bluuebunny/crossref_metadata_2025 huggingface dataset:
UV-Vis remote sensing of atmospheric pollutants from a wind turbine platform in the North Sea: the SEMPAS project
Authors: Mettepenningen Gytha , Fayt Caroline , Tack Frederik , Van Doorne Cato , Bogaert Pieter , Jacobs Lars , Berkenbosch Sophie , Aubry Aurélien , Desmet Filip , Robert Charles , De Mazière Martine , Van Roozendael Michel
Published: March 2024

Ship emissions comprise up to 15% of global transport pollution. To regulate this pollution, Nitrogen Emission Control Area (NECA) and Sulphur Emission Control Area (SECA) zones have been introduced in the North Sea, which define a threshold for shipping emissions of respectively NOx and SOx. The current method of control of these regulations in the Belgian North Sea uses an aircraft equipped with sniffers to fly through the plume. As this is an intensive method, only a limited number of ships can be evaluated. The Ship Emission Monitoring by Passive Absorption Spectroscopy (SEMPAS) project develops a UV-Visible Differential Optical Absorption Spectroscopy (DOAS) instrument to permanently monitor ships from a Belgian offshore windfarm and to complement the aircraft-based measurements.The instrument is an imaging DOAS system, with a field of view of 0.5x3 degrees corresponding to 3x15 pixels. The imaging functionality is obtained by means of an optical fiber bundle where fibers are organised in a matrix structure. Every fiber provides a separate measurement and corresponds to a pixel in the image that is created. The light is then fed into a grating spectrometer that measures slant columns of both SO2 and NO2 in the UV at a spectral resolution of 0.4 nm, based on the DOAS fitting principle. Next to the DOAS system, a second channel uses a Bruker EM27 FTIR instrument to measure CO2 and SO2 in emission mode. The aim is to quantify emission factors based on measured ratios of SO2 to CO2, NO2 to CO2 and SO2 to NO2.The instrument is accompanied by a simple visible camera. An image recognition AI-based algorithm on the live feed of this camera ensures active tracking of passing ships, to increase sensitivity. From the measured image, the plume concentrations can be derived, as well as the background concentrations measured next to the plume.In addition, the instrument can be set to MAX-DOAS mode, by binning the signals from the fibers to a point measurement with high sensitivity. This mode will be used when no ships are in the area. As the network of MAX-DOAS instruments in a marine environment is limited, this instrument can help in studying the marine atmosphere in more detail.The instrument’s development is currently being finalised and it will be installed and start operations in spring 2024. The proposed poster presents an instrumental description, including calibration and initial results from test measurements.
Quantifying how surface complexity influences properties of the solar corona and solar wind
Authors: Evans Caroline , Downs Cooper , Schmit Don , Crowley James
Published: March 2024

Astrophysical simulations require trade-offs between compute time and physical accuracy. This frequently includes targeting certain physical scales at the expense of others. Simulations investigating solar coronal heating and solar wind acceleration usually select either high resolution for a small domain or low resolution for a global domain. Bridging this gap requires linking structures present on the solar surface to both the middle corona (approximately 1.5 - 6 solar radii) and the solar wind. In this work we analyze three simulations of the global solar corona that vary the resolution of the surface boundary condition while keeping the same parameterization of a thermodynamic, wave-turbulence-driven magnetohydrodynamic model. We quantify structural differences endemic to each simulation using spherical harmonic decomposition and associated statistics. We use this information to examine how surface resolution influences heating and magnetic complexity in the corona and solar wind and the subsequent impacts on density, temperature, and flow structure. In principle, this can enable more efficient subgrid modeling in future low resolution simulations.
Sea-ice variability along the Antarctic continental margin since the Last Penultimate Glacial 
Authors: Khoo Wee Wei , Müller Juliane , Esper Oliver , Xiao Wenshen , Stepanek Christian , Gierz Paul , Lohmann Gerrit , Geibert Walter , Mollenhauer Gesine
Published: March 2024

Antarctic sea ice plays a crucial role in buttressing ice shelves, enhancing their stability, and protecting them from potential catastrophic collapse – a significance underscored by recent calving events along the Antarctic Peninsula. Presence or absence of sea ice in the Southern Ocean, and details of its distribution patterns, therefore have relevance far beyond the realm of high latitudes of the Southern Hemisphere. Investigating past sea-ice conditions in proximity to ice shelves, and changes in sea ice distribution over time, particularly across glacial-interglacial cycles, is therefore essential. We may gain insights into the sea-ice’s response to a changing climate, and address gaps in our understanding of ocean-sea ice-ice shelf interactions and dynamics. In our study, we adopt a multiproxy approach to explore glacial-interglacial environmental variability since the Last Penultimate Glacial close to the Antarctic continental margin in the Weddell Sea. We analyze the novel sea-ice biomarker IPSO25 (a di-unsaturated highly branched isoprenoid (HBI)), open-water biomarkers z-/e-trienes (tri-unsaturated HBI), diatom assemblages and primary productivity proxies in a marine sediment core (PS118_63-1) retrieved from Powell Basin in the northwestern Weddell Sea. These biomarkers are reliable proxies for reconstructing near-coastal sea-ice conditions in the Southern Ocean, where the use of sea ice-related diatoms may be subject to bias due to silica dissolution. We present the first continuous record of ice-proximal Antarctic sea ice since the Last Penultimate Glacial. Our results unveil a highly dynamic environment, characterized by significant shifts from a climate with perennial (sea) ice cover to more seasonal sea-ice cover and open ocean conditions, over the last approximately 145 kyrs. Furthermore, to gain a better understanding of the spatial heterogeneity of sea-ice distribution and sea ice-ice shelf system dynamics in the Southern Ocean, we use numerical climate modeling to expand our view across the Southern Ocean, while comparing data from marine cores PS67/219-1 (southern Scotia Sea) and PS128_14 (eastern Weddell Sea) helps track latitudinal sea-ice changes and identify common forces driving sea ice-ice shelf system dynamics along continental margin, respectively.
Development of a Land-Use Regression of Hourly Surface NO2 in preparation for GeoXO Atmospheric Composition Data
Authors: Nawaz Omar , Anenberg Susan , Goldberg Daniel , Kerr Gaige , Kondragunta Shobha
Published: March 2024

The Geostationary Extended Observations (GeoXO) satellite system is the intended successor to the GOES-R Series from NOAA, and it is planned to begin operating in the early 2030s. This next generation system will be outfitted with an Atmospheric Composition Instrument (ACX) that will provide hourly observations of tropospheric trace gases and aerosols including pollutants associated with poor health; the highest priority factors for air quality monitoring in this new system include some of the pollutants most hazardous to human health such as ozone (O3), particulate matter (PM), and nitrogen dioxide (NO2). GeoXO will be a geostationary satellite with multiple overpasses of the United States per day in contrast to the TROPOspheric Monitoring Instrument (TROPOMI) on board the sun-synchronous polar-orbiting Sentinel-5P satellite. This satellite – launched by the European Space Agency – overpasses each place on Earth 1-2 times per day around 1:30 PM.In this project, we evaluate the influence that GeoXO remote sensing capabilities could have for assessing air pollution-related health impacts in the United States. We do this by comparing the health effects associated with predicted NO2 exposure at TROPOMI overpass times to predicted NO2 exposure during daylight hours. To conduct this comparison, we develop a land-use regression (LUR) model that predicts hourly surface-level NO2 data per month in the United States using monthly oversampled TROPOMI NO2 columns, static land-use data including roads, population density, built environment and elevation differential, and hourly meteorological reanalysis data of temperature, boundary layer height, precipitation, and total liquid water column amount. We fuse these variables using different regression techniques including both a lasso and multi-layer perceptron regression to predict monthly surface-level NO2 during daylight hours.We compare the predicted hourly surface-level NO2 to NO2 derived just at TROPOMI overpass time – approximately 1:30 PM – to quantify how geostationary observations could better reveal how populations are exposed to pollutants like NO2 than exposures that are reliant on data from a single overpass time. We additionally investigate the health disparity introduced from this assumption by estimating the new pediatric asthma cases and premature mortality associated with hourly daylight NO2 exposure versus NO2 exposure from just a single overpass time. Additionally, we discuss how data from the new TEMPO instrument – that was launched by NASA in 2023 – will influence and improve this TROPOMI-derived LUR.
Chemical analyses of surficial covers associated with alluvial fans in the western state of Bahia, Brazil
Authors: Brito Artur Magalhães , Santos Tania Augusto da Silva , Machado Icaro Gabriel Lima , Bedendo João Pedro , Silva Emanuelly Cristina Leal , Souza José João Lelis Leal , Souza André de Oliveira
Published: March 2024

This work aimed to present partial results of chemical analyses conducted on surficial cover samples collected in alluvial fans located in the lower course of the Fêmeas River, in the Western region of Bahia, Brazil. This region is characterized by a sub-humid climate with two well-defined seasons: a rainy season (November to April) and a dry season (May to October). The hypothesis of this study considers that the deposits exhibit erosive-depositional discontinuities with different values of potassium (K) and sodium (Na), which could indicate the influence of complex morphodynamic processes throughout the Holocene. Therefore, the amounts of K and Na in different layers identified in the field and confirmed through laboratory textural analyses were measured. The analysis of these two cations allows for the possibility to infer a relative geochronology considering different exposures of the layers to weathering. The samples were collected at three sites on the left bank of the Rio das Fêmeas (LQME4; LQME5; LQME6). In LQME4, the results showed high potassium and sodium content at 20-30 cm (K=358 mg/dm³, Na=36.73 mg/dm³), 30-50 cm (K=347 mg/dm³, Na=36.73 mg/dm³), and 50-70 cm (K=307 mg/dm³, Na=53.38), except for the more superficial layer at 0-20 cm (K=8 mg/dm³, Na=16.08). This result suggests that the deeper layers underwent less weathering, while the low values of K and Na in the surface layer are possibly due to leaching from the runoff. With two layers, LQME5 presented high K and low Na values in the deeper layer of 20-60 cm (K=228 mg/dm³, Na=4.95 mg/dm³) contrasting with the more superficial layer at 0-20 cm (K=111 mg/dm³, Na=13.88 mg/dm³), where the K value decreases considerably while Na increases. The values in the most superficial layer are correlated with the modern sub-humid period that has resulted in lower runoff activity and, therefore, influencing mineral dissolution as indicated by the low Na value. The deeper layer suggests more humid periods characterized by lower K and higher Na values, indicating a more humid period resulting in more efficient mineral dissolution. In LQME6, six layers were analysed: 0-10 cm (K=195 mg/dm³, Na=11.07), 10-50 cm (K=147 mg/dm³, Na=11.49), 50-60 cm (K=69 mg/dm³, Na=13.72 mg/dm³), 60-75 cm (K=42 mg/dm³, Na=13.19), 75-85 cm (K=85 mg/dm³, Na=12.90 mg/dm³), 85-140 cm (K=87 mg/dm³, Na=16.30). The first two layers presented the highest K value in contrast to the other layers showing low values. LQME6 exhibits several discontinuities in K values, indicating that the upper layers underwent less weathering than the deepest ones. This research is being funded by the Bahia State Research Support Foundation (Grant 4341/2022).
Fate and Transport of Rare Earth Elements (REEs) in Arctic Watersheds in Alaska
Authors: Baxter Brad , Barker Amanda , Douglas Thomas , Barbato Robyn , Smith Joseph
Published: March 2024

The distribution and concentrations of rare earth elements (REEs) in soils can be important controls on REE sourcing for transport to surface waters, where their ecological impacts are not wholly understood. Previous studies have recognized the importance of parent material and soil texture associations on soil REE concentrations and transport, but few studies have addressed the fate of REE distributions in permafrost, were unique thermal and hydrological conditions influence soil weathering and transport processes. Seasonal freeze-thaw cycles coupled to the pedogenic forces specific to Arctic environments create uncertainty for the controls on REE distributions and transport in permafrost environments. Further uncertainty arises with the potential for enhanced permafrost degradation, which is expected to increase mineral weathering and amplify REE transport to Arctic surface waters where they can bioaccumulate in Arctic biota and discharge to the marine environment. In order to evaluate potential REE transport and distribution mechanisms in permafrost, this study compares soil REE concentrations to active layer thickness, stream and soil pore water REE concentrations, surficial geology, and catchment chemistry. Soils from three sites in the Arctic Foothills of Alaska were analyzed for solid REE concentration with inductively coupled plasma-mass spectrometry (ICP-MS) to compare vertical distributions with soil properties. Active layer thaw was continuously monitored with buried temperature sensors to compare vertical REE distribution with weathering and reduction-oxidation (redox) zones governed by permafrost thermal processes. These data are discussed in relevance to potential mechanisms for stream loading and translocation in permafrost environments. Finally, relationships between REE distribution both spatially at the landscape scale and vertically at the soil profile are evaluated alongside parent material source and history to offer insight to long-term weathering and accumulation of REEs in permafrost soils.
NOAA’s Environmental Modeling Center Update: Transitioning to Unified Forecast System Applications for Operations
Authors: Stajner Ivanka , Gross Brian , Tallapragada Vijay , Levit Jason , Montuoro Raffaele , Mehra Avichal , Kleist Daryl , Yang Fanglin
Published: March 2024

National Oceanic and Atmospheric Administration’s (NOAA’s) Environmental Modeling Center (EMC) is a lead developer of operational Numerical Weather Prediction (NWP) systems at the National Weather Service (NWS), which are used for the protection of life and property and the enhancement of the economy. EMC transitions to operations and maintains more than 20 numerical prediction systems that are used by NWS, NOAA, other United States (U.S.) federal agencies, and various other stakeholders. These systems are developed through a close collaboration with academic, federal and commercial sector partners. EMC maintains, enhances and transitions-to-operations numerical forecast systems for weather, ocean, climate, land surface and hydrology, hurricanes, and air quality for the U.S. and global domains. NOAA’s operational predictions are transitioning to the Unified Forecast System (UFS) framework in order to simplify the operational prediction suite of modeling systems. The UFS is being designed as a community-based, comprehensive atmosphere-ocean-sea-ice-wave-aerosol-land coupled Earth modeling system with coupled data assimilation and ensemble capabilities, organized around applications spanning from local to global domains and predictive time scales ranging from sub-hourly analyses to seasonal predictions.  Disparate legacy operational applications that have been developed and maintained by EMC in support of various stakeholder requirements are being transitioned to the UFS framework. The transition started several years ago and is planned to continue over the next few years. Fewer resulting applications will consolidate NCEP’s Production Suite that shares a set of common scientific components and technical infrastructure.  This streamlined suite is expected to accelerate the transition of research into operations and simplify maintenance of operational systems. This talk describes major development and operational implementation projects at EMC over the last couple of years including for example a new UFS-based hurricane application, recent advances in the use of satellite data and a new verification system. We will present EMC plans for the next few years, within the overall NOAA strategy, and how planned efforts link with other modeling efforts within NOAA, in the broader U.S. and international community.
Modulation of the Maritime Continent diurnal cycle of precipitation by the Madden-Julian Oscillation
Authors: Mustafa Jack , Matthews Adrian , Hall Rob , Heywood Karen
Published: March 2024

The manifestation of the diurnal cycle (DC) over the Maritime Continent is influenced by the large-scale environment, including the state of the Madden–Julian Oscillation (MJO). It is widely recognised in existing literature that the amplitude of the DC of precipitation is greatest at around the same time as, or perhaps slightly ahead of, greatest mean precipitation. However, there is weaker consensus on the impact of the MJO (if any) on the phase of the DC.Here, the boreal winter (DJF) composite DC of precipitation is calculated for each of the 8 MJO phases (P1–8) defined by Wheeler and Hendon (2004), using 20 years of IMERG — the state-of-the-art gridded satellite-derived precipitation data product with 30-minute resolution. With such high temporal resolution, subtle changes in the phase of the DC can be, and are, identified. The western sides of Sumatra, Borneo and Java typically experience an earlier than usual diurnal precipitation maximum around P5–6, while the eastern sides of these islands experience an earlier than usual diurnal precipitation maximum around P2–3. An analogous west–east divide in DC phase regime is also observed over certain water bodies, such as the Makassar Strait. The magnitude of this phase fluctuation is greatest across eastern Sumatra, parts of eastern Borneo, the western Java Sea and the eastern Makassar Strait, where a range of DC phase of over four hours is frequently observed. The opposing nature of the western and eastern local regimes is a consequence of changes to the direction of phase propagation; westward phase propagation is favoured over the Makassar Strait and the eastern sides of Sumatra and Borneo during P2–3, while eastward phase propagation dominates across entire islands and water bodies during P5–6.If, by extension, the DC of cloud cover shows strong regional fluctuations in timing, these results will have significant implications for the influence of the MJO on regional radiation budgets.
A street-level assessment of greenhouse gas emissions associated with traffic congestion in the city of Nairobi, Kenya 
Authors: Sitati Cynthia
Published: March 2024

Traffic congestion significantly contributes to climate change due to the emissions of greenhouse gases such as carbon dioxide (CO2 ), nitrous oxide (N2 O) and ozone (O3 ). Rapid urbanization and poor planning coupled with increased motorization and fragmented public transport systems in cities such as Nairobi have led to increased vehicle emissions especially during heavy traffic along the various roads and within the central business district. To reduce greenhouse gas emissions in the urban transport sector, institutional coordination and relevant policy tools must be considered. This study aimed at estimating CO2 emissions from different vehicle categories during traffic congestion, using Uhuru Highway as a case study. The relationship between traffic congestion and CO2 emissions was analyzed using qualitative and quantitative methods, through a bottom-up approach. 120 questionnaires were administered to vehicle owners, passengers and pedestrians to get individual vehicle characteristics and opinions on the best actions for reduction of CO2 emissions along Uhuru Highway in Nairobi. The average annual daily traffic (AADT) for different vehicles from 2014 to 2019 was used to estimate the CO2 emissions. Results showed that private cars predominate over other vehicle types, contributing 73% of the total CO2 emissions in the Nairobi CBD. Private cars are the highest contributors of CO2 emissions with a total of 25.3 million grams of carbon dioxide equivalent (gCO2 e), between 2014 and 2019. In comparison, public service vehicles, commonly referred to as Matatus, emitted 6.89 million gCO2 e, light commercial vehicles 1.82 million gCO2 e, heavy goods vehicles 251,683 gCO2 e and motorcycles 181,054 gCO2 e. To minimize CO2 emissions, the study recommends the enforcement of strong mobility policies to control the high motorization rate. One of these policies is the prioritization of the development of a mass public transport system to achieve the potential health, economic and environmental gains within the CBD.
Extending measurements of ice nucleation activity to large-size mineral dust particles
Authors: Vergara Palacio Sebastian , Vogel Franziska , Fösig Romy , González-Romero Adolfo , Kandler Konrad , Querol Xavier , Umo Nsikanabasi Silas , Hoose Corinna , Möhler Ottmar , Pérez García-Pando Carlos , Klose Martina
Published: March 2024

Mineral dust is considered one of the most important seeds for heterogeneous ice nucleation in clouds. In the past decades, several studies have worked on establishing a relationship between mineral dust, number concentration, nucleation temperature, supersaturation, and the number of ice crystals. The explored dust particle-size range was usually limited to a few micrometers for two main reasons: (1) larger and heavier particles are difficult to keep suspended in an experimental setting; and (2) the fraction of coarser aerosol was considered negligible. However, recent studies have shown that dust particles as large as 100 μm or even more can be transported over long distances, leaving a knowledge gap concerning their role as ice-nucleating particles.In this work, we aim to contribute to closing this gap by investigating the ice nucleation activity for large-size mineral dust particles, extending the studied size range to particles of up to several tens of microns. For this purpose, we used natural dust samples with different mineralogical composition, collected consistently during field campaigns in Morocco and in Iceland, and segregated into five different size classes. In the framework of the MICOS (Dust-induced ice nucleation: effects of Mineralogical COmposition and Size) campaign, we conducted experiments with the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) chamber and with the Ice Nucleation Spectrometer of the Karlsruhe Institute of Technology (INSEKT), in which the size-segregated samples were tested at different temperatures in the range between -16 and -27 °C. The ice nucleation efficiency was quantified in terms of the ice nucleation active surface site (INAS) density approach for the immersion freezing mode. Preliminary results from the AIDA and INSEKT experiments are presented, in which we extended the size range at which cloud chamber experiments are typically conducted.
Traceable onsite measurement of ammonia and greenhouse gas emissions from livestock production
Authors: Rajamäki Timo
Published: March 2024

Agricultural processes are the main source of ammonia emissions, and they are a significant source of methane emissions. For quantification of emissions from livestock animal housings onsite measurements for these gases are needed in parallel with certified reference standards that enable SI-traceability of the measurement results. We have developed dynamic reference gas generation method that is suitable for onsite use when calibrating the analysers and sensors applied either inside or outside the animal housings, for determination of ammonia concentrations in large enough concentration range spanning several orders of magnitude. In combination with static reference gas mixtures for greenhouse gases that are measured in parallel with ammonia, this method is used to calibrate and validate measurements of these most important molecular emissions from agriculture. We present the results of application of this methodology onsite for calibration of different types of sensors and analysers that provide the primary concentration data used in calculations sourcing data for corresponding emissions inventory reports.
Divergent patterns of Carbon, Nitrogen and Sulfur storage in grassland soils
Authors: Bauke Sara L. , Iser Jospehine , Schimmel Heike , Burger Dymphie , Amelung Wulf
Published: March 2024

Sulfur (S) in soils mainly occurs in organic forms, and its cycling should be primarily controlled by the same factors as those for carbon (C) and nitrogen (N), two other main constituents of soil organic matter. Here, we aim to test this assumption based on a global meta-analysis of soil organic C, N and S contents in grassland soils. We reviewed existing literature with a focus on grassland soils as one of the major global ecosystems, including both native grasslands and managed grasslands with additional fertilization. Element concentrations and supplementary parameters (mean annual temperature and precipitation, texture, pH, soil group, management) were retrieved from the studies, while C:S and N:S element ratios were either directly obtained from the studies or calculated. Additionally, we analyze isotope ratios of the respective elements (δ13C, δ15N and δ34S) in soil samples collected from native and managed grassland sites along climatic transects across Europe and North America.In literature data concentrations of OC and N, but not S, were significantly higher in pastures compared to native grassland. As a consequence, C:S and N:S ratios were significantly lower in cultivated grassland than in native sites. Further, climatic conditions and soil group significantly affected C:S and N:S ratios, with significantly lower ratios in arid climate and in soil groups typically occurring there (e.g. Kastanozems) compared to more humid conditions and respective soil groups (e.g. Luvisols). However, the variation of C:S and N:S ratios was considerably higher than for C:N ratios. This was also evident in the isotope data obtained from the soil samples along the continental transects. Here, compared to δ13C and δ15N, δ34S values showed strong variation that was only partially explained by climate and land use, and was additionally affected by the specific parent material at each site. We therefore suggest that the availability and turnover of S in organic matter of grassland soils is not strictly analogous to C and N cycling. 
Non-stationary extended generalized Pareto distribution  for joint assessment of trends in the bulk and extreme precipitation
Authors: Haruna Abubakar , Blanchet Juliette , Favre Anne-Catherine
Published: March 2024

Accurately quantifying the impact of climate change on past and future precipitation, especially in terms of extreme precipitation events, remains a significant challenge. Furthermore, the scarcity and high variability of extreme events make this task particularly daunting. Current approaches based on extreme value theory (EVT),  relying on annual maxima series or exceedances above large thresholds, are limited in their efficiency as they only consider a small fraction of the available data. Additionally, these methods do not model the bulk of the distribution, which has applications in areas such as water resources management, urban water supplies, and hydropower. To address these limitations, Naveau et al. (2016) proposed the Extended Generalized Pareto distribution (EGPD), which models the entire non-zero precipitation range while remaining consistent with EVT in both lower and upper tails. While the EGPD has seen wide applications in modeling precipitation in various regions, its application has predominantly been within a stationary framework (e.g. Haruna et al.,2022, 2023). This study explores the potential of a non-stationary version of the EGPD to jointly model trends in both the bulk of the precipitation distribution and in the extremes. The non-stationarity is accommodated by allowing the EGPD parameters to be parametric functions of relevant explanatory variables. The proposed model is then applied to precipitation datasets in Switzerland, a region where long term warming of twice the global average has already been experienced.Haruna, A., Blanchet, J., and Favre, A.-C. (2023). Modeling Intensity-Duration-Frequency Curves for the Whole Range of Non-Zero Precipitation: A Comparison of Models. Water Resources Research, 59(6):e2022WR033362.
Naveau, P., Huser, R., Ribereau, P., and Hannart, A. (2016). Modeling jointly low, moderate, and heavy rainfall intensities without a threshold selection. Water Resources Research, 52(4):2753–2769
Haruna, A., Blanchet, J., and Favre, A.-C. (2022). Performance-based comparison of regionalization methods to improve the at-site estimates of daily precipitation. Hydrology and Earth System Sciences, 26(10):2797–2811
New geological constraints on Holocene retreat-readvance of the West Antarctic Ice Sheet in the Weddell Sea Embayment
Authors: Small David , Smedley Rachel , Dunai Tibor , Lees Tom , Trabucatti Stephan , Boeckmann Grant
Published: March 2024

Predicting future change to the Antarctic Ice Sheets requires high quality data to constrain numerical ice sheet models. A major uncertainty stems from a lack of knowledge regarding the late Holocene trajectory of the West Antarctic Ice Sheet (WAIS). There are two hypotheses regarding the late Holocene behaviour of the WAIS. A) Steady retreat throughout the Holocene with stabilisation at or near the present-day position (ice relaxation hypothesis) or, B) retreat to a smaller-than-present configuration with subsequent readvance to the present-day position (the retreat-readvance hypothesis). The two hypotheses represent profoundly different ice sheet trajectories. These hypotheses have been discussed with particular reference to the Amundsen, Ross and Weddell Sea sectors of the WAIS.Initial studies proposing the retreat-readvance model suggested that GIA related uplift caused re-grounding of ice rises in the Weddell Sea, increasing ice shelf buttressing and leading to grounding line re-advance. In the southern Weddell Sea major ice streams are currently at threshold positions on reverse bed slopes where they are vulnerable to Marine Ice Sheet/Cliff Instabilities. As this region drains ~22% of Antarctica the lack of geological constraint on the current ice sheet trajectory contributes significant uncertainty to future predictions. Any groundling line retreat beyond present day limits would be accompanied by up-stream ice sheet thinning thus retreat to a smaller-than-present configuration would be accompanied by thinning of the ice sheet surface below the present-day level. Consequently, determining whether sub-glacial rock samples from the Weddell Sea sector have been exposed in the recent past can robustly test for a smaller-than-present ice sheet configuration.We present an update on two field seasons where, using a modified Winkie Drill, we recovered sub-glacial rock samples from the Ellsworth Mountains and Pensacola Mountains. These mountain ranges bracket the proposed zone of retreat and can thus provide limiting data points on the extent and duration of any retreat. The subglacial cores are to be analysed using in situ 14C and luminescence to test for any past exposure to cosmic rays and sunlight respectively. We will present a summary of the field season outcomes and preliminary analytical data along with initial interpretations.
The Cross-track Infrared Sounder Level 1B Product: NASA’s Accurate and Stable Infrared Hyperspectral Radiance Record
Authors: Tobin David , Taylor Joe , Strow Larrabee , Revercomb Hank , Martin Graeme , DeSouza-Machado Sergio , Braun Jess , DeSlover Daniel , Garcia Ray , Loveless Michelle , Knuteson Robert , Motteler Howard , Quinn Greg , Roberts William
Published: March 2024

The Cross-track Infrared Sounder (CrIS) is an infrared Fourier Transform Spectrometer onboard the Suomi-NPP (SNPP), JPSS-1, and JPSS-2 satellites. The CrIS instrument was designed to provide an optimum combination of optical performance, high radiometric accuracy, and compact packaging. While CrIS was developed primarily as a temperature and water vapor profiling instrument for weather forecasting, its high accuracy and extensive information about trace gases, clouds, dust, and surface properties make it a powerful tool for climate applications.The goal of the NASA CrIS Level 1B project is to support NASA climate research by providing a climate quality Level 1B (geolocation and calibration) algorithm and create long-term measurement records for the CrIS instruments currently on-orbit on the SNPP, JPSS-1, and JPSS-2 satellites, and for those to be launched on JPSS-3 and JPSS-4. The long-term objectives of the project include:Create well-documented and transparent software that produces climate quality CrIS Level 1B data to continue or improve on EOS-like data records, and to provide this software and associated documentation to the NASA Sounder Science Investigator-led Processing System (SIPS).
Provide long-term monitoring and validation of the CrIS Level 1B data record from SNPP and JPSS-1 through JPSS-4, and long-term maintenance and refinement of the Level 1B software to enable full mission reprocessing as often as needed.
Provide a homogeneous radiance product across all CrIS sensors through the end of the CrIS series lifetime, with rigorous radiance uncertainty estimates.
Develop and support of the CrIS/VIIRS IMG software and datasets, which provide a subset of Visible Infrared Imaging Radiometer Suite (VIIRS) products that are co-located to the CrIS footprints.
Develop and support of the Climate Hyperspectral Infrared Product (CHIRP) for the AIRS and CrIS sounders. The CHIRP product converts the parent instrument's radiances to a common Spectral Response Function (SRF) and removes inter-satellite biases, providing a consistent inter-satellite radiance record.
The NASA CrIS products are available via the NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC) at https://www.earthdata.nasa.gov/sensors/cris. This presentation will include (1) an overview of the NASA Level 1B calibration algorithm and product, (2) example post-launch calibration/validation results demonstrating the accuracy and stability of the CrIS Level 1B data, and (3) example science results.
Mesoscale Convective Systems in DYAMOND Models: A Feature Tracking Intercomparison.
Authors: Feng Zhe , Leung Ruby , Prein Andreas , Fiolleau Thomas , Jones William , Moon Zachary , Maybee Ben , Song Fengfei , Song Jinyan , Núñez Ocasio Kelly , Klein Cornelia , Varble Adam , Roca Remy , Li Puxi
Published: March 2024

The DYAMOND project (Stevens et al. 2019) provides an intercomparison framework for state-of-the-art global convection-permitting models with km-scale horizontal grid spacing that can directly simulate convective storms. We recently assessed the fidelity of the convective storms simulated by DYAMOND models using a novel feature tracking technique (Feng et al. 2023) and found a surprisingly large inter-model spread in the simulated frequency of ordinary deep convection and mesoscale convective systems (MCSs), as well as their associated precipitation. Recent works also showed that different feature tracking algorithms have significant impacts on estimating MCS characteristics including frequency, size, lifetime and precipitation (Prein et al. 2023). To further investigate how feature tracking methods affect the evaluation of global MCS simulations and our understanding of convective organization in observations and DYAMOND simulations, we are organizing a new international initiative called MCSMIP (MCS tracking Method Intercomparison Project). Preliminary results from several different feature trackers show that DYAMOND models generally underestimate observed MCS precipitation amount and their contribution to total precipitation in the tropics (Fig. 1), and the simulated MCS precipitation is too intense. However, some models have notable differences in MCS frequency and characteristics among the trackers. Potential paths towards more process-oriented model diagnostics to better understand the differences in simulated MCS and precipitation characteristics will be discussed.Figure 1. (a) Observed MCS contribution to total precipitation during DYAMOND Phase II, (b) model relative mean difference (%) from observations in the tropics. Each group of bars in (b) is from a feature tracker: PyFLEXTRKR, MOAAP, TOOCAN, tobac, TAMS, and simpleTrack, and each bar denotes a DYAMOND model.ReferencesFeng, Z. et al. (2023). Mesoscale Convective Systems in DYAMOND Global Convection-Permitting Simulations. Geophys. Res. Lett., doi: 10.1029/2022GL102603.Prein, A. et al. (2023). Km-Scale Simulations of Mesoscale Convective Systems (MCSs) Over South America – A Feature Tracker Intercomparison. DOI: 10.22541/essoar.169841723.36785590/v1.
Modeling flood fatalities in the Italian context: an empirical approach
Authors: Yazdani Mina , N. Gencarelli Christian , Salvati Paola , Molinari Daniela
Published: March 2024

Floods are among the most frequent and damaging natural hazards, affecting millions of people worldwide, and the risk of catastrophic losses due to flooding is expected to increase as a result of climate change. The possibility of predicting and estimating the expected fatalities in flood-prone regions is among the top priorities of decision-makers in flood risk management. Thus, predicting the conditions leading to loss of life is crucial for assessing the risk to the population. Here we focus on the Po River District in Northern Italy which covers the largest Italian hydrographic basin. We demonstrate that the occurrence of flood-related fatalities can be estimated by utilizing a random forest (RF) algorithm applied to a dataset of fatalities that occurred in this area from 1970 to 2019. This method relies on nine explanatory variables that describe the hazard intensity, and the environmental and sociodemographic conditions leading to fatalities. The proposed model is a primary attempt to estimate the probability of flood-related fatalities in the Italian context, and it provides a proxy for the quantitative estimation of flood risk to the population.
Nanostructures as an indicator for deformation dynamics 
Authors: Incel Sarah , Ohl Markus , Aben Frans , Plümper Oliver , Brantut Nicolas
Published: March 2024

Grain-size reduction – with amorphization or melting as its extreme forms – plays a crucial role in fault-zones dynamics, e.g., the nucleation or arrest of earthquakes. Previous experiments have been mostly conducted on powdered samples and structural investigations of experimentally generated fault-gouge material provide contrasting results when it comes to the initiation of melting during fault slip. In the present study, we deformed four intact Westerly granite samples, to decipher whether there is a correlation between failure mode, i.e., controlled, self-stabilised, or dynamic, and grain-size reduction within the developing fault gouge. Controlled failure took place over several hours, self-stabilised failure occurred within a few seconds and dynamic failure lasted less than a second. To test the influence of aqueous fluids on the grain-size evolution within fault gouges, two runs were performed on samples, dynamically failing either in the presence or absence of pore fluids. All samples were deformed at the same effective pressure of 40 MPa and displacements along the newly created faults were with 1.2 to 2.0 mm in a similar range. We investigated the microstructures of each sample using a scanning electron microscope (SEM) and cut two focused-ion beam (FIB) sections per sample from selected areas, located within the fault gouges, to analyse their nanostructures using a transmission electron microscope (TEM). At low magnification at the SEM, no striking differences between the different fault gouges are visible. Features resembling “cooling cracks” become apparent at the highest magnification at the SEM and are only found in the samples that failed dynamically. Major differences between the samples are only obvious when comparing their nanostructures using TEM imaging. In the high-resolution TEM images as well as with the aid of selected area electron diffraction (SAED), we observe a clear correlation between failure mode or rupture speed and grain-size reduction, with an increase in amorphous material as rupture speed increases. Regardless of the availability of fluids, the samples that underwent dynamic failure reveal similar nanostructures. Both exhibit flow structures created by amorphous material. We believe that latter is the result of melting as we find numerous structural and chemical evidence for melting, e.g., euhedral magnetite crystals of a few tens of nanometer with adjacent depletion halos. Such indicators for melting are absent in samples that failed in a controlled or self-stabilised manner, highlighting the importance of rupture speed on fault gouge melting.
Sensitivity and linearity of surface temperature response to solar irradiation changes
Authors: Sedlacek Jan , Sukhodolov Timofei , Egorova Tatiana , Rozanov Eugene
Published: March 2024

During the last millennia, prior to the industrialization, long-term climatic variations correlate with low-frequency total solar irradiance (TSI) changes. This long-term correlation does, however, not prove or disapprove a causal relationship. An additional natural forcing is the volcanic activity. The exact magnitudes of these two natural forcings are not known because reconstructions are based on proxy data which include substantial uncertainty. The Maunder Minimum, a period between roughly 1600 and 1700 A.D., is characterized by lower temperatures, low solar activity, and relatively high volcanic activity. There is still a debate on how forcing, i.e., solar vs. volcanic, influenced the climate and to which extend during that time. The amplitude of the TSI decrease is especially uncertain and suggestions range from a few W/m2 to a few tens of W/m2 lower than today’s value. Here we present simulations with the chemistry-climate model SOCOL where different solar forcings ranging from +10 W/m2 to -20 W/m2 in TSI terms are applied. On a global scale, changes in temperature are linear with changes in TSI. On a regional scale, however, the temperature response can be non-linear especially at high latitudes. The mechanisms leading to the non-linear behavior are explored. 
Advancing Progress on Earth System Digital Twins through an Integrated AI-Enabled Framework
Authors: Smith Brandon , Pelissier Craig , Nearing Grey , Cruz Carlos , Raghunandan Deepthi , Saeedimoghaddam Mahmoud , Valenti Vanessa
Published: March 2024

The development of Earth System Digital Twins (ESDTs) represents an ongoing journey towards more accurate and integrated simulations of Earth processes. Inherently interdisciplinary, the endeavor grapples with the challenge of melding subsystems developed by experts in different fields and organizations, requiring communication between different science domains, technology stacks, and data modalities. The Coupled Reusable Earth System Tensor (CREST) framework is a key aspect of our efforts to address these difficulties: by implementing a generic abstraction layer over existing tensor libraries (e.g. TensorFlow, PyTorch, JAX), CREST provides the software foundation for building, operating, and deploying community developed ESDTs. This framework is designed to allow scientists to easily couple together process-based and data-driven models into broader digital twin workflows, while taking advantage of significant efficiency improvements from hardware accelerators.CREST aims to be a step forward in combining traditional modeling techniques with emerging computational methods, particularly in the context of machine learning. Machine learning plays a foundational role in our approach, both contributing to the development of new data-driven models and aiding in efficient coupling with existing models. Through CREST, we aim to enhance model integration and foster more dynamic interactions within the modeling pipeline – primarily addressing the issues of limited support in current frameworks for gradient propagation, hardware acceleration, and federation with external models. In addition, CREST operational capabilities will include data assimilation, end-to-end distributed model training, black-box model coupling, what-if scenario analysis, and an easy-to-use GUI interface for end users.In the context of practical applications, the Terrestrial Environmental Rapid-Replication and Assimilation Hydrometeorological (TERRAHydro) system serves as an example of applying these principles in practice. Using CREST, TERRAHydro couples together several hydrologic and land surface subcomponents, such as soil moisture, evapotranspiration, and net ecosystem exchange, into a coupled land surface model. The efficiency of AI-based LSDTs such as TERRAHydro are expected to be able to carry out scenario analysis beyond existing traditional land surface models. Here we show results and comparisons for this application, discuss progress on CREST and TERRAHydro overall, and outline our roadmap going forward.
The automatic seismic event bulletin of the Swedish National Seismic Network
Authors: Roth Michael , Eggertsson Gunnar , Schmidt Peter , Shomali Hossein , Oskooi Behzad , Lund Björn
Published: March 2024

The Swedish National Seismic Network (SNSN) currently operates 67 permanent and 13 temporary broadband seismic stations. All stations transmit continuous realtime data to the data centre in Uppsala, and data streams of about 40 stations are automatically forwarded to subscribing institutes in the neighboring countries and to ORFEUS. In addition to the SNSN stations we receive realtime data from about 120 stations located in Norway, Finland, Denmark, Germany, Poland, the Baltic States, and Russia. SNSN processes the waveform data of this virtual network of about 200 stations using the SeisComp and Earthworm systems in parallel. Both systems are set up to be very sensitive in order to detect as small events as possible, which also increases the probability of generating spurious events. In order to screen out spurious events we generate a common bulletin which contains events that have been located by both systems independently. Our common bulletin is very reliable (no spurious events during the last 1.5 years), captures events down to about ML = 1 and contains almost all events with ML > 1.5 in Fennoscandia.All events in the common bulletin are automatically classified by an artificial neural network as earthquakes, blasts or mining-induced events. The classifier has been developed in the framework of a PhD project, and was implemented into the SNSN processing queue during 2023 (Eggertsson et al, "Earthquake or Blast? Classification of Local-Distance Seismic Events in Sweden using Fully-Connected Neural Networks", accepted GJI 2024). It has been thoroughly tested, and, comparing the automatic classification with analyst-reviewed classification, we found a 97% matchSince December 2023, SNSN provides the automatic common bulletin as a simple webpage https://www.snsn.se/combullUTC/ - mainly for the general public and for quick reference. For the seismological community, SNSN has set up an automatic real-time forwarding of complete event parameters for all events with ML >= 2 to the European-Mediterranean Seismological Centre.