bluuebunny/crossref_metadata_2025 huggingface dataset:
Drought impact-based forecasting of crop yield in India
Authors: Shyrokaya Anastasiya , Uttarwar Sameer , Di Baldassarre Giuliano , Majone Bruno , Messori Gabriele
Published: March 2024

The reliable prediction of drought impacts on crop yield in India poses a significant challenge due to the complex interactions of climatic variables, systems vulnerabilities and impacts propagation. Advanced approaches, such as impact-based forecasting, become necessary to address the intricate nature of this challenge. In this study, we leveraged remote sensing-based vegetation indicators as proxies for crop yield, along with multiple drought indices across various accumulation periods, to establish a robust indicator-impact relationship. We further performed a comparative analysis of various machine-learning algorithms to assess their efficacy in predicting crop yield impacts on a subseasonal-to-seasonal scale. We finally evaluated the accuracy of predicting the crop yield impacts based on drought indices computed from ECMWF’s seasonal forecast system SEAS5.Our analysis not only unveils seasonal trends and spatio-temporal patterns in indicator-impact links but also marks a pioneering effort in comparing diverse machine-learning algorithms for establishing an impact-based forecasting model. As such, these findings offer valuable insights into the dynamics of drought impacts on crop yield, providing a monitoring tool and a foundational basis for implementing targeted drought mitigation actions within the agricultural sector. This research contributes to advancing the understanding of impact-based forecasting models and their practical application in addressing the challenges associated with drought impacts on crop yield in India.
Refinements of regional gravimetric and hybrid geoid models in support of the GeoNetGNSS CORS network in Northern Greece
Authors: Natsiopoulos Dimitrios A. , Vergos Georgios , Mamagiannou Elisavet G. , Tzanou Eleni A. , Triantafyllou Anastasia I. , Tziavos Ilias N. , Ramnalis Dimitrios , Polychronos Vassilios
Published: March 2024

In the frame of the GeoNetGNSS project, funded by the European Union and National Funds through the Region of Central Macedonia (RCM) in Northern Greece, regional gravimetric and hybrid geoid models have been determined with the main goal being to support a newly established network of Continuously Operating Reference Stations (CORS). The main aim was to assist everyday surveying purposes by delivering accurate orthometric heights based on GNSS/Levelling, i.e., determining orthometric heights without the need to carry out levelling. With that in mind, a regional gravimetric geoid was determined based on historical and newly acquired high-accuracy and density gravity data, employing the Remove-Compute-Restore (RCR) technique and both stochastic and spectral evaluations of Stokes’ integral. Consequently, a hybrid deterministic and stochastic approach was used to model the residuals of the gravimetric geoid solution relative to available GNSS/Levelling geoid heights. The latter refer to 533 geodetic benchmarks in the entire study area, where accurate static GNSS observations and orthometric heights from the Hellenic Military Geographic Service (HMGS) were available. Various parametric models ranging from simple north-south bias and tilt to 2nd and 3rd order degree polynomial models were evaluated in terms of the fit residual absolute and relative differences. After the deterministic fit, a collocation approach employing exponential and 2nd order Gauss-Markov covariance functions was used to model the stochastic residuals. Finally, the hybrid deterministic and stochastic corrector surface, provided as grid corrections for the entire area under study, has been determined to accommodate user needs for orthometric height determination. From the results acquired, absolute differences of the order of 1-2 cm and relative ones at the 3-4 ppm have been achieved after validation against independent GNSS/Levelling observations.
Notebook-as-a-VRE (NaaVRE): From private notebooks to a collaborative cloud virtual research environment
Authors: Pelouze Gabriel , Koulouzis Spiros , Zhao Zhiming
Published: March 2024

Studying many scientific problems, such as environmental challenges or cancer diagnosis, requires extensive data, advanced models, and distributed computing resources. Researchers often reuse assets (e.g. data, AI models, workflows, and services) from different parties to tackle these issues. This requires effective collaborative environments that enable advanced data science research: discovery access, interoperation and reuse of research assets, and integration of all resources into cohesive observational, experimental, and simulation investigations with replicable workflows. Such use cases can be effectively supported by Virtual Research Environments (VREs). Existing VRE solutions are often built with preconfigured data sources, software tools, and functional components for managing research activities. While such integrated solutions can effectively serve a specific scientific community, they often lack flexibility and require significant time investment to use external assets, build new tools, or integrate with other services. In contrast, many researchers and data scientists are familiar with notebook environments such as Jupyter. We propose a VRE solution for Jupyter to bridge this gap: Notebook-as-a-VRE (NaaVRE). At its core, NaaVRE allows users to build functional blocks by containerizing cells of notebooks, composing them into workflows, and managing the lifecycle of experiments and resulting data. The functional blocks, workflows, and resulting datasets can be shared to a common marketplace, enabling the creation of communities of users and customized VREs. Furthermore, NaaVRE integrates with external sources, allowing users to search, select, and reuse assets such as data, software, and algorithms. Finally, NaaVRE natively works with modern cloud technologies, making it possible to use compute resources flexibly and cost-effectively.We demonstrate the versatility of NaaVRE by building several customized VREs that support legacy scientific workflows from different communities. This includes the derivation of ecosystem structure from Light Detection and Ranging (LiDAR) data, the tracking of bird migrations from radar observations, and the characterization of phytoplankton species. The NaaVRE is also being used to build Digital Twins of ecosystems in the Dutch NWO LTER-LIFE project.
Let’s be SMART about climate goals
Authors: Mengis Nadine
Published: March 2024

Although largely scientifically robust, there are elements within the politically-negotiated Paris Agreement where defined methods deviate from the best available assessment of what is physically required to achieve its set goals. Fundamentally, one such deviation is about the net zero greenhouse gas (GHG) emissions goal: current interpretations and applications thereof in nationally determined contributions deviate from what is actually required to halt human-induced global warming.Here I show that, while attempting to be comprehensive, most of the nationally declared climate goals are unspecific if not misleading, do not actually deliver on temperature stabilisation and have a problematic treatment of future carbon removal (CDR) expectations. On the one hand, the net zero CO2-eq goals overemphasise the need for CDR deployment to reach climate targets, since net-negative CO2 emissions are required to compensate for non-CO2 GHGs. On the other hand, accounting for natural sinks as CDR within national net-zero goals overestimates current and future CDR potentials and mitigation actions, and will not actually deliver anthropogenic net zero CO2.I accordingly propose to re-orient national climate action towards Specific, Measurable, Achievable, Relevant and Time-bound (SMART) goals, such as a net zero fossil fuel CO2 emissions target by mid-century.
Evaporation of seawater produces amorphous calcium-magnesium carbonate when aragonite precipitation is inhibited
Authors: Methley Peter , Jiang Clancy , Strauss Justin , Tosca Nicholas
Published: March 2024

As a metastable precursor to crystalline carbonate minerals, amorphous calcium-magnesium carbonate (ACMC) has been implicated in the formation of enigmatic fabrics and minerals, such as calcite microspar, fibrous cements and fabric-retentive dolomite, that characterise both modern and ancient carbonate systems (e.g. Wang et al., 2012). The detection of nanocrystals within ancient dolomicrite, using high-resolution transmission electron microscopy, strengthens this hypothesis (Meister & Frisia, 2019).However, it has remained unclear whether natural, abiotic processes could produce ACMC, because of a requirement for extreme carbonate supersaturation. This study tests the hypothesis that – in the presence of micromolar concentrations of aqueous phosphate, which can inhibit aragonite precipitation (Roest-Ellis et al., 2021) – the evaporation of Neoproterozoic seawater may have increased alkalinity, pH, and carbonate saturation enough to precipitate ACMC in shallow-water settings.We conducted evaporation experiments using phosphate-free and phosphate-bearing ([PO4]Total = 50 μmol/kg) synthetic seawater with Tonian composition. Solution samples, pH and alkalinity measurements were collected at regular intervals over 9-14 days. Final solids were collected and analysed using X-ray diffraction, Raman spectroscopy, and scanning electron microscopy.Experimental data show that phosphate-bearing seawater undergoing evaporative concentration reaches increasingly high alkalinity, pH and carbonate saturation until the first solid phase forms. Analytical data indicate that ACMC precipitated during evaporation of phosphate-bearing seawater, whereas aragonite dominated in phosphate-free systems. When evaporating the water more slowly, the ACMC is observed to recrystallise into other metastable carbonate minerals – either fibrous monohydrocalcite or needles of hydromagnesite, depending on the solution’s initial Mg/Ca ratio.These results suggest that low concentrations of species which inhibit crystalline carbonate precipitation allow extreme carbonate supersaturation to be reached upon evaporation. We speculate that this pathway may have facilitated platform-scale production of metastable precursors to syndepositional and early diagenetic dolomite in shallow-water late Proterozoic carbonate sediments, consistent with sedimentological and stratigraphic evidence for evaporation.
Observation of different multifractal phase transitions over three typhoon events
Authors: Chou Ching-Chun , Gires Auguste , Wang Li-Pen , Tchiguirinskaia Ioulia , Schertzer Daniel
Published: March 2024

Rainfall is extremely variable in both space and time, which makes its analysis complex. A widely used framework to properly handle these features is Universal Multifractals (UM), which is a physically based and mathematically robust framework. It relies on three parameters, meaning it is parsimonious. Two types of multifractal phase transitions can affect the analysis of a series: (i) the divergence of moments, which is related to the singular limit of the underlying cascade process at small scales and notably explains the power law fall-off observed on numerous geophysical fields, (ii) sampling limitations, which is related to the fact that great moments cannot be observed on finite series. This study employs UM to analyse the time series of rainfall intensities observed by the Parsival2 disdrometer at the 10-second resolution from three distinct typhoons over the period of July to October 2022, revealing differences and limitations in their statistical characteristics. It enables us to illustrate the  two previously mentioned concepts of divergence of moments and sampling limitations and their impact on the analysis of rainfall data.The analysis of typhoon Hinnamnor exhibited limitations due to the sampling dimension, indicating that the current data length was insufficient to capture the multifractal nature of the rainfall events for large moments, reducing the robustness of the analysis for moments greater than 5.43. It reflects sampling limitations, leading to a constrained understanding of extreme events.For typhoon Nalgae, our analysis highlighted the occurrence of divergence of moments, i.e. a limitation associated with a critical moment. As higher-order moments were calculated, we observed statistical values tending towards infinity, suggesting that extreme rainfall events significantly influenced this typhoon and pointing out the inadequacy of traditional statistical methods in such scenarios. Such multifractal phase transition is seldom observed on individual series, highlighting the interest of studying this typhoon series. Finally, the analysis of the typhoon Nesat presented a behavior affected by both multifractal phase transitions resulting in a more complex interpretation. Our findings provide new insights into the multifractal analysis of typhoon rainfall intensities, emphasising the importance of considering multifractal theory and its associated phase transitions when dealing with natural phenomenon data. These discoveries lay a crucial methodological foundation for more accurate prediction and response to extreme weather events. In case of rainfall, it then has some hydrological consequences notably in terms of stormwater management or optimization of dams for hydraulic production.
Influence of the soil water content and heavy metals/metalloid on woody plant’s aboveground biomass
Authors: Lovynska Viktoriia , Wiche Oliver , Sytnyk Svitlana
Published: March 2024

Toxic elements causing soil pollution and degradation are able to enter the substance cycle of ecosystem. Woody plants often act as critical objects for accumulating toxicants with their subsequent removal from the cycle of substances for a long period. Understanding the conditions of soil water saturation is essential for hydrological processes, and therefore influences this parameter in soil on the transfer of toxicants to vegetation too. The objective of this study was therefore to determine whether soil water saturation relate with heavy metals/metalloid accumulation in soils and whether it is possible to describe the relationship between accumulated toxic elements in soils and woody plants. The was conducted at 21 locations in the Freiberg region, Germany, where soil contamination with toxic metals is increasingly becoming problematic.The content of metals in the soil, leaves and branches were measured by ICP-MS. The relationship between soil saturation and accumulated heavy metals/ metalloid levels in the soil and the aboveground biomass of plants was analyzed. The maximum concentration of the studied toxic elements reached 7.36 mg kg-1 in the soil for Cd (Freiberg city forest), 618.1 for Pb (Freiberg Davidschaft vicinity), and 23276 for As (Davidschaft). The ability of woody plants Populus tremulae and Salix caprea to accumulate heavy metals/metalloid (Cd, Pb, and As) in aboveground biomass was studied under the condition of their growth in areas with increased content of these elements in the substrates.  The ability of the studied plants to absorb heavy metals/metalloid was determined based on the bioaccumulation coefficient. The accumulation of metal elements occurs more intensively in the assimilation part of plant biomass as compared to the wood of tree branches. The study demonstrates a more significant accumulation of toxic elements in  Salix caprea trees' aboveground biomass than Populus tremulae. The level of Cd accumulation in the biomass of Salix caprea defines this species as a potential hyperaccumulator of this element, allowing the strategies to be adjusted for the phytoremediation purposes of disturbed landscapes.
Impactor-Based Size Fractionation of Aerosol Particles over the Tropical Atlantic Ocean: Source Identification using Nd, Sr, and Pb Isotopes 
Authors: Teruel-Cabello Oriol , Pena Leo , Garcia-Solsona Ester , Paredes Eduardo , Cacho Isabel , Rosell-Melé Antoni , Villanueva Joan
Published: March 2024

Airborne mineral dust is a significant constituent of the Earth's climate system that warrants detailed investigation to comprehend its impact on climate processes. This work presents a comprehensive multiproxy approach, utilizing Sr-Nd-Pb isotopes, to discern mineral dust source areas from North Africa, a region contributing approximately 55% of the global annual dust load. Our research not only focuses on identifying provenance but also explores the relationship between climate processes in source areas and aerosol properties at remote locations. We collected samples during three oceanographic campaigns in the tropical Atlantic Ocean conducted in 2020, 2021, and 2022, spanning late winter and entire spring periods. The interannual aspect allows us to capture variations, enhancing our understanding of dust emission and transport dynamics. The implementation of a sampling device that separates aerosol particles of different sizes allows for the detailed isotopic characterization of particles in each size range. Our results indicate the existence of diverse origin and transport patterns depending on the particle size. Differentiation based on particle size uncovers compelling insights into the dynamics of dust dispersion, revealing size-dependent variations in dust behavior. Notably, we observe distinctive pathways for the mass of elements at each size, elucidating the complex interplay between Nd, Sr, and Pb. 
Optimized resolution of gridded data from European agricultural census
Authors: Skøien Jon Olav , Lampach Nicolas , Ramos Helena , Seljak Rudolf , Koeble Renate , van der Velde Marijn
Published: March 2024

The European agricultural census  in 2020 collected a large number of variables from the major share of all the farms within the European Union. There are many potential applications of such a data set, from direct estimates of agricultural indicators to use as input in more complex analytical models. However, the individual responses in the data set cannot be shared directly, as they are regarded as confidential information. Instead, the data must be aggregated to a level where individual responses cannot be identified, typically NUTS regions or grid cells. As a minimum, each aggregated value must be estimated from at least 10 farms (frequency rule). Additionally, a dominance rule requires an aggregated value to be treated as confidential if the 2 largest farms are responsible for more than 85% of the value within a grid cell.Whereas such requirements are clear, there are many methods for creating grids that respect them. The distribution of data is usually not homogeneous, and different methods have varying effects on the result.  We will outline the advantages and drawbacks of certain methods and present the most promising one that involves grid cells of varying sizes. Whereas there are some examples of this method in the past, it will be the first time it is applied on a continental scale and high-resolution data set such as the European agricultural census data.
Power outages in windstorms: the influence of rainfall preconditioning, wind direction and season
Authors: Manning Colin , Wilkinson Sean , Fowler Hayley , Kendon Elizabeth , Dunn Sarah
Published: March 2024

Windstorms are the main cause of large power outages in the UK. Faults to electricity distribution networks during windstorms are predominantly a result of windthrow, the uprooting or breakage of trees by winds that then fall on assets such as overhead lines. The impact of strong winds on windthrow is influenced by a several conditions: trees uproot more easily in saturated soils, they are more vulnerable to strong winds from unusual directions, and they are more susceptible to strong winds in the growing season when their leaves catch the wind. Despite this, risk assessments of impacts, such as power outages, during windstorms generally focus on wind intensity alone. Here, we quantify the influence of contributing variables of windthrow including antecedent rainfall, wind direction of the maximum wind gust, and the season a windstorm occurs in. We demonstrate that including them in a logistic regression model alongside wind speed can improve the predictive skill of the number of electricity faults during windstorms compared to a reference model that only includes wind speed. The analysis uses fault data from the National Fault and Interruption Scheme (NaFIRs) database during the period 2006-2018 in four regions in the UK: South Wales, Southwest England, East Midlands, and West Midlands. Meteorological data is provided by ERA5. Each variable is shown to modulate the impact of strong winds and improve predictive skill, though with some regional variability. The probability of a high fault numbers in a windstorm with winds exceeding 25 m/s can be doubled following high rainfall accumulations and five times higher when strong winds come from a direction that deviates more than 40 degrees south or west from the prevailing south-westerly direction. Furthermore, this probability is doubled in summer months compared to winter. These results can help improve impact forecasting during windstorms and highlight the importance of including these variables in historical and future risk assessments of assets vulnerable to windthrow. Ignoring such contributions may lead to misrepresentation of risk and potential maladaptation, particularly for electricity distribution networks that will undergo a huge transformation as we reduce our dependence on greenhouse gases in the future.
Comparing the Performance of Single U-tube, Double U-tube and Coaxial Medium-to-Deep Borehole Heat Exchangers
Authors: Brown Christopher , Kolo Isa , Banks David , Falcone Gioia
Published: March 2024

The UK heating sector must be decarbonised to achieve net zero targets by 2050; and geothermal energy can help to provide low carbon heat. Closed-loop geothermal systems can provide low-risk solutions via the repurposing of ex-hydrocarbon and unused geothermal exploration wells. Closed-loop, medium-deep borehole heat exchangers (MDBHEs), at depths defined from 500-1000 m, could potentially use a variety of configurations, including single U-tube, double U-tube and coaxial. U-tube MDBHEs involve one or more pipes being inserted in the borehole with heat being transferred to a chilled circulating fluid within the U-tube(s) via conduction through any grout and the borehole wall. Coaxial MDBHEs consist of a concentric central pipe being inserted within an outer pipe (often, the borehole casing). Cool fluid is circulated down the annular space, gaining heat by conduction through the outer pipe wall, before being pumped to the surface through the central pipe. This study addresses the thermal and hydraulic performance of these different configurations under a range of geological and engineering conditions. Simulations were undertaken using OpenGeoSys software to evaluate optimal configurations by minimising hydraulic (and thus parasitic power) losses, while maximising the thermal output.Under the base case scenario at 800 m, assuming water as the circulation fluid, it was observed at the end of the 25-year simulation, with a flow rate of 5 L/s and inlet temperature of 5 °C, that single U-tube, double U-tube and coaxial configurations provide specific heat extraction rates of 32.8, 36 and 39.1 W/m, respectively. These correspond to pressure losses of 1.46 MPa, 423 kPa and 85 kPa. From the analyses, it was observed that the coaxial configuration led to the lowest pressure losses and generally maximised the thermal output. The coaxial system was then applied to a case study for the Newcastle Science Central Deep Geothermal Borehole, where there are plans to repurpose the well to c.920 m in 2024 for geothermal testing. Results indicate that a thermal power of 50 kW could be attainable for a geothermal gradient of 33.4 °C/km, rock thermal conductivity of 2.5 W/(m.K) and flow rate of 5 L/s.
Simulations of Langmuir-wave emission by magnetic holes in the solar wind
Authors: Liu Jingting , Verscharen Daniel , Coburn Jesse , Agudelo Jeffersson , Germaschewski Kai , Reid Hamish , Nicolaou Georgios , Owen Christopher
Published: March 2024

Langmuir waves are frequently detected in the solar wind and affect the energetics of the plasma electrons. Previous observational studies have found Langmuir waves associated with magnetic holes in the solar wind. In our work, we aim to understand the connection between magnetic holes and these waves.The Langmuir instability is a well-known consequence of electron beams in plasmas. We use particle-in-cell (PIC) simulations of a collisionless electron-ion plasma in a magnetic hole structure. We study the triggering of Langmuir waves by inhomogeneous beam instabilities in this configuration.Our simulations reveal patterns that suggest that injecting a beam into the magnetic hole has the potential to create spatially inhomogeneous Langmuir wave packets by instability. We support our PIC simulations with linear stability calculations and discuss the conditions required for magnetic holes to emit Langmuir waves through our proposed mechanism. Our simulation results will be used in comparative studies with observational data of Langmuir-wave emitting magnetic holes.  
Linking biogeochemical potential to depositional processes
Authors: Cantarella Vitor , Mellage Adrian , Cirpka Olaf
Published: March 2024

Biogeochemical reactions are microbially mediated chemical reactions that occur naturally in the subsurface, involving naturally occurring and anthropogenically enriched reactants as well as microbes. These reactions play a crucial role in determining the fate of reactive solutes in groundwater. In Quaternary aquifers, the depositional (sedimentological) processes modulate the composition of the sedimentary matrix, leading to strong spatial variability in both hydraulic and reactive properties. For example, the presence or absence of reduced minerals or organic matter in the sediment matrix determines its “reactivity” with respect to oxidized reactants, auch as dissolved oxygen and nitrate. Additionally, the depositional processes determine properties relevant to groundwater flow, notably the hydraulic conductivity. In this work, we attempt to link depositional processes and the physico-chemical makeup of sediment matrices with the ability of an aquifer to naturally attenuate electron acceptors. We focus on nitrate and denitrification as dissolved electron acceptor and associated biodegradation pathway, respectively. Traditional numerical modeling approaches that account for physical heterogeneity in reactive transport rely on geostatistical methods using, e.g., multi-Gaussian random fields, and often fall short in capturing the link to the geological generating processes. We propose the use of object-based modeling to realistically represent the subsurface's physical characteristics and bridge the gap between geology and biogeochemical potential. Object-based models depict various sedimentary features as 3-D geometries (geo-bodies) within a hierarchical framework. On the largest spatial scale, the model represents strata, corresponding to the sedimentary deposition setting. Within each stratum, facies elements (with internal structure such as crossbedding or layering) representing architectural elements, such as channels or scour-pool fills, are assigned. We illustrate the construction of an object-based aquifer scale groundwater flow model informed via sedimentological descriptions (core logs), integrating field and lab-derived information. Furthermore, we apply a travel-time based reactive transport modelling approach to quantify the effect of the realistic distribution of reactive sedimentary faces on the extent of denitrification. We expect our ongoing analysis to shed light on the quantitative link between the sedimentological architecture of an aquifer and its denitrification potential.
Challenges in analysing and modelling extreme floods: The case study of Ahr catchment
Authors: Shehu Bora , Bronstert Axel
Published: March 2024

The extreme weather conditions of July 2021 caused major flooding’s in multiple tributaries of the Meuse and Rhine rivers. Particularly the Ahr Valley in Germany was greatly affected, where exceptional damage and severe human loss was registered. Since then, several studies have been conducted to understand the extremity, the major driving forces, the particular mechanisms of this flood and the possible impacts of climate change on the generation of such an event. Here the main objective is to perform a hydrological analysis of the July 2021 Ahr event and discuss the challenges in modelling or analysing this event.First, we show that particularly the rainfall field is associated with high uncertainty, as seen by the high variability between the different rainfall products available. The average areal rainfall volume can differ between products with as much as 50mm/day, which constitutes almost 55% of the rainfall volume estimated by Radolan. To capture the full uncertainty-range of the rainfall field, rainfall simulations conditioned both on radar and station observations are implemented.  Next, based on rainfall simulations and reconstructed discharge data, runoff coefficients (Rc) are shown to be ranging between 0.6 to 1.2 (median 0.7). These values are clearly higher than expected in continental climate (Rc ~ 0.20-0.51) and the latest 100-year return flood observed in 2016 (with Rc ~ 0.4). The high lower range suggests, that the dominant processes have changed, with slower components of surface runoff shifting to faster ones. This agrees well with the observed traces of erosion, surface water and flow paths in parts of the catchment.Lastly, the reconstructed discharge data are also subjected to uncertainty due to lack of observations and the non-representativeness of the stage-discharge curve during the flood wave. Hence, high Rc values do not only originate from underestimated rainfall but as well from possible overestimated flood volume. For this purpose, discharge was estimated with the Larsim model. As expected due to the change of the dominant processes, the pre-event parameter set underestimates considerably the flood volume, while the post-calibration one agrees better with the reconstructed data. On both cases, the computed runoff coefficient ranges between 0.4 to 0.7.To conclude, extraordinary events such as the July 2021 in Ahr Catchment, are accompanied with high uncertainty and as such are difficult to be analysed or modelled. Nevertheless, the results dictate that the surface runoff played an important role in July 2021. At the same time, it is clear that the landscape still has a considerable retention effect, between 30% and 50%, even for such a heavy rainfall.
Exploring Garnet’s Geochemical Variations: Insights into Base Metal Deposits 
Authors: D'Andres Joëlle , Mavrogenes John , Belousova Elena , Magrini Fabrizio
Published: March 2024

This study addresses a significant gap in the geochemical literature by systematically investigating garnet compositions within and around base metal deposits -- a topic that remains relatively understudied, despite the mineral's known significance in various geological contexts. Garnet, traditionally associated with diamond exploration and recognized for its potential as an indicator mineral for deposits like skarns,emerges in our research as a key geochemical tracer in the context of base metal exploration.Focusing on the Eastern Succession of the Mount Isa Inlier in Australia, a globally significant mineral province, we characterized the major and trace element compositions of garnets associated with diverse base metal systems. Our new dataset, containing more than 2500 datapoints, was complemented by literature data compiled from a range of mineral systems including skarns, IOCGs, subaqueous volcanic-related (VMS, Broken Hill, sedimentary-exhalative), porphyry-epithermal and granite-related pegmatite systems. Comparative analyses with background metamorphic/igneous garnets reveal distinct trends in Mn-Fe and Ca-Mg space in ore-associated garnets, along with unique trace element patterns (e.g., Eu anomalies) and chalcophile element variations (e.g., Zn, Cd, Ga) in diverse ore systems.To clarify the importance of these anomalous compositions, we refined our dataset by considering specific garnet associations and their related geological context. Garnets in the database were categorized depending on their occurrence within the ore bodies, the alteration haloes, or the background lithologies. Additionally, we carried out a multivariate statistical analysis through a principal component analysis (PCA) and subsequent cluster analysis, to identify hidden spatial patterns. Our results shed light on the geochemical variations in garnet composition across various ore systems and provide new insights into the sources of these variations.This research not only contributes valuable geochemical data for base metal exploration but also establishes the efficacy of multivariate statistical analyses in deciphering complex garnet data structures. The implications of our findings extend beyond the Eastern Succession of the Mount Isa Inlier, fostering a broader understanding of the geochemical dynamics associated with base metal deposits globally.
Teleseismic body wave phase extracted from ambient noise interferometry constrains the secondary microseism sources of Northern Hemisphere
Authors: Gao Yajian , Rietbrock Andreas , Frietsch Michael , Agurto-Detzel Hans , Kufner Sofia-Katerina , Dushi Edmond , Rama Besian , Koxhaj Damiano , Schurr Bernd , Tilmann Frederik
Published: March 2024

Dense seismic networks are ideally suited to detect daily or even hourly variations of the global secondary microseism via ambient noise cross-correlation beamforming (CCBF) and backprojection (BP) in the slowness-backazimuth domain. We combine the seismic recordings from Hi-net in Kyushu (HINET) network, Southern California Seismic Network (SCSN), and the Large-N AlbaNian TectonIcs of Continental Subduction (ANTICS) network to capture 3-hourly and daily northern hemisphere secondary microseism variations during 2022-2023. We calculate stable ambient noise CC with 300 s lag and 24 substacks per day. In the secondary microseism period band, 1-10s, we detect clear and vigorous high apparent velocity P phase (> 8 km/s) arrivals in 3-hourly and daily stacks for these networks. Both the 3-hourly and daily stacks show clear temporal amplitude and delay time changes in station-pair-distance and symmetry changes of causal and acausal branches, indicating the active evolution of ambient noise source location and strength. For ANTICS, the strongest energy patch emerges with back-azimuth (BAZ) 280°-330° and slowness around 8-10 s/deg. Further two energy patches appear with BAZ 90°-135° and slowness of 4-6 s/deg as well as 0° BAZ and slowness of 5-7.5 s/deg . We back-project the energy from the beamforming to the source location based on IASP91 velocity model assuming the propagation of teleseismic energy as direct P wave (including Pdiff, PKiKP and PKIKP). The back-projection results reveal that the strongest energy comes from the North Atlantic covering a broad arc-shape area (from the northeast coast of the US to the west coast of the UK, and from the south of Greenland and Iceland down to 45°N). The two other energy patches with much higher apparent velocities originate from the south Indian Ocean and the north Pacific near the Aleutian Islands. The 3-hourly and daily changes are tracked and recovered by the CCBF and BP approach for all three networks. The secondary microseism variations in the north Pacific could be improved by the SCSN and HINET whereas the north Atlantic is constrained by ANTICS and SCSN. Some small-scale autumn storms near the Japanese trench are also detected and tracked. Our results are consistent with existing wave height maps and provide a new and cheap observation for hindcasting of the state of the coupling of oceans and the solid earth. 
Tipping cascades, future Earth system trajectories and the prospect of a hothouse: insights from the SURFER model
Authors: Couplet Victor , Martínez Montero Marina , Crucifix Michel
Published: March 2024

A tipping cascade is a series of tipping events in the Earth system where transitions in one subsystem can trigger further transitions in other subsystems. A concern for the future is that such a cascade could lock the Earth system in a pathway towards a so-called hothouse state. We investigate this possibility with SURFER, a reduced complexity model with a process-based carbon cycle that can reliably predict CO2 concentrations, global mean temperatures, sea-level rise, and many ocean acidification metrics on timescales from decades to millions of years. We have incorporated in the model a network of interacting tipping elements and their feedback on the climate through albedo changes and additional greenhouse gas emissions. This has allowed for a systematic investigation of the effects of a family of realistic emission scenarios on the future trajectories of the Earth system. Our results show that a permanent shift to a hothouse state within the next few centuries is implausible. On longer time scales, however, tipping cascades can lead to enduring additional warming and particularly sea level rise.
Retrieving Sea Ice Information in the Pan-Arctic Region from Synthetic Aperture Radar
Authors: Wulf Tore , Buus-Hinkler Jørgen , Singha Suman , Ribergaard Mads Hvid , Rasmussen Till Soya , Kreiner Matilde Brandt
Published: March 2024

The Arctic’s unprecedented transformation due to anthropogenic warming necessitates close monitoring of sea ice to understand and address climate change impacts. As the sea ice retreats and becomes thinner, increased human activity in the region emphasizes the urgent need for detailed, near real-time sea ice information as well as improved sea ice forecasts for maritime safety and planning.Current methods of Arctic sea ice retrieval relies on passive microwave (PMW) sensors, which offer global coverage but struggle to capture fine-scale features and changes in the sea ice. Synthetic Aperture Radar (SAR) imagery, with its high spatial resolution and independence from sunlight and clouds, is pivotal in the year-round mapping of Arctic sea ice conditions that is carried out manually at the national ice services. Yet, automating SAR-based sea ice retrieval remains challenging due to inherent ambiguities in the observations.Recent advances in deep learning vision methodologies show promise in SAR-based sea ice retrievals. A robust pan-Arctic SAR-based sea ice retrieval system can serve maritime sectors, national ice services, and local communities by providing timely, high-resolution sea ice information. Furthermore, SAR-based sea ice retrievals can be assimilated in numerical ocean and sea ice models, improving sea ice forecasts crucial for local communities and maritime sectors.Here, we present a comprehensive deep learning approach to retrieve high-resolution sea ice concentration and calibrated uncertainties from Sentinel-1 SAR and AMSR-2 PMW observations at a pan-Arctic scale for all seasons. Daily pan-Arctic sea ice products based on our methodology will be operationally provided as part of the Copernicus Marine Service portfolio by the end of 2024. Further, we are in the process of producing daily pan-Arctic products for the entire Sentinel-1 era, which began with the launch of Sentinel-1A in 2014. Lastly, we present preliminary results for the impact of assimilating level-2 SAR-based sea ice concentrations gap-filled with level-2 PMW-based sea ice concentration in the HYCOM-CICE coupled ocean-sea-ice forecasting system for the pan-Arctic region. 
Seasonal Variation of Mesoscale Horizontal Stirring in the North Pacific Ocean
Authors: Yi Gyuseok , Park Wonsun , Lee June-Yi
Published: March 2024

The mesoscale horizontal stirring (MHS) is closely linked to various mesoscale dynamical phenomena, encompassing not only eddies but also meanders, filaments, and fronts. A clear understanding of its seasonality holds the potential to enhance our understanding of horizontal mixing and material dispersion. Here, we analyze the seasonal variation of MHS in the North Pacific surface ocean using ocean reanalysis (GLORYS12) current velocity data with a horizontal resolution of 1/12° from 1993 to 2019. Based on the characteristic of stirring to separate adjacent fluid trajectories, MHS is quantified using the finite-size Lyapunov exponent (FSLE), one of the Lagrangian diagnostics. The FSLE in the North Pacific shows clear seasonality but the phases of its evolution differ regionally. We identify two major modes, which contribute to over 80% of the seasonality of FSLE in the North Pacific, through the application of empirical orthogonal function (EOF) analysis to the climatological monthly mean FSLE. The first mode (57%) exhibits a variation peaking in April within the Kuroshio Extension region and the Subtropical Countercurrent region, where baroclinic instability plays a significant role. The second mode (25%) peaks during the summer season over the Kuroshio area and coastal upwelling areas of western North America. It is found that the strong seasonality in the upwelling area is induced by the North Pacific High.
Unveiling End Users Needs and Requirements for Coastal and Underwater Heritage Sites under the impacts of Climate Change 
Authors: Oliveira Sónia , Veiga-Pires Cristina , Ikiz Kaya Deniz , Michalis Panagiotis , Mazzoli Claudio
Published: March 2024

Coastal and underwater cultural heritage play a crucial role in local and regional cultural resources. However, this tangible cultural heritage is under threat due to extreme weather events, changing conditions caused by climate change, natural hazards, and environmental pollution. This study aims to understand how end users (entities or people related to or who interact with heritage sites ) perceive these risks and what they need to better cope, adapt, or be resilient to the anticipated changes. Additionally, it explores how science can address the needs and requirements of local and regional end users.This research is part of the larger THETIDA project, focusing on technologies and methods for improved resilience and sustainable preservation of underwater and coastal cultural heritage, funded by the European Union’s Horizon 2020 research and innovation programme. The THETIDA project concentrates on seven pilot sites, comprising coastal locations such as Svalbard in Norway, Ijsselmeer in the Netherlands, Mykonos in Greece, and underwater sites including Algarve in Portugal, Gallinara and Spezia in Italy, and Paralimni in Cyprus.The THETIDA team conducted surveys to analyze threats, needs, and preservation requirements for each pilot site, incorporating data from consortium partners and workshops held with local stakeholders in several pilot sites. The results identified material deterioration and human-induced development interventions as primary threats. Essential needs include assessing risk and exposure to various hazards, implementing conservation measures for buildings and sites, and promoting awareness, education, and training.Survey responses unanimously emphasize the critical requirement for site assessment and risk evaluation concerning both human-induced and climate changes. These findings offer valuable insights for developing tools and services within the project to support local and regional end users. Furthermore, they underscore the importance of fostering a scientific culture among communities, a role that science centers and museums can fulfill, as verified during the 2023 Portuguese Science and Technology Week.Finally, the resulting end-user ecology is integrated into the Living Lab methodology, another facet of THETIDA Project research, aiming to co-create, test, and validate a new crowdsourcing tool in real-life contexts. Acknowledgement:  This research has been funded by European Union’s Horizon Europe research and innovation funding under Grant Agreement No: 101095253, THETIDA project (Technologies and methods for improved resilience and sustainable preservation of underwater and coastal cultural heritage to cope with climate change, natural hazards and environmental pollution). Authors would also like to acknowledge the financial support of the Portuguese Foundation of Science and Technology (FCT) to CIMA through UID/0350/202
Can polarimetric wide-angle radar surveys teach us more about ice fabric anisotropy?
Authors: Oraschewski Falk M. , Ershadi M. Reza , Henry Clara , Drews Reinhard
Published: March 2024

The fabric anisotropy of ice and its flow dynamics are co-dependent. Parameters used in models that solve the evolution of ice fabric are currently unconstrained, for which comparisons with observations are needed. In observations and models, the ice fabric can be represented by a crystal orientation tensor, describing the spatial distribution of ice crystal orientations. Because ice crystals are not only mechanically, but also dielectrically anisotropic, the fabric anisotropy causes birefringence and anisotropic scattering and can be inferred by polarimetric radar surveys. In recent years, the advancement of polarimetric radar methods has resulted in a surge of available observational data. However, all existing methods are performed with a nadir-looking radar geometry. As a consequence, these approaches are only sensitive to horizontal fabric anisotropy, making the assumption necessary that one eigenvector of the crystal orientation tensor is aligned in vertical (nadir) direction. We aim to develop an approach to measure the actual orientation of this eigenvector. Here, we present the results of a polarimetric wide-angle common midpoint (CMP) survey conducted on Ekström Ice Shelf, Dronning Maud Land, Antarctica, using the Autonomous phase-sensitive Radio Echo Sounder (ApRES). Our CMP survey had a maximum antenna offset of 200 m, with an ice shelf thickness of 250 m. For several englacial reflectors, we observe offset-dependent phase shifts between orthogonal antenna orientations. We explore these phase variations by modelling the off-nadir radio wave propagation in the birefringent ice. These wide-angle radar surveys have the potential to infer the full crystal orientation tensor, required for a constitutive paramerization of glacial flow.