bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatiotemporal variability of heatwave-driven streamflow in nival and glacial basins: Future insights from a century of observations
Authors: Anderson Sam , Chartrand Shawn
Published: March 2024

Heatwaves – short-term periods of anomalous warmth – can play an outsized role in shaping downstream water resources as they impact the timing and magnitude of snow and glacier melt.  Melt-driven runoff enhanced during spring heatwaves is particularly important as it can cause downstream flooding and damage.  It is well understood that heatwaves will become more frequent and more severe in the future due to climate change; however, it is not well understood how the hydrological response to heatwaves will change in the future.Here, we quantify the streamflow response to heatwaves over the past century across Western Canada.  We investigate how such streamflow responses vary in space, time, by streamflow regime, and by hydroclimate conditions, and we present a simple mathematical framework to partition the responses into seasonal and heatwave-driven components.  We use freshet timing and winter snowfall as metrics that are expected to change under climate change, and we compare how streamflow responses to heatwaves differ between baseline historical years (later freshet and more snowfall) and future proxy years (earlier freshet and less snowfall). We find that in future proxy years, the streamflow response to spring heatwaves is diminished when seasonal streamflow is enhanced, indicating that peak streamflow during heatwaves does not necessarily increase under climate warming.  We also find that the proportion of spring streamflow generated by heatwaves is lessened relative to seasonal streamflow, and this proportion is diminished as the freshet progresses.Our results contextualize how the streamflow responses to heatwaves have varied over the past century, to better understand how they may change in the future.  Importantly, our findings have implications for future heatwave-driven flooding in nival and glacial basins at both regional and global scales, and we present novel observational signals of change in heatwave-driven streamflow that can be further investigated by future modelling studies.
Climatology and moisture sources of heavy rainfall in the Andes of southern Ecuador
Authors: Urdiales-Flores Diego , Mariethoz Gregoire , Célleri Rolando , Peleg Nadav
Published: March 2024

Mountains cover approximately one-quarter of the total land surface on the planet, and a significant fraction of the world’s population lives in their vicinity. Orography critically affects weather processes at all scales and, in connection with factors such as land-cover heterogeneity and mesoscale atmospheric process, is responsible for high spatial variability in mountain weather, such as the Tropical Andes. Due to this high complexity, monitoring the atmosphere in the Ecuadorian Andes has remained a challenge due to the lack of high spatio-temporal resolution operational observing systems. We studied heavy rainfall associated with floods to identify the main rain types and their sources of moisture based on non-stationary rainfall-similarity indices and Lagrangian approaches. We analyzed five years of data collected from a high space-time resolution (5 min and 500 m) X-band weather radar that was located at 4450 m a.s.l in the Tropical Andes of southern Ecuador. To identify the origin and trajectories of water vapor masses, we used the NOAA meteorological database (GDAS, global data assimilation system, at 0.5° resolution). Our analysis shows that the heavy rainfall in the region can be divided into five rainfall types: two spatially-clustered rain types (convective) and three spatially-homogenous rain types (stratiform). We found that air masses typing as convective reach the study area preferentially from the eastern flank of the Andes through the Amazon basin (~ 70% of all events). We also compared discharge data with rain types and discussed the type and source of rainfall potentially responsible for triggering flash floods in the Andes of southern Ecuador.
Microplastic trajectories and fates in the Canary Current System using TrackMPD
Authors: Cubas Álvaro , Aguiar-González Borja , Vega-Moreno Daura , Fraile-Nuez Eugenio , Machín Francisco
Published: March 2024

The pollution caused by marine microplastic debris is a significant environmental problem that affects the world’s oceans. Therefore, understanding their movement, distribution and fates in the ocean is crucial for addressing this issue. We explore the sensitivity of microplastic trajectories and fates to physical processes in the Canary Current System by employing the TrackMPD modeling framework, an existing open-access toolbox developed in MATLAB. TrackMPD resolves the limitations of previous toolboxes considering particle dynamical properties and a diverse set of physical processes. The sensitivity tests were performed through the release of virtual particles upstream the Canary Islands, using the horizontal velocity field extracted from the operational Atlantic – Iberian Biscay Irish (IBI) Ocean Analysis and Forecasting dataset. We base the sensibility test on varying the advection resolving method (RK4, RK2 and Euler Method) and the horizontal dispersion coefficient. Comparisons between scenarios are conducted by descriptive visualization of the trajectories and by computing a dimensionless Skill Score based on normalized cumulative Lagrangian separation that allows to estimate differences between trajectories. Results underscore the impact that varying physical processes parameters have on microplastic transport within the Canary Current System. These preliminary findings indicate that the transport and fates of microplastics are strongly influenced by the noteworthy mesoscale activity in the region, especially the eddies, and a coastal jet located east of the islands. After 90 days of simulation, most of the particles remain in the open ocean and those that reach the coast will mainly do so on the east coast of the islands. In all cases, average Skill Score values are above 0.8. The main differences are related to the horizontal dispersion, resulting in lower Skill Scores with higher dispersion coefficients. This effect shows no significant differences between advection scheme resolution. Moreover, the Skill Score indicates variability differences between advection schemes, where the Euler method exhibits more variability than the RK2, and the RK2 more than the RK4. This analysis provides insights into the importance of basic physical processes on the distribution and fate of microplastic debris, thereby increasing the knowledge on the topic. Ongoing analyses test the performance of the above different schemes against real case scenarios of surface drifters navigating through the Canary Current system
The Setting and Timing of Copper Mineralization in the Timna Igneous Complex, southern Israel.
Authors: Elhadad Alon , Bar Elisha , Vapnik Yevgeny , Haviv Itai , Kylander-Clark Andrew , Golan Tzahi , Katzir Yaron
Published: March 2024

The absence of primary sulfides challenges the interpretation of metal ore genesis, particularly where ore is hosted within several separate stratigraphic horizons. In the Timna Valley, S Israel, copper ore bodies occur mostly in Cambrian and Cretaceous sandstones and rarely in the underlying late Neoproterozoic Timna igneous complex (TIC), as secondary Cu-sulfides in veins and nodules and more abundantly as Cu-hydroxides. The timing and setting of copper mineralization in the TIC and its relation to the sedimentary ore are unknown. Quartz phenocryst-hosted fluid inclusion assemblages (FIA) in quartz porphyry (QP) stock and dykes are associated with sulfide inclusions of pyrite, chalcocite, and chalcopyrite, indicating a magmatic-hydrothermal genetic relationship. Mineralization-associated fluid inclusion assemblages (FIAs) in QP are: (FIA.a)
Comparison and validation of state-of-the-art fire emissions models for the Amazon
Authors: van Wees Dave , Huijnen Vincent , Forkel Matthias , de Laat Jos , Andela Niels , Wessollek Christine
Published: March 2024

Amazon forest conservation is critical for reaching net-zero carbon emissions and protecting regional biodiversity but these efforts are at risk from deforestation, fire and drought. In particular, accurate quantification of carbon losses from forest and deforestation fires are required to understand long-term impacts of fire on the carbon cycle and inform management strategies. Recent developments in the detection of burned area, near-real time tracking of fire patch metrics, and higher-resolution fire emissions models allow for improved estimates of carbon losses from fire. Nevertheless, independent validation of these novel approaches often remains elusive, leading to large disagreement between different emissions inventories.Here, we compare carbon emissions estimates from several state-of-the-art fire emissions models, including a 500-m resolution GFED version, GFAS, and the Sense4Fire project, in a case-study for the Amazon region. Where necessary, we have updated the models to extend to 2022 and to include the most recent version of model input data from MODIS (Collection 6.1). We analysed the added years of data to elucidate recent trends in fire-related carbon emissions across the Amazon and adjacent biomes. For validation, we ingested the CO emissions from the considered fire emissions models into an atmospheric transfer simulation (IFS-COMPO) and compared those to column CO observations from Sentinel-5P TROPOMI. Finally, we propose an optimization methodology for matching modelled CO concentrations to observations with the objective of constraining regional carbon losses from fire. Results provide novel insights into carbon losses from fire across different fire types and land use practices, and can be extended to global scale for improved estimates of global fire emissions.
A petrogenetic approach on the St. Martin/Maarten granitoids (Lesser Antilles Arc) and associated mantle processes  
Authors: Koutsovitis Petros , van der Meulen Michiel J. , van Daalen Tirza , Tyrologou Pavlos , Koukouzas Nikolaos , Sideridis Alkiviadis , Karkalis Christos , Grégoire Michel , Petrounias Petros , Ntaflos Theodoros , Lentas Konstantinos
Published: March 2024

In St. Martin, the Oligocene granitoids comprise granodiorites, leucotonalites, melatonalites and Qz-monzodiorites. Tonalites are low-K, whereas granodiorites and Qz-monzodiorites are related with calc-alkaline suites. Mineralogical, geochemical and Sr-Nd isotopic data denote that most rocks are I-type calc-alkaline, except for the melatonalites that seemingly resemble peraluminous S-type granitoids. The melatonalites display the lowest Al2O3/TiO2 and highest CaO/Na2O ratios, pointing to high temperature conditions. Various geothermometry applications, which include Ti-in-zircon thermometry reveal high generated temperatures for the melatonalites, exceeding by ~100 °C those calculated for the other granitoids. Regarding the granodiorites (Type-I low REE; Type-II high REE), Type-II are associated with higher temperature conditions by ~70 °C. Zircon saturation thermometry also show higher crystallization temperatures for the melatonalites and Type-II granodiorites. Thermobarometric results elucidated from mineral chemistry and bulk-rock geochemical point to  higher temperature and pressure crystallization conditions for the melatonalites compared to the leucotonalites and granodiorites. The granitoids were affected by extensive differentiation processes; plagioclase preferably fractionated in the Type-I granodiorites; Type-II mainly involved K-feldspar removal. Fluctuation of hydrous and slab-derived fluid fluxes  contributed to magma differentiation as inferred by the Th/Nb and Ba/La ratios, with hydrous-saturated conditions favouring formation of granodiorites rather than leucotonalites.Melatonalites and Type-II granodiorites likely formed at proto-arc settings, with melting of a fertile mantle during subduction initiation. Melatonalites may have involved magma mixing via interaction of a hotspot plume within the forearc mantle, as denoted by geochemical and geothermometry results. The geochemical features of the Type-II granodiorites likely reflect formation at the early subduction stages, associated with a fertile source.Reference: Koutsovitis et al. 2024. Granitoids from St. Martin/Maarten Island, Caribbean: Insights on the role of Mantle processes in the Lesser Antilles Arc. Lithos (Under Review).
Exploring water quality and pCO2 dynamics in major rivers of Uttarakhand, India
Authors: Upadhyay Pooja , Kumar Prajapati Sanjeev , Kumar Amit
Published: March 2024

Rivers receive substantial amounts of organic carbon from adjacent terrestrial areas, transforming into carbon dioxide (CO2) emissions and contributing to global warming and climate change. The riverine emissions are discussed globally and yet less explored. Notably, anthropogenic land use can influence riverine CO2 emissions, leading to significant uncertainty in estimation. With the increased rates of population and industries, the GHG emissions from rivers are expected to worsen soon. Therefore, effective river management is essential to mitigate emissions and restore river ecosystems. The present study examined the relationship between water quality and CO2 emission of rivers in the Uttarakhand state of India. The partial pressure of CO2 (pCO2) showed obvious spatial variation ranging from ~235 to 12,000 µatm with a mean value of 1860 µatm. Besides, pH, Biochemical Oxygen Demand (BOD), and Alkalinity emerged as significant predictors of pCO2 (R2=0.95). Moreover, pCO2 also had a strong positive correlation with BOD, Chemical Oxygen Demand (COD), phosphate, and nitrate. This study reveals the significant influence of pH, BOD, and Alkalinity on pCO2 levels, underscoring the complex relationship between water quality and carbon dynamics in studied rivers. The correlation also emphasizes the impact of anthropogenic influences on CO2 emissions in major rivers of Uttarakhand, providing valuable insights into the complex nature of carbon dynamics in studied rivers. The strong correlation between water parameters and anthropogenic activities highlights the need for targeted riverine ecosystem management and restoration interventions. 
Legacy seismic refraction and gravity anomaly data in the vicinity of Great Meteor Seamount and its implications for plate flexure 
Authors: Watts Anthony , Grevemeyer Ingo
Published: March 2024

The Great Meteor Seamount is a guyot and the largest seamount in the North Atlantic Ocean with an estimated volume of some 24,000 km3. Located ~1280 km west of Africa and ~720 km south of the Azores, the seamount forms part of a group of seamounts which include Hyeres, Irving, Cruiser, Plato, Atlantis, and Tyro. Previous dredged rock, magnetic anomaly lineation, and predicted hotspot track studies suggest the seamount is ~17 Myr in age, was emplaced on oceanic crust and lithosphere with a thermal age of ~68 Ma and is linked to the New England Seamount Chain. However, bathymetric, free-air gravity anomaly and geochemical data are inconsistent with these ages and such a tectonic setting: bathymetric data suggest a guyot depth of ~400 m which is deeper than expected (~187 m), gravity data suggest an effective elastic thickness, Te, of ~20 km which is lower than expected (~26 km) and geochemical data suggest a link, not to the New England Seamount Chain, but to the Azores Islands instead. To address these inconsistencies, we used legacy Ocean Bottom Hydrophone, free-air gravity anomaly and bathymetry data to reassess the seismic structure, Te, and tectonic evolution of Great Meteor Seamount and its neighbouring seamounts. We show the uppermost crustal structure of Great Meteor Seamount is characterised by a relatively low velocity volcano-clastic sediments (2.0-4.5 km/s) and extrusive lava (5.0-6.0 km/s) drape which overlies a relatively high P-wave velocity intrusive ‘core’ of 6.0-6.5 km/s. The lowermost crust, in contrast, is characterized by a 4-km-thick body of P-wave velocity 7.00-7.75 km/s intermediate in velocity between the crust and mantle, the base of which is at depths at ~16 km. This seismic structure has been verified by gravity modelling assuming a Gardner and Nafe-Drake relationship between P-wave velocity and density, but 3-D flexure modelling reveals that a Moho depth at ~16 km requires a low elastic thickness (Te ~10 km) which is inconsistent with the amplitude and wavelength of the free-air gravity anomaly and the relatively flat depth to the top of the oceanic crust beneath the flexural moats flanking the guyot ‘core’. We found that gravity and seismic data are consistent if the Te of flexed oceanic crust at Great Meteor Seamount is ~20 km and is underlain by a ~4-km-thick magmatic underplated body. In contrast, we found that the Irving, Cruiser, Plato, Atlantis, and Tyro seamounts are characterised by a best fit Te of ~10 km and no evidence of underplating. We discuss these findings here with respect to the guyot depth at Great Meteor, terrace depths at Plato, and the tectonic setting of Great Meteor and its neighbouring seamounts.
Diving into the Future: Advanced Ocean Observation with Cost-Effective AI-Enhanced Autonomous Underwater Vehicles
Authors: Madonia Nicola , Gualdesi Lavinio , Piermattei Viviana , Marcelli Marco
Published: March 2024

Our project addresses the growing demand for extended oceanographic observation network. We are developing an innovative and affordable Autonomous Underwater Vehicle (AUV), named Jolly Oscar, that incorporates artificial intelligence for path determination and destination determination based on marine meteorological conditions. AUVs play a crucial role in marine monitoring by enabling independent exploration of areas that are difficult to access by other platforms. The goal of our approach aims to supply a cost-effective solution compared to existing options, allowing for the acquisition of a fleet of Jolly Oscar vehicles to enhance data collection. Simultaneous data gathering by multiple AUVs not only improves efficiency but also supplies a deeper understanding of marine phenomena. This cost-effective approach enables efficient and extensive spatial coverage, making easier the rapid collection of oceanographic data. Jolly Oscar can be equipped with a different array of interchangeable instrumental packages, including sensors for Conductivity-Temperature-Depth (CTD) and pH, chlorophyll fluorescence, turbidity, passive (hydrophone) and active (side-scan sonar or multibeam sonar) acoustic systems, Acoustic Doppler Current Profiler (ADCP). This versatility is crucial for gathering detailed oceanographic data which are essential for feeding numerical models, deepening our understanding of marine ecosystems, and checking ongoing environmental changes. By developing a cost-effective solution, Jolly Oscar aims to supply broader access to advanced oceanographic exploration. This inclusivity aims to encourage participation and involvement from the scientific community, allowing more researchers to use these technologically advanced tools. This collaborative approach contributes to the global effort of monitoring and understanding the intricate dynamics of our oceans, which is crucial for environmental conservation and responsible marine management.
Exploring Neural Network Performance in Hydrological Modeling in a Mountainous Region of Morocco: A Case Study on LSTM and GRU Architectures for Runoff Prediction
Authors: Nifa Karima , Boudhar Abdelghani , Elyoussfi Haytam , Eljabiri Youssra , Bousbaa Mostafa , Bargam Bouchra , Chehbouni Abdelghani
Published: March 2024

This study thoroughly compared two types of neural networks, namely Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU) recurrent neural networks (RNNs), within the context of hydrological modeling for predicting runoff in the Oum Er Rabia sub-basins. By assessing their performance on both daily and monthly scales, we aimed to understand the dynamics of runoff, which is crucial in water resources management. The combined analysis of predictions at both time scales provides a comprehensive perspective, using daily outputs for short-term decisions and monthly predictions for longer-term planning.Using a hydroclimatic time series dataset from 2000 to 2019, incorporating key factors such as snow cover area, temperature, and rainfall that influence hydrological processes and significantly impact flow patterns, the research evaluates the predictive accuracy of the models at both scales. The results reveal nuanced differences in predictive accuracy, with average Kling-Gupta Efficiency (KGE) values for LSTM and GRU at daily and monthly scales, respectively, being 0.64, 0.52, and 0.46, 0.54. These findings provide insights into the strengths and limitations of each architecture in the mountainous region of Morocco.The study enhances our understanding of the applicability of LSTM and GRU architectures in hydrological modeling, aiding practitioners in selecting models tailored to specific needs. By establishing a robust framework for short-term decision-making and long-term planning in water resource management, this research contributes to advancing predictive modeling and promoting sustainable water use while mitigating flood risks. The knowledge acquired paves the way for improved decision support in the critical area of water resource management.
Towards dating marine sediments using 26Al
Authors: Lausecker Marleen , Wieser Alexander , Marchhart Oscar , Koll Dominik , Lachner Johannes , Merchel Silke , Adolphi Florian
Published: March 2024

Radiometric dating methods are indispensable tools for providing a common and precise timescale for different paleo-environmental archives and their climate records. The cosmogenic radionuclides 26Al and 10Be decay with half-lives of 0.7 Ma (26Al) and 1.4 Ma (10Be), respectively, allowing radiometric dating of climate archives far beyond the range of 14C (t1/2=5730 a) and 230Th (t1/2=75 ka). While 10Be has become a common tool in marine geology, 26Al has been studied significantly less. Low atmospheric 26Al production rates and high stable 27Al concentrations result in very low 26Al/27Al ratios, often near the detection limit of accelerator mass spectrometry (AMS). However, with its half-life of 0.7 Ma 26Al would be perfectly suited to bridge a gap of the currently available radiometric dating methods and may allow for constructing better age models in the 1-3 Ma range. Recently, new developments in the field of AMS enable measurements of low 26Al/27Al ratios by isobar suppression using selective photodetachment via ion laser interaction (ILIAMS at University of Vienna). We use these advances to study 26Al/27Al of globally distributed core-top marine sediments. In combination with the corresponding 10Be/9Be we can now assess the spatial variability of authigenic 26Al/27Al and 26Al/10Be in core-top marine sediments as an important premise for the use of 26Al as a dating tool. Based on these measurements we are able to identify suitable locations for further studies on the behaviour of 26Al/27Al and 26Al/10Be during deposition in the sediment. Ackn.: Parts of the measurements were supported by the RADIATE project from the EU Research and Innovation programme HORIZON 2020 under grant agreement No 824096. Parts of this research were carried out at the Ion Beam Centre (IBC) at the Helmholtz-Zentrum Dresden-Rossendorf e. V., a member of the Helmholtz Association.
2D simulations of Uranium diffusion in clay: geochemical surrogate models and accelerated coupled reactive transport simulations with POET
Authors: De Lucia Marco , Lübke Max , Schnor Bettina
Published: March 2024

The computational burden associated with coupled reactive transport simulations limits their application coarse models and thus to oversimplified geological and geochemical features, with obvious repercussions on uncertainty and safety assessment of nuclear waste disposal facilities. Techniques from approximated computing can however be leveraged to accelerate simulations of large-scale, heterogeneous domains. These include both surrogate models based on machine learning and artificial intelligence (ML/AI) to replace more costly numerical geochemical simulators, and algorithmic improvements such as interpolation from previously computed geochemical simulations stored and indexed in efficient data structures such as  Distributed Hash Tables during coupled simulations. In this contribution we demonstrate recent advancements in physics-based geochemical surrogates achieved within the ML-Benchmark initiative from the DONUT/EURAD project for Uranium diffusion in clay subject to exchange and sorption. Furthermore, the algorithm implemented in the reactive transport simulator POET [1] based on automatic clustering of multivariate data and subsequent interpolation enables the simulation of large-scale, heterogeneous reactive transport scenarios on uniform grids of magnitude of million grid elements at reduced computational costs.[1] Marco De Lucia, Michael Kühn, Alexander Lindemann, Max Lübke, and Bettina Schnor, 2021: POET (v0.1): speedup of many-core parallelreactive transport simulations with fast DHT lookups, Geoscientific Model Development, 14, 7391--7409. https://doi.org/10.5194/gmd-14-7391-202
Fault Nucleation and Reactivation in Displaced Fault Systems: An Experimental Study
Authors: Naderloo Milad , Jansen Jan Dirk , Barnhoorn Auke
Published: March 2024

Understanding fault slip nucleation within the reservoir interval and its propagation beyond the reservoir is essential. Analytical and numerical studies have shown that, depending on the type of operation (injection/depletion), fault slip can nucleate at external or inner corners along the displaced fault system, driven by positive peak shear stresses. In the case of depletion, slip patches gradually start at the inner corners and grow towards the inner part of the reservoir, merging with further depletion. Conversely, injection or increased pore pressure leads to slip patches at external corners, potentially propagating beyond the reservoir into the overburden and underburden. We conducted triaxial experiments on small-scale (mm scale) cylindrical samples containing an entirely displaced vertical fault to investigate fault reactivation and slip nucleation in such settings. Two types of stress paths, monotonic and cyclic, were applied to examine the effects of stress patterns on slip nucleation. For this purpose, we utilized strain gauges to measure differential compaction along the displaced fault directly on the small-scale samples. Direct measurements with a strain gauge network adjacent to the displaced fault system during the monotonic test revealed that differential compaction intensifies from the top of the sample towards the internal corner at the center of the fault where different layers are juxtaposed vertically, indicating a variation in the stress field surrounding the fault plane. Furthermore, results from the cyclic test showed that the differential compaction increases with an increasing number of cycles. Our direct measurements near the displaced fault plane confirm/match the anomalies and peaks in stress observed in previous numerical and analytical studies.
Long-term interventions by conservation and development projects support successful recovery of tropical peatlands in Amazonia
Authors: Honorio Coronado Euridice ,   Research team
Published: March 2024

Sustainable management of non-timber forest products, as a means to increase the value of standing forest, has long been a goal of conservation in the tropics. However, there are few studies of the long-term ecological, social, and economic impacts of sustainable management initiatives. This study addresses this issue in the context of fruit harvesting of the arborescent palm, Mauritia flexuosa. In Amazonia, M. flexuosa grows naturally at high densities in carbon-rich peatland ecosystems and its fruit is an important resource for local communities. Typically, the fruit has been harvested by felling the trees. However, over recent decades, some communities have adopted climbing techniques to harvest the fruits. We analyse for the first time the potential of M. flexuosa populations and fruit production to recover in two rural communities in Peruvian Amazonia where climbing palms was adopted between 1999 and 2002. Since then, these communities have been supported by conservation and development projects.In both communities, we conducted interviews to assess the perceptions of change after the introduction of climbing and carried out forest inventories to estimate changes in two socio-economic indicators (volume of harvested M. flexuosa fruits and income) and three ecological indicators (pole stem density of M. flexuosa, seedling and sapling density, and the sex ratio of adult palms). Our results highlight the positive impacts of the use of climbing to harvest fruits on a range of both ecological and socio-economic indicators in these communities. These results demonstrate that sustainable fruit production is a viable way to conserve the forests, the high carbon stocks beneath the ground and the livelihood of people living in these ecosystems. These findings therefore will be of interest to a wide range of researchers, policymakers, and practitioners seeking to promote sustainable practices in these, and similar, ecosystems across the world and provide support for community-led conservation across the tropics.
A detailed science and operations analysis of the first flyby of Europa by the Juice spacecraft
Authors: Vallat Claire , Lorente Rosario , Altobelli Nicolas ,   The Juice Science Team
Published: March 2024

Juice is the first large mission chosen in the framework of ESA’s Cosmic Vision 2015-2025 program.The focus of Juice is to characterize the conditions that might have led to the emergence of habitable environments among the Jovian icy satellites, in particular Ganymede, Europa and Callisto. Juice will also perform a multidisciplinary investigation of the Jupiter system as an archetype for gas giants.The spacecraft payload consists of 10 state-of-the-art instruments (and one experiment that use the spacecraft telecommunication system with ground-based instruments) that will perform remote and in-situ measurements of Jupiter, its moons and their environment. From a trajectory’s point of view, the mission calls for a three-year orbital survey of the Jupiter system followed by an additional 9 months in orbit around Ganymede for an in-depth characterization of Ganymede as a planetary object and possible habitat. During the Jupiter orbital phase, Juice will perform a sequence of 67 orbits of different periods and inclinations around the planet including several flybys of the Galilean moons, 2 of which as close as 400km altitude from Europa in July 2032.The Juice top level Europa science goals are the determination of the composition of the non-ice materials and understanding their origin (deep interior vs exogenic), the search for liquid water under active sites and the study of the activity processes at play on the moon.A representative detailed science operations plan has been developed by the science team covering a 24 hour-period around the first flyby of Europa in July 2032. The plan considers the latest knowledge on instrument and spacecraft resources and performances available at the time of the study.This work presents the geometry and mission constraints associated to the flyby as well as the observation strategy chosen by the different payload; the remote sensing package’s strategy includes exosphere characterization (including potential plume detection) through limb observations and surface characterization at different scales and wavelengths, both on the inbound (dayside) and outbound (nightside) part of the flyby. At low altitude and centered around closest approach, the geophysics package will perform topography and surface roughness measurement using the laser altimeter as well as surface sounding down to a depth of up to ~ 9 km with the ice penetrating radar. Radio science range rate measurement will support the estimate of the main quadrupole coefficients and the testing of the hydrostatic hypothesis. The in-situ package will operate continuously to monitor the Europa plasma, neutral and electromagnetic wave environment. The resulting harmonized operations timeline, together with resources limitations and the assessment on the expected science return is discussed.
The I-T response to most recent solar eclipses: Observations and modeling
Authors: Mrak Sebastijan , Cantrall Clayton , Maruyama Naomi , Chamberlin Phil , Aryal Saurav , Deng Yue , Hairston Marc
Published: March 2024

We discuss multiple observations of atmospheric dynamics during recent solar eclipses: 21 August 2017, 4 December 2021, 20 April 2023, 14 October 2023, and 8 April 2024. We use GOLD and TIMED/GUVI instruments to observe the changes in the lower thermosphere related to atmospheric oxygen O, and molecular nitrogen N2. We discuss the problematic nature of O/N2 composition estimation from brightnesses under solar obscuration conditions, and how the observations should be properly interpreted. The Ionosphere-Thermosphere (I-T) system responds to solar X-Ray and Extreme Ultra Violet (EUV) radiation, which is highly non-uniform during solar eclipses. We introduce a new model of solar eclipse obscuration and irradiance by combining the solar occultation software PyEclipse and Flare Irradiance Solar Model 2 (FISM2) -- FISM2-Eclipse. We implemented FISM2-Eclipse into the Global Ionosphere thermosphere Model (GITM) and Whole Atmosphere Model Ionosphere-Plasmasphere-Electrodynamics model (WAM-IPE) to conduct a model-data comparison. We discuss some salient features noted during the recent eclipses.
A New Lens on Atmospheric Rivers
Authors: Asharaf Shakeel , Guan Bin , Waliser Duane
Published: March 2024

This presentation introduces the ROTated Atmospheric river coordinaTE (ROTATE) system – a storm-centric coordinate system designed specifically for analyzing long, narrow filamentary regions of intense water vapor transport in the lower atmosphere or so-called atmospheric rivers (ARs). It effectively preserves key AR signals in the time mean that may be lost or obscured in simple averaging due to diverse AR orientations and shapes. We used ROTATE to look at crucial characteristics of atmospheric rivers such as how wet the air is, how fast the wind blows, how much water vapor is being transported, and how much rain falls. We found more apparent AR patterns with ROTATE compared to the conventional non-rotated AR centroid-based compositing approach. The new method also helps us see finer details in rain distributions over land versus over the oceans. It is further apparent that the ROTATE system more distinctly delineates the finer details in precipitation distributions for landfalling and oceanic ARs. Overall, the ROTATE system has the potential to serve as a valuable tool for better comparing and understanding the characteristics, processes, and impacts of ARs across different regions. Details about the analysis and challenges associated with the current results will be discussed in this presentation.
Attributing the role of sudden stratospheric warming events in surface weather extremes and their impacts: insights from SNAPSI Working Group 2
Authors: Seviour William , Butler Amy , Garfinkel Chaim , Hitchcock Peter ,   SNAPSI Working Group 2
Published: March 2024

Sudden stratospheric warming events (SSWs)–in which the westerly polar vortex rapidly breaks down during winter–are  some of the most dramatic examples of dynamical variability in Earth’s atmosphere. It is now well established that SSWs are, on average, followed by large scale anomalies in near-surface circulation patterns, including an equatorward shift of the eddy driven jet that can persist for several months. These anomalies have, in turn, been related to an increase in the likelihood of a variety of high impact weather extremes. However, not all SSWs are followed by impactful weather events; equally, most winter weather extremes are not preceded by SSWs.Here we will discuss the extent to which the occurrence of individual extreme weather events and their impacts can be attributed to polar stratospheric variability, drawing upon new results from the Stratospheric Nudging And Predictable Surface Impacts (SNAPSI) project (Working Group 2). This project involves a set of controlled subseasonal hindcast experiments, targeted at three SSW case study events, in which the stratospheric state can be either freely-evolving or nudged towards a climatological or observational state. These simulations reveal that the stratospheric evolution can more than double the regional risk of extreme temperature, rainfall, and snow events. We will go on to explore the attribution of the subsequent impacts of these weather extremes, including on the energy sector, health, and wildfires.  
Climate change signature on Euro-Mediterranean lee cyclogenesis
Authors: Sangelantoni Lorenzo , Tibaldi Stefano , Cavicchia Leone , Peano Daniele , Scoccimarro Enrico
Published: March 2024

This study explores whether and why a warmer climate induces alterations in climatological statistics and the underlying physical features of lee cyclogenesis in the Euro-Mediterranean region.The investigation focuses on a specific cyclogenesis type, wherein orography (the Alps), influences the spatial structure and growth rate of the cyclone.This regional scale phenomenon is inspected within the framework of a general weakening and poleward shift of the mid-latitude jet. This large-scale signal, despite being evident in zonal-averaged results from the majority of climate models, remains subject to considerable uncertainty when specific regions and seasons are considered. This uncertainty stems from the intricate interplay and delicate equilibrium among numerous competing mechanisms.The analysis focuses on historical and future trends during the cold semesters across the Euro-Mediterranean region. The historical period is examined using ERA5 reanalysis spanning from 1940 to the present, supplemented by a higher-resolution regional reanalysis product (COSMO-REA6) at approximately 6 km resolution, covering the period 1995-2019 over the Euro-CORDEX (EUR11) domain. State-of-the-art high-resolution climate models are employed to assess historical reproducibility and future trends through an ensemble of global climate models from the HighResMIP initiative.Methodologically, two distinct approaches are pursued. Firstly, changes in statistical properties of lee cyclogenesis are examined, along with composites of precipitation and wind extremes footprint, utilizing two tracking algorithms: TempestExtremes (Ullrich et al., 2021) and TRACK (Hodges, 1994). These algorithms differ in their identification/tracking variables, i.e., mean sea level pressure and 850hPa relative vorticity, respectively. Secondly, an empirical orthogonal function (EOF) analysis is employed to evaluate whether dominant spatial patterns of relevant variables (e.g., mean sea level pressure and 500hPa geopotential height) associated with cyclogenesis undergo significant changes across different time segments.This investigation is conducted as a spin-off of the Copernicus-ECMWF-funded contract C3S2_413 - Enhanced Operational Windstorm Service. The findings aim to enhance our understanding of the complex dynamics of Euro-Mediterranean lee cyclogenesis in the context of a changing climate, providing further insights for climate science and operational windstorm services.
A cloud-by-cloud approach for studying aerosol-cloud interaction in satellite observations 
Authors: Alexandri Fani , Müller Felix , Choudhury Goutam , Achtert Peggy , Seelig Torsten , Tesche Matthias
Published: March 2024

Aerosol-cloud interactions are of central importance for understanding climate processes but remains the largest uncertainty associated with climate change. Hence, the effective radiative forcing (ERF) due to ACI and rapid adjustments (ERFaci) is still assessed only with medium confidence. An important part of this uncertainty originates from the difficulty of quantifying ACI using observations, especially for ice-containing clouds. In this study, we present a novel Cloud-by-Cloud (CxC) approach for studying ACI in satellite observations that merges properties of individual clouds that have been tracked from geostationary satellite observations with height-resolved concentrations of cloud condensation nuclei (nCCN) and ice nucleating particles (nINP) from polar-orbiting lidar data. This approach lays the foundations for better understanding of ACI through a thorough investigation of matched aerosol-cloud cases at cloud level. The methodology is applied to satellite observations over Central Europe and Northern Africa for several years, resulting in a bottom-up dataset of combining parameters that can be stratified accordingly for assessing the impact of changes in cloud-relevant aerosol concentrations on the surrounding quality assured liquid and ice-containing clouds. The first preliminary results of this novel CxC approach are promising and constitute a step forward in the quantification of ERFaci from space.
Discovering global-scale processes in the marine atmosphere
Authors: Carpenter Lucy , Callaghan Anna , Chance Rosie , Evans Mat , Lee James , Read Katie , Rowlinson Matthew , Shaw Marvin , Sherwen Tomas , Andersen Simone , Tinel Liselotte , Plane John
Published: March 2024

Measurements in the remote unpolluted atmosphere have tremendous power to reveal processes that are happening on a global scale.   In the marine atmosphere where nitrogen oxide (NOx) levels are very low,  the photochemical loss rate of tropospheric ozone dominates over production, allowing loss processes to be sensitively explored.   We showed that bromine and iodine emitted from open-ocean marine sources initiate important global-scale catalytic ozone-destroying cycles and found that the deposition of ozone and subsequent reactions at the sea surface are a substantial pathway for production of volatile iodine.   Production of ozone in the remote atmosphere is predominantly regulated by the abundance of NOx, which also exerts substantial control over the hydroxyl radical (OH), the most important oxidant in the atmosphere.  It is now emerging that NOx regeneration pathways, namely the photolysis of particulate nitrate, could provide the dominant source of NOx to the marine atmosphere.  This has significant implications for our understanding of the chemistry of the remote troposphere.  This presentation discusses advances made in understanding these important, predominantly natural, cycles and their impacts on the atmosphere.
The EOLIS dataset: Monitoring Land Ice from CryoSat-2 Swath Processing
Authors: Jakob Livia , Gourmelen Noel , Michael Carolyn , Dubber Sophie , Ewart Martin , Bizon Julia , Horton Alex , Goss Tristan , Incatasciato Andrea , Di Bella Alessandro , Bouffard Jerome , Parrinello Tommaso
Published: March 2024

Satellite radar altimetry has been routinely used to monitor land ice heights since the 1990s. However, the launch of CryoSat-2 – the first altimetry mission to carry a synthetic aperture radar interferometer on board – has allowed several technical breakthroughs and led to many new applications that were previously unforeseen. One such breakthrough is Swath processing of CryoSat’s SARIn mode, making full exploitation of the information contained in CryoSat’s waveforms and leading to one to two orders of magnitude more measurements than the conventional so-called Point-Of-Closest-Approach (POCA) technique.Following on from the early demonstration of the technique and of its potential impact, the CryoTEMPO EOLIS (Elevation Over Land Ice From Swath) dataset now routinely provides information of elevation over land ice at high resolution on a monthly basis. The dataset allows the use of radar altimetry in new environments such as the more complex terrain over glaciers and ice caps, as well as new applications thanks to the superior spatial and temporal resolution, such as the more precise quantification of subglacial lake drainage events. Currently, the EOLIS dataset is provided at monthly intervals over both ice sheets as well as all larger glacier regions, with future developments such as the expansion of the dataset to the ice shelves and new gapless annual DEMs over the two ice sheets coming soon.With the aim of making CryoSat-2 altimetry data available to non-altimetry experts and encouraging its use more broadly by the community, the platform CS2EO (cs2eo.org) provides advanced data access to the EOLIS suite datasets. In CS2EO, users can query coincident data with other altimetry sensors, as well as explore and download custom elevation change time series over desired areas on ice sheets and glaciers, without having to download the EOLIS data first.
Testing sensors for validating microwave products of forest water status
Authors: Vermunt Paul , Rietbroek Roelof , Van der Tol Christiaan , Zeng Yijian , Su Zhongbo
Published: March 2024

European forests are experiencing a significant increase in mortality as a result of plagues and wildfires, often enhanced by droughts. Understanding, managing, and adapting our forests to future changes requires large-scale spatiotemporal monitoring of forest water status. Microwave remote sensing products, such as Vegetation Optical Depth (VOD), are a valuable addition to optical metrices due to their direct relationship to vegetation water content (VWC) and consistent time series. These products are increasingly used for studying drought-stressed vegetation. However, unlike soil moisture, there is little continuous ground-based data to validate VWC estimates from microwave instruments. To accelerate the development of VWC products, we need continuous ground-based measurements for various locations. In a Dutch coniferous forest, we have tested state-of-the-art sensors and approaches to measure water content and potential continuously (i.e. using frequency- and time domain reflectometers, GNSS receivers, microtensiometers, dielectric leaf wetness sensors, sap flow sensors, dendrometers). The objectives are (I) to perform long-term continuous measurements, (II) to use our insights to scale up the measurements to other locations. After multiple months of measuring, we here present our first results.