bluuebunny/crossref_metadata_2025 huggingface dataset:
Reducing climate change impacts and inequality of the global food system through diet shifts
Authors: Li Yanxian , He Pan , Shan Yuli , Li Yu , Hang Ye , Shao Shuai , Ruzzenenti Franco , Hubacek Klaus
Published: March 2024

How much and what we eat and where it is produced can create huge differences in greenhouse gas emissions. Bridging food consumption with detailed household-expenditure data, this study estimates dietary emissions from 13 food categories consumed by 201 expenditure groups in 139 countries, and further models the emission mitigation potential of worldwide adoption of the EAT–Lancet planetary health diet. We find that the consumption of groups with higher expenditures generally creates larger dietary emissions due to excessive red meat and dairy intake. As countries develop, the disparities in both emission volumes and patterns among expenditure groups tend to decrease. Global dietary emissions would fall by 17% if all countries adopted the planetary health diet, primarily attributed to decreased red meat and grains, despite a substantial increase in emissions related to increased consumption of legumes and nuts. The wealthiest populations in developed and rapidly developing countries have greater potential to reduce emissions through diet shifts, while the bottom and lower-middle populations from developing countries would cause a considerable emission increase to reach the planetary health diet. Our findings highlight the opportunities and challenges to combat climate change and reduce food inequality through shifting to healthier diets.
Assessing the Impact of Changing Warming Patterns on Transient Global Warming: A Multivariate Energy Budget Approach
Authors: Guillaume-Castel Robin , Meyssignac Benoit , Roca Rémy
Published: March 2024

The pattern of surface warming plays a significant role in determining the Earth's response to radiative forcing. Indeed, the Earth's radiative response is intricately linked to the intensity of climate feedbacks, which, in turn, are influenced by the regional distribution of surface warming. Distinct patterns of surface warming lead to divergent equilibrium and transient responses to identical forcing, emphasizing the need to analyse this pattern effect to understand the climate responses to external forcing.While existing studies have primarily focused on assessing the influence of warming patterns on long-term warming, such as equilibrium climate sensitivity or committed warming, the role of warming patterns in shaping the transient trajectory of global warming remains poorly understood. In this study, we introduce a novel analytical method to quantify the importance of evolving warming patterns on transient global warming.Our approach involves developing a multivariate global energy budget, which provides a unified framework for interpreting the sensitivity of the radiative response of the Earth to the warming pattern. This framework explicitly separates the radiative response caused by the global mean temperature increase, from the additional response induced by changing temperature patterns.Using this new energy balance model, we assess the relative contributions of the direct radiative forcing and changing temperature patterns to the global mean temperature change in linearly increasing forcing experiments (1pctCO2) from nine CMIP6 models. We show that the pattern effect consistently dampens global warming in the first 100 years of all simulations studied. Specifically, we quantify that the transient climate response, reached after 70 years of simulations, would be 0.4±0.2K higher (equivalent to a 20±15% increase) if the warming was uniformly distributed (i.e. in the absence of changing warming patterns).Furthermore, our study demonstrates that distinct models exhibit significantly divergent transient global warming patterns solely due to variations in the pattern effect. Overall, our results highlight the importance of changing warming patterns, specifically through the pattern effect, in influencing decadal-scale transient warming. These findings notably support recent suggestions to incorporate warming pattern uncertainties in future climate projections.
What is the uncertainty of the uncertainty and (why) does it matter?  Propagating uncertainties of weight estimates through soil moisture data merging
Authors: Formanek Maud , Gruber Alexander , Stradiotti Pietro
Published: March 2024

This study aims to improve the ESA CCI soil moisture dataset uncertainty estimates by including the sampling uncertainty of the triple collocation analysis in the uncertainty propagation of the data merging scheme. The ESA CCI soil moisture product merges data from multiple sensors through a weighted average. This strategy aims to increase both the temporal and spatial sampling density while reducing random retrieval errors. Optimal error reduction is obtained by assigning the weights according to each sensor’s specific uncertainty characteristics, expressed as σi-2/(∑σj-2) . The uncertainties σi are determined via triple collocation analysis (TCA) applied to soil moisture estimates from a land surface model, and from a passive and an active microwave satellite instrument.However, the uncertainty estimates obtained from TCA are themselves uncertain as a result of finite sample size. Notably, this ‘uncertainty of the uncertainty’ (UU) can be derived analytically for simple error models, but lacks a similar analytical solution for the affine error model (which includes both additive and multiplicative biases) employed in the CCI SM algorithm.The magnitude of the UU has serious implications for the weighted averaging and the resulting uncertainty of the merged products: 1) it introduces an additional term in the uncertainty of the merged product stemming from the uncertainty of the weights themselves, and 2) the UU can reach a threshold, where the weighted average yields worse results than an unweighted average. In this study, we calculate the UU via bootstrapping of the TCA results for three sensors (ASCAT, SMAP and SMOS) and investigate its impact on the uncertainty of the merged dataset.
Roe Deer and Plant Phenology Nexus – Match or Mismatch?
Authors: Kauffert Johanna , Ehrmantraut Christian , Tryjanowski Piotr , Mikula Peter , König Andreas , Menzel Annette
Published: March 2024

Plasticity and factors driving parturition dates of ungulates is a topic that has been addressed in many studies. These factors potentially give us clues about a possible trophic mismatch between the timing of seasonal events and resources due to an earlier onset of phenological spring introduced by climate change. Particularly, roe deer (Capreolus capreolus L.), the most widespread and abundant ungulate in Central Europe, has been a species of great concern. As an income breeder, it must finance the energy-demanding end of gestation and lactation by currently available resources in spring. Yet, roe deer is the only artiodactyl species known to undergo embryonic diapause, a temporal suspension of embryonic development, for four to five months after mating in summer. Hence, it could potentially adjust the end of embryonic diapause to shifting environmental conditions to match the parturition of their offspring with the advancing greening in spring. Potentially resulting shifts in parturition timing in May and June are also of great interest to farmers as parturition and rearing of fawns coincide with annual spring mowing. Due to the fawns’ hiding strategy to protect themselves from natural predators, they often fall victim to approaching mowing machinery. Although farmers are legally obliged (in Germany) and are already untiringly searching meadows before mowing, not all fields can be searched simultaneously when mowing is constrained to short time windows due to periods of favourable weather for hay and silage production. Therefore, knowledge about the much-debated plasticity to environmental conditions in roe deer may provide helpful information for preventing accidental mowing death of fawns in spring by anticipating when most of the young and immobile fawns are forecasted to be present in the meadows and allocating targeted measures.
Turbulence in the tropical stratosphere, Kelvin waves, and the quasi-biennial oscillation
Authors: Atlas Rachel , Podglajen Aurélien , Wilson Richard
Published: March 2024

Turbulence in the tropical stratosphere affects the vertical transport of aerosols and gases, with implications for global atmospheric chemistry and the radiative budget of the Earth. However, it is unresolved in global models of the atmosphere, and turbulence parameterizations have not been evaluated within this region. Observational estimates of vertical mixing, including turbulent mixing, in the tropical stratosphere vary widely. We use two decades of high vertical resolution (10 m) radiosonde data from three near-equatorial sites in the tropical West Pacific to quantify the occurrence of stratospheric turbulent layers of at least 200 m thickness, and investigate its temporal and spatial variability, using subcritical Richardson number as a proxy for turbulence. Our estimates of upper tropospheric and lower stratospheric turbulence frequency agree well with published estimates from aircraft data in the same region. We find that stratospheric turbulence typically occurs within downward propagating Kelvin waves, and is most common (3.3% occurrence) right before the quasi biennial oscillation (QBO) phase switches from negative to positive, which coincides with a maximum in Kelvin wave activity. It is least common (0.3% occurrence) during the negative phase of the QBO. Thus, the frequency of tropical stratospheric turbulence varies over a factor of ten depending on the phase of the QBO.
Numerical optimization for drinking water distribution network design: ideas and questions provided by practice
Authors: van Laarhoven Karel , Mitrović Djordje , Vertommen Ina , Hillebrand Bram
Published: March 2024

In the past decades, the potential of numerical optimization for the automated design of drinking water distribution networks has been extensively studied. In particular, evolutionary algorithms have been shown to be a powerful and versatile tool for several design tasks. In the past few years in the Netherlands, drinking water utilities have started to embrace this approach more and more to explore new design philosophies as well as to address immediate asset management decision challenges. Key to meaningful application has been the possibility to iteratively and flexibly develop the optimization problem throughout the design process. The traditional 'benchmark problems' from academia provide a strong starting point for a design process, giving utility experts a taste of the possibilities. Subsequently, however, the problem definition has to be adapted and fine-tuned in order to keep up with the evolving perspective of the utility experts on the design problem. During this type of practical implementation, it frequently occurs that questions emerge which greatly increase the complexity of the optimization task without an approach being readily available from scientific literature, requiring workarounds to be created on the spot. Here, we present recent examples of such questions and their workarounds, which we ran into while tackling different practical design challanges, namely: how to incorporate deal with the prohibitively large complexity of a pipe dimension optimization for the city of Amsterdam, and how to incorporate topological properties regarding flushability as a performance constraint into a sectorization problem for the city of Rotterdam.
Trace metal transport during managed aquifer recharge with monovalent-partial desalinated water: The role of divalent ions and organic matter
Authors: Braeunig Laura , Longman Jack , Gäng Frederik , Massmann Gudrun
Published: March 2024

Global fresh groundwater resources are threatened due to increasing withdrawal and salinization. Managed Aquifer Recharge (MAR) is an effective approach to augment overexploited aquifers and can also be applied to improve the groundwater quality by infiltration of desalinated water. But MAR can also bear risks when the soil passage or aquifer contains trace metals (e.g. As, V, Co, Cd) with their mobilization and subsequent human uptake. Understanding of metal mobilization (especially As) due to mineral dissolution at MAR sites with desalinated water was subject of investigation in many studies. Ionic strength and divalent ions concentration of the infiltrating water are known to influence the transport behaviour of trace metals by controlling dissolution and stabilization. As a new approach for water desalination, the aim of the cooperative project “innovatION” is the development of a monovalent-selective membrane capacitive deionization method to remove monovalent ions from brackish water. Other than fully desalinated water, the product water is still enriched in divalent ions. Here, we present first insights on how trace metal transport during MAR depends on the chemistry of the infiltrating water. Trace elements, as for example As, were found in sands of the East Frisian Island Langeoog, Northern Germany, and could be mobilized during potential MAR. We conducted column experiments with infiltration of a fresh groundwater (fGW), monovalent partial desalinated water (mPDW) and pure water (PW) into grey dune sand from Langeoog.Our results show As mobilization due to shifting redox conditions and iron mineral dissolution up to a maximum of 16 µg/l in the outflow. Notably, the infiltration of mPDW, with a higher ionic strength than fGW and PW, lead to a temporary retention of As with a concentration decline to 2 µg/l and subsequently a slow increase. Whereas As is further mobilized with a very slow decrease with infiltration of fGW and PW. Arsenic concentrations were positively connected to dissolved organic carbon concentrations of the outflow, an indication that organic complexation of As takes place after dissolution of Fe-minerals. Clearly, the infiltration of mPDW can mitigate potentially harmful colloidal trace element transport. These results help to understand the mechanisms of sorption, desorption and transport of trace metals in environments with changing pore water chemistry during MAR. Our research also aids to better assess the functionality of this novel desalination technique that has high potential to improve groundwater quality.
Overview of DCMEX project, progress made towards goals, and measurements of primary ice particles
Authors: Blyth Alan , Finney Declan ,   DCMEX team
Published: March 2024

The Deep Convective Microphysics EXperiment (DCMEX) was held in and around the convective clouds that formed and grew steadily over the Magdalena Mountains near Socorro, New Mexico during July and August, 2022. The overall goal of DCMEX is to reduce the uncertainty in cloud feedbacks associated with deep convection by improving the representation of microphysical processes in the UM/CASIM model. It is part of the NERC CloudSense programme that aims to reduce the uncertainty in climate sensitivity due to clouds. The aim of the field campaign was to make observations of the aerosols, ice nucleating particles (INPs), and the microphysics and dynamics of the clouds in order to both make new discoveries and to provide novel measurements to improve models. Measurements were made with the FAAM aircraft, ground-based aerosol instruments, radars and routinely with the NEXRAD radars and GOES-17 satellite instruments. In this talk, we will present an overview of the project and of the progress that has been made so far towards the overall goals, such as a new representation of INP in CASIM based on the observations and good measurements of the ice concentrations at several temperatures and stages of development. We will also present results on the observations of primary ice in the context of the measured INPs
How rainfall interception influences soil erosion in agricultural, urban and forest catchments
Authors: Parajka Juraj , Széles Borbála , Marjanovic Dušan , Zabret Katarina , Lebar Klaudija , Vilhar Urša , Bezak Nejc , Šraj Mojca
Published: March 2024

Rainfall intercepted by vegetation is, in many regions, an important part of the hydrological water cycle. Part of the intercepted rainfall evaporates into the atmosphere, and throughfall and stemflow contribute to runoff generation, control soil moisture and runoff connectivity patterns and affect soil erosion. The question of how changing climate and land cover conditions impact rainfall interception, raindrop microstructure, and their erosive power still needs to be better understood.This presentation introduces the main aims of a bilateral research project between TU Wien, University of Ljubljana and the Slovenian Forestry Institute that focuses on the understanding of the effect of meteorological and vegetation characteristics on changes in raindrop microstructure and, therefore, on the erosive power of rainfall. The main idea of the research cooperation is to analyse and understand the main mechanisms of the rainfall interception process in different climate conditions and vegetation settings. The high-resolution disdrometer measurements from the experimental urban and forest plots in Slovenia and a small agricultural basin in Austria are used to determine and compare raindrop distributions and their changes. The high-resolution observations of discharge, sediment concentrations and isotope analyses contribute to the understanding of the erosion processes and sediment transport in the streams. Acknowledgment: This contribution is part of the ongoing research project entitled “Evaluation of the impact of rainfall interception on soil erosion” supported by the Slovenian Research and Innovation Agency (J2-4489) and it was funded in part by the Austrian Science Fund (FWF) I 6254-N.
Changes in Holocene sediment deposition in the Aegean Sea: climatic versus early anthropogenic forcing
Authors: Müller Daniela J. M. , Koutsodendris Andreas , Kaboth-Bahr Stefanie , Pross Jörg
Published: March 2024

Since the Lateglacial, the Eastern Mediterranean region has been subject to repeated climatic and environmental change. It is also home to some of the earliest cultural centres in human history. These cultures have closely interacted with their environment, but it is still unclear to what extent climatic change has influenced their evolution. At the same time, the onset and extent of early anthropogenic impact on terrestrial and notably in marine ecosystems is still poorly constrained. In order to decipher the impact of early societies on sediment deposition in the Aegean Sea versus climatically driven changes in sedimentation, we have analyzed five sediment cores from coastal settings in the Aegean Sea retrieved during METEOR expeditions M144 (in 2017/18) and M195 (2023), as well as Eurofleets+ cruise ‘MYRTOON’ (2021). Spanning the entire Holocene and partially even dating back to ~13 ka, these cores exhibit extraordinarily high sedimentation rates. We have carried out grain-size analysis at decadal resolution to obtain insight into the different processes underlying sediment transport and deposition (e.g., fluvial versus aeolian, naturally versus anthropogenically induced).For all cores, the application of end-member modelling shows clusters of grain-size distributions of c. 2 µm and 21 µm with distinct variability over time linked to changes in fluvial  and dust input. The finer grain-size end-member is interpreted to represent fluvial input, with the coarser material having been deposited proximally near the river mouths and the finer fraction remaining in suspension and being transported over longer distances into more distal settings. We find finer sediments during the deposition of sapropel S1 at ~10–6 ka BP, suggesting higher fluvial input into the Aegean Sea during that time. In contrast, a stronger prevalence of coarser-grained sediments from ~6 ka BP onwards suggest a decrease in fluvial input at that time. Notably, intervals with finer sediments appear during the past ~4 ka at sites located closer to the coast, whereas such intervals do not occur at sites from more distal settings. This suggests that the proximal sites are sensitive recorders of early anthropogenic forcing during the Late Holocene, as a result of erosion due to deforestation. These sedimentological results are currently augmented by ongoing x-ray fluorescence (XRF) core scanning and x-ray diffraction (XRD) analyses that will provide element geochemical insight into changes in detrital input connected to sediment provenance.
Direct evidence of drainage divide migration reveals intermittent dynamics linked to 100 kyr climate oscillations
Authors: Goren Liran , Harel Elhanan , Qu Tianyue , Crouvi Onn , Porat Naomi , Ginat Hanan , Shelef Eitan
Published: March 2024

It is common to assume that when there are erosion rates and slope gradients across a drainage divide, the divide is prone to migrate and change the drainage area distribution of its bounding catchments. However, direct records of divide migration are exceptionally rare. This raises the following questions: Could the assumption be wrong, and can divides sustain topographic and erosion rate asymmetry over geomorphic and geologic (104– 106 yrs) timescales? And when divides eventually migrate, is the migration driven by endogenic feedback within the basin, or by exogenic forcing, such as climate change?To address these issues, we study a field area along the escarpments of the Dead Sea plate boundary, Israel, where direct records for divide migration are present in the form of terraces that grade opposite to the channel flow direction. These terraces are interpreted as a record of the divide’s paleo-locations, such that terraces are formed when the divide migrates inland from the edge of an escarpment, inducing drainage reversal and gradually extending the reversed channel that drains toward the escarpment.Absolute dating of these terraces using luminesces techniques and relative dating using soil chronosequence markers reveal that the terraces become older from the present locations of the divide toward the escarpment, consistent with the interpreted process of their formation. Terrace ages show an average divide migration rate of ~1100 m myr-1 over the past ~230 kyr, supporting active divide migration over timescales of 105 yrs or shorter.Terrace groups with similar ages indicate ~100 kyr cycles of periods of divide stalling and episodes of rapid divide migration with rates up to fourfold relative to the average rate. We use numerical simulations to explore possible drivers for the inferred divide intermittent dynamics. Simulations show that the dynamics are inconsistent with landscape evolution under uniform environmental conditions due only to internal basin dynamics. Instead, the inferred intermittency is best explained with time-dependent erosional efficiency that is sensitive to global climate change and correlates with regional paleoclimate proxies.This study provides the first detection of divide migration rate intermittencies at timescales of 104-105 yrs, and the association between divide dynamics and changing climatic conditions. This highlights the potentially significant impact of climate changes on the plan-form evolution of drainage basins.
Rapid verification visualization of atmospheric modeling relies on high-performance computing
Authors: Cheng Zhen
Published: March 2024

The verification of atmospheric model simulation results with the ambient observation is one of the essential tasks in understanding and researching climate change, weather forecasting, and the environmental impact of atmospheric pollutants. Data visualization plays a crucial role in comprehending model outputs and identifying potential issues. However, existing visualization tools are usually not sufficiently practicable for handling large-scale data in batch processing, and the resulting images do not meet the quality requirements of scientific graphics. This paper introduces PostAtmos, a plotting toolkit designed for verifying atmospheric models based on high-performance computing. It enhances the efficiency of batch processing for large-scale datasets and offers support for flexible personalized configurations, such as background information and figure’s element details. Three typical plots of spatial distribution, time series and scatter plots are included in our toolkit. By harnessing the parallel computational capabilities of high-performance computing platforms, the cost time of plotting can be reduced from 263 to 5 minutes, accelerating ~50 times compared to traditional serial techniques. The toolkit serves as a robust and versatile tool, providing researchers with a potent instrument for visualizing outputs from atmospheric models. In doing so, it contributes to the ongoing refinement of model precision and reliability.
Source apportionment of PM2.5 in a major city in an Alpine valley during the cold season: the effects of atmospheric dispersion and inversion dynamics
Authors: Masiol Mauro , Formenton Gianni , Visin Flavia , Bonetto Alessandro , Rovea Manuela , Ficotto Silvia , Danesin Elisa , Toffanin Tommaso , Maggiulli Anita , Battistel Maria , Mazzi Giovanna , Gambaro Andrea , Piazza Rossano , Hopke Philip K.
Published: March 2024

Urban areas in mountain environments are generally located on valley floors surrounded by slopes, where mountain orography drives peculiar meteorology and atmospheric circulation. Also, persistent inversion dynamics may occur strongly affecting air pollution. This study characterised the PM2.5 pollution in a major city located in an Alpine valley (Belluno, Northeastern Italy) during the cold season (Autumn-Winter). Major aerosol species (elemental and organic carbon, major inorganic ions) and minor/trace elements conventionally used as tracers for source apportionment were analysed, including oxalate and specific PM2.5-bound tracers for biomass burning (K+, levoglucosan, mannosan, galactosan) and for primary biogenic organic aerosol (arabitol, mannitol, glucose). The major aerosol components are reconstructed through mass closure, while the major sources are identified through positive matrix factorization and a series of post-processing tools. Results indicate that biomass burning, mostly emitted by residential wood combustion for domestic heating, is the major PM2.5 source (52% PM2.5 mass concentration), followed by secondary aerosol, biogenic aerosol, traffic, and dust resuspension. The source contributions are therefore handled by accounting for the local meteorology. Insights on the dispersion or buildup of PM2.5 sources were then investigated by dispersion normalization. In addition, the possible effects of persistent thermal inversion events occurring across the Alpine valley are evaluated by assessing the inversion strength from temperature profiles measured from multiple ground-based weather stations at different elevations with respect to the air quality sampling station. Data analysed in this study reflects typical autumn/winter air pollution in a major Alpine valley. Significantly higher concentrations are recorded in colder months, i.e., when the newly proposed maximum daily concentrations for PM2.5 (25 μg m-3 not to be exceeded more than 18 times per calendar year, according to the Proposal for a Directive COM(2022) 542 final/2, 2022/0347(COD)) or the newest WHO air quality guidelines are frequently breached, posing serious concerns for meeting the forthcoming European air quality standard for PM2.5. Beyond the indication of which emission sources require further mitigation actions, this study also analyses the potential effects of local meteorology on PM2.5 pollution and air mass transport from the nearby Po Valley. This study is supported by the project iNEST (Interconnected North-Est Innovation Ecosystem) funded by the European Union Next-Generation EU.
How well does 3DCORE perform at fitting flux rope signatures in real-time?
Authors: Amerstorfer Ute , Rüdisser Hannah , Weiss Andreas , Möstl Christian
Published: March 2024

The 3D coronal rope ejection (3DCORE) method has been used to fit magnetic fields of CME flux ropes to in situ observations. Its assumed Gold-Hoyle-like flux rope has an elliptical cross-section and expands self-similarly, thereby staying always attached to the Sun. An approximate Bayesian computation sequential Monte Carlo algorithm performs the fitting and allows us to get error estimates of the model parameters. Extending our previous studies, we investigate the ability of 3DCORE to fit the magnetic field of a flux rope in real time, when only the first hours of an observation are available. Therefore, we use past events mimicking a possible real-time application, but also any real-time events possibly happening. If performing well, this real-time application of 3DCORE can further advance the efforts of space weather prediction. 
Interplanetary shocks and particle energisation in the inner heliosphere
Authors: Trotta Domenico , Hietala Heli , Horbury Timothy S. , Vainio Rami , Dresing Nina , Dimmock Andrew , Blanco-Cano Xochitl , Kartavykh Yulia , Wimmer-Schweingruber Robert , Kilpua Emilia , Jebaraj Immanuel , Gieseler Jan , Espinosa Lara Francisco , Gomez Herrero Raul
Published: March 2024

Interplanetary (IP) shocks are important sites of particle acceleration in the Heliosphere and can be observed in-situ utilizing spacecraft measurements. Such observations, crucial to address important aspects of energy conversion for a variety of astrophysical systems.From this point of view, Solar Orbiter provides observations of interplanetary shocks at different locations in the inner heliosphere with unprecedented time and energy resolution in the suprathermal (usually above 50 keV) energy range. The general trends observed by Solar Orbiter and other spacecraft in the near-Earth environment for such shocks, highlighting their typical parameters, will be presented first. Then, the presence shock-induced wave activity in association with such shocks and their association with the presence of energetic particles will be discussed, summarizing some of the work performed in the framework of the the Solar EneRgetic ParticlE aNalysis plaTform for the INner hEliosphere (SERPENTINE) Project funded by EU H2020. Finally, particular emphasis will be devoted on the role of space/time irregularities at IP shocks and their effect on suprathermal particle production, focusing on some of the most interesting shocks observed by Solar Orbiter. 
Fluid-driven metasomatism in the mantle wedge: the hidden role of carbon-saturated COH fluids
Authors: Tiraboschi Carla , Sverjensky Dimitri , Sanchez Valle Carmen
Published: March 2024

COH fluids have a crucial role in a variety of geological processes in subduction zones, where carbon-bearing aqueous fluids released from the down-going slab infiltrate the overlying mantle wedge prompting metasomatic modifications. Yet, the ability of these fluids to mobilize rock components, and hence their metasomatic potential remains poorly constrained. This is mainly due to the scarcity of experimental data on mineral solubility and fluid speciation in COH-bearing systems at high-pressure conditions. Graphite-saturated COH fluids have been suggested as potentially efficient metasomatic agents, due to their high solute concentrations even at relatively low-pressure conditions. Graphite-saturated COH fluids in equilibrium with forsterite and enstatite can contain up to 11 wt.% of total solutes at 1 GPa and 800 °C, an amount significantly higher compared to the solute content for the same phase assemblage in a H2O-only fluid (i.e. 2.4 wt.%) [1].Investigating the metasomatic effect of solute-bearing fluids moving away from the source rock and reacting with different lithologies is a complex task. Experimentally, this would require the fluid to be transferred from the initial experimental charge to a different one. However, after quenching most of the dissolved solids originally dissolved in the fluid precipitate. The precipitated solids are both heterogeneous and physically fragile, making their collection and analysis a challenging aspect of the experimental design. Thermodynamic models, such as the Deep Earth Water model [2], allow to tackle the issue from a different perspective and assist in investigating the effect of solute-bearing fluids reacting with different rock assemblages.Here, we present thermodynamic modeling relative to the interaction between solute-rich COH fluids and mantle wedge rocks (i.e. lherzolite, harzburgite and dunite), to assess their ability to generate orthopyroxene at 1 GPa and temperatures from 700 to 900 °C. Our results show that the fluid generated from the sole dissolution of forsterite and enstatite in graphite-saturated COH fluids at relatively low-pressure conditions can modify the starting ultramafic rock composition, especially at high fluid/rock ratio, through enstatite formation. Fluid-driven metasomatism operated by COH fluids can thus represent an efficient mechanism to produce orthopyroxene-rich levels in the mantle wedge, without the concomitant formation of carbon-bearing phases, which would conceal the trivial role of carbon in the formation of these solute-rich fluids in the exhumed rock record.[1] Tiraboschi C. et al. (2018) Contributions to Mineralogy and Petrology 173, 1–17.[2] Sverjensky D.A. et al. (2014) Geochimica et Cosmochimica Acta 129, 125-145.
Large scale influence on extreme precipitation
Authors: Fauer Felix , Rust Henning
Published: March 2024

Extreme precipitation and flooding events in middle Europe lead to high death tolls and huge existential and financial losses. Evaluating how the probability of such events changes with respect to climate change can help in preventing casualties and reducing impact consequences. We create Intensity-Duration-Frequency (IDF) curves which describe the major statistical characteristics of extreme precipitation events (return level, return period, time scale). They provide information on the probability of exceedance of certain precipitation intensities for a range of durations and can help to visualize how extreme the event for different durations is. We modeled the underlying distribution of block maxima with the Generalized Extreme Value (GEV) distribution. Maxima from different durations are used and enable a model that can evaluate different time scales. All durations are modeled in one single model in order to prevent quantile-crossing and to assure that estimated quantiles are consistent.Large-scale information is included by letting the GEV parameters depend on variables like NAO, temperature and blocking. We found an increase in probability of extreme precipitation with year as proxy for climate change and temperature, while the effect of the other variables depends on the season. Since it is easier to project average values than extremes, we use the relations between average large-scale covariates and extreme precipitation to create future IDF-relations based on climate projections. Furthermore, we plan to add a spatial component to the model that enables the usage of data from several neighboring stations in one model and interpolate to ungauged sites. This will be the basis for investigating how gridded data sets can be used to complement the station-based approach. One focus will lie on the challenge of dependence between neighboring grid points.
Operational postprocessing at MeteoSwiss: lessons learned
Authors: Bhend Jonas , Spirig Christoph , Nerini Daniele , Moret Lionel
Published: March 2024

Local forecasts are the most viewed product on the MeteoSwiss mobile app and website. In the past year, MeteoSwiss has integrated statistical postprocessing into its automated forecasting system for medium-range, local forecasts. The postprocessing takes advantage of limited area and global NWP ensemble systems with different forecast horizons to provide seamless probabilistic hourly predictions up to ten days ahead. Postprocessing allows us to objectively optimize forecast quality in a targeted manner, resulting in local probabilistic forecasts that are more skilful and better calibrated than the legacy system. In the process of introducing statistical postprocessing into operations, we have identified a few key challenges that we would like to share.
One key challenge relates to predictability. We aimed at providing high resolution local forecasts; to achieve interpretable and useful forecasts for end users, however, postprocessing of lower-resolution features with higher signal-to-noise ratio is preferrable. This can be achieved for example by reducing the spatio-temporal granularity of the forecasts with increasing forecast lead time. Another aspect that proved challenging is the diversity of requirements from our end users. Prior to introducing new data-driven forecasts we evaluate the quality of the forecasts with a range of metrics to ensure that key requirements are met. In the future, we envisage using multi-objective optimization to target different aspects of forecast quality already during training. Generating realistic scenarios (ensemble members) of postprocessed forecasts is currently performed post-hoc using ensemble copula coupling. Using postprocessing methods that are ensemble-native would allow us to jointly optimize quality for different spatio-temporal aggregations while still providing high-resolution local forecasts as an end product. In addition to the scientific challenges outlined above, we will also address the operational challenges related to the robustness of the system, to the monitoring, and to the communication that were identified.
Fate and changes in moisture evaporated from the Tibetan Plateau (2000–2020)
Authors: Zhang Chi , Chen Deliang , Tang Qiuhong , Huang Jinchuan , Yan Mei
Published: March 2024

The Tibetan Plateau (TP) has been termed the “Asian water tower” and it plays an important role in regulating the Asian water cycle, which affects billions of people. Although the areal mean evaporation of the TP is not high, the total evaporation integrated over the vast terrain of the TP is huge and may strongly influence downwind regions. However, the ultimate fate of this evaporation moisture remains unclear. This study tracked and quantified TP-originating moisture using an extended WAM2Layers model. The findings reveal that the involvement of moisture from the TP in the downwind precipitation is most pronounced near the eastern boundary of the TP and gradually diminishes eastward. Consequently, the TP moisture ratio in precipitation reaches the highest of over 30% over the central-eastern TP. 44.9–46.7% of TP annual evaporation is recycled over the TP, and 65.1–66.8% of the TP evaporation is reprecipitated over terrestrial China. Moisture recycling of TP origin shows strong seasonal variation, with seasonal patterns largely determined by precipitation, evaporation and wind fields. High levels of evaporation and precipitation over the TP in summer maximize local recycling intensity and recycling ratios. Annual precipitation of TP origin increased mainly around the northeastern TP during 2000–2020. This region consumed more than half of the increased TP evaporation. Further analyses showed that changes in reprecipitation of TP origin were consistent with precipitation trends in nearby downwind areas: when intensified TP evaporation meets intensified precipitation, more TP moisture is precipitated out. This study also analyzed the uncertainty due to different tracking modes in WAM2Layers, i.e., backward and forward moisture tracking. In forward moisture tracking, the annual precipitation recycling ratio (PRR) of the TP was estimated to be 26.9–30.8%. However, due to the non-closure issue of the atmospheric moisture balance equation, the annual PRR in backward tracking could be ~6% lower.
Bedform migration’s impact on streambed oxygen distribution: A novel field experiment
Authors: Villa Alejandra , Schulz Hanna , Spahr Stephanie , Arnon Shai , Lewandowski Jörg
Published: March 2024

Several studies have investigated the high reactivity of the hyporheic zone (HZ) and the interactions between moving bedforms and biogeochemical processes. However, the impact of bedform migration on the attenuation of trace organic compounds in the streambed has not yet been investigated. The oxygen distribution and dynamics in the HZ play a major role in this regard. So far, there have been no in-situ measurements of two-dimensional oxygen distributions in the HZ. To address this gap, we developed a novel device and tested it for the first time in the Erpe River, Germany. Our setup included a planar optode installed in the streambed to visualize the redox zonation within the HZ. Additionally, we tested five different stream flow velocities (from 10 to 50 cm/s) to investigate typical bedform celerities in lowland streams more thoroughly. By repeatedly sampling the surface and pore water, our aim was to determine how dynamic flow patterns and variable bedform celerities in sandy streams influence water constituents. The field experiment confirmed that changes in flow conditions can non-linearly influence bed movement and oxygen consumption, thereby affecting the fate of trace organic compounds.Keywords: Biogeochemical processes, bedform celerity, in situ measurements, field experiments, redox zonation, hyporheic zone, oxygen distribution, planar optode.
Assessing slope-river connectivity for evaluating cascading landslide hazards: A case study of Tordera river basin, NE Spain.
Authors: Abancó Clàudia , Guinau Marta , González Marta , Pinyol Jordi , Palau Rosa M
Published: March 2024

Landslides and torrential flows are among the most dangerous processes that occur on hillslopes, and they are mostly triggered by intense rainfall events. These phenomena are not only hazardous in themselves, but they can also have a more significant impact downstream when they interact with channels or the river network. When multiple landslides are simultaneously triggered by a rainfall event that affects an extensive area, they can initiate chains of further hazards due to the sudden and massive influx of sediment they bring onto channels and rivers. Therefore, it is crucial to study the connectivity between slopes and the river network to evaluate areas with a potentially higher sediment contribution to the river network. Ultimately, this information will help to assess flood hazards and mitigate risks, as well as assist in the planning of protective structures, drainage works, and other relevant measures.We conducted a study on the slopes of the Tordera River basin (NE Spain). This river flows from the Montseny (Catalan Coastal range)  into the Mediterranean Sea. The study area was affected by a regional landslide event that occurred in January 2020 during the Gloria Storm (more than 480 mm of rainfall was measured in 96 hours in the region). We employed the index of connectivity, which is based on Borselli et al. (2008), to examine the connectivity between the slopes and the river network. The outcomes of this analysis were subsequently compared to a landslide inventory (more than 1000 mass movements) to determine whether the high amount of sediment present in the lowlands could have originated from landslides in the upper part of the basin.According to the results of this study, slopes with high connectivity experienced a high density of landslides. The sediment that flowed down the slopes and reached the rivers added to the flood that occurred downstream. This flood carried a considerable amount of sediment which caused the widening of the active channel and the growth of the Tordera delta. The impacts of the Gloria storm on the infrastructure caused significant economic losses. Borselli, L.;  Cassi, P.;  Torri, D. Prolegomena to sediment and flow connectivity in the landscape: A GIS and field numerical assessment, CATENA, Volume 75, Issue 3, 2008, Pages 268-277, ISSN 0341-8162, https://doi.org/10.1016/j.catena.2008.07.006.
FLEXWEB - A flexible particle dispersion model web interface
Authors: Blaschek Michael , Bakels Lucie , Dütsch Marina , Stohl Andreas
Published: March 2024

Flexpart (FLEXible PARTicle dispersion model) is a numerical model that simulates the dispersion of gases and aerosols in the atmosphere. In order for Flexpart to be used, it must be installed and run on a (super)computer. However, this is associated with obstacles, as not all scientists have access to a supercomputer and there are often technical problems during installation or execution. In this project, we therefore want to develop a Flexpart Web Service (FLEXWEB) in which Flexpart can be run via a website. We will show first results and details on the implementation of a test project for a potential operational service. Flexpart will be containerized and the service will be run in a Kubernetes cluster (in “the” cloud or on premises) to calculate trajectories and make these results easily accessible to users. As soon as the simulation is complete, the output files will be made available for download and displayed graphically. In this way, we hope to simplify access to Flexpart for scientists worldwide.
A new method for remote sensing assessment of water quality status based on ZY1-02D hyperspectral imagery—A case study of large lakes and reservoirs in China
Authors: Tang Hongzhao , Xiao Chenchao , Shang Kun , Wu Taixia
Published: March 2024

Water quality is crucial for human health and the sustainable development of the ecological environment. Traditional water quality monitoring methods rely on discrete in-situ measurements, limiting our understanding of water quality variations at large temporal and spatial scales. While remote sensing technology offers efficient water quality observation, it is mostly confined to monitoring optical active substances, making it challenging to assess water quality changes caused by chemical indicators. This study proposes a concept that changes in water quality status caused by chemical indicators within a certain range are responsive in terms of water-leaving reflection. To validate this hypothesis, water quality index (WQI) was initially calculated using data from water quality monitoring stations, resulting in water quality status data (ranging from excellent to severe pollution). Following this, an information extraction and classification inversion approach was proposed to establish a connection between ZY1-02D hyperspectral imagery and water quality status, leading to the development of a robust water quality status identification model. Validation results showed an average model accuracy of up to 82%, confirming the hypothesis of this study. Subsequently, this model was used to assess the water quality status of 180 large lakes and reservoirs (hereafter referred to as lakes) within China from 2019 to 2023 for the first time. The results indicated that 76.1% of the lakes exhibited excellent to good water quality conditions, with a spatial distribution pattern showing a "better in the west, worse in the east" trend. Over the 4-year period, 33.33% of the lakes showed improvement, while 50% remained stable, with the western and eastern regions primarily exhibiting stability and improvement, respectively. The long-term changes in water quality status are influenced by various interacting factors, with different patterns of influence existing in different time periods and regions. In the early years, natural factors (average elevation) played a dominant role. However, over time, the impact of meteorological factors (precipitation and wind speed) and anthropogenic factors (gross domestic product) gradually increased. These influences can be attributed to significant climate changes and effective management measures over the past two decades. The findings support rapid assessment of environmental conditions and sustainable resource management, highlighting the potential of remote sensing technology in water quality monitoring.