bluuebunny/crossref_metadata_2025 huggingface dataset:
Lunar Imaging Earthshine Telescope, juLIET, for Earth Albedo Measurements 
Authors: Winther Katcha , Thejll Peter , Fléron René
Published: March 2024

The average global temperature of Earth is governed by the energy balance equation, comparing energy entering and leaving the Earth system. A key parameter in this balance is the Earth’s albedo, determining the ratio of the Sun’s energy being reflected from or absorbed by Earth. The global albedo varies on several different timescales – daily due to changes in cloud cover, seasonally due to changes in foliage and snowfall, and on greater timescales a change in albedo is a reflection of our changing climate. To measure these changes, multi-decadal data is needed.Data of top-of-the-atmosphere shortwave radiation used in albedo estimation, are primarily gathered by LEO satellites using absolute measurement techniques. These are however affected by the harsh space environment, especially radiation, which causes drift errors in the data, requiring in-flight calibration. The purpose of NASA’s and ESA’s upcoming missions CLARREO and TRUHTS respectively, is to provide state of the art calibration data to account for these errors. However, they do not remove the issue all together.As an alternative to these absolute measurements, the space based earthshine telescope juLIET (ju Lunar Imaging Earthshine Telescope) aims to estimate the albedo through relative measurements. The Earthshine albedo technique is based on comparing the intensity of Moonlight coming from the visible dayside of the Moon and the Earthshine reflected off the visible nightside of the Moon. As a relative measurement, it is more resilient to calibration drift.Albedo measurements using the Earthshine technique have been successfully carried out from Earth, but due to Moonlight being several magnitudes brighter than Earthshine, atmospheric scattering of Moonlight reduces the possible precision on the Earthshine intensity. While the issue of atmospheric scattering is removed by going into orbit, measuring the dim Earthshine with a sufficiently high precision to be used for albedo estimation, using the same sensor that measures the Moonlight, still poses a significant challenge, due to scattering and diffraction of Moonlight within the telescope.To determine the feasibility of the juLIET instrument, an analysis of the optical noise of the telescope is conducted. This analysis is carried out using Zemax OpticStudio and MATLAB, where main contributors to the uncertainty of the measurement are isolated and quantified.The results of this noise analysis will be extended to determine which lunar phases juLIET can provide measurements of the Earth albedo, during its mission time as primary payload on the small-sat ROMEO developed by IRS, University of Stuttgart. 
A data-driven method to retrieve XCO2 and XCH4 using artificial neural networks in preparation for the European Copernicus CO2 Monitoring Mission CO2M
Authors: Reuter Maximilian , Hilker Michael , Noël Stefan , Di Noia Antonio , Weimer Michael , Buchwitz Michael , Bovensmann Heinrich , Bösch Hartmut , Burrows John P.
Published: March 2024

Carbon dioxide (CO2) and methane (CH4) are the most important anthropogenic greenhouse gases because they are the main drivers of climate change. Monitoring their concentrations from space can help to detect and quantify anthropogenic emissions, supporting the mitigation efforts urgently needed to fulfill the Paris Agreement. Additionally, it can help to better understand the processes of the carbon cycle and thus allow better climate projections.These are key objectives of the European Copernicus CO2 Monitoring Mission CO2M, scheduled for launch in 2026, for which three retrieval algorithms are currently being developed and implemented in the EUMETSAT ground segment. These are so called conventional retrieval techniques that base on radiative transfer calculations. Despite shortcuts and approximations, the vast amount of satellite data makes them computationally expensive, requiring thousands of CPU cores. Although conventional retrieval methods base on physical principles, they typically require empirical data-driven methods to correct for biases in order to meet the demanding accuracy and precision requirements. The biases arise, e.g., from inaccuracies of the radiative transfer computations or unknown instrumental issues. Machine learning methods have the potential to combine both steps into a single data-driven retrieval algorithm, reducing the computational cost by several orders of magnitude.We used the radiative transfer model SCIATRAN to simulate two years (2015 and 2020) of sub-sampled realistic radiances of three instruments on board CO2M: the main instrument CO2I (CO2 imager), MAP (multi angle polarimeter), and CLIM (cloud imager). We use data from the first year of this data set to train artificial neural networks (ANNs) to retrieve XCO2 and XCH4 (the column-average dry-air mole fraction of atmospheric CO2 and CH4, respectively) plus related uncertainties and column averaging kernels. We will introduce a method which allows us to modify the training data making it representative for a wider range of atmospheric states. This ensures that the ANNs learn from the spectral signatures of CO2 and CH4 and that learning from spurious correlations is minimized. Despite the annual growth of CO2 and CH4, we will show that the ANNs trained with data from 2015 have almost the same quality when applied to data from 2020. We will analyze and compare the performance of different input vector settings, e.g., with and without MAP data and will discuss potential advantages or disadvantages of our ANN approach.
Online pesticide concentration and fluxes measurements over crops with a PTRMS shows unexpected volatilisation rates
Authors: Loubet Benjamin , Lafouge Florence , Bsaibes Sandy , Bedos Carole , Decuq Céline , Esnault Baptiste , Ciuraru Raluca , Kammer Julien , Vuolo Raffaella , Gros Valérie
Published: March 2024

Pesticide usage has been expanding since the 1950s. Their use has been known to harm human and environmental health for decades. Pesticide volatilisation to the atmosphere is a known process which is however not well documented, especially for periods beyond a few days after pesticide application. This is partly due to the difficulty to measure gaseous pesticides concentration in the atmosphere continuously for long time periods. Indeed, current state-of-the-art measurements is made by thermo-desorption gaseous chromatography involving semi-manual sampling with cartridges.In this study, we report first monthly outdoor online measurement of concentrations and volatilisation of one fungicide and two herbicides by proton transfer reaction, quadrupole injection, time of flight, mass spectrometry (PTR-QI-TOF-MS). The fungicide Chlorothalonil was measured over a wheat field in spring, while the herbicides Prosulfocarb and Pendimethalin were measured over a bare soil in autumn. Comparison with state-of-the-art TD-GC-MS and calibration by a home-made permeation system proved the PTRMS to be adapted for pesticides measurements.Maximum measured concentrations ranged from 12 ppt for Chlorothalonil to 600 ppt Prosulfocarfb. Maximum daily volatilisation fluxes ranged from 35 ng m-2 s-1 for Chlorothalonil to 350 ng m-2 s-1 for Prosulfocarb. We found that volatilisation of Chlorothalonil lasted more than three weeks, leading to up to 50% of the applied quantity volatilised, a duration and an amount much larger that what has been reported before.Volatilisation of pesticides may contribute much more significantly than expected to atmospheric burden, and be wet and dry deposited over larger areas. Further PTRMS pesticides measurements should be done to gain insight into pesticide transfer to the environment, and better characterize human exposure to these harmful compounds.
Drought Affects Export Patterns Across Different Solutes
Authors: Winter Carolin , Knapp Julia L. A. , Kirchner James W.
Published: March 2024

The severe 2018 drought affected water quantity and quality across Europe. While the consequences for water quantity have received substantial attention, the effects on water quality are intricate and require careful analysis. Nevertheless, understanding these impacts is crucial because the scarcity of water resources elevates the importance of their quality.Here, we conducted a comprehensive analysis of a high-frequency dataset (hourly) encompassing stream water chemistry across various solutes, including nutrients, heavy metals, and other ions, in the pre-alpine Erlenbach catchment (0.7 km², Switzerland). We used concentration-discharge (C-Q) relationships to detect the drought impacts on solute export patterns at the catchment outlet. The month of July 2018, characterized by the highest annual average temperature, experienced the most pronounced drought conditions. During this period, all solute concentrations exhibited a notable divergence in export patterns compared to the same month in other years with normal conditions (July 2017, 2019, 2020). In August, when conditions returned to normal, some solute concentrations also reverted to typical patterns, while others continued to deviate. These observations suggest a drought-induced alteration in solute mobilization, hydrologic transport, and retention, accompanied by potential solute-source-specific memory effects.The extensive and unique dataset documenting stream water chemistry in the Erlenbach catchment provides valuable insights into the processes shaping water quality during drought. If this knowledge can be extrapolated to other catchments, it may offer a foundation for safeguarding our precious freshwater resources in the face of an increasing risk for the occurrence of severe and prolonged droughts.
Critical decade for freshwater discharge into the Adriatic Sea
Authors: Aragão Leonardo , Mentaschi Lorenzo , Verri Giorgia , Senatore Alfonso , Pinardi Nadia
Published: March 2024

Located in the central Mediterranean Sea, the Adriatic Sea experiences complex water circulation patterns driven by saltwater inflow from the Ionian Sea through the Strait of Otranto and the outflow through the same strait but richly charged by fresh and dense waters formed in the northern Adriatic Sea. These circulation patterns place the unique hydrodynamics of the Adriatic Sea as the mainframe in shaping its diverse marine ecosystem, making it a primary region in dense water formation within the Mediterranean Sea. However, in recent decades, the region has continually recorded longer and more intense periods of drought. Some studies account for the loss of about 80 billion tons of freshwater during the 2021-2022 drought only at the Po River basin. To explore this matter further, the present work aims to analyse the last decade (2013-2022) of river discharges into the Adriatic Sea and frame the impacts of recent drought events in the current climatological period. To this end, the hydrological data reconstructed with the European Flood Awareness System (EFAS) were analysed for the period 1991-2022, quantifying river discharges separately in the four subregions of the Adriatic Sea: Shallow Northern Adriatic Sea (SNAd), Northern Adriatic Sea (NAd), Central Adriatic Sea (CAd), and Southern Adriatic Sea (SAd). Over the past 32 years, river discharges have shown different trends along the Adriatic Sea subregions, where a delicate balance between dry seasons in some subregions has been slightly balanced by flood seasons in others and vice versa. This delicate balance, combined with the diversity of its river basins, prevents us from estimating a trend with statistical significance for the Adriatic Sea. However, the river discharge trends are forthright when computed individually for each subregion, balancing slightly negative trends in the northern subregions (-0.6% and -1.0% per year in SNAd and NAd) with intriguingly positive trends in the southern subregions (+0.4% and +1.3% per year in CAd and SAd). When the analysis window narrows to the last decade (2013-2022), this balance breaks down, and a strong negative trend emerges across the entire Adriatic Sea, without exception, indicating reductions of -4.2% per year in freshwater input throughout the river basin. As suggested by the Standardised Flow Index (SFI) results, a climate indicator used to estimate the long-term impact of drought and flood periods on river discharges, 2022 was crucial for the last negative decadal trend. During this year, the northern Adriatic experienced the driest period in the last 32 years, while the southern Adriatic experienced river discharge reductions during flood months. Nevertheless, the most worrying element about the extreme drought of 2022 is that this year is part of a drought cycle that has continuously reduced freshwater availability in the Adriatic Sea every 4-5 years since 2008.
Assessing Short-Term Variability in Seasonal Patterns: Analysis of Chlorophyll-a Dynamics and Environmental Interactions in Lake Müggelsee
Authors: Kaligatla Rokhya Bhano , Dadi Tallent , Köhler Jan , Friese Kurt , Rinke Karsten , Schubert Hendrik
Published: March 2024

Comprehending the dynamics of shallow lakes is vital for effective ecosystem management. Shallow lakes exhibit frequent fluctuations in mixing regime, temperature, and nutrient availability, nurturing a dynamic environment. While numerous studies emphasize the long-term variability within lakes, there is a limited focus on short-term variability. This investigation delves into the relationships, processes, and short-term interactions among chlorophyll-a concentrations and various limnological and meteorological factors throughout the spring, summer, and autumn seasons. A thorough analysis of a high-frequency dataset spanning from April to December 2021 was conducted to explore the driving forces of phytoplankton phenology and dynamics over time.
Our study employed Wavelet coherence analysis, a valuable tool in limnological research, to explore relationships between variables at different time scales. This method, assessing correlations between two time series in the time-frequency space, offers a quantitative representation of covariance across various scales and over time. It assists in studying connectivity at a high temporal resolution, identifying synchronization periods, and revealing correlations between signals of diverse types. This analytical approach is essential for unraveling simultaneous processes within complex systems by examining synchronicity across variables and time scales.
The study reveals an algal bloom that occurred beneath the ice preceding spring, followed by a clear water phase in spring characterized by a higher respiration process than photosynthesis, indicating a potential influence of top-down control. This points to a dominant biological driver of chlorophyll in spring. Summer featured brief, weak blooms influenced by chemical processes in the lake as a result of prolonged warmth due to global warming, pointing to a combination of physical and chemical drivers. Autumn displayed a uniformly mixed water column, with high coherence between turbidity and wind speed indicating wind-induced resuspension, suggesting meteorological drivers in autumn. Each of these drivers is significant only during specific time intervals, with different processes gaining importance at other times.
The analysis in our study was essential in unraveling complex relationships and understanding short-term seasonal variations in environmental variables within a shallow lake. The study underscores the need for a holistic approach to comprehend intricate lake ecosystem dynamics, highlighting the potential impacts of climate change and external factors. This also helped us understand the phenological changes in response to global warming. It enhances our understanding of interactions, time scales, and cyclical patterns, providing insights into short-term dynamics and their impact on the overall ecosystem.
Transcrustal, interconnected, or isolated magma reservoirs, can we tell the difference?
Authors: Costa Fidel , Metaxian Jean-Philippe
Published: March 2024

The organization of melts below active volcanoes plays a large role on the size, composition, and character of the ensuing eruptions. In principle it should be possible to determine the distribution of melts with geophysical data, such as inversion of seismic velocity, density, and gravity. In practice, it appears that the size and distribution of the melts have a topology that only allows for very approximate information, typically made of “hot big potatoes” where melts are likely to reside. This is specially the case for many calderas and large stratovolcanoes from subduction zones, and unfortunately such view is not good enough to address the likely size of future events. Petrological studies of erupted crystals can, also in principle, provide a view of the depth and possible variety storage areas. However, geothermobarometry data tend to have large errors on pressure, and in a similar manner to most geophysical data many calderas and stratovolcanoes show a very wide distribution of depths (transcrustal systems?). Notwithstanding, many systems show a broad agreement between the petrological and geophysical data, with three or more storage areas, roughly at 30 km (or deeper), 7-10 km, and 1-3 km. Moreover, the configuration of the distribution of the melts may change over time, and crystal-kinetic and some geophysical data suggest that in mafic volcanoes new connections and merging of melts from different environments may occur days prior to eruption, whereas large-scale amalgamation melts from multiple reservoirs to a much larger one can occur in years to decades in silicic eruptions from calderas. Yet, data from geophysical and petrological studies of several recent monogenetic dike-fed eruptions, show simpler magma plumbing configurations, with well-defined areas of isolated magma storage and connections between them near-real time, from which magmas of different compositions are erupted. In this presentation we will review the data on magma plumbing structure and dynamics from different datasets and discuss how could progress be made for their use in mitigation of volcano hazards.
Availability of nightglow ground observations for atmospheric dynamics monitoring
Authors: Bellisario Christophe , Simoneau Pierre , Derelle Sophie , Jaffré Ewen , Froissart Pierre-Yves , Keckhut Philippe , Hauchecorne Alain , Tremoulu Samuel , Chane-Ming Fabrice
Published: March 2024

The infrared emission lines observed between 80 and 100 km known as nightglow allow the investigation of dynamic phenomena such as gravity waves with adapted cameras. In particular, the OH nightglow emission peaking at 87 km can be observed with short wave infrared InGaAs cameras and most of studies use these observations to investigate dynamics at this height. In this study, we briefly describe the methodology to assess the availability of nightglow observations at ground level depending on the spectral bands and the local atmospheric conditions. The impact of clouds on the spectral radiance propagation is estimated by the use of radiative transfer models. Sensitivity tests are completed on clouds characteristics, such as vertical width or the type of clouds. In addition, we integrate directional fluxes on the celestial dome to assess the level of radiance available at the ground level for night vision imaging. Statistical temporal comparisons are performed using available observations campaigns at Observatory of Haute-Provence (OHP) and at Maïdo Observatory.
Geochemistry and geochronology of the High Arctic Large Igneous Province on Svalbard
Authors: Sartell Anna Marie Rose , Beier Christoph , Söderlund Ulf , Senger Kim , Shephard Grace E. , Jørgen-Kjøll Hans , Galland Olivier
Published: March 2024

Large Igneous Provinces are defined as magmatic provinces with large magma volumes (> 100,000 km3) emplaced and/or erupted in an intraplate tectonic setting over a vast area within a few Myr, thus having the potential for significant impact on the global climate. The High Arctic Large Igneous Province (HALIP) was emplaced during the Cretaceous. The available ages, ranging between ~140 and 80 Ma, suggests that the magmatism was apparently long-lived and multi-phase. Extrusive and intrusive remnants of the HALIP can be found across the circum-Arctic, specifically in Arctic Canada, Russia, Svalbard, Northern Greenland, and the Arctic Ocean. On Svalbard, the HALIP magmatism is regionally called the Diabasodden Suite. Here, the dolerites have mainly been emplaced as sills at shallow depths and occur all over the archipelago. Despite the relative accessibility of outcrops, the HALIP on Svalbard has been mostly unexplored. As such, available U-Pb geochronology of the Diabasodden Suite is limited, but indicates a shorter time span of 125 – 122 Ma.Yearly field campaigns since 2020 have resulted in over 150 collected samples from Spitsbergen and Nordaustlandet. This has been accomplished through a collaborative effort, and by strategically targeting outcrops to build a good representative dataset of the Diabasodden Suite. Additionally, a large number of samples have also been taken for a detailed case-study in central Spitsbergen. The dolerite samples are used for whole-rock major and trace element geochemical analysis, U-Pb baddeleyite geochronology and petrological studies. Furthermore, during all field campaigns, high-resolution drone images have also been acquired. These data form the basis for digital outcrop models (DOMs), which are used for thickness measurements of the sills and to put the geochemical data into a 3D perspective. The resulting DOMs are made openly available through the geoscientific database of Svalbard, SvalBox.Here we present a review of the available geochronology of the HALIP in the circum-Arctic, as well as new data from Svalbard. Specifically, new U-Pb baddeleyite ages of one mafic sill in northern Isfjorden, and an extensive dataset of whole-rock geochemical data from the HALIP on Svalbard to better understand the magmatic history of the HALIP as a whole.
Comparing radiative transfer model-based LAI retrieval with in-situ observations and mechanistic modelling for grassland growth assessment
Authors: Larcher Daria , Ledain Sélène , Aasen Helge
Published: March 2024

Grasslands cover a significant portion of Switzerland’s landscape, primarily serving for livestock production, but also providing many ecosystem services like safeguarding biodiversity, habitat provision, carbon storage or water purification. Yet, through exposure to climate change, but also intensive land use such as frequent mowing and intensive grazing grasslands are increasingly threatened.
To evaluate the state of grasslands and optimize sustainable management practices, it is necessary to understand their ecological state, the management strategies and use intensity they're exposed to. A reliable data basis is a prerequisite for an accurate assessment. However, the acquisition of ground-field data is a costly and time-consuming process, and often requires financial resources and human capacity.  

Satellite data may provide a cost-effective alternative. The derivation of physical based quantities like the Leaf Area Index (LAI) through Radiative Transfer Models (RTM) has shown great potential to estimate several biophysical and biochemical plant traits from spectral data. This contribution presents a method to estimate grass growth using satellite data time series along with an RTM inversion-based LAI retrieval approach. The results are compared to in-situ observations and results from a mechanistic model. The methodology includes 1) suitable parameterization of the RTM for grasslands and generation of a spectral library, 2) training of the retrieval algorithm (neural network/random forest), and 3) the extraction of LAI time series from satellite images to compute LAI progress over time. We evaluate this method by comparing the results to a grass growth curve computed by the mechanistic model ModVege as well as in-situ data from multiple sites in Switzerland.  

The investigation of LAI retrieved from satellite data and RTM inversion for grassland growth assessment provides valuable insights into optimizing grassland management practices. These findings are further utilized to improve the long-term sustainability of grasslands in the face of changing environmental conditions.
Evaluation of different precipitation and potential evapotranspiration time series for hydrological modeling in Australian catchments 
Authors: Niu Jingyi , Vis Marc , Seibert Jan
Published: March 2024

For hydrological modeling in snow-free catchments, precipitation (P) and potential evapotranspiration (Epot) are the two key input time series. There are different methods to observe, calculate and interpolate these time series. In the Australian large sample data set for hydrological modeling (CAMELS-AUS, Catchment Attributes and Meteorology for Large-sample Studies)  with data for 222 catchments, two different time series for P and seven different time series for Epot are provided. Here, we address the open question of which data should be used as input to an hydrological model.Our basic assumption is that the most suitable combination of P and Epot is the one that results in the best model performances in terms of runoff simulations. For this we first tested the differences between the different input time series. Secondly, we conducted a thorough comparison of the 14 possible combinations of P and Epot time series. First analyses show that the differences between the two P time series are relatively minor, whereas the seven Epot time series differ more substantially from each other, especially in terms of seasonality and magnitude. Despite these differences, preliminary modeling results show that for the majority of the catchments there is no significant difference in model performance between the model calibrations carried out for each of the 14 different P/Epot combinations, suggesting that the model has a certain capability to compensate for differences in the input data by adapting its (soil) parameters. However, for some of the catchments there is a clear trend between the mean Epot and the corresponding model performance. Characterizing and further investigating these catchments can help to gain insight in the impact of different input data on the model performance, as well as to provide general recommendations that can help the user of a hydrological model to make an informed choice when it comes to the selection of the input data.
The non-linear response of the AABW to the removal of the West Antarctic Ice Sheet and implications to future climate
Authors: Power Katherine , Matos Fernanda , Zhang Qiong
Published: March 2024

The West Antarctic Ice Sheet (WAIS) is considered one of the tipping points of the Earth System. Its retreat due to climate change progressively results in sea level rise, affecting large numbers of the world's population. We aim to understand the potential consequences of a future WAIS collapse by implementing a mid-Pliocene Warm Period (MP) Antarctic Ice Sheet configuration, based on reconstructions, where the WAIS is severely reduced.We perform simulations with the EC-EARTH3.3 model at low resolution spanning 1400 years under 280, 400, and 560 ppmv of CO2 and derive the mean state of the last 200 years of simulation and the variability of climate patterns for the entire runtime.With the near removal of the WAIS, we find a non-linear response in Antarctic Bottom Water (AABW) formation to increasing CO2 levels. The AABW formation is highly sensitive to increased stratification, which results from sea surface temperature increase driven by current climate change. With the presence of a modern WAIS, Antarctic surface air temperature and Southern Ocean sea surface temperature are positively correlated to atmospheric CO2, and we see a strengthening of the positive phase of the Southern Annular Mode (SAM). This affects mid-latitude westerlies and reinforces the negative feedback between surface warming and AABW formation.However, with the near removal of WAIS, we observe a dampening in the otherwise doubling of atmospheric warming observed with increasing CO2 and the same pattern occurs for the SAM. This results in a non-linear behaviour of AABW formation, where the AABW is suppressed up to 4 Sv during a longer period compared to the control experiments (modern WAIS), followed by a recovery to pre-industrial strength levels that is not sustained under 560 ppmv. This response also induces a further weakening of the Atlantic Meridional Overturning Circulation (AMOC) and a reduced reach of the AABW transport into the Atlantic and Pacific Oceans, with potential cascading effects on the global climate.Our longer simulations reveal that the AABW formation thresholds are highly dependent on atmospheric CO2concentrations and the freshwater input into the surrounding basins of the Antarctic region. These results suggest that WAIS retreat already deeply impacts societal development, but a collapse would induce a new climate regime that needs further investigation to allow for climate adaptation.
Hydrogen and Oxygen Isotopes as Mass Proxies Along the South Atlantic Ocean
Authors: Godoy Jose Marcus , Gerringa Loes , Rijkenberg Micha
Published: March 2024

It was determined the values of δ(D) and δ(18O) on 432 seawater samples from 18 depth profiles collected during the Geotraces West Atlantic cruise leg 3; JC057 on RRS James Cook, 03/2011-04/2011. The first sampling station was located north of Falkland Island and the last one near the Equator line. The samples were collected using a 24 bottles rosette and storage on 2 mL glass vials, kept at 3-4 oC until the measurement. The measurements were carried out applying a PICARRO water analyzer, using IAEA VSMOW2, SLAP2 and GISP reference materials as standards, each batch consisted of the three standards and six samples, with seven injections each and the sample result represent the mean value of the three last injections.The delta values ranged from -0.91 (station 9, 1250 m) to 1.46 (station 7, 250 m) for δ(18O) and -4.5 (station 5, 5150 m) to 8.2 (station 13, 10 m).The δ(18O)-salinity relationship varies with the depth range with a slope of 0.37 (R=0.845) for (10- 100 m), 0.39 (R=0.747) for (100-250 m), 0.53 (R=0.813) for (250-1000 m) but poor correlated (R = 0.506) for deeper samples (>1000 m). Similar figure was observed for the δ(D)-salinity relationship with a slope of 3.04 (R=0.938) for (10- 100 m), 3.02 (R=0.879) for (100-250 m), 4.21 (R=0.898) for (250-1000 m) and poor correlated (R = 0.610) for deeper samples (>1000 m).The δ(18O)-temperature presented a similar figure as observed for the salinity although constant for the depths higher than 1000 m changing for deeper samples. The δ(18O)-temperature relationship had a slope of 0.053 (R=0.820) for (10- 100 m), 0.054 (R=0.739) for (100-250 m), 0.048 (R=0.716) for (250-1000 m) but poor correlated (R = 0.582) for deeper samples (>1000 m). The δ(D)-temperature relationship has also quite constant until 1000 m with a slope of 0.45 (R=0.933) for (10- 100 m), 0.43 (R=0.886) for (100-250 m) and 0.41 (R=0.850) for (250-1000 m) changing the slope to 0.82 (R=0.710) for deeper samples (>1000 m). 
Tree Mortality in a Relict Scots pine forest due to climate change
Authors: Horváth Adrienn , Lakatos Ferenc , Szűcs Péter , Patocskai Zoltán , Végh Péter , Winkler Dániel , Bidló András , Gálos Borbála
Published: March 2024

An investigated old-growth Scots pine (Pinus sylvestris L.) forest is located in a protected area. Climate, soil, and local hydrological conditions highly influence the health conditions of this relict forest stand. Drought symptoms are already visible thus complex analyses assessing of these site factors were investigated. Site conditions always influence vegetation. Conversely, vegetation always affects site conditions. Therefore, the relationship between forest stand vitality and stand growth becomes more complicated in the case of damage chain appearance in an elderly, resistant forest stand. Our research aimed to answer the following questions:How have site conditions changed in the research area in recent decades?
Which are the most significant site-limiting factors in this case?
Can a relict and protected ecosystem adapt to the changed conditions?
To identify the complex causes of tree mortality, climatic and soil conditions were analyzed and completed with bryological and biotic (pests) surveys. Altogether unfavorable soil conditions (coarse sand) and increasing aridity have led to a decline in tree vitality. Bark beetles have a high population density in the stand, so the beetles contributed to tree mortality. New spreading invasive moss species have appeared in the recently formed gaps, where crone projection is low. The disappearance of this relict forest stresses the urgent need for Hungarian forest management to prepare strategies for adaptive tree species selection.This article was made in the frame of the project TKP2021-NKTA-43 which has been implemented with the support provided by the Ministry of Innovation and Technology of Hungary (successor: Ministry of Culture and Innovation of Hungary) from the National Research, Development and Innovation Fund, financed under the TKP2021-NKTA funding scheme.
Riverine nitrogen exports to the Wadden Sea – a travel time-based modelling approach
Authors: Musolff Andreas , Ledesma José L.J. , Nguyen Tam V. , Ebeling Pia , Sarrazin Fanny , Borchardt Dietrich , Attinger Sabine , Kumar Rohini
Published: March 2024

Elevated nutrient levels in inland, coastal and marine waters have led to negative eutrophication impacts such as algal blooms and biodiversity loss. In the European Union, measures to reduce nutrient pollution have been implemented as part of the Water Framework Directive, the Nitrates Directive, the Urban Wastewater Directive and the Marine Strategy Framework Directive. However, the water quality targets defined in these frameworks are not always coherent and may be too rigid when considering the future impact of climate change on nutrient cycling. This ambiguity adds to the scientific challenge of assessing current nutrient fluxes and concentrations and their future dynamics under changing boundary conditions.Within the EU-funded project NAPSEA – N and P from Source to Sea, we address the continuum of nutrient fluxes from terrestrial sources in the Elbe and Rhine basins to the delivery in the Wadden Sea at the Dutch, German and Danish coasts. To model nitrogen (N) concentrations and fluxes, we use the water quality model (mQM, Nguyen et al. 2023) in a setting consisting of more than 500 mesoscale catchments with longer-term riverine N observations in the Elbe and Rhine basins. The model takes into account the storage, removal (denitrification) and release of N in the soil zone as a function of temperature and soil moisture. Importantly, subsurface transport and denitrification are based on a dynamic travel time approach using storage selection functions that explicitly account for N legacy effects. The model runs at an annual time-step, accounting for instream integration and retention of N, and is constrained against observations at the catchment outlets.In this contribution, we present the model results that allow us to identify the hotspots of N export in the Elbe and Rhine basins. We capture the decadal trajectories of N fluxes and concentrations and quantify the amount of N stored as biogeochemical legacy in soils and as hydrological legacy in groundwater. The model also makes it possible to disentangle the contributions of point vs. diffuse sources to N export in time and space as well as the efficiency of N retention. The calibrated model will allow for future projections of riverine N exports to estuaries and the Wadden Sea with the aim to differentiate the effects of climate change on the one hand, and different nutrient management scenarios on the other. References:Nguyen, V.T., Sarrazin, F.J., Ebeling, P., Musolff, A., Fleckenstein, J.H., Kumar, R. (2022): Toward understanding of long-term nitrogen transport and retention dynamics across German catchments. Geophys. Res. Lett. 49 (24), e2022GL100278
Gone with the currents? – Seabed erosion data of EMODnet Geology
Authors: Kihlman Susanna , Kaskela Anu , Kotilainen Aarno , Alanen Ulla , Vallius Henry , partners EMODnet Geology
Published: March 2024

Increasing anthropogenic pressure in marine and coastal environments emphasizes the importance of the easily accessible, reliable, and suitable data on marine environment, to support conservation, research, and sustainable marine management decisions. The EMODnet (European Marine Observation and Data network) Geology project has been aiming to address this demand by collecting and harmonizing geological data at different scales from all the European sea areas since 2009, at present with a collaboration of about 40 partners and subcontractors.Multiscale Seabed substrate is one of the key data products of EMODnet Geology that has been collected since the beginning of the project. The seabed substrate map, harmonized from the national data by the sediment grain size, has evolved and complementary data products have been developed during the years. Sedimentation rates information has been collected since the beginning, and the seabed substrate database also includes information on the seabed surface characteristics that have significance for marine environment but cannot be defined by grain size only (e.g., seagrass meadows, glacial clay, moving sediments, ferromanganese concretion bottoms and bioclastic features). Similarly, the geographical scope has expanded currently including the Caspian Sea and Caribbean Sea.Seabed dynamics, sediment accumulation and erosion, provide an indication of potential temporal seabed-sediment variability, and thus of uncertainty. To obtain this essential information, the latest addition in the seabed substrate data products is the seabed erosion index database, i.e. literature catalogue of erosion studies. The first version of the database was published in September 2023, including metadata information (e.g., purpose, time frame, erosion rate and data availability) about known erosional studies and different erosional areas. The index data collection will continue within the current phase of the EMODnet Geology, and it will serve as the basis for the discussion which kind of erosional data information could be the most valuable, but also as widely as possible feasible and useful. The development of usable and valuable data products requires the careful consideration and preferably collaboration with different stakeholders and end users. At best, this kind of data could be a valuable addition to understand and define marine environment in dealing with various challenges the future will hold us.The EMODnet Geology project is funded by The European Climate, Environment, and Infrastructure Executive Agency (CINEA) through contract EASME/EMFF/2020/3.1.11 - Lot 2/SI2.853812_EMODnet – Geology.
Dynamics of subducting slabs and origin of deep-focus earthquakes
Authors: Čížková Hana , Pokorný Jakub , Bina Craig , van den Berg Arie
Published: March 2024

Most earthquakes are associated with subduction zones. While earthquakes occur on very short time scales, they reflect thermal conditions and stress state attained in the subducted slab during its long term evolution. The source models of deep earthquakes thus might provide unique information about stress distribution in subduction zones which could be used to constrain geodynamic models.  In the Tonga region, ordinary deep (620-680 km) earthquakes exhibit down-dip compressional stresses as expected, but unusually deep (≥680 km) earthquakes have unique focal mechanisms with vertical tension and horizontal compression. Here we employ geodynamic slab models to investigate the effects of the phase transitions and rheology on the stress and thermal state in Tonga slab in the transition zone and shallow lower mantle and we discuss its relation to deep earthquakes. We show that the direct buoyancy effects of the endothermic transition at 660 km depth are overprinted by bending-related forces and resistance from the more viscous lower mantle transmitted by a strong slab up-dip. The stress pattern that best fits seismogenic stresses is found for the cold plate (150 Myr old) and a viscosity increase at 1000 km depth. An abrupt change in stress orientations occurs as the slab temporarily deflected by the endothermic phase transition penetrates the shallow lower mantle while the fold in the flat-lying part tightens.
Towards a Multi-Criteria Analysis for the evaluation of risk reduction strategies effectiveness in multi-hazard environments
Authors: Molinari Daniela , Asaridis Panagiotis , Caporale Diana , Ottonelli Daria , Rubino Alessandro ,   RETURN WP 7.2 research team
Published: March 2024

Within the context of the Italian RETURN (Multi-risk science for resilient communities under a changing climate) project, the objective of WP 7.2 is the definition of national guidelines for the evaluation of the effectiveness of alternatives of intervention in natural risks management, by considering in detail Multi Criteria Analysis (MCA) tools. The focus is on (i) multi-hazard contexts, for which state-of-the-art and knowledge is limited, (ii) the different phases of the risk management chain, and (iii) the variety of structural and non-structural measures that can be adopted. The present contribution describes results reached so far in this direction. First, First, we propose a flowchart that illustrates the process leading to the ranking of alternative strategies through MCA. The objective of the flowchart is to highlight the operative steps required for its implementation, including: (i) the identification of intervention alternatives and their characterization in terms of spatial and temporal scale of effectiveness, potential risk reduction, and secondary impacts on interested communities, (ii) recognition of stakeholder’s objectives and their respective dimensions, (iii) definition of attributes and indicators according to which alternatives are evaluated, (iv) selection of the most appropriate MCA tool and definition of related parameters, and (v) performance of sensitivity analysis. The development of the flowchart emphasized that establishing guidelines for applying MCA to multi-hazard risk management requires two ongoing fundamental steps (i) an in-depth, generalized investigation of the types of elements exposed to the different natural hazards as well as the identification of potential direct and indirect impacts on them in case of an event; (ii) the definition of an abacus of alternatives which identifies the most promising measures that can be implemented in a given context, and characterizes them in terms of potential risk reduction or increase (with respect to different hazards), and temporal and spatial scale of effectiveness.
Controls on soil dissolved organic carbon along the 4000 km North-South forest transect in Eastern China
Authors: Gu Jie , Bol Roland , Wang Yang , Zhang Huanchao
Published: March 2024

Dissolved organic carbon (DOC) is both a potential source and stability indicator of soil organic carbon (SOC), and plays a pivotal role in global C cycling and sequestration. However, at a large scale, still not enough information is known about relations between DOC in soils and various controlling factors in natural forest ecosystems. We sampled 252 soil samples (6 replicates and 3 depths for each site) from four long-term forest ecosystem stations in Changbaishan, Beijng Donglingshan, Shennongjia and Dinghushan along a 4000 km North-South transect in Eastern China. We found that higher soil DOC concentrations were observed in subtropical forests over the North-South transect. The highest and lowest DOC concentrations in the upper 60 cm soil layer were found in monsoon evergreen broadleaved forest (DIII, 113.8 ± 1.4 mg C/L) and Yue spruce-fir forest (CIII, 57.6 ± 3.0 mg C/L), respectively. The Haplic ferralsol (DII-DIV, 89.7 mg C/L) and Haplic Andosol (CIII, 57.6 mg C/L) showed the highest and the lowest DOC concentrations in the upper 60 cm soil layer, respectively. The soil DOC concentrations generally decreased from surface soil to subsoil in the forests with mean annual precipitation (MAP) ≥ 1500 mm. The lower proportion of DOC accounting for SOC in the upper 20 cm soil layer in temperate forests, among which Yue spruce-fir forest (CIII, 3.2 %) presented the lowest ratio, indicated a larger long-term soil C sequestration potential. The DOC concentrations in the upper 60 cm soil layer significantly correlated with mean annual temperature (MAT) (R2 = 0.50) and MAP (R2 = 0.46). However, in the upper 20 cm soil layer, forest type (R2 = 0.48) was the most significant correlation factor to DOC concentration. We concluded that in the North-South transect of Eastern China, MAT, MAP and forest type are the most significant large-scale factors controlling soil DOC, with temperate forests (especially Yue spruce-fir forest) possessing the highest long-term soil C sequestration potential. 
Multi-scale analysis of green infrastructure morphology for climate change adaptation
Authors: Valide Lou , Versini Pierre-Antoine , Bonin Olivier
Published: March 2024

Nature-based Solutions, even if not identified as such, are becoming more and more popular in land planning, especially in cities. Conserving and restoring green infrastructure in urban context is now recognised as being a good practice in the face of climate change adaptation: ecosystem services provided by green spaces can help reduce urban heat island effect and risks of flood, improve resilience of ecosystems to preserve biodiversity and enhance human well-being through access to nature. Simultaneously, cities have to face another challenge: containing land take and urban expansion. The European Commission, in its Roadmap to a Resource Efficient Europe (2011), claimed the “aim to achieve no net land take by 2050”, a goal already transcribed in French law since 2021. Hence, the competition for land use which already existed between housing, industry, roads and recreational purposes will only become fiercer and have to include a new competitor: Nature-based Solutions. In this context, the ability of optimizing the implementation of such solutions – through the different scales at which they provide ecosystem services (building, neighbourhood, city and landscape) – is becoming primordial. Where should we conserve or restore green spaces in priority to ensure the providing of the ecosystem services needed for urban climate change adaptation? This question implies a multi-scale spatial analysis of the impact of green infrastructures on cities. To do so, the question of urban form is tackled by focusing on what is between buildings and streets, where green infrastructure can be deployed and woven into the urban fabric. To establish a multi-scale typology of green infrastructures based on their morphologies, classical approaches are combined with mathematical tools such as fractal analysis for characterizing their dispersion or graph theory for characterizing their connections, essential when studying biodiversity issues. This typology, associated with ecosystem services and biodiversity assessment for different French case studies (including the conurbations of Niort and Dijon), could help understand how to spatially implement Nature-based Solutions within cities, and be integrated into land-planning scenarios.