bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing perceptual models of hydrologic behavior across the North American continent
Authors: Knoben Wouter , Clark Martyn , Fan Ying , McMillan Hilary , Read Jordan , van Werkhoven Katie
Published: March 2024

The North American continent is home to a wide range of different hydro-climates. A key research gap is that there is currently limited understanding on the spatial variability of dominant hydrologic processes across these different hydro-climates. This limited understanding makes it difficult to select computational models that faithfully represent the hydrologic processes across such large domains, yet faithful representation of the different hydro-climatic behaviors is critical for accurate numerical prediction.Here we present progress on a synthesis of dominant hydrologic processes under different combinations of climate-terrain-human forcings, engaging the broader community of catchment and Critical Zone scientists. The product from this research will be a continental “Hydrologic Mosaic”, with each landscape in the mosaic described by a set of perceptual and conceptual models. In this first step, we produce a continental map of hydrologic landscapes defined through the juxtaposition of hydroclimate, terrain and geology, and vegetation, land use, and management. We will define hydrologically meaningful indicators of terrestrial hydrology that concisely describe a location’s (i) hydroclimate (e.g., aridity, snow fraction, energy/water seasonality), (ii) topography and geology (e.g. depth to bedrock, soil porosity, topographic slope), and (iii) vegetation, land use and management (e.g., vegetation type, agricultural drainage, reservoir size), and calculate values for these indicators for each location on the continent. We then use clustering analysis to create a manageable number of representative hydrologic landscapes.This work functions as a starting point in a wider project, where these initial hydrologic landscapes will be refined through interactions with regional experts. Together, we will develop perceptual (sketches and descriptions) and conceptual (box-and-arrow diagrams) of the dominant processes in each hydrologic landscape. These conceptual diagrams will contribute to large-domain modeling efforts by allowing targeted model selection and comparison efforts for each hydrologic landscape.
Obscured Contribution of Oxygenated Intermediate-Volatility Organic Compounds to Secondary Organic Aerosol Formation from Gasoline Vehicle Emissions
Authors: Huang Dan Dan , Hu Qingyao , He Xiao , Huang Rujin , Ding Xiang , Ma Yingge , Feng Xinwei , Jing Shengao , Li Yingjie , Lu Jun , Gao Yaqin , Shi Xu , Qian Chunlei , Yan Chao , Zhu Shuhui , Lou Shengrong , Wang Hongli , Fu Qingyan , Fu Qingyan , Huang Cheng
Published: March 2024

Secondary organic aerosol (SOA) formation from gasoline vehicles spanning a wide range in emission types was investigated using an oxidation flow reactor (OFR) by conducting chassis dynamometer tests. Aided by advanced mass spectrometric techniques, SOA precursors, including volatile organic compounds (VOCs), intermediate/semi-volatile organic compounds (I/SVOCs), were comprehensively characterized. The reconstructed SOA produced from the speciated VOCs and I/SVOCs can explain 69% of SOA measured downstream of OFR upon 0.5-3 days’ OH exposure. While VOCs can only explain 10% of total SOA production, contribution from I/SVOCs is 59%. We also found that oxygenated I/SVOCs (O–I/SVOCs, e.g., benzylic or aliphatic aldehydes and ketones), as an obscured source, accounted for 16% of total nonmethane organic gas (NMOG) emission and 20% of SOA production. More importantly, with the improvement in emission standards, the NMOG was effectively mitigated by 35% from China 4 to China 6, which is predominantly attributed to the decrease of VOCs. Real-time measurements of different NMOG components as well as SOA production further revealed that the current emission control measures, such as three-way catalytic converters (TWCs), are effective in reducing the “light” SOA precursors (i.e., single ring aromatics), but not for the I/SVOC emissions, indicating that the catalyst are selective upon reacting with different exhaust components. Our results highlight the neglected contribution from I/SVOCs, especially O-I/SVOCs to SOA formation and the urgent need in further investigation in their origins, i.e., incomplete combustion, lubricating oil, which requires improvements in real-time molecular-level characterization of I/SVOC molecules and in turn will benefit the future design of control measures.
Towards mapping total currents and winds during the BioSWOT-Med campaign with the OSCAR airborne instrument
Authors: Martin Adrien , Lemerle Eva , Mccann David , Macedo Karlus , Andrievskaia Daria , Gommenginger Christine , Casal Tania
Published: March 2024

The BioSWOT-Med cruise focused on the Western Mediterranean Sea, known for its rich plankton biodiversity under oligotrophic and moderate energy conditions. The cruise aimed to investigate the role of fine-scale circulation as a driver of plankton diversity, coinciding with the SWOT satellite's daily "fast-sampling" orbit over the same region. SWOT, with its high-resolution 2D observations of sea surface height at 15-120km spatial scale, offered a unique perspective on ocean dynamics.Mesoscale and submesoscale currents play a crucial role in ocean-atmosphere interaction and marine biosphere processes. The SeaSTAR satellite mission concept (former ESA Earth Explorer 11 candidate at phase 0), is designed to observe small-scale ocean surface dynamics with a remarkable 1 km resolution, contributing to our understanding of carbon, water, energy, gases, and nutrient exchanges across various Earth systems.To prepare for the SeaSTAR mission, the OSCAR (Ocean Surface Current Airborne Radar) airborne instrument was developed, providing a synoptic 2D view of ocean and atmosphere dynamics, including currents, waves, and winds, at fine scale. During the SEASTARex campaign in May 2022 over the Iroise Sea in Brittany, France, OSCAR demonstrated excellent performance against various measurements, including marine radar, ADCP, and HF radar.Building on OSCAR's success, a campaign was organized in May 2023, coinciding with the Bio-SWOT campaign, to fly together with SWOT over a non-tidal dominated area, mapping small-scale dynamics. Satellite SAR images from various sources, including RCM, TerraSAR-X, Sentinel-1, RadarSat-2, and PAZ SAR, were collected for comparative analysis with OSCAR and SWOT data.Initial comparisons between OSCAR and satellite data, spanning remote sensing instruments like SWOT, SAR imagers, and optical sensors, showed a high level of agreement. SWOT data, analyzed with a diverse dataset, promises to enhance understanding and characterization of dynamics observed in the new 2D images.OSCAR's Doppler and scatterometry capabilities offer a fresh perspective on dynamic processes, particularly at fine scales, bridging the gap between in-situ point measurements and space-based sensors. The ongoing synergy between OSCAR and satellite data holds potential to advance our understanding of oceanic and atmospheric phenomena, addressing critical challenges related to climate, weather, and marine ecosystems.
Next Generation Drought Monitoring: Forecasting to Emotion-Focused Coping
Authors: Kam Jonghun , Choi Seunghui , Liu Anqi
Published: March 2024

A severe drought causes catastrophic economic losses, resulting in mental degradation/deterioration. While drought monitoring has been focused on detecting and characterizing an emerging drought (physical system-focused), artificial intelligence with big data from social monitoring provides a unique opportunity to investigate sentimental alterations of the public along the drought propagations and explore their triggers (social system-focused). This study examines the potential of an AI technique, Natural Language Processing (NLP), in monitoring sentimental alterations of the public. This study is a case study of the recent Korea drought, leveraging X (formerly, twitter) and Google Trends data. In this study, we evaluate the seasonal-to-seasonal predictability of drought measures in the southwest region of the Korean Peninsula for the 2022/23 period and analyze spatiotemporal changes in media and public interest in drought phenomena during the 2022/23 drought period through newspapers and social media. Initially, to understand the predictability of drought measures in March 2023, we evaluate the predictability of drought measures based on probabilistic and deterministic seasonal-to-seasonal forecasts for the 2022/23 Korea drought. Subsequently, using drought-related articles in newspapers and Twitter data from the 2022 to 2023, we utilize natural language processing and text mining technologies to detect and monitor the topic and emotional alternation of the titles of news article and public, respectively, regarding the 2022/23 drought. The results of this study indicate that the predictability of drought measures in May 2023 is skillful at the sub-seasonal scale but limited at the seasonal scale. Statistical forecasts provide crucial information on precipitation needed for drought recovery through weekly precipitation forecasts, aiding in assessing the drought condition. The public interest in the 2022/23 drought shows spatiotemporal differences based on the drought-affected areas and drought stages. Especially in April 2023, when a severe drought occurred in the southwestern Korean region, an increase in the number of newspaper articles with negative titles was observed, and negative emotions were detected from the social media data. This study provides an insight about the role of AI in developing the next-generation drought monitoring system.  
Trace gas balloon borne in situ measurements in the Southern Hemisphere
Authors: Blazaki Kyriaki , Rolf Christian , Laube Johannes , Ploeger Felix , Voet Florian , Geldenhuys Markus , Mkololo Thumeka , Labuschagne Casper , Labuschagne Pieter
Published: March 2024

The Southern Hemisphere has long been underrepresented in high altitude in situ trace gas measurements. This leads to significant uncertainties in understanding and predicting their effects on stratospheric chemistry and circulation. In a pioneering effort, a balloon campaign took place in Beaufort West (32.3540 ˚S, 22.5833˚E) in early 2023, the first of its kind in South Africa. Two different sensor packages were launched during six balloon flights and reached altitudes up to 33 km. These balloon flights provided unique measurements of key atmospheric constituents, including water vapor, ozone, CO2, CH4, CO, SF6, and various ozone depleting substances.Here, we present an overview of these findings, along with a comparison with similar data from the Northern Hemisphere, and with data from the Chemical Lagrangian Model of the Stratosphere (CLaMS). A first notable result revealed the sampling of tropical air masses with unusually low water vapor mixing ratios [2.1 ppmv] around the upper troposphere and lower stratosphere (UTLS) region. A follow-up campaign is planned for 2024 to further enrich the dataset and enhance insights into stratosphere-troposphere exchange dynamics.
  Tsunami Simulation and Seismic Source Characterization: A Case Study of the March 18, 2021 Offshore Bejaia Earthquake (Mw 6.0) in the Western Mediterranean
Authors: Heinrich Philippe , Dupont Aurélien , Menager Marine , Trilla Aurélie , Gailler Audrey , Delouis Bertrand , Hebert Hélène
Published: March 2024

On March 18, 2021, a magnitude Mw 6.0 earthquake occurred offshore the Algerian coasts near Bejaia, resulting in a tsunami with offshore amplitudes smaller than a few millimeters that crossed the western Mediterranean Sea. This study pursues three primary objectives: firstly, to assess the ability of tsunami simulations to replicate tide-gauge observations; secondly, to ascertain the relevance of seismic sources calculated within the context of tsunami early warning systems, against tsunami generation and observations; and thirdly, to evaluate the sensitivity of simulations to grid resolutions and earthquake parameters.Within the Mediterranean Sea, only a limited number of coastal tide gauges recorded the tsunami. Among these, select French tide gauge stations captured water waves with amplitudes smaller than a few centimeters and periods ranging from five to twenty minutes, often associated with harbor or bay resonances.Numerical simulations of the tsunami were conducted utilizing the operational code Taitoko employing six distinct source fault models. Notably, two of these models provided rapid source detection and characterization within the framework of tsunami warning systems at CENALT (Centre National d’Alerte aux Tsunamis, France). The integrated code Taitoko employs a system of multiple nested grids. For this event, it solved standard Boussinesq equations within the Mediterranean grid, while employing nonlinear shallow water equations in coastal and harbor grids, each with resolutions of 25 and 5 meters, respectively. Regardless of the fault model employed, the model satisfactorily reproduced the observed time series of water heights in both phase and amplitude at Nice and Monaco, while some discrepancies are found and discussed for most of the other locations.
Hydrological and Sediment Transport Regime on Rivers in the Balkans: The Case of the Seman River in Albania
Authors: Doko Alban , Bronstert Axel , Francke Till
Published: March 2024

Hydrological and sediment transport regime are important in water resource management. Aim of this study is to identify the flow regime and the suspended sediment transport in a Mediterranean River Basin. Precipitation, temperature, soil, land use, discharges and suspended sediment concentration are used to quantify runoff and sediment yields at daily scales. WASA-SED (Water Availability in Semi-Arid environments – SEDiments) a spatially semi distributed model it is developed to simulate the flow and sediment transport in Seman Basin. Sediment deposits in Seman Basin contribute to a significant annual loss in the water storage capacity of the dams. Runoff and suspended sediments in Mediterranean hill slopes are closely related to rainfall intensities and land surface cover. This study gives a valuable approach in improving the prediction of flow and sediment transport in Mediterranean River Basin.Keywords:Flow, Sediment transport, WASA-SED, Mediterranean River Basin
Robustness Framework Leveraging Stochastic Dual Dynamic Programming in the Indus River Basin
Authors: Rougé Charles , Sarfraz Amal , Mihaylova Lyudmila
Published: March 2024

Water uses in the Indus River Basin (IRB) – agriculture, hydropower, etc. – primarily depend on meltwater from Himalayan glaciers, seasonal snow, and monsoon rains. This dependency makes the IRB vulnerable to climate change and associated deeply uncertain shifts in seasonal melt patterns, long-term glacier recession and erratic monsoon patterns. Therefore, there's a growing emphasis on creating robust adaptation plans suitable for various future scenarios, rather than focusing on a specific uncertain future.
Our research aims to develop a robustness framework to capture the multi-reservoir system with multiple contributions to streamflow from various sources with unique characteristics for the IRB. Our methodology quantifies streamflow components across multiple reservoirs for the IRB into base flow, rainfall, snowmelt, and glacial melt. This breakdown enables us to model each individual component's impact under a changing climate. We use Fourier series transformations to represent shifts in magnitude and seasonality of each component. This then enables us to explore how these shifts impact the resilience of reservoir operating policies, typically based on static hydrological conditions.
To determine operating policies in complex multi-reservoir systems, we use Stochastic Dual Dynamic Programming (SDDP), due to its ability to capture the stochastic nature of streamflow amidst dynamic and uncertain hydrological inputs. Running SDDP with historical flows yields policies whose robustness to streamflow change can be tested; alternatively, running SDDP with select climate change scenarios yields altered policies whose climate “niche” can then be determined.
This approach enables the design of coordinated reservoir operation policy, optimal under different streamflow conditions, as well as their evaluation over a wide range of potential future conditions, enhancing the optimisation of water use and management policies for the IRB. Our findings are expected to offer valuable insights assisting policymakers, stakeholders, and water resource managers in developing more resilient and sustainable strategies to address the impacts of climate change on water resources.
Disentangling the role of different sources of uncertainty and model structural error on predictions of water and carbon fluxes with CLM5 for European observation sites
Authors: Eloundou Fernand Baguket , Strebel Lukas , Naz Bibi S. , Terán Christian Poppe , Vereecken Harry , Hendricks Franssen Harrie-Jan
Published: March 2024

The Community Land Model version 5 (CLM5) integrates processes encompassing the water, energy, carbon, and nitrogen cycles, and ecosystem dynamics, including managed ecosystems like agriculture. Nevertheless, the intricacy of CLM5 introduces predictive uncertainties attributed to factors such as input data, process parameterizations, and parameter values. This study conducts a comparative analysis between CLM5 ensemble simulations and eddy covariance and in-situ measurements, focusing on the effects of uncertain model parameters and atmospheric forcings on the water, carbon, and energy cycles.Ensemble simulations for 14 European experimental sites were performed with the CLM5-BGC model, integrating the biogeochemistry component. In four perturbation experiments, we explore uncertainties arising from atmospheric forcing data, soil parameters, vegetation parameters, and the combined effects of these factors. The contribution of different uncertainty sources to total simulation uncertainty was analyzed by comparing the 99% confidenceintervals from ensemble simulations with measured terrestrial states and fluxes, using a three-way analysis of variance.The study identifies that soil parameters primarily influence the uncertainty in estimating surface soil moisture, while uncertain vegetation parameters control the uncertainty in estimating evapotranspiration and carbon fluxes. A combination of uncertainty in atmospheric forcings and vegetation parameters mostly explains the uncertainty in sensible heat flux estimation. On average, the 99% confidence intervals envelope >40% of the observed fluxes, but this varies greatly between sites, exceeding 95% in some cases. For some sites, we could identify model structural errors related to model spin-up assumptions or erroneous plant phenology. The study guides identifying factors causing underestimation or overestimation in the variability of fluxes, such as crop parameterization or spin-up, and potential structural errors in point-scale simulations in CLM5.
Assessing post-fire soil erosion and water contamination risk in European fire-affected catchmentswith WEPPcloud-EU WATAR watershed model
Authors: Neris Jonay , Sánchez-García Carmen , Basso Marta , Lew Roger , Srivastava Anurag , Dobre Mariana , Robichaud Pete , Brooks Erin , Santin Cristina , Doerr Stefan
Published: March 2024

Soil and ash are key sources of sediment, carbon, nitrogen, and associated pollutant movement following a wildfire. Their transport into freshwater systems can pose severe environmental and socio-economic implications including impacts to water quality and aquatic ecosystems, disruptions to drinking water supply and high remediation costs, as well as the depletion of carbon and nutrients from areas affected by erosion. We assessed the risk of soil erosion, ash and contaminant transport, and water contamination in three burned European catchments in Central Europe (Germany and the Czech Republic), Portugal and Spain using the European Water Erosion Prediction Project cloud interface with the Wildfire Ash Transport and Risk (WEPPcloud-EU WATAR) watershed model. The watersheds varied in size from 100 to 22,000 ha and represent distinct climatic conditions. To our knowledge, this is the first application of this model in European post-fire scenarios. We calibrated and validated the model using catchment runoff data (where available) and nearby streamflow data from both pre- and post-fire periods when runoff data was unavailable. Additionally, we used sediment transport data (where available) along with ash contaminant content data to calibrate and validate erosion and ash transport rates. Model performance was assessed using statistics like Nash-Sutcliffe Efficiency (NSE), coefficient of determination (R2) and percent bias (PBias (%)). Once the model was calibrated and validated, we estimated the post-fire risk of soil erosion, ash transport, and ash pollutant concentrations in the affected areas. The simulations provided the probabilities of occurrence and return periods for severe erosion events, as well as for ash and contaminant transport events. Based on these simulations, we identified hillslopes that were the main sources of runoff, erosion, ash and contaminant transport. This information is important to managers who can prioritize the application of mitigation treatments and prevention plans. Given the projected increase in fire weather in many regions in Europe, our findings suggest that the WEPPcloud-EU WATAR model is an increasingly useful tool in predicting and mitigating soil erosion and water contamination impacts of European burnt catchments.
Investigating potential sources of Ice Nucleating Particles around the Antarctic peninsula
Authors: van den Heuvel Floortje , Tarn Mark , Murray Benjamin , Lachlan-Cope Thomas
Published: March 2024

Clouds are a major source of uncertainty in climate model projections, especially in the Southern Ocean where the large model biases in short and long wave radiative fluxes affect the model representation of sea surface temperatures, sea ice and ultimately large scale circulation in the Southern Hemisphere. Evidence suggests that the poor representation of mixed phase clouds and the role of Ice Nucleating Particles (INPs) in these clouds are likely to be responsible for the model biases in this region. To understand how clouds will respond in a future climate we need to both better understand the effects and sources of INPs in the present, and attempt to anticipate the importance of new sources of INPs which could be revealed in a warming climate and by a reduction in glacial coverage. In order to achieve this, we have dispersed samples of dusts from the Antarctic peninsula and James Ross Island in the Leeds aerosol chamber to characterise the size-resolved ice-nucleating activity of Southern high latitude dusts and to determine the heat lability of the INPs as a potential indicator for biogenic ice nucleators. We’ve also created suspensions from a number of Antarctic mosses and lichen to measure the ice-nucleating activity of these potential sources of INPs. Preliminary results indicate that the collected dusts nucleated ice at temperatures between -18 ºC and -14 ºC while mosses and lichen nucleated ice at temperatures ranging from -18 ºC to -6 ºC, depending on the source. Future work will include a comparison with ambient air filter samples collected around Rothera (Antarctic peninsula) and in the Arctic.
Lineament analysis for characterizing regional fracture system – A case study from the Oslo region, Norway
Authors: Svendby Anne Kathrine , Torgersen Espen , Redfield Tim , Dichiarante Anna Maria , Arctander Karoline
Published: March 2024

Lineament analysis from topographic maps is a well-known method to identify regional fracture systems and the potential for weakness zones, but the significance of lineaments can easily be misinterpreted. A topographic lineament (topolineament) is just an elongated depression, which may or may not contain important structural information. In which case lineaments represent faults or fractures, and do all brittle structures appear as a lineaments? This is the focus of our project.In this study, we investigate the applicability of lineament analysis to characterize the fracture system in the Oslo region, Norway. Topolineaments, derived by automatic detection using an in house-developed algorithm (OttoDetect) on a 10x10m digital elevation model, are combined with field structural observations and measurements. Special emphasis was placed on comparing the orientation of brittle structures from field data with that of the detected topolineaments.The fieldwork was carried out by measuring fractures at selected locations both along and away from larger topolineaments. In some areas, data collection also included measuring scanlines parallel and orthogonal to selected topolineaments. Structural measurements were split into different geographical areas of Oslo and plotted on stereonets. The topolineaments were analyzed and classified by parameters such as orientation, length, density (number of lineaments over a given distance) and width-depth ratio (within the lineament), etc. Rose diagrams of all lineaments within a given radius from a geographical center point were used to show the dominant lineament orientations in the studied area. We pay especially close attention to lineaments in regions dominated by bedrock, in order to represent only bedrock-incised topolineaments, so that the rose diagrams could be used to compare with fracture orientations.Preliminary results show that both field data and topolineaments are dominated by two orthogonal sets: E-W and N-S. However, the relative dominance of either set in the two datasets seems less correlated. Further analysis is ongoing to also constrain the relationship between fracture and lineament densities.
Satellite altimetry derived glacier mass changes over High Mountain Asia during 2003‒2022
Authors: Zhao Fanyu , Long Di , Han Pengfei , Wang Yiming , Cui Yifei , Duan Xingwu
Published: March 2024

High Mountain Asia (HMA) is a hotspot for research on global glacier change and its environmental impacts. Over the past few decades, HMA glaciers have undergone relatively slow but accelerating mass loss. However, our current understanding of the inter- and intra- annual variations in these glaciers remains insufficient. In this study, we derived glacier mass changes in HMA at different spatiotemporal scales through the integration of three altimetry products (i.e., ICESat, CryoSat-2, and ICESat-2). We constructed seasonal time series of glacier mass balance in HMA and its subregions and produced multiple elevation change maps for these glaciers over different periods. Our results showed that HMA glaciers experienced heterogeneous glacier ablation with a mean mass loss rate of 26.72 ± 3.30 Gt/yr during 2003 ‒ 2022. Among various subregions, the glaciers in Hengduan Shan experienced the most severe depletion and the most substantial mass loss (3.81 ± 0.47 Gt/yr). The glaciers in Western Himalaya and Eastern Himalaya suffered significant mass loss as well. The melting rate of HMA glaciers over the second decade has significantly accelerated compared to the preceding decade. Furthermore, in 2022, HMA glaciers experienced pronounced mass loss attributed to abnormally high temperatures, with the glacier ablation in the Qilian Mountains being the most severe on record. Our spatially explicit and high-temporal-resolution (monthly to seasonal) features of glaciers would improve understanding of HMA glacier changes and serve as a reference for future research in this field.
Seasonal controls on methane flux components in a boreal peatland - combining plant removal and stable isotope analyses
Authors: Jentzsch Katharina , Männistö Elisa , Marushchak Maija E. , Korrensalo Aino , van Delden Lona , Tuittila Eeva-Stiina , Knoblauch Christian , Treat Claire C.
Published: March 2024

Wetlands are the largest natural source of atmospheric methane and highly vulnerable to climate change. In our study we aim to better understand the environmental controls on the strength and seasonal variation of methane flux components from hollows, typically the high-emitting wettest microtopographic features in a boreal bog. We measured methane fluxes from intact vegetation as well as on vegetation removal treatments and analyzed pore water methane concentrations and stable carbon isotopes of dissolved and emitted methane. Using these data, we quantified the rates of total methane emission, methane oxidation and plant-mediated methane transport for the summer and shoulder seasons of 2021 and 2022. Total methane emissions from areas with intact vegetation range from 13 to 2171 mgCH4 m–2 d–1 during shoulder seasons and summer months and are mainly controlled by the leaf area of aerenchymatous plants. Methane oxidation in the Sphagnum moss layer decreases total methane emissions by 82 ± 20 % while transport of methane through aerenchymatous plants increases methane emissions by 80 ± 22 %. Both methane oxidation and plant-mediated methane transport rates follow a seasonal cycle with lower but still significant rates during the shoulder seasons compared to the summer months. As a net effect, the presence of Sphagnum mosses and vascular plants reduces methane emissions from the study site. This balance, however, appears to be highly sensitive to climate change, i.e. increasing soil temperatures and changing leaf area and composition of the wetland vegetation. The provided insights can help to improve the representation of environmental controls on the methane cycle and its seasonal dynamics in process-based models to more accurately predict future methane emissions from boreal peatlands.
Do catchment characteristics drive extreme discharge tail behavior in the Meuse catchment? Insights from 1,040 years of synthetic discharge data. 
Authors: Couasnon Anais , Bouaziz Laurène , Imhoff Ruben , Winsemius Hessel , Hegnauer Mark , van der Sleen Niek , Slomp Robert , van Voorst Leon , van den Brink Henk
Published: March 2024

Understanding extreme discharge behavior is of importance for flood design and risk management. For example, estimates of large extreme discharge return periods such as the 100-year return period or higher are often needed as a basis for flood hazard maps or dike design. Yet, frequency analysis based on decade-long discharge records show a large uncertainty for these frequencies, among others due to the statistical uncertainty from the distribution parameters.  This is not the case for the shape parameter, a key parameter that describes the upward or downward curvature of the tail of the distribution and thus an indicator of extreme discharge behavior. This study provides robust estimates of the shape parameter by using the 1,040 years of synthetic daily discharge generated for the Meuse catchment as part of the EMfloodResilience project from the Interreg Euregio Meuse-Rhine program. The spatially-distributed hydrological model wflow_sbm, calibrated and validated for the Meuse catchment, is forced with 16 synthetic climate ensembles of 65 years representative for the current climate from the physically-based KNMI regional climate model RACMO climate model at a daily and hourly time step. The annual maxima (AM) from hydrological years (Oct-Sep) are retrieved from these continuous time series, and a GEV distribution is fit to the AM. We observe a clear spatial pattern of the shape parameter across the Meuse catchment. Using this large dataset of shape parameters, we also review the possible reasons for the different tail behavior obtained with respect to rainfall statistics, catchment characteristics and river systems following the In doing so, we aim to bridge the extreme value statistical modelling with our current understanding of the extreme hydrological signatures present in the catchment.
Climatic and environmental impacts of an Oruanui-like supereruption in the Southern Hemisphere extratropics
Authors: Brodowsky Christina , Barker Simon , Sigl Michael , Krüger Kirstin
Published: March 2024

Explosive volcanic eruptions have disrupted the climate system dramatically in the past. Recent volcanological fieldwork suggests that at least four VEI 8 events took place in the past 100’000 years, depositing large amounts of volcanic volatiles onto polar ice sheets, each one with potentially significant impacts on human life on Earth. Previous studies on this research topic and time period tend to focus either on tropical eruptions or only consider changes in radiative forcing due to orbital parameters, solar variability, or changes in atmospheric CO2. Here, we seek to evaluate the climatic and environmental impacts of the ~25.5 ka Oruanui eruption (Taupō caldera, 38°S, 175°E, New Zealand). We thereby refine our understanding of the volcanic forcing based on volcanological and ice core data to provide a basis for long-term climate simulations. We use existing emission details for an idealized Oruanui-like eruption scenario. We run an ensemble of CESM2/WACCM simulations with 1850 pre-industrial conditions and instantaneously emit 260 Tg SO2, and the corresponding halogen load derived from petrological estimates into the stratosphere. We then analyze the climatic effects in the decades following the eruption compared with available paleo proxies. Our overarching goal is to provide comprehensive insights into the climatic and environmental repercussions of an Oruanui-like eruption, with a specific emphasis on the differences to tropical events of comparable magnitude. By comparing these two distinct types of eruptions, we aim to contribute to a refined understanding of volcanic impacts on Earth's climate and human life.
Canadian lakes are changing in response to anthropogenic disturbances: a Pan-Canadian geochemical study using micro-X-ray fluorescence sediment core-scanning.
Authors: Zilkey David R. , Jenny Jean-Philippe , Baud Alexandre , Francus Pierre , Antoniades Dermot , Gregory-Eaves Irene
Published: March 2024

Understanding how lake ecosystems respond to anthropogenic disturbances including mining, agriculture, deforestation, and more is often best answered with historical time series. Unfortunately, a lack of long-term monitoring data can make this difficult; paleolimnology offers an alternative, allowing for the reconstruction of past conditions using proxies from sediment records. As part of the nationally funded Canadian Lake Pulse Network, we analyzed sediment cores from 116 lakes across Canada using micro-X-ray fluorescence core-scanning (µXRF). µXRF served to generate abundance profiles for several elements (e.g., Ca, Sr, Ti, Pb, Cu, Zn), allowing for the assessment of spatiotemporal geochemical changes in Canadian lakes dating back to ~1850 AD. We calibrated µXRF core-scanning with conventional geochemical methods in a 48-lake subset and found strong correlations for numerous elements between conventional wet chemistry and µXRF-measured concentrations (Zilkey et al., accepted, Environmental Advances). We then assessed the temporal variability in sediment cores using constrained hierarchical cluster analysis and generalized additive models. Our preliminary results indicate that geochemical change demonstrates significant regional structure. On balance, lakes in eastern Canada predominantly demonstrated a temporal enrichment in metallic elements (e.g., Pb and Zn), while lakes in central and western Canada had a temporal enrichment of elements commonly associated with catchment erosion (e.g., Ti, Sr, K). Our results highlight the heterogeneity in responses across a vast landscape with diverse geological characteristics and land uses, and in the relative importance of anthropogenic disturbances shaping lake sediment geochemistry over time. Key next steps include the investigation of lakes that are distinct relative to their regional trends and the local environmental factors that might explain their contrasting response.
Tree water deficit as a drought stress indicator
Authors: Ziegler Yanick , Alongi Franklin , Knüver Timo , Grote Rüdiger , Ruehr Nadine
Published: March 2024

The frequency and severity of droughts is expected to increase as climate change develops, which negatively affects forests and their numerous benefits. However, some species may be adapted better to the new conditions than others. Hence, evaluating the stress level of trees under ranges of water-limited conditions is crucial to judge and predict forest health. While water potential measurements are valuable for indicating stress, they are hardly applicable to monitoring continuous developments or investigating large numbers of individuals simultaneously. An alternative attempt is to utilize high-resolution dendrometer measurements of stem shrinkage, which is caused by the reduction of the tree's internal water storage (tree water deficit; TWD) and is thus an indirect indicator of stress. There is first proof of correlations between TWD and water potential under moderate drought stress. However, we still lack observations that relate stem diameter variations to severe drought stress when embolism formation (air bubbles in the xylem preventing water flow) occurs. Also, recovery responses after re-wetting, and the respective linkages to physiological states and processes are fairly unknown.Here, we present results from a greenhouse experiment on potted tree saplings. Two widespread temperate conifers (Pinus sylvestris, Larix decidua) were exposed either to drought-recovery cycles or to lethal drought until complete dehydration under controlled experimental conditions. We found strong relations between TWD and both midday water potential and gas fluxes across the full range of dehydration, with only minor differences between the two species. Re-wetting after a short drought period had no effect. Conversely, re-wetting after a drought severe enough to cause hydraulic damage significantly affected the correlations due to different recovery times.Our results indicate the great potential of dendrometers to provide continuous and cost-efficient time series that allow valuable insights into the water status and thus drought stress of trees. While all stages of dehydration can be covered, the dependencies of re-wetting responses after severe droughts are still unclear and more species-specific investigations are required. Nevertheless, applying TWD seems to be a promising way forward to improve our understanding of drought-stress-induced forest decline and drought-recovery dynamics. 
The Potential of Remote Sensing for Enhancing a Sustainable Agricultural Intensification under a Changing Climate in West Africa
Authors: Meier Jonas , Thonfeld Frank , Huber Garcia Verena , Aidoo Kenneth , Heiss Niklas , Gessner Ursula
Published: March 2024

The challenges of climate change in West Africa are closely linked to food security in the region. Rising temperatures and increasingly variable precipitation threaten traditional rain-fed agriculture relying on the rainy season. Climate change is affecting the rainy season in West Africa in multiple ways, e.g., by shifting the onset, shortening its duration and increasingly interrupting the growing period by dry spells. An increase of extreme weather events such as heavy precipitation or storms add another risk to agriculture. The risk of crop failures hits an already vulnerable system. Since a large portion of food is imported the West African countries are vulnerable to external economic shocks. Furthermore, West Africa has one of the highest population growth rates in the world, its population will increase to 1.2 billion people by 2050. To guarantee sufficient food supply and to achieve the Sustainable Development Goals (SDG), a sustainable intensification of agriculture is needed (i.e., increasing yields without additional land consumption and without adverse effects on climate change) and mitigation and adaption strategies against the negative effects of climate change are required. Remote sensing has proven to be a suitable instrument to measure and evaluate both, mitigation and adaptation actions in a reliable and cost-effective way. Depending on the method of cultivation, agriculture causes different amounts of greenhouse gas (GHG) emissions. Remote sensing can provide information about biophysical development as input and reference data for land surface models to assess the produced GHG under different cultivation practices. Since the negative impact of climate change on agriculture is already measurable and visible, adaptation measures are highly important. They differ in terms of their complexity, their technical feasibility and their costs. Adaptation measures can be for example a change in land management, the choice of crop variety or technical innovation like weather forecast or irrigation systems. In various interdisciplinary research projects (CONCERT, COINS, AgRAIN), we selected adaptation measures of varying complexity and monitor and evaluate them using remote sensing-based analysis, mainly on Sentinel-1, Sentinel-2 and Planet data. The analyses range from land cover and land use mapping to crop classification, crop suitability modeling, field boundary delineation, identification of management events, and site-specific productivity measurements. We employ a range of methodologies, including random forest regression, convolutional neural networks (CNN), fuzzy logic approaches, and time series analysis. The results serve as a basis for local stakeholders and decision-makers, enabling the implementation of proven adaption measures to enhance resilience against climate change and promote sustainable agricultural intensification.
Near real-time dike tracking using GNSS networks
Authors: Drouin Vincent , Ófeigsson Benedikt Gunnar , Geirsson Halldór , Hreinsdóttir Sigrún
Published: March 2024

Volcanic activity can take several forms ; one of them is magma moving horizontally along the crust and forming a dike, i.e. subvertical magma-filled structures. Dikes pose substantial risk to population and infrastructure at the surface. They can transport the magma far away from the main volcanic edifice and result in eruptions in unexpected locations. The larger dikes will also induce surface faulting and even the formation of grabens. However, this means that we can measure this deformation at the surface to infer characteristics of the dike. This is traditionally done after the dike as finished propagating by using a combination of GNSS and InSAR measurements.In Iceland, there have been 6 dikes intrusion on the Reykjanes Peninsula since 2021. The first four dikes occurred in uninhabited areas, originating from the Fagradalsfjall volcanic system. The last two dikes, in November and December 2023, originated from the Svartsengi volcano and are along an axis that goes partly under the town of Grindavik. All these dike intrusions have been recorded by the local continuous GNSS network. We tested the applicability of near real-time tracking of the dike propagation for all of these events. This is done by searching for the best-fitting Okada dislocation that explains the GNSS displacements, with some assumption about the origin and direction of the magma. The earlier events cannot be easily tracked because the GNSS network was too sparse. However, the network has been densified with time and the later events are easier to track. For the largest one, in Nov. 2023, we are able to observe the initial vertical propagation of the magma, its horizontal propagation to the SW and the NE, and its focus to SW at the end. We can measure the magma inflow rate within the dike hour by hour through the event. It peaks at over 9000 m3/s two hours after the beginning of the event. These results show that, given a network of a few continuous GNSS stations, it is possible to have a near real-time monitoring of a dike. Having this information would be extremely valuable to the decision takers and the civil protection. Therefore, it is planned to have this tool implemented at the Icelandic Met Office in the coming weeks to be able track future events. It will be set up for specific volcanoes and run automatically based on real-time GNSS solutions.
Kelvin-Helmholtz Instability associated with reconnection and Ultra Low Frequency Waves at the ground
Authors: Kronberg Elena , Gorman Jamie , Nykyri Katariina , Smirnov Artem , Gjerloev Jesper , Grigorenko Elena , Ma Xuanye , Trattner Karlheinz , Friel Matt
Published: March 2024

The Kelvin-Helmholtz instability (KHI) and its effects related to the transfer of energy and mass from the solar wind into the magnetic environment of the Earth remain an important focus of magnetospheric physics. One such effect is the generation of Pc4-Pc5 ultra low frequency (ULF) waves at the ground. On July 3, 2007 at ∼0500 magnetic local time the Cluster space mission encountered Pc4 frequency Kelvin-Helmholtz waves (KHWs). Typically, KHI is thought to occur during the northward polarity of the interplanetary magnetic field and at low latitudes, however, the event occurred during a period of the southward polarity  according to the OMNI data and THEMIS observations at the subsolar point and at the high latitude magnetopause. Several of the KHI vortices were associated with magnetic field reconnection. Global magnetohydrodynamic simulation of the event confirmed the generation of KHWs at the magnetopause. The observed KHWs associated with reconnection coincided with recorded ULF waves at the ground whose properties suggest that they were driven by those waves. 
Determination of land deformation indices based on UAV-derived very-high-resolution images
Authors: Puniach Edyta , Gruszczyński Wojciech , Ćwiąkała Paweł , Matwij Wojciech , Strząbała Katarzyna
Published: March 2024

In recent years, uncrewed aerial vehicle (UAV)-based photogrammetry has developed rapidly and is increasingly used for monitoring and determining displacements. The presentation discusses the author's solutions for the automatic determination of horizontal and vertical displacements of land surface in urban areas, dedicated to very-high-resolution UAV-photogrammetry products. The processing path is based on orthomosaics and digital elevation models and implements normalized cross-correlation for matching multi-temporal images. Its integral part is the process of semi-automatic removal of outliers. As a result of data processing, displacement vectors are determined in a regular grid, which constitute the basis for determining other indices of terrain deformation, such as ground tilts and horizontal deformations. Based on a comparison with reference data, it was estimated that the root mean square error of determining the displacements is 1-2 pixels for the horizontal components and 2-3 pixels for the vertical component. Therefore, the components of ground tilt and horizontal deformation can be determined based on UAV photogrammetry with a root mean square error of 0.3 pixels.