bluuebunny/crossref_metadata_2025 huggingface dataset:
Validating SWOT in the coastal zone: a radar altimetry and tide gauge case study in the Bristol Channel and Severn River-Estuary system
Authors: Lichtman Ian Dougal , Banks Chris , Calafat Francisco J. M. , Gommenginger Christine , Bell Paul
Published: March 2024

The Bristol Channel and Severn River-Estuary system is highly dynamic with one of the largest tidal ranges in the world. The Severn is the longest river in the UK, with the second largest mean flow.  The coastline surrounding these waters and upriver is covered by a network of tide gauges (TGs), which has been continuously operational for a period of decades. This makes it an ideal area for the validation of new satellite altimetry sensors such as those on the Surface Water and Ocean Topography (SWOT) mission,  which for the first time collects 2D maps of water level, and to explore quality of SWOT data in the coastal zone. The SWOT-UK project  used this area for these purposes, for a comprehensive programme of field campaigns and multidisciplinary research in a coastal and estuarine context, as part of the UK contribution to the international SWOT Science Team validation work.For the SWOT-UK project, a set of TG, CryoSat-2 and Sentinel-3 data has been gathered to validate total water level and surface slope during the 1-day repeat SWOT CAL/VAL mission phase. Extra in situ GNSS-IR instruments were deployed to fill gaps in the existing TG network. This combined data set was used to assess the consistency and quality of the TG network and develop a validation scheme for the SWOT L2 and L3 altimetry data, in coastal and estuarine settings. This will highlight issues of how the coastal dynamics, hydrology and morphology affect the comparison of satellite altimetry and TGs, and how these features may be seen in the SWOT data. The slope along the satellite passes (across-channel), near-shore coastal dynamics and intertidal morphology have been seen to affect the comparison of satellite altimetry and TG data, and these geographic characteristics are expected to influence the uncertainty in the comparison with the SWOT data.The validation data from Bristol Channel and Severn Estuary has been used for an assessment of the performance of these novel 2D altimeter measurements. Cross-comparisons with in situ and satellite data will be presented, with an exploration of the effect of coastal dynamics and morphology on these data. This will lead to an improvement of satellite altimetry in the coastal zone. In addition, the SWOT data will be relevant to the improvement of numerical models, by providing a quality of validation and assimilation data not previously available, and help understand and reduce uncertainties due to changing intertidal morphology.
Spatio-temporal distribution of extreme rock-ice avalanches in the Cordillera Blanca (Peru)
Authors: Lehmann Benjamin , Zerathe Swann , Concha Ronald , Carcaillet Julien , Valla Pierre G. , Torres-Lázaro Juan C. , Jara W. Harrinso , Cosi Manuel
Published: March 2024

The Cordillera Blanca, located in Peru between latitudes 8-10°S, is the most glacierized intertropical mountain range in the world, with peaks over 6,000 meters still carrying numerous glaciers today. Ongoing climate change has resulted in a 41.50% reduction in glacier extent from 1962 to 2020, increasing natural hazards such as icefall, glacial lake overflow flooding, and rock avalanches. These events mainly affect the highest reliefs, but can reach the low elevation valleys, where around 300,000 inhabitants are exposed. Since the 1950s, these hazards have caused tens of thousands of casualties, including two major disasters: rock-ice avalanches from the northern summit of Huascaran (6,757m) traveling over considerable distances and destroying populated areas such as Ranrahirca (1962) and Yungay (1970), resulting in approximately 7,000 casualties in total.In this context, our objective is to construct a comprehensive "spatio-temporal" inventory of substantial rock-ice avalanches (volume > 106 m3) within the Cordillera Blanca. Our aim is to enhance our understanding of their spatial distribution, temporal frequency, and magnitude while pinpointing potential triggering factors. Our specific focus involves investigating potential correlations between avalanche records and climatic oscillations spanning the past hundred thousand years. The primary area of interest is the Yungay site, situated directly downstream from Huascaran North, where successive debris avalanche (historical and paleo) have accumulated, forming debris cones that extend across several square kilometers. Preliminary field observations have identified numerous large boulders indicative of events surpassing the reported magnitude for historical avalanches and their associated deposits.Employing a multi-method approach that integrates fieldwork, remote sensing, geochronology, and numerical modeling, we intend to assess rock-avalanche deposits and volumes. A preliminary field mission conducted in August 2023 in Yungay facilitated the mapping and sampling of approximately 30 boulders of pluri-decametric size for surface-exposure dating (in situ 10Be on quartz). Anticipating dating results by early 2024, one of the primary expected outcomes of this study is to achieve a comprehensive reconstruction of the geomorphic response of the high Cordillera Blanca during past climate oscillations. This understanding will contribute to better anticipating the future evolution of natural hazards within the context of ongoing global climate warming, glacial retreat, and accelerated permafrost degradation. Additionally, our objective is to characterize the triggering mechanisms for low-frequency (recurrence time >100 yr) high-magnitude (volume >106 m3) events.
Elucidating Isoprene Oxidation: Pathways to Highly Oxygenated Molecules formation
Authors: Yang Liwen , Nie Wei , Yan Chao , Ehn Mikael
Published: March 2024

Isoprene is globally recognized as the preeminent biogenic volatile organic compounds (BVOCs) and is the most extensively researched species among volatile organic compounds (VOCs). Nevertheless, prevailing global and regional atmospheric models inadequately represent its molecular-level oxidation process. The predominate explicit chemical mechanisms, such as Master Chemical Mechanism (MCM) and CalTech isoprene mechanism, underestimate the complexities of isoprene oxidation, particularly the formation of Highly Oxygenated Molecules (HOMs) — a vital process from VOC to secondary organic aerosol (SOA). Here, we address a critical gap in the understanding of isoprene oxidation mechanism within existing models, especially the formation of fragmentation products and HOM-level oxidation products. The updated model integrates the influence of multigenerational OH-initiated oxidation and photolysis processes, thereby enriching the dynamics of free radical cycling. Our updated model was validated against previous molecular-level chamber experiments, demonstrating an enhanced ability to simulate the radical cycle and HOM formation, thus more accurately reflecting SOA formation.
Magnetospheric Auroral Asymmetry eXplorer: observing the auroral to uncover how energy flows in space - A Phase A SMEX Mission concept
Authors: Halford Alexa , Liemohn Michael , Ridley Aaron , Welling Daniel , Immel Thomas , Connor Hyunju , DeJong Anna , Fasel Gerard , Gabrielse Christine , Garcia-Sage Katherine , Harding Brian , Spanswick Emma , Zoe Shasha , MacDonald Elizabeth
Published: March 2024

The Magnetospheric Auroral Asymmetry Explorer (MAAX) mission concept makes a significant leap in determining how magnetosphere-ionosphere electrodynamic coupling regulates multi-scale energy flow through the near-Earth space environment. Recently selected for a competitive Phase A mission concept study for NASA's Heliophysics Small Explorer program, MAAX accomplishes this by:Understanding how seasons and tilt of the magnetic field regulate energy flow from the solar wind through the geospace system.
Discovering how the auroral background conductance governs the formation, evolution, and interhemispheric asymmetries of nightside meso-scale auroral features.
Determining how the time-dependent magnetospheric energy flow controls multi-scale auroral dynamics.
The solar wind energy enters the magnetosphere mainly through dayside reconnection. It is stored in the magnetospheric lobes, released in the tail, converted to plasma thermal and kinetic energies. The dynamic processes in the nightside magnetosphere map from the magnetosphere to the ionosphere, resulting in auroral structures. Observations of the aurora have been used as a window to probe and understand these dynamics even beyond the Earth system. The magnetic field lines in which the aurora occurs thread through both hemispheres. Traditionally, auroral observations from one hemisphere are assumed to be conjugate, while limited observations suggest this may not always be applicable. Thus, we can only understand some of the processes that control energy flow through the system from one hemisphere. With observations in both hemispheres, we gain a deeper understanding of the dynamics of this integrated system. MAAX comprises two observatories in circular polar orbits at 20,850 km altitude to view the two auroral ovals. Each satellite carries a high-heritage UV imager that operates poleward of +/-35° latitude. For the mission's 1st year, the observatories are spaced at 90° to allow continuous coverage of each oval with a 6-hour duty cycle. This phase also provides intervals in which both view the same hemisphere or the exact longitude but different hemispheres. For the 2nd year of the mission, the observatories are spaced at 180° to have simultaneous complete viewing of both auroral ovals with a 4.5 hr/1.5 hr on/off duty cycle. Discussed here are the scientific motivations of the mission concepts.
Key role of AquaINFRA Interactive Platform integrated in blue research infrastructures
Authors: Otsu Kaori , Pesquer Lluís , Garcia Xavier
Published: March 2024

The increasing acquisition of observations in hydrological research is a critical factor to accelerate FAIR and open data sharing across relevant scientific communities.  Conventionally, research infrastructures have developed in silos that are specific to the domains and/or countries. With the ambition of tackling this fragmentation, the establishment of European Open Science Cloud (EOSC) is in progress to federate multidisciplinary research infrastructures by ‘Enabling an operational, open and FAIR EOSC ecosystem (INFRAEOSC)’ projects.  One of them, AquaINFRA (https://aquainfra.eu), has been funded to protect oceans, seas, coastal and inland waters, in support of the EU Mission 'Restore our Ocean and Waters' by 2030.AquaINFRA will develop a research infrastructure equipped with FAIR multi-disciplinary data and services, allowing seamless data discovery and processing through the AquaINFRA Interaction Platform (AIP) to support freshwater and marine scientists and integrate with EOSC seamlessly. More specifically, the AIP will include a data discovery and access service as well as spatio-temporal models in Virtual Research Environments (VREs) to provide the optimal environment for the global hydrosphere research through interoperability with external infrastructures such as the European Digital Twin of the Ocean (EDITO).Regional studies will highlight the Mediterranean case in Tordera and Maresme, Catalonia, with a VRE workflow to evaluate the marine ecological state impacted by land catchment interactions in a system of the hydrological cycle.  Based on the methodology of coupling freshwater and marine models using different types of data (e.g. in-situ, remote sensing, socio-economic) and services (e.g. Copernicus, EMODnet) from local, regional, national to European sources, we conclude with the challenges and opportunities for enabling a FAIR research environment among the interested regional stakeholders including scientists and decision-makers to provide feedback to the EOSC Partnership.(This project has received funding from the European Commission’s Horizon Europe Research and Innovation programme under grant agreement No 101094434.)
Drag in Vegetation Canopy: Considering Sheltering and Blockage Effects
Authors: Wang Ping , Liu Yuyan
Published: March 2024

Vegetation plays a crucial role in river hydrodynamic processes, and the accurate prediction of vegetation drag force is essential for effective river management and ecosystem protection. The interactions within the vegetation canopy must be quantified to understand their impact on drag force. This study delves into the canopy interaction mechanisms of rigid emergent aquatic vegetation, with a specific focus on blockage and sheltering effects. Through a series of flume experiments, we systematically explored various combinations of lateral and longitudinal spacing, including special single row and single column arrangements. Our experimental design includes various combinations of lateral and longitudinal spacing, as well as special single row and single column arrangements. This allowed us to provide a more precise understanding of how lateral and longitudinal spacing affect the blockage and sheltering effects. Furthermore, we introduced a unified reference velocity that combines two effects, based on which we have established a widely applicable drag model that can predict drag under various density conditions. Additionally, we propose a critical characteristic value for quantifying drag, shedding light on the ultimate performance of drag under different spacing arrangements. These findings offer a reliable framework for predicting drag in rigid emergent vegetation canopies, significantly advancing our comprehension of vegetation's influence on hydrodynamic processes. The established drag model serves as a practical tool for river management and ecosystem protection, providing valuable guidance for sustainable environmental practices.
Weak Aerosol Hygroscopicity Measured over the Southern Tibetan Plateau: Implication for Cloud Activation
Authors: Wang Yuan , Li Jiming , Fang Fang , Zhang Ping
Published: March 2024

Cloud activation over the Tibetan Plateau (TP) plays a pivotal role in regional cloud-precipitation processes and, by extension, global climate. However, its characteristics remain elusive due to the absence of observations in the TP. Leveraging the Second Tibetan Plateau Scientific Expedition and Research Program, we conducted a ground in-situ aerosol-cloud-precipitation experiment in the southern TP (GACPE-STP) from August to October 2023, thereby unveiling, for the first time, the aerosol activation characteristics in this crucial region. Our findings reveal a discernibly weak aerosol activation capacity, with mean cloud condensation nuclei number concentration (NCCN) ranging from 24 to 483 cm-3 and activation fraction from 2% to 48% at the supersaturation (SS) range from 0.07% to 0.7%. Through multi-method measurements of aerosol hygroscopicity (k), including derivation from both dry and humidified particle number size distribution (PNSD) and scattering coefficients, along with calculations based on NCCN(SS) and dry PNSD, we consistently observe low hygroscopicity with mean values below 0.1. This contrasts starkly with the recommended continental k value of 0.3, a departure that may be linked to unique surface characteristics and local fuel-usage practices in the TP region. As the dry aerosol diameter (D) increases, k exhibits an initial rise followed by a decline, adhering to a Gaussian distribution. The resulting k(D) fitting serves as a parameterization for predicting cloud activation in this region. Notably, utilizing the recommended continental κ value of 0.3 leads to a significant overestimation of cloud droplet number concentration (77% to 426%), subsequently contributing to an overestimation of cloud optical thickness and an underestimation of cloud-rain autoconversion. This cascade effect results in a substantial overestimation of the aerosol indirect effects. Employing the k(D) parameterization can significantly enhance the precision of cloud activation predictions in this region. These findings peel back a layer of mystery surrounding cloud activation in the TP region. To construct a comprehensive understanding, we advocate for additional in-situ experiments, including ice nuclei measurements, crucial for a nuanced depiction of cloud activation in the TP region.
Exploring the possibilities to reduce irrigation demands through adaptations in soil and crop management
Authors: Heinz Malve , Turek Maria Eliza , Holzkämper Annelie , Schaefli Bettina , Raible Christoph
Published: March 2024

In Central Europe, increasing temperatures and declining summer precipitation intensify the water and heat stress on crops and reduce water availability for irrigation from rivers and groundwater. Thus, approaches that reduce the need for irrigation are required. In this study, we quantify the potential of soil and crop management adaptations to reduce irrigation deficits for a mid-sized rainfed catchment in Switzerland. The Broye catchment, comprising 68 % agricultural land with a notable portion dedicated to irrigated agriculture, faces frequent summer irrigation bans. We employ the field-scale agro-hydrological model (SWAP) aiming to 1) quantify irrigation demand at the catchment scale, 2) assess the impacts of temporary irrigation bans on irrigation deficits, and 3) explore the potential of soil and crop management adaptations to reduce these irrigation deficits. SWAP simulates horizontal solute, heat and water flow in the vadose zone and crop growth at a daily timestep. The model calibration process involves a comprehensive global sensitivity analysis and parameter optimization. The optimization aims to maximize the model's fit to reference data on crop yield and seasonal irrigation amounts from the study region. Spatial climate, land use, and soil input data enable the quantification of irrigation water demand on the catchment scale. We simulated the exceptionally hot and dry summer of 2022, revealing a 57 % deficit in water supply and again emphasizing the importance of reducing reliance on irrigation. We further evaluate the effectiveness of measures such as increased soil organic carbon content and planting earlier maturing crop varieties in reducing irrigation demand. Our findings provide valuable insights for sustainable water management in midsized rainfed catchments, particularly in the face of climate change and evolving water use conflicts. As a next step, we plan to couple the field-scale model with a catchment-scale rainfall-runoff model to evaluate the effects of implementing such measures on the catchment's water balance.
TRIQUERTA: Towards next generation risk assessment and mitigation of climate change and natural hazards threatening cultural heritage
Authors: Ioannidis Charalabos , Spyrakos Constantine , Verykokou Styliani , Istrati Denis , Soile Sofia , Charalampopoulou Vasiliki (Betty) , Georgiadis Panagiotis
Published: March 2024

Cultural heritage (CH) sites face increasing risks from climate change (CC) and various hazards, posing threats such as rising sea levels, extreme weather events, and environmental degradation, endangering their preservation and long-term existence. A lot of research has been done on protecting CH sites, but we still lack systemic approaches towards identifying and mitigating risks to CH sites. The TRIQUETRA EU research project proposes a technological toolbox and a methodological framework for tackling climate change risks and natural hazards threatening CH, in the most efficient way possible. The main strategic objectives of TRIQUETRA include: the creation of a repository of knowledge on effects of CC and natural hazards on CH, including lessons learnt from existing mitigation measures; the implementation of a systemic approach towards identification of upcoming risks and hazards to CH; and the usage of novel technologies allowing efficient and accurate quantification of threats to CH.The TRIQUETRA project’s methodology is structured around three fundamental stages: (i) identifying risks, (ii) quantifying risks, and (iii) mitigating risks, forming what is known as the “trifecta” approach. This approach constructs a robust framework for evaluating and addressing the following categories of risks: (i) climate-related risks; (ii) extreme water, snow and ice hazard risks; (iii) geological and geophysical risks; and (iv) chemical and biological hazard risks. Furthermore, it assesses the damage and failure modes of CH structures as well as the compounded effects of various environmental stressors on CH sites. TRIQUETRA will be validated in eight different CH sites across Europe. The main project results can be summarized as follows:a novel risk quantification framework for CH sites;
an expanded knowledge base platform;
a decision-support platform (TRIQUETRA DSS) including risk severity quantification tools and mitigation measure selection and optimization tools;
novel protective materials;
a novel flash LiDAR;
water quality analysers; and
a CH site digitization framework.
Nitrification inhibitors in the soil-groundwater-river continuum of Germany
Authors: Weidemann Eva , Dülfer Johanna , Matthes Katrin , Gassmann Matthias
Published: March 2024

Nitrification inhibitors and urease inhibitors are organic chemicals that have been used in agriculture for decades to slow down nitrification in order to keep plant-available ammonium in the soil for longer and to reduce the leaching of nitrate. Furthermore, they serve to reduce the rapid conversion of urea to ammonia, which also has a positive effect on climate protection. Being applied to agricultural fields, there is a high risk that these substances are contaminating water bodies. We therefore initiated both an environmental sampling campaign and a lab study of the environmental fate characteristics of selected nitrification inhibitors and urease inhibitors.In our first study, we took samples in Northern Hesse and the area of Goettingen (Germany) from streams, lakes and groundwater between October and December, mainly in agricultural areas. The samples were then analysed for six different nitrification and urease inhibitors (1) 3,4-dimethylpyrazole phosphate (DMPP), (2) 4-amino-1,2,4-triazole (ATC), (3) Dicyandiamide (DCD), (4) N-(2-nitrophenyl)phosphoric triamide (2-NPT), (5) Mixture of N-((5-methyl-1H-pyrazol-1-yl)methyl)acetamide and N-((3-methyl-1H-pyrazol-1-yl)methyl)acetamide (MPA) and (6) H-1,2,4-Triazol. We found solely two of the inhibitors in the samples, DCD and H-1,2,4-Triazol, which corresponds to the results of a study from 2014 published by the DVGW.In a second study, we wanted to examine under what circumstances and with what dynamics the inhibitors are transferred to deeper soil zones and what influence they have on the leaching of nitrate at different temperatures and in different soils. For this purpose, we chose the above mentioned five nitrification or urease inhibitors (1-5), which are currently used in agricultural fertilizers in Germany. In order to obtain information about their behavior in the environment, we have planned a study to investigate their leaching and transformation behavior in the unsaturated soil zone. For this purpose, agricultural topsoils were selected and filled into 25 cm high columns with a diameter of 7 cm. Three fertilizers containing the above-mentioned compounds were applied separately to the soil columns at an application rate of 150 kg N/ha. Each of the variants was tested in triplicate in two different temperature ranges (12 °C, 20 °C). Irrigation was carried out over 12 weeks with a groundwater recharge rate of the fall/winter period. The leachate was analyzed 1-2 times a week and at the end of the study the soil was analyzed at two different depths for the inhibitors as well as nitrate and nitrite.
A reference facility for the comparison of CO2 in Air isotope ratio standards
Authors: Flores Edgar , Choteau Tiphaine , Moussay Philippe , Eun Han Jun , Allison Colin , Wielgosz Robert I.
Published: March 2024

The commercial development of laser-based instruments over the last decade that can measure real-time isotopic ratio variations of greenhouse gases, and notably CO2, has allowed their application across a wide range of scientific and technical disciplines. Precise measurements can be achieved, and appropriate calibration strategies [1] and standards need to be applied to achieve accurate results and consistency with traditional mass spectrometric measurement methods. For CO2, calibration strategies can be based on using CO2 in air standards with the same isotopic ratios but containing different amount fractions, or the same amount fraction and different isotope ratios. This has resulted in the availability of calibration standards containing different isotope ratios at different amount fractions, which may or may not contain nitrous oxide. An international comparison programme at the BIPM (BIPM.QM-K4) is in development to demonstrate the equivalence of such standards, which would allow them to be used interchangeably by operators.The BIPM’s comparison facility is based on a dual inlet isotope ratio mass spectrometer with a custom built (BIPM) Air Trapping system (BAT) to extract CO2 from air mixtures using cryogenic separation for determination of δ13Cand δ18O-CO2, with a correction for the N2O present in the sample. A procedure for regularly determining the relative ionization efficiency of N2O in relation to CO2 has been developed and is applied as a function of the amount fraction of N2O in the sample. Metrological traceability is achieved through a hierarchy of low-pressure CO2 standards with δ13C values nominally at -1 ‰, -35 ‰ and -43 ‰, calibrated on the VPDB scale via IAEA 603 carbonate standard material. Initial validation of the performance of the facility has been performed with the extraction of CO2 from gas mixtures within the range of 380 μmol mol−1 to 800 μmol mol−1 and δ13C and δ18O-CO2 values from 1 ‰ to -43 ‰ and -7 ‰  to -35 ‰, respectively. The method demonstrates excellent reproducibility, with standard deviations of 0.005% and 0.05%. for δ13C  and δ18O-CO2, respectively. In addition, the robustness of the N2O correction has been demonstrated by comparing δ13C  and δ18O-CO2 values from standards produced from the same CO2 source gas but at differing amount fractions. The performance and validation of the facility will be described. [1] Flores, E., Viallon, J., Moussay, P., Griffith, D. W. T. & Wielgosz, R. I. Calibration strategies for FT-IR and other isotope ratio infrared spectrometer instruments for accurate δ13C and δ18O measurements of CO2 in air. Anal. Chem. 89, 3648–3655 (2017).
Identifying direct deforestation drivers in Cameroon using deep learning and optical satellite data
Authors: Debus Amandine , Beauchamp Emilie , Lines Emily R.
Published: March 2024

Deforestation rates have been increasing in the Congo Basin in recent years, especially in Cameroon. To support actions to slow deforestation, Earth Observation (EO) has been used extensively to detect forest loss, but approaches to automatically identify specific drivers of deforestation in a level of detail that allows for intervention prioritisation have been rare. In this paper, we use deep learning to classify direct deforestation drivers in Cameroon and create a country-specific dataset for this task. We also compare the effectiveness of two types of freely available optical satellite imagery: Landsat-8 (pan-sharpened to a 15 m spatial resolution) and NCIFI PlanetScope (4.77 m spatial resolution). Our detailed classification strategy includes 15 direct deforestation drivers for forest loss events taking place between 2015 and 2020. We obtain an overall accuracy of 82% (F1-score: 0.82) with Landsat-8 data and an overall accuracy of 76% (F1-score: 0.76) for NICFI PlanetScope. Despite a coarser spatial resolution, Landsat-8 performs better than NICFI PlanetScope overall, including for small-scale drivers, although results vary by class. With Landsat-8, using only a single-image approach, we achieve an accuracy of at least 70% for all classes except for ‘Hunting’, ‘Oil palm plantation’, and ‘Fruit plantation’. These results show the potential of using this approach to monitor or analyse land-use changes leading to deforestation with more refined classes than before. In addition, our study demonstrates the potential of leveraging existing available datasets and straightforwardly adapting a generalised framework for other tropical locations with a relatively small amount of location-specific data.
Development CNtrace tool
Authors: Jansen-Willems Anne , Kleineidam Kristina , Clough Tim , Dannenberg Lea , Müller Christoph
Published: March 2024

The Ntrace tool was developed as a flexible 15N analysis tool to determine gross nitrogen (N) transformations. Since the development of the tool, it has been applied to many ecosystems world-wide as documented in more than 190 peer-reviewed publications. Over time, the tool has evolved to become much more flexible including different pools and determining more transformation rates. Up until now, the focus has been on the N cycle. However, the N and carbon (C) cycle are closely connected. Considering both cycles concomitantly provides a more comprehensive understanding of how elements move through the system. Thus, the next step in the development of the Ntrace tool includes connecting the N and C pools (CNtrace) in order to simultaneously quantify gross N and C transformations based on the observed 15N and 13C dynamics. Data from specifically designed experiments, using either labelled organic matter or C4 plants in a C3 soil, with the addition of differentially 15N labelled mineral fertilizer will be used for the development of the CNtrace tool. The theoretical background and the various development steps will be presented.
The start of frozen dates over northern permafrost regions with the changing climate
Authors: Li Jialing , Wu Chaoyang , Peñuelas Josep , Ran Youhua , Zhang Yongguang
Published: March 2024

Climate warming exerts important impacts on the freeze-thaw cycle in permafrost regions. Although increasing attention has been paid on understanding the responses of spring thawing to climate change, the mechanisms controlling the global interannual variability of the start date of permafrost frozen (SOF) remain unclear. Using long term SOF derived from the freeze–thaw Earth system data record (FT-ESDR) over 1979-2020, and analytical techniques, including partial correlation, ridge regression, path analysis, the Random Forest (RF) and SHapley Additive exPlanations (SHAP), we explored the responses of SOF to multiple climate factors, including warming (surface and air temperature), start date of permafrost thawing (SOT), soil properties (soil temperature and volume of water), and the snow depth water equivalent (SDWE). In summary, while climate warming exerted predominant influence on SOF, SOT in spring also played a significant role in shaping SOF variability. Among the observed 65.9% significant correlations between SOT and SOF, 79.3% were positive, indicating that an earlier thawing would contribute to an earlier frozen in winter. Machine learning analysis reinforced the significance of SOT as the second most crucial determinant of SOF. To elucidate the mechanism behind the SOT-SOF relationship, path analysis was employed, revealing that changes in soil temperature had the maximum impact on this relationship, irrespective of the permafrost type. Finally, we analyzed the temporal changes in these responses using the moving window approach and found an increasing influence of soil warming on SOF. In conclusion, these findings offer valuable insights for understanding and predicting variations in SOF in the context of future climate change.
The influence of submicron sized aerosol scavenging by snow in the Cb cloud
Authors: Savic Darko , Vuckovic Vladan , Vujovic Dragana
Published: March 2024

In this work we have investigated the effect of aerosol particles (APs) scavenging by snow in a cumulonimbus cloud. It was shown that APs in the atmosphere have a major impact on cloud formation, development and its products, climate, environment, public health, etc. The scavenging coefficients for various snow scavenging processes were calculated, analyzed and implemented in a three-dimensional, three-moment microphysical model in which all the number concentrations and the mixing ratios, were explicitly calculated for all hydrometeor categories. Analyzing the AP scavenging coefficients we concluded that Brownian/turbulent diffusion is the dominant process for smaller diameter aerosols, up to a point, where inertial interception overpowers. Impaction scavenging is by far the most dominant process of APs scavenging by snow for particles larger than ~0.5 µm in diameter, therefore it was neglected because most of the APs injected into the cloud are of the diameter
Evaluating the numerical modeling of storm surges induced by hurricanes
Authors: Chaigneau Alisée A. , Menéndez Melisa , Ramírez-Pérez Marta , Toimil Alexandra
Published: March 2024

Coastal zones are increasingly threatened by extreme sea level (ESL) events. Storm surges (i.e. sea level variations due to meteorological drivers) are one of the most hazardous components of ESLs, especially in regions prone to tropical cyclones. This study aims to explore factors affecting the performance of numerical modeling in simulating storm surges induced by hurricanes. The focus is on the tropical Atlantic region, covering the Caribbean Sea and the Gulf of Mexico.Several historical hurricanes causing severe coastal impacts are simulated. The skill of the simulations to reproduce the storm surge contribution to ESLs is evaluated against recorded values from tide-gauge stations. The modeled peak surge maxima and the hourly time series are analyzed during these extreme events.The factors explored in this study encompass the numerical model, oceanic and atmospheric forcings, physical parameterizations, spatial resolution, and baroclinic/barotropic modes.Two ocean models (ADCIRC and NEMO) are intercompared using a similar configuration: domain, spatial resolution (~9 km), bathymetry and barotropic mode. The sensitivity of the atmospheric forcings is assessed by comparing storm surges induced by ERA5 reanalysis data and parametric wind models usually applied for hurricanes (e.g. Dynamic Holland Model, Generalized Asymmetrical Holland Model). The effect on storm surge due to non-linear interactions with the astronomical tide and variations in mean sea level is also investigated, as well as the sensitivity to different wind stress schemes. In addition, the baroclinic contribution to ESLs is studied using a configuration with 75 vertical levels. Finally, the role of the spatial resolution on the modeled storm surges is evaluated with a high-resolution domain of about 500 m in coastal areas.The analysis of the numerical experiments reveals some interesting insights. ADCIRC and NEMO can simulate storm surges due to tropical cyclones in a similar way compared to tide gauges. In general, the ERA5 forcing outperforms the various parametric wind models for storm surge modeling, in terms of maximum values, correlation, and duration of extreme events. Non-linear interactions of tides and mean sea level with storm surges have minimal contribution in the storm surges induced by hurricane events. However, the baroclinic response significantly improves the storm surge estimations in some coastal areas (e.g. along the southeastern Florida peninsula). All the authors would like to thank the Government of Cantabria through the FENIX Project GFLOOD.
Chronology of ancient water installations and the history of human activity in the Negev Highlands, Israel 
Authors: Fuchs Markus , Junge Andrea , Lomax Johanna
Published: March 2024

In antiquity, the development of techniques to collect and store water was fundamental to sustain life in arid regions. One way to overcome the problem of water supply in the desert was to construct water reservoirs and cisterns which collect surface runoff during rare rain events. Indeed, open reservoirs and rock-cut cisterns are widely spread over the arid zone of the Negev Highlands / Israel. They were an important component of human activity in the area. Today, they can serve as sedimentary archives for archaeological and paleoenvironmental reconstruction. Here we provide the final assessment of a large-scale optically stimulated luminescence (OSL) dating project of water installations in the arid Negev Highlands. By sampling spoil piles, feeding channels, and accumulation of sediments within reservoirs and cisterns, the construction, the phases of maintenance and abandonment were dated. The significance of these results for reconstructing the history of human activity in the region is discussed.
Reclassifying historical disasters: from single to multi-hazards
Authors: White Christopher , Adnan Mohammed , Lee Ryan , Douglas John , Mahecha Miguel , O'Loughlin Fiachra , Patelli Edoard , Ramos Alexandre , Roberts Matthew , Martius Olivia , Tubaldi Enrico , van den Hurk Bart , Ward Philip , Zscheischler Jakob
Published: March 2024

Multi-hazard events, characterized by the simultaneous, cascading, or cumulative occurrence of multiple natural hazards, pose a significant threat to human lives and assets. This is primarily due to the cumulative and cascading effects arising from the interplay of various natural hazards across space and time. However, their identification is challenging, which is attributable to the complex nature of natural hazard interactions and the limited availability of multi-hazard observations. This presentation, focused on a recently published article in Science of the Total Environment (https://doi.org/10.1016/j.scitotenv.2023.169120), presents an approach for identifying multi-hazard events during the past 123 years (1900-2023) using the EM-DAT global disaster database. Leveraging the ‘associated hazard’ information in EM-DAT, multi-hazard events are detected and assessed in relation to their frequency, impact on human lives and assets, and reporting trends. The interactions between various combinations of natural hazard pairs are explored, reclassifying them into four categories: preconditioned/triggering, multivariate, temporally compounding, and spatially compounding multi-hazard events. The results show, globally, approximately 19% of the 16,535 disasters recorded in EM-DAT can be classified as multi-hazard events. However, the multi-hazard events recorded in EM-DAT are disproportionately responsible for nearly 59% of the estimated global economic losses. Conversely, single hazard events resulted in higher fatalities compared to multi-hazard events. The largest proportion of multi-hazard events are associated with floods, storms, and earthquakes. Landslides emerge as the predominant secondary hazards within multi-hazard pairs, primarily triggered by floods, storms, and earthquakes, with the majority of multi-hazard events exhibiting preconditioned/triggering and multivariate characteristics. There is a higher prevalence of multi-hazard events in Asia and North America, whilst temporal overlaps of multiple hazards predominate in Europe. These results can be used to increase the integration of multi-hazard thinking in risk assessments, emergency management response plans and mitigation policies at both national and international levels.
The relationship between volatile organic compounds and apple replant disease
Authors: Wachter Anne-Sophie , Tissier Alain , Harding Esther Armah , Vetterlein Doris
Published: March 2024

Apple replant disease (ARD) refers to the observed decline in plant growth, fruit yield, and quality after repeated planting of apples at the same site. It is a phenomenon in all apple-producing areas worldwide which leads to an estimated profitability reduction of 50 % over the lifetime of an apple orchard. Up to now, the mechanisms behind ARD are only poorly understood. It has been attributed to the action of a site-specific, multi-kingdom, pathogenic, and parasitic biological complex. Thus, the soil faces (micro-) biome alterations due to previous apple cultures.Upon initial contact, apple roots can detect and avoid soil affected by ARD. So far, it is not known how the roots can sense ARD in soil. Volatile organic compounds (VOCs) are promising candidates as communicators between soil and plant. It is known that VOCs mediate many cases of plant responses to pests or pathogens. Nevertheless, their role in ARD has so far been neglected.A rhizobox experiment was set up to determine the volatile emission of apple plantlets growing in ARD and non-ARD soil. Volatiles are analyzed using untargeted gas chromatography-mass spectrometry with prior concentration on an adsorbents (here: stir bar sorptive extraction, SBSE) and thermodesorption.This first pre-experiment run with the interpretation of the gas chromatogram as the next step. Our aim is to determine whether there are any differences between the volatiles detected in the close proximity of apple roots growing in ARD and in non-ARD soil. Noticeable VOCs will be identified to specify the occurring volatile profiles.We will examine the potential role of VOCs as communicators between plants, the microbiome, and soil. It will be addressed whether the sensing of ARD is related to volatile production.
METAS: the new WMO-GAW Central Calibration Laboratory for halogenated VOCs
Authors: Bühlmann Tobias , Roos Diana
Published: March 2024

Many halogenated volatile organic compounds (VOCs) are found in the atmosphere in the pmol/mol range. These halogenated VOCs have negative impacts on the environment as they are strong greenhouse gases and/or contribute to the depletion of the stratospheric ozone layer or their degradation products may have a negative impact on the environment. This underpins the importance to accurately measure the amount fractions of these substances in the atmosphere on the long-term.The Global Atmosphere Watch (GAW) Programme of the World Meteorological Organization (WMO) is a long-term international global programme that coordinates observations and analysis of atmospheric composition changes. The GAW Programme is a collaboration of more than 100 countries and it relies fundamentally on the contributions of its members to help to build a single, coordinated global understanding of atmospheric composition and its change. For most substances there is a Central Calibration Laboratory (CCL) that is responsible for maintaining and distributing the WMO references for instrument calibration for a specified gas in air. However, until summer 2023 there was no CCL for halogenated VOCs. METAS applied successfully for the CCL function for a total of ten halogenated VOCs because METAS' gas analysis laboratory has a decade of experience in the production of reference gas mixtures for halogenated VOCs. Here, we will present our new function as CCL including our services, the work done in the past and the planned work for the next years.
Anomalous Arctic Warming Linked with Severe Winter Weather in Northern Hemisphere Continents
Authors: Cohen Judah , Francis Jennifer , Pfeiffer Karl
Published: March 2024

We have extended a recently developed index of accumulated winter season severity index (AWSSI), originally based on temperature and snowfall observations from weather stations in the United States only, to the entire Northern Hemisphere using reanalysis output. The expanded index (rAWSSI) is analyzed to reveal relationships between Arctic air temperatures/geopotential heights and the probability of severe winter weather across the midlatitudes. Cold temperatures dominate the index, while snowfall contributes mainly over high elevations.  We find a direct and linear relationship between anomalously high Arctic temperatures/geopotential heights and increased severe winter weather, especially in northern and eastern continental regions.  Positive temperature trends in specific Arctic regions are associated with increasing trends in severe winter weather in particular midlatitude areas. These trends are more robust during recent decades when Arctic warming has accelerated, exceeding the pace of global-average warming by a factor of two to four. We also explore trends in the variability of daily rAWSSI. During the era of rapid Arctic warming, variability has decreased over the Arctic Ocean and Europe – suggesting less volatile winter weather -- while it has increased along the United States (US)/Canadian border, western Canada, and northeast Asia, indicating more pronounced shifts in weather conditions. This finding suggests an increased tendency for volatile weather swings known as weather whiplash.  Finally, we find that when the stratospheric polar vortex is weak (anomalously warm stratosphere), the rAWSSI tends to increase, suggesting an association between disruptions in the polar vortex and severe winter weather across certain regions of the Northern Hemisphere continents.
Characterizing volcano deformation with DInSAR and GNSS data: the Sotará Volcano case study. 
Authors: Euillades Pablo Andres , Alpala Rosa Liliana , Euillades Leonardo Daniel , Alpala Jorge , Rosell Patricia , Roa Yenni , Battaglia Maurizio
Published: March 2024

Sotará is a stratovolcano located at a remote region of the Southern Cordillera Central, in Colombia.  It presents signs of unrest since 2011, evidenced by increased seismicity and crustal deformation formerly detected by tilt-meters, and later by inflation measured at several GNSS permanent stations operated by the Colombian Geological Survey.  In this contribution we processed a set of ascending and descending SAR scenes acquired by the Sentinel-1 Mission by using the Small Baseline Subsets (SBAS) multi temporal DInSAR approach. The region is challenging for DInSAR processing using C-Band data, because it is covered by thick forest causing temporal decorrelation, except for the peaks higher than 3500 m above sea level. As deformation in the site is subtle, i.e. in the order of 2cm/year, atmospheric contamination can potentially hide the geophysical signal, leading to misleading conclusions. To decide if atmospheric corrections should be applied, we analyzed the correlation between the unwrapped phase and topography at each interferogram before and after applying atmospheric corrections provided by the Generic Atmospheric Correction Online Service for InSAR (GACOS). We search for data clustering in the plane correlation coefficient vs. time, which allow for detecting atmospheric stratification signals and evaluating the convenience of applying corrections or not. As a result, we decided not applying atmospheric corrections, and the deformation time series without them show a good agreement with the LOS projected GNSS ones. The results were used for estimating the source parameters through inverse modelling of ascending, descending SAR data and GNSS data using the DMODELS inversion software. We detect migration of the deformation source in the Sotará volcano towards shallower positions between 2011 and 2020. This work is an example of the capability of Sentinel-1 long data series for measuring subtle deformation even in though environment conditions.