The large dataset of Swarm LPs in-situ observations at 2-Hz rate, covering the years 2014−2021, allowed us to investigate the correlation properties of the topside ionospheric plasma for different diurnal and seasonal conditions, with a coverage and a detail never reached before. Spearman correlation coefficients (RSpearman) are calculated on joint probability distributions between Ne and Te for specific conditions. Results are given as maps of RSpearman as a function of the Quasi-Dipole (QD) magnetic latitude and magnetic local time (MLT) coordinates, for different seasons. This study highlights, for the first time, the Ne−Te correlation at high latitudes, and provides a global description of the corresponding diurnal trend for different seasons. A negative correlation is found at the equatorial morning overshoot, during daytime at mid latitudes, and during night-time at subauroral latitudes (ionospheric trough). Conversely, a positive correlation dominates the night-time sector at mid and low latitudes, and to a minor extent the low latitudes from 09:00 MLT onwards. A seasonal dependence of the correlation is visible only at very high latitudes where the general pattern of anti-correlation is broken around ±75° QD latitude in the summer season.
Capture of colloidal fine suspended particle by aquatic vegetation under rainfall
Authors: Yu Congrong
Published: February 2023

The capture of colloidal fine suspended particles by vegetation plays an important role in water quality of the shallow aquatic system under rainfall. Quantifying impact of rainfall intensity and vegetation condition on this process remains poorly characterized. In this study, the colloidal particle capture rates under three rainfall intensities, four vegetation densities and with submerged or emergent vegetation were investigated in different travel distance in a laboratory flume. Considering vegetation as porous media, non-Darcy’s law with rainfall as a source term, was coupled with colloid first-order deposition model, to simulate the particle concentration changes with time, determining the particle deposition rate coefficient (kd), representing capture rate. We found that the kd increased linearly with rainfall intensity; but increased and then decreased with vegetation density, suggesting the existence of optimum vegetation density. The kd of submerged vegetation is slightly higher than emergent vegetation. The single collector efficiency (η) showed the same trend as kd, suggesting colloid filtration theory well explained the impact of rainfall intensity and vegetation condition. Flow hydrodynamic enhanced the kd trend, e.g., the theoretical strongest flow eddy structure represented in the optimum vegetation density. This study is helpful for the design of wetland under rainfall, to remove colloidal suspended particles and the hazardous material, for the protection of the downstream water quality.
The role of nature reserves on conservation effectiveness of ecosystem services in China
Authors: liu yue
Published: February 2023

 Establishment of nature reserves (NRs) is a common method to avoid biodiversity loss and degradation of ecosystem services (ESs). The evaluation of the ESs in NRs and the exploration of associated influencing factors are the basis to improving the ESs and management. However, the ESs effectiveness of NRs over time remains questionable, namely due to the heterogeneity of landscape characteristics inside and outside the NRs. This study (i) quantifies the role of 75 NRs in China to maintaining ESs (i.e., net primary production (NPP), soil conservation, sandstorm prevention and water yield) from 2000 to 2020; and (ii) reveals the trade-offs/synergies; (iii) identifies the main influencing factors of ESs effectiveness of NRs. Results show that more than 80% of NRs had positive ESs effectiveness, and higher ESs effectiveness in older rather than recent NRs. For different ESs, effectiveness over time increases for NPP (E_NPP) and soil conservation (E_SC), but decreases for sandstorm prevention (E_SP) and water yield (E_WY). There is a clear synergy relationship between E_NPP and E_SC. Moreover, the ESs effectiveness are closely correlated with elevation, precipitation, and perimeter area ratio. Our findings can provide valuable information for supporting management, improvement of ESs effectiveness and site selection planning of NRs.
Investigating Vibroseis Sweeps using 6 Rotational Sensors in Fürstenfeldbruck, Germany
Authors: Izgi Gizem , Eibl Eva , Krüger Frank , Bernauer Felix
Published: February 2023

Rotational motions can be recorded directly or derived from translational motion recordings. Fairly new rotational sensors allow seismologists to directly record and investigate rotational motions. In order to further investigate and compare recently developed rotational sensors an experiment was made in Fürstenfeldbruck. Within this scope, a vibroseis truck was operated starting from 20 November 2019, 11:00 UTC until 21 November 2019, 14:00 UTC. We recorded 480 Sweep signals at 160 different locations. The truck was operating at 30%, 50%, and 70% relative to a peak force output of 276 kN exciting the ground vertically and each sweep lasted 15 seconds starting with 7 Hz increased up to 120 Hz. We derived back azimuths of each sweep from 6 rotational sensors and calculated root mean squares of each component. We observed that within the first day, the North component of all sensors recorded the largest ground motion energy SV type of energy is dominant. The sweep sources were distributed over two North–South profiles and two East–West profiles.  While the truck moved to the east and its location moved from west to south of the rotational sensors, the signals dominate more and more on the East component.. From our preliminary results, we state that although having different signal to noise ratios all rotational sensor calculated the direction of each sweep. Thus, we can follow the movements of vibroseis truck using all rotational sensors.
Long-term impact of land-use change on soil organic carbon in German agriculture
Authors: Emde David , Don Axel , Poeplau Christopher , Schneider Florian
Published: February 2023

Land-use change and land management practices alter soil organic carbon (SOC) dynamics in agricultural systems. Changing natural vegetation to agriculture in particular has resulted in a loss of approximately 5% of the current global terrestrial carbon stock. However, this carbon loss is reversible. Increasing the area of grassland is, therefore, an increasingly discussed climate change mitigation option since grasslands often store similar SOC stocks to natural vegetation. However, the time it takes for cropland to return to its pre-cropland carbon state after conversion to grassland is far from certain. Using soil and land-use history data gathered during the German Soil Inventory as well as from historical land use maps, this study therein aims to answer two questions: i) how does land-use change affect SOC stocks in agricultural systems; and ii) how long does it take for agricultural lands to reach a new SOC equilibrium following land-use change. By substituting space for time and accounting for differences in site properties via stratification, our results challenge the established “slow in, fast out” paradigm. At a national scale, topsoil SOC is lost relatively slowly when grassland is converted to cropland, and gained relatively quickly when cropland is returned to grassland. Further, neither direction of SOC change agreed with the 20 years’ timescales on which current emission reporting and climate mitigation policy is based, and SOC stocks were influenced by land-use changes for more than 100 years.
Mg/Ca carbonates with curved crystal surfaces: an experimental study
Authors: Zhang Yifan , Mueller Mathias , Hoffmann René , Riechelmann Sylvia , Chakraborty Sumit , Beyer Christopher , Immenhauser Adrian
Published: February 2023

Dolomite, CaMg(CO3)2 and related Mg/Ca carbonates (disordered calcian dolomite, high Mg calcite, and similar) are common rock-forming minerals that occur widely in numerous diagenetic settings. They represent pore-filling precipitates (cements), diagenetic replacement phases of precursor carbonates or hydrothermal/metamorphic phases. Dolomites crystallize in the space group R-3 with trigonal symmetry and quite typical rhombohedral growth habit. A unique subtype of dolomites are saddle-dolomites which are characterized by curved (warped) surfaces. These show sweeping extinction under cross-polarized light which points to internal lattice strain. Saddle dolomites are of significance because, based on empirical evidence, they are considered to be one of the key indicators of warm-to-hot hydrothermal fluids in the burial diagenetic realm. However, saddle dolomites are not present in all natural hydrothermal deposits, and where they occur, they may coexist with Mg/Ca carbonates that often (but not always) lack warped crystal surfaces. Thus, the physicochemical conditions that lead to their formation remain unclear. We have undertaken an experimental study to explore the growth of saddle dolomites systematically as a function of various parameters (temperature, crystal size of reactants, fluid salinity, and Mg/Ca ratio of solutions). It was found that newly formed dolomites that grow epitaxially on rhombohedral or saddle dolomites exhibit warped surfaces whereas Mg-rich calcite crystals that grow on calcite seeds form flat surfaces. High Mg-calcite that forms at high temperatures (~ 220 °C) from calcium-rich fluids (Mg/Ca = 0.43) also have curved surfaces. In all cases, crystals with curved surfaces are characterized by excess calcium (Mg/Ca ~ 0.31 – 0.35). These results suggest that curvature of high Mg calcites and dolomites are related to excess Ca in the structure that causes lattice strain. Availability of dolomite precursors on which the crystals can grow, environments that provide excess Ca (e.g. highly saline ones) and rapid growth kinetics at high temperatures seem to facilitate the formation of crystals with curved surfaces. Thus this study identifies some factors that control the formation of high Mg-carbonates with curved surfaces and will aid to anticipate settings where they may be expected to occur in nature and understand why dolomites with curved as well as flat surfaces may coexist.
Evaluation of stochastic parameter representation of microphysics parameterization uncertainty for convective scale ensemble data assimilation and prediction
Authors: Vukicevic Tomislava , Posselt Derek , Jurlina Srdjan
Published: February 2023

It has long been known that microphysics parameterizations are among leading sources of model uncertainty in storm and convective scale weather prediction.  The uncertainty results from combination of imperfect knowledge of the microphysics processes, inability to explicitly resolve them at computationally feasible spatial and phase-space resolutions, as well as from inherent limited predictability of micro to turbulent scale processes.   Representing these in the context of improving probabilistic prediction skill using ensembles has been the subject of many studies, but remains an outstanding problem.  The problem is especially acute in storm and convective scale ensemble prediction, where there may be strong coupling of errors between ensemble data assimilation and forecasting.  Over the last decade, the inclusion of stochastic representation of model uncertainty associated with physical parameterizations has emerged as a viable approach for representing the intrinsic uncertainties of the microphysical parameterizations.  This study examines sensitivity of storm scale ensemble simulations to representation of microphysics parameterization uncertainties using a cloud resolving model.  We compare several stochastic parameter (SP) perturbation methods, including various parameter distributions and parameter covariance models, applied to physical parameters in a bulk microphysics parameterization.  The study follows a prior study, in which a 1D column version of the 3D cloud resolving model was used to test non-stochastic and several SP perturbation methods for which the parameter perturbation statistical distributions were based on Markov Chain Monte Carlo (MCMC) inversions with synthetic observations. That study indicated that SP schemes produce significantly more ensemble variance of microphysics states than non-stochastic, and that inclusion of parameter covariances, and specifically those that vary with the state of the system, improve their performance. The current study investigates impacts of SP scheme configurations on microphysics with dynamical feedbacks in 3D ensemble simulations.  The statistical parameter distributions used for the SP scheme are obtained as in the 1D study using MCMC inversions with synthetic observations. The results are evaluated in terms of changes to the ensemble mean and variance of microphysical and dynamical states and the simulated column integral microphysics-sensitive satellite-based observable quantities. We discuss the results and note the implications for convective scale ensemble data assimilation and forecasting. 
Precipitation isoscapes in areas with complex topography and Mediterranean conditions: Influence of large-scale atmospheric dynamics versus microclimatic phenomena
Authors: Huneau Frédéric , Nlend Bertil , Garel Emilie , Santoni Sebastien , Mattei Alexandra
Published: February 2023

While studies of the spatial distribution of precipitation isotope contents is well known at large scale and for more or less homogeneous areas, regions with complex topography and aerology are more sparsely or not at all documented. The aim of this research is to understand the factors influencing spatial/temporal changes of isotopes content in rainfall over a heterogeneous region. The region presents strong topographic contrasts, an insular context with varied weather exposure and subsequent microclimates. The approach consists in building 'isotopes landscapes (isoscapes)' for different months taking advantage of the 7 year-long monthly monitoring survey of the Corsica Network for Isotopes in Precipitation (CNIP, Corsica, France). Isoscapes use linear predictions based on multiple regressions of station-based precipitation isotope, climatic and topographic data. These regressions reveal the controlling effect of altitude (with a dichotomous pattern observed between the winter and the summer periods) and slope, while meteorological settings partially influence isotope contents. By explaining 88% of the δ18O spatial variability, isoscapes highlight both a controlling effect of local-scale meteorological circulation, and a contribution of micro-scale dynamics (due to topographic forcing), on the precipitation isotopes content. The analysis of residual values revealed that these two effects are not sufficient to explain the depletion in heavy isotopes. The deuterium-excess was used to investigate the influence of large-scale meteorological systems. Taking into account previous meteorological investigation, it was possible for the first time to hypothesize an influence of types of precipitation (convective or stratiform) on the rainwater isotopic composition in the study region. Finally, these results appear as evidence of the climate complexity in areas with steep reliefs and a potential limitation for generating reliable isoscapes in Mediterranean regions. They also demonstrate the role that isoscapes can play in documenting the microclimate processes in the world.– Nlend B., Huneau F., Garel E., Santoni S., Mattei A. (2023) : Precipitation isoscapes in areas with complex topography: influence of large-scale atmospheric dynamics versus microclimatic phenomena. Journal of Hydrology, 617, 128896. [ 10.1016/j.jhydrol.2022.128896 ]
Benefit of Quantum Technology for Geodesy
Authors: Müller Jürgen
Published: February 2023

Current developments in quantum physics and the application of general relativity open up advanced prospects for satellite geodesy, gravimetric Earth observation and reference systems and thus strongly help to meeting the geodesy challenges in a unique way. As Vening-Meinsz advanced gravimetry 100 years ago with his pendulum apparatus, quantum optics can push it further using atoms today. These novel concepts include the application of atom interferometry for realizing quantum gravimetry and gradiometry, the enhanced use of laser interferometry for inter-satellite tracking and accelerometry at future gravity field missions, and relativistic geodesy with clocks for the determination of gravity potential differences via gravitational redshift measurements.We briefly illustrate those novel techniques and present in which fields geodesy and geosciences will benefit from them. We show various application areas ranging from the direct determination of physical heights and the monitoring of mass variations using clock networks up to the use of quantum technology for gravimetric Earth observation on ground and in space. Realizing these innovative methods is key to quantify climate change processes (groundwater changes, ice mass loss, seal level rise, etc.) with largely increased precision and resolution.Finally, we would like to mention the IAG project “Novel Sensors and Quantum Technology for Geodesy (QuGe)” that advances those activities in close collaboration between geodesy and physics, see https://quge.iag-aig.org/  -  see also: Van Camp, M., Pereira dos Santos, F., Murböck, M., Petit, G., Müller, J. (2021): Lasers and Ultracold Atoms for a Changing Earth. EOS, 102, https://doi.org/10.1029/2021EO210673Acknowledgment: This study has been funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy EXC 2123 Quantum Frontiers - Project-ID 90837967 and the SFB 1464 TerraQ - Project-ID 434617780.
Aerosol Radiative Forcing Over Indian Subcontinent for 2000-2021 using satellite observations
Authors: Srivastava Shreya , Ghosh Sushovan , Dey Sagnik
Published: February 2023

Aerosols directly affect Earth’s radiation budget by scattering and absorbing incoming solar radiation and outgoing terrestrial radiation. While the uncertainty in aerosol radiative forcing (ARF) has decreased over the years, it is still higher than that of greenhouse gas forcing, particularly in the South Asian region, due to high heterogeneity in aerosols’ chemical properties. India has been identified as an aerosol hotspot. Understanding the Spatiotemporal heterogeneity of aerosol composition is critical in improving ARF estimation.                            In this study, we have taken aerosol data from Multi-angle Imaging Spectro-Radiometer (MISR) level-2 version 23 aerosol products retrieved at 4.4 km and radiation data from Clouds and the Earth’s Radiant Energy System (CERES, spatial resolution=1ox1o), for 21 years (2000-2021) over the Indian subcontinent. MISR aerosol product includes size and shapes segregated aerosol optical depth (AOD), Angstrom exponent (AE), and single scattering albedo (SSA). Additionally, 74 aerosol mixtures included in version 23 data are used for aerosol speciation. In addition, we have used CERES radiation data in four different atmospheric conditions: all-sky (AS), clear-sky (CS), pristine (PR) and no aerosol (NAER), for estimating aerosol radiative forcing in different aerosol-cloud conditions.We have seasonally mapped aerosol optical and microphysical properties from MISR for India at quarter degrees resolution. Results show strong Spatio-temporal variability, with a constant higher value of AOD for the Indo-Gangetic Plain (IGP). The fractional contribution of small-size particles to AOD is higher (>0.4) throughout the year, spatially during post-monsoon and winter seasons (October to February). SSA is found to be overestimated by MISR, where absorbing particles are present. The climatological map of short wave (SW) ARF at the top of the atmosphere (TOA) shows a strong cooling except in only a few places (values ranging from +2.5W/m2 to -22.5 W/m2). Cooling due to aerosols is higher in the absence of clouds. Higher aerosol cooling is found over the IGP region, given the high aerosol concentration over the region. Aerosols are causing a surface cooling effect over our study domain, which is higher in clear conditions. The results strongly correlate with AOD from MISR and ARF from CERES. 
Establishment of soil moisture data using satellite information and calculation of hydrological drought index using it
Authors: Kwon Yoon-Jeong , Urangchimeg Sumiya , Park Minwoo , Kwon Hyun-han
Published: February 2023

The drought risk in Korea has been gradually increasing, and the southern part of South Korea has experienced prolonged exposure to extremely low precipitation from the summer of 2021 until 2022, leading to the depletion of available water within two months. Droughts can be classified into meteorological, agricultural, and hydrological droughts under different definitions. The drought indices are routinely used to effectively monitor and cope with different drought conditions. In this perspective, various hydrometeorological factors (precipitation, temperature, streamflow, and soil moisture) are required to derive the drought indices according to the classification. Among the factors, the lack of soil moisture data has been an issue in effectively deriving the agricultural drought index compared to precipitation and temperature-based drought indices such as SPI and SPEI. Currently, research on satellite (i.e., C-band SAR) for water resources management is being conducted in South Korea. The agricultural drought index is commonly based on the satellite-based soil moisture and vegetation index, thus, an accurate estimation of soil moisture from the satellite information could be viewed as a main issue in terms of monitoring agricultural drought. In this study, we develop a novel hybrid stochastic simulation model for soil moisture at multiple locations (or grids) with relevant predictors, including hydrometeorological variables and satellite information. Acknowledgement : This work was supported by Korea Environment Industry & Technology Institute(KEITI) through Water Management Program for Drought, funded by Korea Ministry of Environment(MOE)(2022003610001)
Analysis of wind direction measurements made by the Rospini family in Graz (Austria), 1822-1850 CE
Authors: Pliemon Thomas , Foelsche Ulrich
Published: February 2023

The Austrian National Library has digitized several volumes of the newspaper "Grätzer Zeitung", which contains daily measurements (morning, noon and evening) of temperature, pressure, short simple weather descriptions, wind direction, and wind strength, recorded in the historic center of Graz by Mr. Rospini (and later by his son and grandsons). Other volumes of the newspaper are available on microfilm or have been found in archives. The measurement series of the Rospini family started as early as 1781, and have been continuously published in the "Grätzer Zeitung" from 1795 onwards. However, in the first years only temperature and pressure data were published and the first publications of wind directions began in March 1822. Thus, we analyze an almost uninterrupted record of wind directions from 1822 to 1850. The measurement times for this period are given as 7 a.m., 3 p.m. and 10 p.m. To assert the validity of the data, we compare it with modern data as well as with the other measurements of the Rospinis. Initial analysis reveal an improvement in measurement accuracy during the measurement period. I.e. the year-round seasonal distributions of the main wind directions differ significantly in the 1820s with respect to modern data, whereas those of the 1840s are comparable.
A theory for self-sustained multicentennial AMOC oscillation and its evidence in CESM
Authors: Yang Kunpeng
Published: February 2023

Multicentennial North Atlantic climate variability revealed by paleoclimate reconstruction has been linked to the Atlantic meridional overturning circulation (AMOC) variability. However, mechanisms of multicentennial AMOC variability in coupled models have yet to reach a consensus, reflecting a necessity of more fundamental theoretical studies. To this end, we propose an ocean-only North Atlantic 4-box theoretical model. A self-sustained AMOC oscillation with a typical period of 300-400 years exhibits. The timescale is largely set by rate of AMOC advection but also modulated by thermal processes, while the self-sustained oscillation mechanism can be generalized as a combination of a linear growing oscillation and a nonlinear restraining. The linear growing oscillation is energized by the salinity advection feedback and stabilized by the temperature advection feedback, while the latter is hampered by surface temperature restoring. Nonlinear restraining processes restrict the runaway tendency of the linear growing oscillation and finally turn it into a self-sustained one. We further identify a 300-400-year AMOC oscillation in a CESM1 control simulation, which can be well explained by the self-sustained oscillation mechanism of the theoretical model. Our work demonstrates that internal variability plays a vital role in multicentennial AMOC variability, while the dominating processes primarily lie in the North Atlantic.
Successive interacting coronal mass ejections: Preconditioning, magnetic reconnection and flux erosion: How to create a perfect storm?
Authors: Desai Ravindra , Koehn Gordon , Davies Emma , Forsyth Robert , Eastwood Jonathan , Poedts Stefaan
Published: February 2023

Coronal mass ejections (CMEs) are the largest type of eruption seen on our Sun and the primary cause of geomagnetic disturbances and storms when they arrive at the Earth. Most geomagnetic storms are created by the impact of single CME yet in a significant fraction of cases they are caused by the interaction of multiple CMEs or CMEs with other transient phenomena. In this paper we implement a spheromak CME description within our 3-D heliospheric MHD model and self-consistently model their interactions with the pre-existing solar wind and with one another. We assess their geo-effectiveness at 1 AU through quantification of the relevant solar wind variables and an empirical measures based upon solar wind-magnetosphere coupling functions. We show how the orientation and handedness of a given CME can have a significant impact on its geoeffectivness due to a prolonged conservation of toroidal flux caused by differential interplay with the Parker Spiral, and how a large range of possible CME-CME interactions can produce a diverse range of geophysical impacts at the Earth.
Elevation-dependent advance of Alpine plant phenology
Authors: Zehnder Michael , Pfund Beat , Alexander Jake , Hille Ris Lambers Janneke , Rixen Christian
Published: February 2023

Global warming causes increased temperatures and a reduction of snow cover in the European Alps. These rapid environmental changes are more pronounced at higher elevations due to a phenomenon called elevation-dependent warming. As a consequence, alpine plant communities are undergoing severe changes in spring phenology and elevational range shifts. However, long-term in-situ monitoring in these fast-changing ecosystems is scarce and time-consuming. Here, we investigate trends of Alpine plant growth, and phenological shifts over the past 25 years (1998 –2022) using ultrasonic plant height measurements from 32 automatic weather stations from 1500 to 2700 m. Our analysis revealed increased Alpine plant growth and advancing phenology over the past 25 years. At higher elevations, the start and peak of growing season happened approximately one month earlier in 2022 compared to 1998. Yet, this effect was not present at lower elevations, indicating strong patterns of elevation-dependency. The observed changes are more pronounced than previously forecasted and are reflecting findings from remote-sensing studies in other mountain ranges. This study provides compelling evidence of the radical impact of climate change on Alpine vegetation phenology based on a unique long-term measurement series.
Quantification of the reasons for the bird lake brownification in Finland
Authors: Rankinen Katri , Junttila Virpi , Futter Martyn , Cano Bernal José Enrique , Butterfield Daniel , Holmberg Maria
Published: February 2023

Browning of surface waters due to increased terrestrial loading of dissolved organic carbon is observed across the Northern Hemisphere. Brownification is often explained by changes in large scale anthropogenic pressures (acidification, climate and land use). We quantified the effect of environmental changes on observed brownification of an important bird lake Kukkia in Central Finland. Water bird densities have decreased there during last decades, probably due to brownification of the lake. We studied past trends of organic carbon loading from catchments based on observations since 1990’s. We created scenarios for atmospheric deposition, climate and land use change to simulate their quantitative effect on brownification of the lake by process-based models (PERSiST for hydrology, INCA-C for carbon loading and MyLake for carbon processes in the lake). Increase in forest cut area appeared to be the primary reason for brownification of the lake. Decrease in acidic deposition has resulted in a lower leaching of dissolved organic carbon, but the effect is small. Runoff and total organic carbon leaching from terrestrial areas to the lake is smaller than it would have been without observed increasing trend in temperature by two degrees. 
Are crops significant sources of Volatile Organic Compounds? A bi-compartmented chamber setup for investigating VOC emissions from aboveground and belowground
Authors: Voyard Auriane , Ciuraru Raluca , Staudt Michael , Loubet Benjamin , Rees Frédéric
Published: February 2023

Plants are the primary worldwide source of Volatile Organic Compounds (VOCs) on Earth and therefore play a significant role in the atmosphere's gas composition. While emissions from foliage have been well documented for decades, emissions from soils with living roots and associated microorganisms are not well understood. In particular, field studies show a wide and inconsistent range of soil-derived VOC net fluxes, possibly due to the variable abiotic and biotic conditions during measurements. In order to figure out the main drivers of soil VOC exchanges, studies under controlled experimental conditions are necessary. We developed a new experimental dynamic chamber, allowing to monitor the gas emissions from 1-9 plants simultaneously, both in the aboveground and belowground compartments. Aside from providing controlled experimental conditions, this setup allows to compare the net VOC, CO2, and H2O flux dynamics from soil to that from the aboveground plant organs at a high time resolution.Using a Proton Transfer Reaction – Time Of Fly – Mass Spectrometer, constitutive emissions from soil-grown rapeseed and tomato plants were recorded over 24h. Methanol was the main VOC emitted by both species, followed by, at one order of magnitude lower, methanethiol and monoterpenes for rapeseed and tomato plants, respectively. Although root-derived VOC emissions were generally much lower than shoot-derived ones, belowground DMDS emissions from rapeseed plants were twice higher than those from aboveground.  Interestingly, a negative correlation was observed between several root-derived VOC and root/soil respiration, suggesting a shift in the carbon allocation to specific metabolic pathways in roots or root-associated microorganisms. This experimental approach opens new perspectives for understanding the specific contributions of VOC emissions from soils and roots in agricultural ecosystems, and how these emissions may be linked to plant carbon budget.