bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing different urban heat metrics in varied settlements and their relation to thermal comfort
Authors: Krikau Svea , Otto Iris , Scheck Natalie , Benz Susanne
Published: March 2024

Rising temperatures, resulting in prolonged heat waves and increased occurrences of tropical nights, present a risk to both morbidity and mortality rates. Urban populations are particularly vulnerable due to the additional elevation of temperatures within urban areas compared to the rural surroundings, commonly known as the "urban heat island effect". For the identification of heat exposure air temperature (Ta) at a high spatial scale is a preferred metric, however due to the scarcity of official measurement stations land surfaces temperature (LST) measurements are often used as a substitute. In addition, most studies focus only on densely populated urban areas, neglecting smaller settlements in a rural environment.Here we show the differences in LST and air temperature extremes at nighttime for the state of Hesse, Germany. This involves comparing various temporal aggregates (such as 90th percentile and mean) and diverse urban heat metrics (including absolute temperatures and rural-urban temperature differences). We furthermore focus on small towns (5000 to under 20000 residents), medium-sized cities (20000 to under 100000 residents) and large urban metropolises (over 100000 residents) separately, taking into account the distinct relations to land cover/land use characteristics (indicated by Local Climate Zones) of the individual urban heat metrics. To gain insights into how these different temperature parameters (as well as daytime LST) relate to human-perceived comfort the Thermal Comfort Index 'Physiological Equivalent Temperature' (PET) is included as a metric.
Significant missing OH reactivity in the tropical marine boundary layer
Authors: Whalley Lisa , Seldon Samuel , Boustead Graham , Lade Rachel , Heard Dwayne , Read Katie , Callaghan Anna , Punjabi Shalini , Lee James , Carpenter Lucy , Neves Luis
Published: March 2024

It has recently been highlighted that observed OH reactivity (kOH) in the remote marine boundary layer cannot be fully explained by the measured or modelled speciated VOCs [1]. Understanding the identity and magnitude of the species that contribute to OH reactivity (and influence the concentration of OH) in the tropical marine boundary layer is particularly important however, as approximately 25 % of the total tropospheric methane removal, driven by the reaction with OH, occurs in this region [2].  Ground-based observations of kOH and comparisons with calculated or modelled kOH from individually measured VOCs and inorganics offers the opportunity to investigate diel trends and variabilities driven by changing air-masses, which can provide a valuable insight into the identity and impact of any missing kOH. We made the first observations of kOH at the Cape Verde Atmospheric Observatory in the remote tropical marine boundary layer in February 2023. The observed kOH ranged from 1.5 s-1 to 2.5 s-1 with the highest reactivity recorded when long-range transport of Saharan air-masses reached the observatory. The calculated kOH from the different inorganic and VOC species measured during the campaign did not capture the total kOH observed and even when the contribution from model-generated species (determined from a detailed 0D box model utilising the Master Chemical Mechanism) were considered, missing reactivity on the order of 0.2 – 0.5 s-1 remained, consistent with the levels of missing kOH previously determined in the marine boundary layer during the ATom aircraft campaign [1]. The diel profile highlighted that missing kOH was greatest during the night and morning and was at its lowest during the afternoon. Missing kOH correlated well with the OH reactivity contribution from species such as alkenes, CO and DMS, but was anti-correlated with the carbonyl reactivity suggesting the nature of the missing reactivity could be related to an unknown or unmeasured primary emission rather than a secondary species formed during the day via OH oxidation. Through modelling studies, we will present the impact that different missing primary emissions have on modelled OH concentrations and on the production of secondary oxygenated VOCs.[1] Thames, A.B., et al., Missing OH reactivity in the global marine boundary layer, Atmospheric Chemistry and Physics, 2020, 20, 4013-4029.[2] Bloss, W.J., et al., The oxidative capacity of the troposphere: Coupling of field measurements of OH and a global chemistry transport model. Faraday Discussions, 2005. 130: p. 425-436.
Still Arctic? - The changing Barents Sea
Authors: Gerland Sebastian , Ingvaldsen Randi B. , Reigstad Marit , Sundfjord Arild , Bogstad Bjarte , Chierici Melissa , Eldevik Tor , Hop Haakon , Renaud Paul E. , Smedsrud Lars H. , Stige Leif Christian , Årthun Marius
Published: March 2024

The Barents Sea is one of the Polar regions where current climate and ecosystem change is most pronounced. In a recent review (DOI: 10.1525/elementa.2022.00088) as a part of the cross-disciplinary Norwegian research project “The Nansen Legacy”, the current state of knowledge of the physical, chemical and biological systems in the Barents Sea is described. Here, we present some of the key findings from this review. Physical conditions in this area are characterized by large seasonal contrasts between partial sea-ice cover in winter and spring versus predominantly open water in summer and autumn. Observations over recent decades show that surface air and ocean temperatures have increased, sea-ice extent has decreased, ocean stratification has weakened, and water chemistry and ecosystem components have changed. In general changes can be described as “Atlantification” and “borealisation,” with a less “Arctic” appearance. In consequence, only the northern part of the Barents Sea can be still called “Arctic”. The temporal and spatial changes have a wider relevance reaching beyond the Barents Sea, such as in the context of large-scale climatic (air, water mass and sea-ice) transport processes. The observed changes also have socioeconomic consequences, such as for fisheries and other human activities. Recent Barents Sea mooring data shows stronger inflow of warm water from the north during winter, affecting the sea ice locally. “The Nansen Legacy” has significantly reduced Barents Sea observation- and knowledge gaps, especially for winter months when field observations and sample collections have been sparse until recent.
Investigations on the Scale Factor Readout of the Laser Interferometer aboard NGGM
Authors: Misfeldt Malte , Mueller Vitali , Heinzel Gerhard
Published: March 2024

The GRACE-FO mission was launched in 2018 and has been providing valuable data since then. However, developments for future missions have been initiated: the US-German GRACE-C Mission with a planned launch in 2028 and the ESA-led Next Generation Gravity Mission (NGGM) with a launch window around 2031. Both use laser interferometers as their primary and only inter-satellite ranging instruments. Accurate knowledge of the laser wavelength, or equivalently the laser frequency, is required to convert the measured phase to a range with a unit of meters.In GRACE-FO, this conversion (or scale) factor can be determined with the main microwave ranging instrument. However, future missions will require a dedicated wavelength or scale factor readout. Additional phase modulations to be applied to the laser light, in parallel with the conventional cavity locking scheme, have been proposed by the Australian National University (ANU) to achieve such a readout. This technique is now being implemented as a novel Scale Factor Unit (SFU) for the Laser Ranging Interferometer (LRI) onboard the GRACE-C mission, and is also being investigated for the European Laser Tracking Instrument (LTI) of NGGM.In this talk we will explain the measurement principle, show first results from a breadboard setup of our Scale Factor Measurement System (SFMS) and give an outlook on the next steps towards an implementation for the NGGM LTI.
Potential earthquake precursory pattern of large Alpine- Himalayan earthquakes as seen by magnetic Swarm satellites
Authors: De Santis Angelo , Alimorady Homayon , Rahimi Habib
Published: March 2024

 Before the occurrence of an earthquake and when the lithosphere is in a state of critical stress accumulation, the lithosphere could react- with the so-called earthquake precursors. One of these precursors is the magnetic field, which, under proper conditions, may produce anomalies due to accumulated stress in the crust before an earthquake occurs. Since several years ago, it has been possible to observe the Earth's magnetic field through satellites. The Swarm satellite mission of the European Space Agency was launched at the end of 2013. It is composed of three identical specialized satellites for observing the Earth's magnetic field. Here, using the magnetic measurements provided by Swarm satellites, we investigate the possibility of identifying several anomalous magnetic signals before the occurrence of earthquakes, which are possibly related to lithosphere-atmosphere-ionosphere coupling. In this study, the earthquakes with a magnitude greater than 5.0 occurred from 2014 to 2023 in the Alpine-Himalayan belt under geomagnetically quiet conditions were examined. Using the algorithm applied to the data from 10 days before the earthquake, obvious anomalies in the components of the magnetic field are identified. Furthermore, a significant relationship between the length (duration) of the anomaly and the magnitude of the earthquake was observed and the empirical relationship between them was estimated. For instance, with the enhancement in the magnitude of the earthquake, the duration of the anomaly also increases.In addition, significant relationships are also found between other parameters and the magnitude of the earthquake with an acceptable correlation.We also performed a confutation analysis synthetizing a random catalogue of earthquakes and made again the correlation with the satellite anomalies: the results were far different from those obtained with real data, so confirming the validity of those results.
Whale teeth as witnesses: assessing anthropogenic impact on whale ecology through a multi-proxy analysis
Authors: Luiten Beau , Jarochowska Emilia , IJsseldijk Lonneke , King Helen
Published: March 2024

Whales are critical organisms in the ocean ecosystems, but direct and indirect human impact has decimated their populations. Because whales have long lifespans and migrate over large areas, there is no ecological baseline to evaluate their population dynamics. However, such information is available in fossil whale remains. Geoscientific expertise can aid conservation by interpreting proxy values from the most chemically stable tissue: their teeth. In this project we focus on North Atlantic toothed whales from the late Pleistocene on, with the aim to reconstruct their migrations and ecologies.Whale teeth contain information about both the individual and its environmental conditions, depending on the proxy that is evaluated. An integrative methodology was developed to be applied on modern and fossil specimens. This includes oxygen isotope analysis to reconstruct migration and bathymetric niches, Sr/Ca and Ba/Ca ratios to assess trophic position and dietary patterns, and Raman spectroscopy for elemental composition and crystallography. Additionally, Scanning Electron Microscopy (SEM) enables growth analysis and measurements of chemical composition through EDX. However, fossil teeth in a marine environment might be altered by diagenesis, making their proxy values unrealistic and not comparable with modern values. By quantifying these changes we can identify and correct for altered proxy values: thus allowing reconstruction of ecologies.In this initial phase of the project the modern teeth have been analysed using Raman spectroscopy and SEM. Notably, Raman has shown that both the enamel and cementum can be used to produce reliable spectra, while the dentine does not allow this. Chemical composition from the EDX can be assessed over growth layers and correlated with the Raman results. We provide an interdisciplinary framework to assess multiple proxies found in fossil and modern teeth, using geochemical methods to answer biological questions. In addition, we utilize physiological data obtained from stranded individuals whose teeth were sampled, along with historical records of whale populations. There is a large emphasis on anthropogenic impact, by evaluating specimens along a timeline for impact of fishing, whaling, climate change and pollution.
Past local summer temperature revealed by the total air content record from the Antarctic EPICA Dome C ice core
Authors: Capron Emilie , Raynaud Dominique , Yin Quizhen , Wu Zhipeng , Parrenin Frédéric , Berger André , Lipenkov Vladimir , Guilluy Héloïse
Published: March 2024

Seasonal temperature reconstructions from ice cores are missing over glacial-interglacial timescales, preventing a good understanding of the driving factors of Antarctic past climate changes. Here we present a new total air content (TAC) record from the Antarctic EPICA Dome C (EDC) ice core covering the last 800 thousand of years (ka).We show that the TAC record is highly correlated with the mean insolation over the local astronomical half-year summer. Benefiting from new climate transient simulations from the Earth system model of intermediate complexity LOVECLIM covering the past 440 ka, we evidence that the EDC TAC record is correlated with the simulated local summer temperature changes. Hence, our new results suggest that the EDC TAC record could potentially be used as a proxy for local summer temperature changes. We present also preliminary results exploring this link between TAC and past summer local surface temperature at other ice core sites in Antarctica and in Greenland.Finally, our simulations show that local summer insolation is the primary driver of Antarctic summer surface temperature variations while changes in atmospheric greenhouse gas concentrations and northern hemisphere ice sheet configurations play a more important role on Antarctic annual surface temperature changes.
Fluid escape submarine geomorphological features in the NW Black Sea
Authors: Ion Gabriel , Popa Adrian , Lazăr Constantin , Apotrosaei Vlad Apotrosaei , Duțu Florin
Published: March 2024

By means of Digital Terrain Models, produced based on multibeam echosounding data and underwater photography, spectacular sea floor geomorphologies and features have been discovered and mapped.In some parts of the NW Black Sea, the submarine geomorphology is characterized by the presence of fluid escape features. These very specific features are present in the flexure area and the upper continental slope. There are prevailing the so-called pockmarks (large depressions on the sea floor) and carbonate chimnies - positive small morphological items on top of the sea bottom, micro-biogeochemically build as the result of the fluid escapes from the sea floor. These kind of submarine geomorphologies are the result of the high dynamics of the fluid escapes that occur in areas with high sedimentation rates, both of sediments and organic matter. The sediments are of Quaternary age and are subject of consolidation processes, that means expulsion of pore water, sometimes accompanied by important amounts of gases, mainly biogenic methane. These submarine sea bottom elements are the best testimonies for the high dynamics of fluids in the pile of young sediments and point out that subjacent to these underwater morphologies could be located hot spots of organic matter accumulations.The pockmarks could be isolated or clustered in groups of scattered elements or linear patterns. Often, mostly the linear clusters of pockmarks, are associated to the local highs of the sea floor geomorphology. The carbonate chimnies cannot be detected by means of multibeam technologies, but in some upper parts of the Danube and Dnieper deep sea fans such structures can by observed by means of underwater photography.
Projected changes in extreme precipitation and floods in central India
Authors: Kumar Nikhil , G.R. Davies Evan , Kumar Goyal Manish , Faramarzi Monireh
Published: March 2024

Precipitation extremes are expected to rise in a warming climate; however, the corresponding increases in flood magnitudes remain a complex and underexplored issue. This study employs the annual maxima approach to assess the relationship between extreme precipitation and floods, using a process-based hydrological model, the Soil & Water Assessment Tool (SWAT), in four river basins of central India (Brahmani and Baitarni, Subarnarekha, Mahanadi and Narmada) for past (1984-2014) and future (2030-2060 and 2070-2100). First, the SWAT models underwent rigorous data selection (climate and land cover data), calibration and validation to ensure a reliable representation of the hydrologic conditions of these basins at a daily scale, based on observations from 26 hydrometric stations for the 1988–2019 period. Second, climate projections from four CMIP6 GCMs were statistically downscaled using Bias Correction/Constructed Analogues with Quantile mapping reordering (BCCAQ) for the SSP245 and SSP585 scenarios. Finally, the SWAT models were used to project future changes in extreme precipitation and flood characteristics in the selected river basins. Considering both daily model performance (Nash-Sutcliffe Efficiency-NSE > 0.60) and catchment representativeness, we selected 10 from 26 hydrometric stations for the extreme value analysis. The analysis of the ensemble mean of the 95th percentile of four GCMs and the modelled 20-year return levels show a future increase in both precipitation (0.27 to 27.93 % and 6.19 to 50.06 %) and discharge (1.31 to 50.35 % and 5.42 to 100.73 %) at 6 out of 10 selected stations, with a more significant increase under the SSP585 scenario than the SSP245 scenario, highlighting a clear link between increased precipitation and discharge The modelling framework developed in this study will improve understanding of processes involved and the thresholds at which the central Indian catchments correspond to extreme precipitation. The findings will help the projection of future flood risks and could help to shape effective adaptation strategies in the region.
The influence of topography on beech water use: evidence from a comparative study
Authors: Fabiani Ginevra , Klaus Julian , Pfister Laurent , Penna Daniele
Published: March 2024

The ongoing climate change is significantly impacting forest ecosystems, intensifying environmental extremes such as droughts and heatwaves. The increased atmospheric evaporative demand, coupled with reduced soil water availability, poses a risk of water deficit to trees, threatening their health status. These extremes can amplify the thermal and hydrologic gradients along hillslopes, driving spatially variable thermal and hydraulic stress for trees. Until now, site-specific case studies have offered only a limited understanding of how hydrological processes at the hillslope scale influence tree water use. Comparative studies hold the potential to offer a more generalized understating of how trees growing in complex terrains respond to spatially varying growing conditions.To address this, we set up a comparative study on two forested hillslopes located in the Weierbach catchment (Luxembourg) and the Lecciona catchment in Tuscany (Italy), respectively. The investigated sites differ in steepness, climate, geology, and soil characteristics, but both are dominated by beech (Fagus sylvatica L.) trees. We combined sap velocity, isotope measures, and wood moisture content with environmental monitoring (soil moisture, groundwater level, and hydro-meteorological variables) at different locations to capture beech trees’ water response to heterogeneous environmental conditions. This combination of measurements allowed us to link the transpiration response of trees to water availability along the two investigated hillslopes over the 2019 and 2020 growing seasons in the Weierbach catchment and over the 2021 growing season in the Lecciona catchment.We observed that surface topography and hillslope structure result in differing sap velocities in response to environmental controls (i.e., vapor pressure deficit and relative extractable water), but not consistently across our study sites. In the Weierbach catchment, we noted a uniform physiological response to environmental controls among trees, even during the drier conditions of 2020, compared to 2019. We attribute this consistency to the homogeneous growing conditions across the slope. On the contrary, in the Lecciona catchment, trees located upslope displayed a more conservative hydraulic behaviour compared to the footslope location. This finding suggests a stronger edaphic and environmental gradient across the hillslope topography. Here, water redistribution through shallow subsurface flow results in more favourable growing conditions and longer growing seasons for trees at the footslope location, compared to the rather uniform growing season observed in the Weierbach catchment. These contrasting results between the two investigated hillslopes suggest that in landscapes where the hydraulic and climatic gradients are stronger, the physiological response among locations will be more spatially variable.
Large-sample evaluation of the water balance for the Spanish catchments using multiple hydroclimatic datasets
Authors: Yeste Patricio , Bronstert Axel
Published: March 2024

Large-sample hydrology aims to identify common patterns in the hydrologic behaviour of numerous catchments at the regional, continental and global scales. Large-sample datasets play a fundamental role in the context of large-sample hydrology as they collect data from multiple catchments and hydroclimatic variables.This study focuses on the characterization of the water balance for 189 Spanish headwater catchments. The different ratios derived from the water balance equation will be calculated using multiple hydroclimatic datasets available for the Spanish domain for two consecutive and equally long periods: 1990-2005 and 2006-2020. Precipitation data will be extracted from a gridded dataset at 0.05º resolution from the Spanish Meteorological Agency (AEMET). Streamflow time series will be provided by the Spanish Center for Public Work and Experimentation (CEDEX). Evaporation data will be gathered from the Global Land Evaporation Amsterdam Model (GLEAM) versions 3.7a and 3.7b.The results of this work will highlight the potential of using large-sample datasets to characterize the water balance for the Spanish catchments and will reveal key changes in their hydrologic behaviour during the last three decades.ACKNOWLEDGMENTS: This study has been funded by a Humboldt Research Fellowship from the Alexander von Humboldt Foundation. 
Exploring the Dynamics of Forests and Climate: A Case Study of India
Authors: Sharma Jyoti , Kumar Pankaj
Published: March 2024

The distribution and composition of forests worldwide are primarily influenced by geographical factors, latitude, and prevailing climatic conditions. These conditions also govern how various types of forests respond to changes in climate. Understanding the feedback loop between vegetation and climate is complex due to regional variations, making it a challenging study area. Previous studies have predominantly focused on the biogeochemical processes, assessing the forest's carbon sequestration potential, while the role of biogeophysical mechanisms- such as evapotranspiration and latent heat flux, apart from albedo- in this relationship remains poorly understood.The present study aims to comprehensively explore both the biogeochemical and biogeophysical mechanisms operating within Indian forests and their influence on climate by utilizing finer-resolution observational datasets. India, characterized by diverse geographical features, harbors 16 distinct forest types. My initial findings indicate an overall increase in forest cover except in wet evergreen and montane wet temperate forests within India. Additionally, evidence suggests heightened gross primary productivity, suggesting the forests' ability to mitigate warming effects. The study will explore the intricate dynamics of evapotranspiration and other related factors, aiming to unravel their synergistic impact on the regional climate. The findings will contribute to a more comprehensive understanding of the complex dynamics shaping forest-climate interactions, providing valuable information for sustainable forest management and climate change mitigation strategies.
Sensitivity tests for improved retrievals of SO2 plume height from TROPOMI observations
Authors: Fabris Lorenzo , Theys Nicolas , Clarisse Lieven , Brenot Hugues , Yu Huan , van Gent Jeroen , Vlietinck Jonas , Van Roozendael Michel
Published: March 2024

Sulfur dioxide (SO2), emitted from volcanic eruptions, can have a major impact on the environment and society. While nadir-viewing satellites have been providing precise information on its Vertical Column Density (VCD) for several decades, the retrieval of its Layer Height (LH) is a more recent development, although it is important for the aviation safety, estimation of SO2 emissions, understanding of volcanic processes and climate research. In the Ultraviolet (UV), the current algorithms are often time-consuming and still lack sensitivity, especially in the presence of aerosols. Our research aims at developing an improved SO2 LH (and VCD) retrieval algorithm for the TROPOspheric Monitoring Instrument (TROPOMI). While the third spectral band of TROPOMI is traditionally used for sulfur dioxide, a shorter UV region has been exploited here to take advantage of the strong absorption of SO2 in the second band. As a demonstration case, Slant Column Density (SCD) retrievals in band 2 were carried out using the Covariance-Based Retrieval Algorithm (COBRA) [1]. We show that SO2 SCDs from both spectral bands are generally in excellent agreement. However, the results in band 2 reveal a greater sensitivity to SO2 than in band 3.Motivated by this result, we performed SO2 plume height retrievals on an extensive set of synthetic spectra representative of TROPOMI observation conditions, using the Look-Up Tables Covariance-Based Retrieval Algorithm (LUT-COBRA) [2]. The SO2 LHs and VCDs we find from the second band are more accurate, and the associated retrieval errors appear to be considerably reduced in comparison to those of the band 3.In addition, sensitivity analyses were conducted to further characterise the wavelength dependence and effect of some observation conditions on the quality of these retrievals. More specifically, we assess the impact of the temperature, air density, ozone profile and VCD, SO2 absorption cross sections, surface albedo and height as well as the SO2 profile shape. Finally, we present the next steps to further develop the LUT-COBRA approach and application to TROPOMI band 2 measurements.  [1] N. Theys et al. Atmospheric Chemistry and Physics, 21(22):16727–16744, 2021.[2] N. Theys et al. Atmospheric Measurement Techniques, 15(16):4801–4817, 2022.
Meteotsunami-HySEA: A GPU accelerated code for simulating atmospherically-driven tsunamis on real bathymetries. Benchmark tests.
Authors: Gonzalez del Pino Alex , Macías Sánchez Jorge , Castro Díaz Manuel , Lumina Denamiel Cléa
Published: March 2024

Atmospherically-driven tsunamis or meteotsunamis are generated by atmospheric disturbances with steep gradients of pressure and/or wind. In recent years, meteotsunamis have received more attention from the tsunami modelling community. Although their destructive potential might be less severe than for earthquake or landslide triggered tsunamis, their frequency is much higher. The two main processes driving the most extreme meteotsunami events are the offshore amplification of the ocean long-waves due to Proudman or Greenspan resonances (i.e., when the atmospheric disturbance travels at the same speed than the long-waves) and, nearshore, the amplification factor of the shelfs, bays or inlets (i.e., resonance frequency associated to the nearshore geometry). As meteotsunamis have a high-dependence on the nearshore geometric characteristics, they often occur at known hotspot locations such as along the coastlines of Croatia, the Balearic Islands, Sicily, Malta, the Nagasaki Bay or the Baltic Sea. One of the most devastating meteotsunami events took place in Menorca (Balearic Islands) in 2006, where tsunami-like oscillations caused an economic loss of several tens millions of euros.The EDANYA group from the university of Málaga is widely known for its GPU-accelerated tsunami simulation codes, such as Tsunami-HySEA (earthquake source) or Landslide-HySEA (landslide source). Here, we present our brand-new code for simulating meteotsunamis following the same philosophy as the previous codes. Meteotsunami-HySEA incorporates the atmospheric forcing together with additional terms such as Coriolis and the wind drag. The PDE system is written in spherical coordinates and implemented in CUDA. An additional feature related to preserving a linear version of the quasi-geostrophic equilibrium is added to the numerical scheme in order to preserve the structure of geostrophic flows, as large scale geophysical flow are often perturbations of this steady state.To demonstrate the Meteotsunami-HySEA reliability, we first applied the code to some carefully-crafted benchmark tests, where Proudman resonance is exhibited and precisely capture, enabling accurate measures of the amplification gain due to the coupling of the propagation velocities. Then we followed the NTHMP’s guidelines for simulating a pilot study in the region of the Gulf of Mexico with a real topobathymetry. Further work will be focused on testing real scenarios, incorporating real atmospheric data and bathymetry for reliable forecast.Acknowledgments: This contribution was supported by the EU project “A Digital Twin for Geophysical Extremes” (DT-GEO) (No: 101058129) and by the Center of Excellence for Exascale in Solid Earth (ChEESE-2P) funded by the European High Performance Computing Joint Undertaking (JU) under grant agreement No 101093038.
 
Aerosol-cloud interactions constrain climatic trends in rainfall and temperature of India
Authors: sarangi chandan , Rai Pradeep , Kant Sunny , Nair Arun , Kuiry Soumendra , Wilcox Eric , Leung Ruby
Published: March 2024

Aerosol-cloud interactions (ACI) is a key uncertainty in our ability to forecast future climate. Robust evidences of aerosol-induced modifications to the structure and lifetime of both, rain bearing and non-rain bearing clouds has emerged from satellite observations across the globe in last two decades. These observations were also substantiated by many process-level simulation studies using weather models at cloud resolving scales in last decade. Thus, the significance of ACI at process scale on short-term meteorological perturbations is well agreed. However, the role of aerosol-cloud interactions on trends at climate scale is not evident yet. For example, if cloud occurrence is increasing over India, it is not clear if there is any substantial role of ACI in comparison to other governing factors. Here, we will present our analysis on the association of ACI with the recent trends in clouds, temperature and rainfall over India using satellite observations and global climate model simulations.First, we will discuss data analysis of simulations from CMIP5 models, to quantify the importance of ACI on extreme climate indices over Indian monsoon region. The climate models were grouped based on whether the models represent only aerosol-radiation interactions (REMADE) or the full suite of aerosol-radiation-cloud interactions (REMALL). Compared to REMADE, including all aerosol effects significantly improves the model skills in simulating the observed historical trends of all three climate indices over India. Specifically, AIE enhances dry days and reduces wet days in India in the historical period, consistent with the observed changes. However, by the middle and end of the 21st century, there is a relative decrease in dry days and an increase in wet days and precipitation intensity. Further, we will also illustrate unprecedented satellite evidences of aerosol induced positive trends in marine cloud occurrences and surface temperature during pre-monsoon over the Bay of Bengal (BOB) region. In last 15 years, increased aerosol emissions over North India have led to an increase in aerosol loading till 3 km over the BOB outflow region in monsoon onset period. The elevated aerosol loading stabilizes the lower troposphere over the region in recent years and leads the low-level cloud occurrences (below 3 km) to increase in recent years by ~20%. Incidentally, the sea surface over entire BOB is steadily warming under climate change except the pollution outflow region, suggesting potential contributing to the observed non-intuitive cooling trends in sea surface temperatures.Our findings underscore the crucial role of ACI in trends and future projections of the Indian hydroclimate and emphasizes the crucial need for improved aerosol representations in coupled models for accurate predictions of regional climate change over South Asia.
Agricultural Drought Propagation over India: A Complex Network Theory Approach 
Authors: Venkatesh Kasi , Sivakumar Bellie
Published: March 2024

Agricultural drought has emerged as a significant threat to global food security and sustainable development. Despite the progress made in the identification and analysis of various characteristics for the assessment and early warning of agricultural drought, our knowledge of the mechanisms governing agricultural drought propagation remains limited. This study aims to address this gap by employing complex network theory. Specifically, the study uses complex network measures to investigate the spatial propagation of agricultural drought propagation across India during 1950–2014. Spatial drought networks are constructed using event synchronization (ES) for mild drought conditions derived from the Standardized Soil Moisture Index (SSMI) at a 3-month aggregated scale (SSMI-3). The investigation delves into the mechanisms of spatial propagation of drought, including propagation source and sink, distance and orientation using directed networks. Several metrics, including network divergence, in-degree, and out-degree, inward and outward distance, inward and outward orientation are used. These metrics play a crucial role in identifying specific locations, namely source and sink regions, propagation distance and orientation, where drought onsets extend to other areas within the regional spatial networks. The results indicate that the northwest India acts as the source region and the west central India and peninsular India act as sinks. The central and east India are identified as vulnerable regions playing crucial roles in spatial drought propagation. The results also reveal that the dominant directions of propagation lead towards the northwestern parts of India. For inward distances, shorter propagation distances of less than 50 km are observed in the peninsular, central, and some parts of the northeastern regions, while longer propagation distances are observed in the western parts of India, exceeding 150 km. For outward distances, shorter propagation distances below 20 km are observed in hilly regions, while longer propagation distances are observed in the peninsular regions of India, exceeding 80 km. These results suggest that most regions propagate droughts inward and outward, covering distances of even hundreds of kilometres. Understanding the dominant inward and outward orientation of drought propagation could play a crucial role in developing early warning systems for droughts.
The interTwin project Digital Twin Engine and the alignment with Destination Earth
Authors: Manzi Andrea , Bardaji Benach Raul , Rodero Castro Ivan , Warde Adam , Geenen Thomas
Published: March 2024

The Horizon Europe interTwin project is developing a highly generic yet powerful Digital Twin Engine (DTE) to support interdisciplinary Digital Twins (DT). Comprising thirty-one high-profile scientific partner institutions, the project brings together infrastructure providers, technology providers, and DT use cases from Climate Research and Environmental Monitoring, High Energy and AstroParticle Physics, and Radio Astronomy. This group of experts enables the co-design of the DTE Blueprint Architecture and the prototype platform;benefiting end users like scientists and policymakers but also DT developers. It achieves this by significantly simplifying the process of creating and managing complex Digital Twins workflows.As part of our contribution, we'll share the latest updates on our project, including the DTE Blueprint Architecture, whose second version is being released in January 2024.  The interTwin Blueprint components, thanks to the collaboration with ECMWF partner in the project, are designed to be aligned with what Destination Earth is designing and building. Therefore, we will show the activities carried out by the project to analyse DestinE architecture and the points of interoperability foreseen. The contribution will also cover the diverse DT use cases we currently support and describe the first software release planned for February 2024. InterTwin is funded by the European Union (Horizon Europe) under grant agreement No 101058386.
Cobalt adsorption on montmorillonite: investigating the influence of dehydration on adsorption properties
Authors: Kim Yeongkyoo , Jang Yeongjun
Published: March 2024

Cobalt is often released into the natural environment through industrial waste from alloying industries and acid mine drainage. Additionally, it exists as a radionuclide (60Co) contributing to high-level radioactive waste. Smectite is a mineral that can be useful for adsorption and isolation of this element. In this investigation, Cheto-type montmorillonite (Cheto-MM), a source clay mineral of The Clay Mineral Society's (CMS) with well-established characteristics, was used as the primary material. The study aimed to assess how cobalt adsorption is affected by the adsorption site in the presence of interlayer water and after subsequent dehydration through heating. Adsorption kinetics and adsorption isotherm models were employed to explore the cobalt adsorption mechanism on Cheto-MM.Results demonstrated notable variations in adsorption characteristics post-dehydration and subsequent shrinkage. Approximately 38% of cobalt was found to adsorb at the edge of Cheto-MM, while about 62% was adsorbed at the interlayer site, indicating the significant influence of the interlayer on cobalt adsorption in Cheto-MM. Adsorption kinetic models showed that the cobalt adsorption kinetics on Cheto-MM can be explained by a pseudo-second-order model. Moreover, isotherm experimental result was best represented by the Langmuir isotherm adsorption model. This study provides fundamental insights into cobalt adsorption characteristics on montmorillonite, emphasizing distinct adsorption sites. Such findings are instrumental in predicting smectite's adsorption behavior in high-level radioactive waste disposal sites in the future.
Impact of increasing storminess and decreasing sea ice cover on high-latitude beach erosion (Hornsund, Svalbard)
Authors: Swirad Zuzanna , Herman Agnieszka , Moskalik Mateusz
Published: March 2024

Observed and further predicted decreasing sea ice extent and increasing storminess over the North Atlantic are deemed to intensify coastal erosion along the shores of Western Svalbard. We investigate these relationships in Isbjornhamna, a bay with ~3 km shoreline located in north-western Hornsund fjord. The bay is delimited by Wilczekodden and Baranowskiodden headlands with 1.5 km opening to the main basin of the fjord where the depth is ~20-25 m. Mean significant wave height is 0.26 m and its 99th percentile is 1.5 m with highest values in autumn (mean of 0.4 m and 99th percentile of 1.91 m). A minor protrusion divides the bay into two basins. In the eastern part (Hansvika) a thick layer of glacier till deposits overlays metamorphic bedrock, while the western part (Krossvika) is cut in shists and paragneisses. Coastal cliffs are present at the outer parts of the bay, while gravel beach occupies its central 2 km section. There is an alongshore variability in beach morphology (width, slope) and grain size distribution. Glacier ice from calving Hansbreen often accumulates at the shore in summer and autumn months, while in winter/spring sea ice and ice foot are present. Polish Polar Station infrastructure is located on the shore which makes it directly exposed to storm waves.We used repetitive Uncrewed Aerial Vehicle surveys combined with Structure-from-Motion photogrammetry to detect beach change over 5 years. In total 13 surveys were performed between July 2018 and August 2023 which allowed a separation of shorter- and longer-term changes in beach morphology. We observed processes such as formation and destruction of beach cusps, creation and disappearance of holes from melting growlers, shoreline retreat and across- and alongshore sediment transport. We calculated mean erosion rates, and analysed its spatial and temporal variability. Finally, the short-term measurements were compared to the decadal-scale erosion rates derived from orthophotographs. Relationships between beach erosion, wind wave conditions, and sea ice coverage were inspected to understand the role of changing climate on the rates of coastal change.
Drivers and trends in Land-use change and associated carbon emissions over Indonesia
Authors: Brasika Ida Bagus Mandhara , Friedlingstein Pierre , Sitch Stephen , O'Sullivan Michael
Published: March 2024

Indonesia is currently known as one of the three largest contributors of carbon emissions from land and land cover change (LULCC) globally, together with Brazil & the Democratic Republic of Congo. However, there is a limited reliable data on LULCC across Indonesia, leading to a lack of agreement on drivers and trends in carbon emissions. This can also be seen in the annual global carbon budget (GCB). Here, we assess the new satellite-based land cover dataset from Mapbiomas over Indonesia to illustrate how changes in forest and agriculture (mainly palm oil) areas across Indonesia determine trends in carbon emissions from land use change (ELUC). ELUC is simulated with a process-based Dynamic Global Vegetation Model, JULES-ES using annually varying LULCC maps from Mapbiomas as input. Our results show that the forest loss and agriculture expansion have a strong correlation and trend in the last two decades. Furthermore, palm oil plantation is the major contribution to the forest-agriculture dynamics, mainly appearing in Kalimantan & Sumatera island. This dynamic has a major impact on Indonesia ELUC with a positive trend in ELUC of 0.06 PgC/yr2 since 2000 . The use of the satellite-based dataset, Mapbiomas, is shown to improve our understanding of the LULCC dynamics over Indonesia, hopefully contributing to a reduction of the ELUC uncertainty for Indonesia and the SE Asia region.
Integrating Sentinel-2 information into a growth model for assessing Alpine grassland dynamics under climate change
Authors: Kramer Kevin , Oriani Fabio , Schneider Manuel , Aasen Helge , Calanca Pierluigi
Published: March 2024

In the Alpine region, as in other mountainous areas of the World, grasslands dominate the agricultural landscape, providing key ecosystem services to human societies. Ongoing climate change is already altering their seasonal growth patterns. Monitoring these responses and predicting future shifts is therefore of great importance for identifying suitable adaptation measures.Recent studies have demonstrated the potential of remote sensing for the observation of grassland dynamics. Satellite data, however, can also be used to inform grassland growth models, which in turn are key tools for translating climate change scenarios into manageable information.In this contribution we discuss the integration of information derived from Sentinel-2 data into a mechanistic model of grass growth that has been validated for low-altitude sites but never systematically applied to grasslands at high Alpine locations. We use satellite inferred growing season start and snow cover information to calibrate and validate the model across the region of the Swiss National Park (Grisons, Switzerland), a biodiversity-rich ecosystem encompassing dry and wet pastures, wetlands and shrubs.The thus established model is then employed in conjunction with the national climate change scenarios for Switzerland to explore possible responses of alpine grasslands to mid-century climate change under the assumption of a business-as-usual emission pathway. In these simulations we account both for the effects of altered temperature and precipitation patterns as well as for the effects of elevated CO2 concentrations.Contributing to the activities of the Swiss National Centre for Climate Services, our work shows how remote sensing products coupled with mechanistic models can provide advanced predictive capabilities for developing scientific baselines needed to underpin climate change adaptation.
The Boost of the GPM Core Satellite in November 2023
Authors: Stocker Erich Franz , Bilanow Steven , Cohoon Christopher , Kelley Owen , Kwiatkowski John
Published: March 2024

During 2023 analysis showed that with the current solar activity an increasingnumber of altitude raising boosts would be needed to keep the Global Precipitation Mission (GPM) core satellite within the required altitude box. Estimates indicate that this would have meant that the station keeping portionof the mission would likely end in 2027 with an additional 3 years of a driftdown period.  This drift down period would have impact on the science data. Less impact for the radiometer data but a significant impact on the radar data.The decision was made to raise the nominal altitude from 405 km to 435 km. Analysis showed this would lead to the station keeping part of the mission to be extended to 2030 with an additional 3 years of a drift down period. Afterthe drift down, the satellite would have a controlled reentry.  This presentation will provide the details of the boost that occurred on 7 and 8November 2023. This will include a discussion of the impact on the data products and its influence on further reprocessings. 
After the boost and totally unrelated to the boost two anomalies occurred. The first was a spacecraft anomaly and the second was a GMI anomaly. Thispresentation will provide information about these anomalies and their impact on processing. 
Ionospheric D-region response to the 22-26 March 2023 Intense Geomagnetic Storm: a manifestation on Very Low Frequency (VLF) Radio Wave Signals received in the Eastern Mediterranean 
Authors: Ajakaiye Muyiwa Paul , Romano Ben , Reuveni Yuval
Published: March 2024

The idea of searching for the manifestations of solar and geomagnetic events on a very low frequency and low frequency (VLF/LF, 3-30/0.5-470 kHz) radio signals as a means of probing the ionospheric  D-region has drawn much attention in the last few decades. In this study, we present the impacts of the 22-26 March 2023 geomagnetic storm (GS) observed from the Atmospheric Weather Electromagnetic System for Observation Modeling and Education (AWESOME) VLF/LF radio waves receiver located in Ariel University, Israel.  The station collects narrowband (NB) and broadband (BB) data of electromagnetic waves originating from various global VLF transmitters, and also from natural sources such as lightning discharges around the globe to complement other available data sources from ground- and space- based observatories. Our careful analysis of the received LF signals amplitude and phase, under distinct GS phases (initial, main and recovery stages), revealed significant spatial and temporal variations along the different transmitters’ propagation path, both for the N/S and the E/W signal channels.  Such manifestations include both signal enhancement (up to several dB) and signal attenuation. Additionally, analysis between other available data sources from ground- and space- based observatories, such as high (SYM-H) and low (Dst) time resolution GS indices under the three GS regimes, was conducted via a wide range of correlation techniques.