bluuebunny/crossref_metadata_2025 huggingface dataset:
A new 1523-year-long varve sequence reveals the influence of the Atlantic Multidecal Variability on Eastern Canada hydroclimate
Authors: Francus Pierre , Gagnon-Poiré Antoine , Lapointe François
Published: February 2023

Grand Lake, Labrador, is a 245-m deep and 55 km long fjord lake deglaciated c.a. 8000 years ago, located at the eastern margin of North America in the high boreal forest ecozone. The lake is fed by two large rivers that transport a substantial amount of sediments, mainly during the snowmelt season. As a result, up to 13 mm thick varves are preserved in the proximal zone of the two main tributaries, while distal varves are 1.26 mm thick on average. Proximal and distal varves can be correlated thanks to cross-correlation of distinctive varves. Varve counts were made from high-resolution images of thin sections at the scanning electron microscope, and from 100 µm-resolution µXRF profiles. The age model was validated by 210Pb, 137Cs and 14C dating. The proximal varves are composed of 3 distinct laminae, while the distal varves contain 2 layers. This paper outlines how the proximal and distal sequences were combined to produce a 1523-year-long record allowing a very long reconstruction of past river mean discharge (Q-mean). The river discharge was higher during the Medieval Climate Anomaly (1050–1225 CE) and lower during the Little Ice Age (15th–19th centuries). The reconstructed Q-mean shows a significant co-variability with Atlantic Multidecadal Variability reconstructions and with reconstructed summer Northern Hemisphere temperature based on tree rings. This suggests that river discharge in Labrador was influenced by ocean-atmosphere interactions across the North Atlantic, and that a longer varved record from Grand Lake has the potential to reconstruct the supra-regional modes of climatic variability for most of the Holocene.
Impact of interplanetary shocks on the radiation belt environment measured by a low altitude satellite
Authors: Gohl Stefan , Němec František
Published: February 2023

We use electron flux data measured by the Energetic Particle Telescope (EPT) onboard the Proba-V satellite in a Low Earth Orbit (LEO) to investigate the radiation belt response to the interplanetary shock arrival. Altogether, as many as 31 interplanetary shocks selected from the OMNI data during 2013-2018 are investigated. While the radiation belt fluxes are nearly unaffected by the shock arrival in some cases, other events reveal a sudden drop of energetic electron fluxes spanning over a broad range of L-shells. Electron flux changes at various L-shells and energies are evaluated and compared with the solar wind dynamic pressure change across the shock front, magnetopause location, and z-component of the interplanetary magnetic field. The aim is to identify parameters governing the radiation belt response to the interplanetary shock passage and to understand the strikingly different responses to the seemingly similar solar wind variations.
First insight into gold enrichment associated with Archean magmatic processes in the deep crust through melt inclusion studies: an example from the Abitibi Subprovince, Québec, Canada
Authors: Hanley Jacob , Meagher Daniel , Neyedley Kevin , Mercier-Langevin Patrick , Zajacz Zoltan
Published: February 2023

Silicate melt inclusions (SMI) in rhyolitic volcanic rocks in the ~2699 – 2697 Ma Bousquet Formation, Subprovince, Québec were studied through integration of a variety of microanalytical methods (petrography, laser Raman microspectroscopy, LA-ICP-MS) to explore links between magmatic metal/volatile endowment and the high gold content of mineral deposits in the world-class Doyon-Bousquet-LaRonde mining district. The study is the first to present melt inclusion data from felsic volcanic rocks of Archean age.Rhyolitic SMI of primary origin were characterized from magmatic quartz phenocrysts from tholeiitic rhyolite sills and calc-alkaline flows near gold-rich volcanogenic massive sulfide deposits. Silicate melt inclusion trace element chemistry records a continuous transition from ocean ridge to volcanic arc tectonic affinity. SMI Sr-Y-La-Yb systematics are  inconsistent with Archean tonalite-trondhjemite-granodiorite (TTG; “adakitic”) compositional domains; rather, they are consistent with post-Archean TTG (“calc-alkaline”) suggesting significant compositional modification of TTG magmas through contamination and/or plagioclase fractionation during magma storage and ascent.  Thermobarometry suggests prolonged phenocryst residence at depth prior to eruption with SMI entrapment at ~10-12 km depth. Concentrations of Au in the SMI are variable and up to two orders of magnitude higher than in the host bulk volcanic rocks. This demonstrates that whole rock data are not representative of the composition of the original magmatic liquids and, thus, cautioning the traditional use of whole rock data as a proxy for volcanic assemblage fertility in such Archean environments. Moreover, SMI show melt co-entrapment with an immiscible, high density, carbonic fluid (CO2-dominant), indicating that rhyolitic melts were saturated in CO2. Saturation of this fluid phase may explain, in part, the variability observed in SMI metal contents, and demands consideration of the relative importance of early separation of magmatic volatile phases versus seafloor hydrothermal leaching of volcanic products in controlling the magmatic metal endowment of Archean exhalative ore-forming systems.  
Optimized Use of Engineered Features from GNSS Reflectometry for Prediction of Significant Wave Heights
Authors: Becker Jan , Roggenbuck Ole
Published: February 2023

GNSS interferometric reflectometry is a well-established technique in Ocean Remote Sensing that can be used for the retrieval of sea surface characteristics. In particular, the evaluation of interference patterns in GNSS signal-to-noise ratio (SNR) observations allows for an estimation of the Significant Wave Height (SWH), e.g. by relating the SWH to the attenuation that is typically present in the oscillating interference pattern for increasing elevation angle of the signal-emitting GNSS satellite.Recently, we developed new machine learning methods for the analysis of GNSS SNR observation data obtained from the research platform FINO 2 in the Baltic Sea. The core element thereof is the extraction of various engineered features from SNR interference patterns  by means of kernel regression and clustering techniques. The various engineered features were used as input for the prediction of the SWH with supervised machine learning models (artificial neural networks, bagged regression trees, linear models). In a case study, these predictions provided a remarkable improvement in accuracy compared to predictions which solely use a common feature stemming from the aforementioned attenuation in the SNR interference pattern.  However, an optimized extraction of information from the various and partially redundant engineered features for the prediction task is desirable, aiming at the reduction of model complexity without reducing predictive performance. This goal is successfully addressed in the present work by applying a forward selection scheme and a principal component analysis for the set of available  engineered features. The usage of the engineered features can also be optimized by tuning the hyperparameters of complex supervised machine learning models used for the SWH prediction. Such a tuning is performd by means of a grid search for a random forest model applied to the engineered features. This optimization represents an advancement of the application of the bagged regression trees with an improvement in accuracy of the respective SWH predictions.The improved methods for SWH prediction at FINO2 are outlined and the impact of the involved optimizations concerning the use of the engineered features is evaluated and discussed in detail in a case study.
Investigating the role of citizens' trust during and after emergencies
Authors: Russo Raffaella , Gargiulo Maria Vittoria , Vitale Maria Prosperina , Quarta Serena , Capuano Paolo
Published: February 2023

During and after catastrophes it is important to investigate the role played by key governmental institutions and scientific community in vehiculating correct information to the whole population on how to manage the consequences of disasters in order to minimize losses and avoid other possible cascading effects. Indeed, messages spread out by policy makers and scientific community get positive effects, only if they are trusted by citizens.The European project entitled “sCience and human factOr for Resilient society” (H2020 CORE) considers trust as a key factor for the individuals’ risk perception, their behavioural response and disaster preparedness. Within this scenario, a survey is promoted by means of an online questionnaire including scales and indicators related to risk perception and trust by controlling for geographical context, socio-demographic and economic backgrounds together with direct and indirect individual experiences. The aim of the survey is twofold: on one hand, it permits to consider the effects on citizens’ behaviors by analysing  different hazards, such as earthquakes, tsunami, wildfire, industrial accident, terrorist attack, flash flood and COVID-19 pandemic; on the other one, it allows to underline best practices adopted by institutions during emergencies in different countries by also investigating the role of fake news.The final aim is to release guidelines devoted to the policy makers and scientific community experts in order to understand what they can do to be trusted by communities. Acknowledgment: The present abstract has been produced for the CORE project that has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101021746.
Bifurcations in mountain rivers: insights on their hydraulics from field measurements
Authors: Pascal Ivan , Miazza Raphaël , de Graffenried Bob , Ancey Christophe
Published: February 2023

Although the importance of studying channel bifurcations is widely recognised, their hydraulic behaviour in shallow, rough mountain rivers has so far received little attention from researchers. Understanding the specific hydraulics of such units is essential for predicting and interpreting their morphodynamic evolution. Water discharge measurements in the incoming channel and distributaries are often difficult to perform in steep streams characterised by high relative roughness (grain size to depth ratio d/h > 0.1), aerated flow, and marked free-surface waves. Nonetheless, recent advances in Acoustic Doppler Current Profiler (ADCP) technologies open new possibilities for studying the flow configuration at stream bifurcations.We monitored the flow repartition in a bifurcation of a mountain gravel-bed river by deploying an ADCP specifically designed for shallow flow conditions. This field campaign was combined with photogrammetric surveys for documenting the geomorphological evolution of the river bed, its surface grain size distribution and structure. Integrating data from these different sources provided useful information on the bifurcation evolution and hydrodynamics. During a period in which the river bed did not undergo noticeable elevation changes, we observed that the water discharge ratio of the distributaries was approximately constant for sensibly different total discharge values. Such result was compared with the outcomes of numerical simulations.
The impact of 4D-Var data assimilation of HF-Radar and SST observations on the surface circulation of the northwestern Mediterranean Sea 
Authors: Bendoni Michele , Moore Andrew , Fattorini Maria , Brandini Carlo
Published: February 2023

We analyze the effect of the assimilation of surface velocities from two HF-Radars (HFR) and satellite SST in an ocean circulation model covering the northwestern Mediterranean Sea.
One HFR observes the area in front of Toulon (France), the other covers the area adjacent to the coast near La Spezia (Italy).
The ROMS 4D-Var DA package is used to analyze a three-month period, from September to November 2020.
The DA is implemented to have a sequence of 3-day assimilation windows, each followed by a 3-day forecast cycle in which the model evolves without adjustments.
Boundary conditions are from the CMEMS Analysis-Forecast product and atmospheric forcing from ECMWF high resolution model (1/10 degree).
The impact of the DA is quantified by comparing the analysis and forecast runs with a freerun that is unaffected by any assimilation procedure.
The results show that both the analysis and the forecast perform better than the freerun considering the HFR and SST observations used in the assimilation procedure.
Moreover, eulerian velocities derived from surface drifters are used as an independent dataset to further validate the quality of the DA output.
Within the area covered by the HFRs, both the analysis and forecast surface velocities show greater agreement with the drifter data than the surface velocities from the freerun.
However, in the rest of the domain, surface circulation improvements and deteriorations tend to balance out, and mean squared error and correlation values are comparable for analysis, forecast, and freerun.
We also analyzed the impact of the observation typology and of the control vector on coastal transport for the upper 50 m at three transects.
Two of them are located at the HFR areas and the other in between.
Both HFR and SST data have a significant effect on surface transport increment.
The HFR observations contribute to the change in the transport magnitude while the SST tends to change the velocity distribution along the transect, leaving the transport magnitude unchanged.
Coastal transport is, in general, mostly affected by corrections to initial conditions in all three transects. The changes to the boundary conditions and atmospheric forcings have different importance depending on the transects analysed.
Comparison of different kinds of models to simulate the alteration of medieval stained glass as a function of climate and pollution
Authors: Verney-Carron Aurélie , Sessegolo Loryelle , Lefèvre Roger-Alexandre , Brimblecombe Peter
Published: February 2023

A large number of stained glass windows were installed from the 13th century. During the Middle-Ages, most of glass pieces have a Si-K-Ca composition with a relatively low SiO2 content, but high content of K2O and CaO.  This chemical composition means that medieval stained glass deteriorates during environmental exposure, from climate and environmental pollution. These alterations are manifested in the form of an alteration layer and secondary phases (mainly gypsum or syngenite). The alteration layer is generally depleted in K and Ca, but rich in Si, Al and Fe. Its thickness varies up to 300 µm after 6 or 7 centuries of alteration. In order to reconstruct the alteration history and predict the deterioration of stained glass windows in the future, it is necessary to determine alteration rates as a function of the climate and environmental parameters.Several methodologies can be used to achieve this. First, short-term exposures or laboratory experiments can assess the first stages of the alteration and short-term kinetics. From these results, dose-response functions (DRF) were established for sheltered and unsheltered rain conditions. They correlate relevant environmental factors (temperature, rain quantity, rain pH, relative humidity, SO2 concentration) with the response of the materials in terms of alteration layer thickness. The second methodology consists in laboratory experiments that aim at parametrizing kinetic laws as a function of specific parameters (temperature, pH of rain, and relative humidity). These kinetic parameters do not directly consider pollution, but they can be extrapolated over long periods and can be inputs to geochemical models. In this study, we have compared both methodologies to simulate the alteration of a model stained glass at different European sites (using data from the ICP-Materials program). Both models give good results, but the geochemical model tends to underestimate the alteration at polluted sites. This indicates that the pollution via the concentration in SO2 for example should be included to improve the model.
Exploring the human influence on surface water availability in the contiguous United States
Authors: Alonso Vicario Sara , Mazzoleni Maurizio , Garcia Margaret
Published: February 2023

Finding which factors control the spatial variability of surface runoff is fundamental for assessing regional surface water availability. These controlling factors drive the water balance and vary from physio-climatic catchment attributes to anthropogenic activities. A few studies evaluated these factors in the Contiguous United States on catchments with non-human influence (Abatzoglou & Ficklin, 2017). Yet, a comprehensive analysis of the human influence on surface water availability is still missing.Here, we employed a parametric Budyko-based framework to assess the long-term runoff sensitivity in the last 30 years of 502 catchments in the Contiguous United States. We linked the Budyko-based framework's landscape parameter with an extensive set of 50 climatic, topographic, anthropogenic, and soil factors that were previously found influential on partitioning precipitation into evapotranspiration and runoff. The catchments belong to the GAGES-II database (Falcone, 2010) and have been grouped in reference and human-impacted basins (urban and agricultural) using the most updated land cover data of 2019. A stepwise multiple linear regression model is developed to find the most significant factors in the partitioning depending on the most extensive human activity on the basin and assess their interactions. Also, we analyzed how anthropogenic activities (e.g., irrigated agriculture, urban settlements) alter the effect of climate variables.Preliminary results suggest that cultivated land is the second most important factor in explaining runoff variability in agricultural basins, and urban settlements increase the runoff in catchments with a high interannual variability of precipitation. ReferencesAbatzoglou, J. T., & Ficklin, D. L. (2017). Climatic and physiographic controls of spatial variability in surface water balance over the contiguous United States using the Budyko relationship. Water Resources Research, 53(9), 7630–7643. https://doi.org/10.1002/2017WR020843Falcone, J. A., Carlisle, D. M., Wolock, D. M., & Meador, M. R. (2010). GAGES: A stream gage database for evaluating natural and altered flow conditions in the conterminous United States. Ecology, 91(2), 621–621. https://doi.org/10.1890/09-0889.
Potential Role of Inter-Basin Interactions in Eurasian Summer Blocking
Authors: Boljka Lina , Omrani Nour-Eddine , Cheung Ho-Nam , Keenlyside Noel , Nakamura Hisashi , Spensberger Clemens , Ogawa Fumiaki
Published: February 2023

Atmospheric blocking events are persistent tropospheric weather patterns that are associated with extreme events, such as heatwaves. In the summer, they primarily occur at high latitudes, e.g., over northern Eurasia. However, blocking frequency over these regions is underestimated in climate models, and often overestimated over the midlatitudes, while causes for such discrepancies remain elusive. To improve model representation of blocking frequency, it is important to understand different processes that affect it. Here, we explore blocking frequency in a reanalysis and experiments with an atmospheric general circulation model forced with different sea surface temperature (SSTs) profiles. The configurations range from an idealized no SST-front experiment and prescribing idealized SST-front in different regions to prescribing realistic climatological SSTs. Surprisingly, this reveals that more idealized (realistic) experiments lead to more (less) realistic blocking frequency. We find that weaker (less realistic) blocking frequency over northern Eurasia is primarily caused by the circulation changes related to SST gradients over the North Pacific. This suggests an important role of inter-basin interactions between the Atlantic and the Pacific. Additionally, tropical teleconnections can also play a role. This may suggest that models struggle with circulation response to SSTs in boreal summer, especially over the North Pacific. Thus, this work has implications for simulating (future) summer heat (and other) extremes over the high latitudes.
Temperate exoplanets observable with Ariel : an update with new targets from TESS
Authors: Encrenaz Therese , Coustenis Athena , Edwards Billy , Molaverdikhani Karan , Ollivier Marc , Tinetti Giovanna
Published: February 2023

In 2018 and 2022, we have published an analysis about the observability of temperate planets (with an equilibrium temperature of about 350-500 K) with Ariel. This presentation is an update of this analysis which aims at using new targets identified in particular from the TESS database and analysing their observability with Ariel. Using the parameters of these new targets, we give an estimate of the number of transits needed for these objects to be observed in the Tier 2 mode of the space mission, and we define the information which could be derived about their atmospheric composition. We have identified about 15 targets which could be observable with ARIEL in the Tier 2 mode, which allows an identification of the main atmospheric absorbers. This list includes a gas giant, a few big Neptunes and several super-Earths/small Neptunes. This study is a follow-up of Encrenaz et al., Exp. Astr. 46, 31 (2018) and Exp. Astr. 53, 375 (2022).
Simulating the impacts of drought on the carbon dynamics in African rainforests
Authors: Gu Qiao-Lin , Papastephanou Phillip , Rammig Anja
Published: February 2023

The trend of hotter and drier climate and the increasing intensity and duration of extreme drought events is affecting African tropical rainforests and could induce higher mortality of tropical evergreen trees. The result may be the forest structure shifting towards a more open type. Such a structural shift would lead to smaller carbon stocks in the rainforests and potentially reduced photosynthetic carbon uptake. To understand the relationships between drought and carbon dynamics in the African rainforests, the newly developed version of the dynamic vegetation model LPJ–GUESS including plant hydraulic features was employed to simulate vegetation growth over the past decades. The results showed that the net carbon flux going into the vegetation decreased during the drought events. Especially in the late 1990s, the net carbon flux decreased to the level before 1960 and remained low until ten years after the consecutive extreme drought. This decrease in the net carbon flux was dominated by the decrease in net primary production rather than the instantaneous loss from tree mortality. Simultaneously, the carbon stock in the rainforests continued to grow but the growth decelerated during and after the drought. To conclude, the drought affected the African rainforests primarily by reducing vegetation productivity rather than causing instantaneous mortality. Such long-term effects are of vital importance since they could easily increase the vulnerability of the forests to other disturbances such as wind throw or pathogens, thus provoking the forest mortality further in the future. This implies that future field experiments should draw special attention to the potential long-term or delayed effects of climate change on trees.
Incorporating the resuspension mechanism into suspended sediment particle tracking by fractional Brownian Motion with Malliavin calculus
Authors: Shen Wei-Min , Tsai Christina W.
Published: February 2023

    Sediment dynamics is a key mechanism of the interaction between sediment particles and fluid particles. Therefore, the stochastic Diffusion Particle Tracking Model (SD-PTM), a Langevin equation-based model, was introduced to randomly simulate suspended sediment particles' movement by incorporating Brownian Motion (BM) in the Langevin equation.    Under the framework of Kolmogorov's turbulence theory, large-scale eddies with a high Reynolds number (Re) show similarity while continuing to break into smaller eddies. A correlation thus exists between time increments. In addition, according to the bursting process near the bed region, we assume that sweep events with eddies of various sizes contribute mainly to the resuspension mechanism. Consequently, a generalized stochastic process is required to incorporate the correlation, interpreted as either a memory effect or long-range dependency. Fractional Brownian Motion (fBm), a continuous and centered Gaussian process characterized by the Hurst parameter(H), can describe the long-range dependency more precisely. Moreover, we seek to develop a relationship between the H-parameter and turbulent intensity.    In addition, the dependent increment assumption invalidates the Ito formula. As such, advanced stochastic calculus should be adopted as an alternative. The Malliavin derivative and Skorohod integral, defined in Weiner space, are introduced to fulfill the assumption and to maintain the fundamental rules in the Riemann integral to a random variable. This study further introduces the Wick-Ito expansion with Hermit Polynomial to overcome the abovementioned computational issue; thus, both the fractional Brownian Motion and the stochastic ordinary differential equation (SODE) can be simulated.    Last, to build a physically based SODE for sediment transport in open channel turbulent flow, we aim to more comprehensively determine the diffusion coefficient and Hurst parameter by the turbulent properties. In addition, the turbulent sweep events are known to entrain the sediment particles back into the water column in the near-wall region. Therefore, when including the particle memory effect attributed to turbulent sweep events by introducing fBm to the resuspension mechanism, particles in the near-wall region impacted by the sweep events can be more precisely simulated.
Well calibrated space sensor systems for GGOS
Authors: Flury Jakob , Koch Igor , Duwe Mathias
Published: February 2023

From the investigation of GRACE and GRACE-FO instrument data, we are aware of quite a number of unmodeled effects and deficiencies in the calibration of instruments. We want to use these deficiencies as an example to discuss how for a core GGOS observation technique, such as GRACE / GRACE-FO, all opportunities to assess and improve sensor calibration and to identify and characterize unmodeled effects affecting the measurements should be explored. This may seem obvious, but we will show that a major effort on this field would be very desirable. We deliberately choose the GGOS session for a broader discussion of the topic, and we want to highlight the importance of an overarching approach that combines insight from different satellite missions and space techniques.
A web-based tool for the quantification of the soil health based on Ecosystem Services
Authors: Basile Angelo , Acutis Marco , Bonfante Antonello , Botta Marco , Langella Giuliano , Manna Piero , Perego Alessia , Puig-Sirera Angela , Terribile Fabio , Bancheri Marialaura
Published: February 2023

A formal definition and quantification of soil health is still a long way off. However, a broad consensus is based on the close connection between the soil capacity to provide ecosystem services and its state of health.We propose a integrate assessment of multiple potential soil-based ecosystem services through the use of a process-based modelling, simulating the water flow and the crop growth in the soil-plant-atmosphere system.Specifically, we evaluate the soil contribution to i) Food provision through the biomass estimation; ii) Nutrient and pollutants retention and release through the estimation of soil filtering capacity; iii) Water regulation/runoff and flood control through the number of days showing a potential runoff triggering; iv) Water regulation/water storage through the water yearly stored in the soil; v) Water regulation/groundwater recharge through its yearly value; and vi) Microclimate regulation through the total evapotranspiration. All of the above ecosystem services are combined into one indicator of soil health. The proposed approach was framed in the context of the geospatial Decision Support Systems LandSupport (www.landsupport.eu) that, in the latest years, proved to be powerful instruments for the what-if scenario analysis in support of multiple stockholders and end-users.Through the what-if scenario analysis the end-user can evaluate the soil health resilience of a specific soil by simulating the effects of some degradation processes occurrence: i) a compacted plow layer at a chosen ploughing depth, ii) a compacted soil surface, iii) a thickness reduction of the Ap horizon following an erosion process. Furthermore, the gain in soil health can be evaluated by simulating the effect of an increase of organic matter.The Soil Health tool is designed to assist Public Authorities, such as regional environmental agencies, farmers and farmer advisors in designing plans and in evaluation of impacts of the measures in order to ensure a good health of the soils.
New age and geochemistry data from the Middle Allochthon ophiolitic units of the Morais Complex (Portugal).
Authors: Malecki Jérémie , Collett Stephen , Martínez Catalán José R. , Gómez Barreiro Juan , Schulmann Karel
Published: February 2023

The allochthonous complexes of the Galicia-Trás-os-Montes Zone (GTMZ) of the NW Iberian Massif consist of an ensemble of peri-Gondwanan terranes and ophiolitic units stacked during the Variscan orogeny. The Middle Allochthon also known as the ophiolitic complex represents the variscan suture of one or more peri-Gondwanan oceans, and includes Cambro-Ordovician to Lower Devonian units. In the allochthonous Morais Complex (Trás-os-Montes, Portugal), the ophiolitic complex comprises four structural units, which from bottom to top are Macedo de Cavaleiros, Pombais, Izeda-Remondes and Morais-Talhinhas.The two first units are quite similar to each other and consist of greenschists and metapelites, with metabasites dominating in Pombais and metapelites in Macedo de Cavaleiros. No age data are available for these two units. Their structural position is comparable to that of the Cambro-Ordovician Vila de Cruces Unit in the Órdenes Complex, but also to that of the Lower Devonian Moeche Unit in the Cabo Ortegal Complex, both in Galicia.The Izeda-Remondes and Morais-Talhinhas units mostly consist of fine grained amphibolites associated with deformed gabbros, mafic cumulates and serpentinized ultramafics. The Izeda-Remondes Unit is structurally the lower and the older of the two, dated by Pin et al. (2006) around 447 ± 24 Ma (Sm-Nd whole rock isochron). The upper ophiolitic Morais-Talhinhas Unit was also dated by Pin et al. (2006) giving U-Pb ages of 405 ± 1 Ma and 396 ± 1 Ma.This contribution brings new geochronological and geochemical data from the Middle Allochthon providing new understanding of the history of the suture of the Morais allochthonous complex. Zircons have been collected for LA-MC-ICP-MS U–Pb analyses in two felsic intrusions in the Izeda-Remondes Unit giving concordant ages ranging from 422 ± 4 Ma to 432 ± 4 Ma. These ages together with new and previous whole rock geochemical data obtained from basic and felsic igneous samples from the ophiolitic complex are interpreted to date and reflect the formation of igneous protoliths in an oceanic ridge setting forming part of the Rheic oceanic realm, during Silurian to Devonian. The mantle source for the basic rocks of all four units is similar to that of N-MORB with some influence from a subduction zone.REFERENCE:Pin, C., Paquette, J. L., Ábalos, B., Santos, F. J., & Gil Ibarguchi, J. I. (2006). Composite origin of an early Variscan transported suture: Ophiolitic units of the Morais Nappe Complex (north Portugal). Tectonics, 25(5).Acknowledgements: Spanish Ministry of Science and Innovation, project PID2020-117332GB-C21.
Improving the spatial accuracy of extreme tropical cyclone rainfall in ERA5 using deep learning
Authors: Ascenso Guido , Ficchì Andrea , Cavicchia Leone , Scoccimarro Enrico , Giuliani Matteo , Castelletti Andrea
Published: February 2023

Tropical cyclones (TCs) are one of the costliest and deadliest natural disasters due to the combination of their strong winds and induced storm surges and heavy precipitation, which can cause devastating floods. Unfortunately, due to its high spatio-temporal variability, complex underlying physical process, and lack of high-quality observations, precipitation is still one of the most challenging aspects of a TC to model. However, as precipitation is a key forcing variable for hydrological processes acting across multiple space-time scales, accurate precipitation input is crucial for reliable hydrological simulations and forecasts.A popular source of precipitation data is the ERA5 reanalysis dataset, frequently used as input to hydrological models when studying floods. However, ERA5 systematically underestimates TC-induced precipitation compared to MSWEP, a multi-source observational dataset fusing gauge, satellite, and reanalysis-based data, currently one of the most accurate precipitation datasets. Moreover, the spatial distribution of TC-rainfall in ERA5 has large room for improvement.Here, we present a precipitation correction scheme based on U-Net, a popular deep-learning architecture. Rather than only adjusting the per-pixel precipitation values at each timestep of a given TC, we explicitly design our model to also adjust the spatial distribution of the precipitation; to the best of our knowledge, we are the first to do so. The key novelty of our model is a custom-made loss function, based on the combination of the fractions skill score (FSS) and mean absolute error (MAE) metrics. We train and validate the model on 100k time steps (with an 80:20 train:test split) from global TC precipitation events. We show how a U-Net trained with our loss function can reduce the per-pixel MAE of ERA5 precipitation by nearly as much as other state-of-the-art methods, while surpassing them significantly in terms of improved spatial patterns of precipitation. Finally, we discuss how the outputs of our model can be used for future research.
The supercooled cloud fraction in the mixed-phase clouds from Himawari-8 observations
Authors: Wang Ziming , Letu Husi , Shang Huazhe , Bugliaro Luca , Voigt Christiane
Published: February 2023

The determination of supercooled cloud fraction (SCF) based on satellite remote sensing is important for research fields including estimation of global radiative energy balance, artificial weather modification, and prevention of aircraft ice accretion. However, nearly all retrieval algorithms for passive instruments provide binary phase information - ice, supercooled or liquid - making it difficult to retrieve mixed-phase cloud properties and understand the transition from supercooled water droplets to ice crystals. Motivated by these questions, we proposed a method to evaluate the ice partitioning of single-layer thermodynamic cloud top phase, under the assumption of the shape of ice crystals.In order to retrieve optical properties of SCF, we use a droxtal habit model to investigate the scattering properties of frozen supercooled water particles. We compare the single scattering phase functions between droxtals and spherical particles at different wavelengths. Furthermore, the difference of satellite observed radiance reflected by supercooled water clouds and ice clouds are discussed. The difference between cloud ice water path of these two categories of clouds and observations from the same satellite channel can be used to evaluate the SCF in single-layer cloud top mixed phase clouds. Taking the ice-to-liquid ratio in the GCM (global climate model)-Oriented CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) Cloud Product (CALIPSO-GOCCP) as the criteria to validate our retrieved SCF, the average deviation, root mean square error and correlation coefficient are 6.98%, 9.62%, and 0.78, respectively. As a future work, we plan to adjust ice particle habits regarding ambient temperature to represent frozen supercooled water particles.Our method could be applied to the to be launched EarthCARE (Cloud, Aerosol and Radiation Explorer) satellite in 2023 as it boards one multi-spectral imager and one atmospheric lidar simultaneously. This study is also of interest for related researches on assessing the climate impacts of supercooled and mixed-phase clouds and validating the associated global model simulations.
Showing the value of green spaces from a climate perspective: a weather sensor network for city spaces in Tallinn
Authors: Hoy Andreas , Gutbrod Karl
Published: February 2023

Grey infrastructures like buildings, roads and parking lots relate to surface sealing, lack of ventilation and anthropogenic heat – leading to effects like urban heat (UHI) and dry islands (= higher temperatures and lower relative humidity), and impact surface runoff during precipitation events. Hence, urban climate conditions differ significantly from their rural surroundings, demanding more granular data to quantify the effect city space has on weather parameters. However, observations and weather forecasts are usually made for rural areas, representative for a larger area – not for spaces where most people live, work and sleep. While a lot of data indeed exist for urban areas already – e.g., from satellites, radar stations and climate models – they all need calibration from measurements, in the city itself.Tallinn is the European Green Capital 2023. While it strives making green spaces more accessible for its people, grey infrastructure development is continuing and even expanding, sustaining and increasing the city’s urban heat and dry islands. On the other hand, Tallinn is conserving and investing in green infrastructure, like turning an old railway track into a green corridor and publicly open space (the so-called “Pollinator Highway”). This corridor connects living quarters of Tallinn`s outskirts with central areas and supports social inclusion by passing through diverse socio-economic districts.We created a concept to show the value of this green corridor for urban climate conditions. In May 2022, SEI Tallinn set up a network of 18 weather sensors measuring temperature, relative humidity and precipitation. The majority of stations are placed in green (5), urban green (5) and urban grey (5) spaces in the vicinity of the “Pollinator Highway”, with two more nearby the sea (to quantify land-sea-wind effects) and one near the official weather station. Data are open access, and live measurements publicly accessible.In this contribution, we evaluate the results of 10 months of measurements, with a spatiotemporal focus on how and where Tallinn’s UHI enhances the impacts of heat and mitigates cold waves. With the data presented in this contribution, we make urban climate challenges visible and climate communication more relevant to people, show the climatic value of green compared to grey city spaces (especially during heat waves) to municipal decision-makers and Tallinn’s citizens, determine the effect of the sea on Tallinn's climate and how it shapes Tallinn`s UHI, and finally support climate resilience and tailored adaptation solutions.
Lithospheric mantle delamination control on orogenic plateau formation
Authors: Xie Yuan , Balázs Attila , Gerya Taras , Xiong Xiong
Published: February 2023

The convergence of continents is accommodated by the subduction of the oceanic lithosphere, followed by continental collision. A long-lasting collisional stage can lead to the rise of wide and high orogenic areas, such as the Tibetan or Iranian Plateau. The mechanisms maintaining high convergence rates during continental collision remain debatable. A viable process involves the peeling off and sinking of the dense continental mantle lithosphere and rise of the asthenosphere underlying crustal accretion. This geodynamic process is so called “delamination”, which is invoked in accounting for a variety of geological and geophysical phenomenon such as widespread igneous rocks, rapidly uplift in geological history, and high velocity anomaly in seismic tomography observed in many orogenic plateaus (Bird, 1979).Different regimes of delamination would lead to different modes of mantle convection and crustal deformation, resulting in various surface expressions and the formation of orogenic plateaus. In this study, we simulate oceanic subduction, followed by continental collision and delamination. We aim to understand and quantify the spatial and temporal evolution of orogenic plateau formation and its connection to lithospheric mantle delamination, upper and lower crustal deformation and deep subduction dynamics.We use 2D numerical modeling with the I2ELVIS code (Gerya & Yuen, 2003), simulating visco-plastic rheology, hydration and dehydration processes, melting and surface processes. Our initial setup involves two continents separated by a ca. 700 km wide oceanic domain. We present preliminary results on the influence of different subduction velocities, plate rheology and different intensity of surface processes for different geodynamic regimes of orogeny and orogenic plateau formation.ReferenceBird, P. (1979). Continental delamination and the Colorado Plateau. Journal of Geophysical Research: Solid Earth, 84(B13), 7561-7571.Gerya, T. V., & Yuen, D. A. (2003). Characteristics-based marker-in-cell method with conservative finite-differences schemes for modeling geological flows with strongly variable transport properties. Physics of the Earth and Planetary Interiors, 140(4), 293-318. 
Spatio-Temporal Asset Catalog (STAC) for in-situ data
Authors: Magin Justus , Odaka Tina
Published: February 2023

In order to make use of a collection of datasets – for example, scenes from a SAR satellite – more efficient, it is important to be able to search for datasets relevant for a specific application. In particular, one might want to search for a specific period in time, for the spatial extent, or perform searches over multiple collections together.For SAR data or data obtained from optical satellites, Spatio-Temporal Asset Catalogs (STAC) have become increasingly popular in the past few years. Defined as JSON and backed by databases with geospatial extensions, STAC servers (endpoints) have the advantage of being efficient, language-agnostic and following a standardized API.Just like satellite scenes, in-situ data is growing in size very quickly and thus would benefit from being catalogued. However, the sequential nature of in-situ data and its sparse distribution in space makes it difficult to fit into STAC's standard model.In the session, we present a experimental STAC extension that defines the most common properties of in-situ data as identified from ArgoFloat and  biologging data.
Climate X: Making climate risk data useful and usable for the financial sector
Authors: Woodhouse Sally , Burke Claire , Leach Nick , Brennan James , Reveley Graham , Ramsamy Laura , Mitchell Hamish
Published: February 2023

Increasingly the financial sector is interested in understanding their risk to the impacts of climate change. This is driven both by governmental regulation that requires financial services to declare their risks due to climate change, as well as a desire to mitigate risks to profits that climate change poses.To generate useful and accurate risks assessments users need access to high quality data of the projected changes to hazard due to climate change. However, there is typically a gap between scientific research and what our clients need to understand their risk. Many of the most damaging hazards, such as flooding and subsidence, are not directly modelled by climate models and require specialist hazard knowledge and well as climate data to assess. Scientific studies often focus on large scale changes or small regional studies, whereas clients need consistent high-resolution data across multiple regions. Additionally, a risk portfolio covers a wide range of climate related hazards, which all must be considered when understanding and attempting to mitigate risk. Users will often not have the inhouse knowledge to use data generated by the scientific community directly or the expertise to assess how this relates to the risks posed by different hazards. Therefore, the financial sector is turning to external data providers for this information, such as Climate X.This talk will cover how at Climate X we make reliable and robust risk assessments of climate hazards that are presented in a way that is usable and useful for the financial sector as well as various other decision makers. The focus will be on how we use open-source climate model data to generate our heat risk metric. This will cover the definition of the metric, how it is calculated and how we how we present the data to users including accuracy and uncertainty. I will also present overview of the other hazards that we provide and the need for an interdisciplinary team to cover the broad range of physical hazards related to climate change.
Passive characterization of aquifers hydro-mechanical properties using tidal signals
Authors: Thomas Augustin , Fortin Jérôme , Vittecoq Benoît , Violette Sophie
Published: February 2023

Following the evolution of the hydrodynamic parameters (hydraulic conductivity and storativity) of an aquifer over time is difficult and does not exist for an aquitard. The primary reason is the small number of observations, which are mainly pumping or slug tests. However, solutions exist to recover these parameters using only groundwater level monitoring data at a sampling rate of 1 hour, data which is extensively available. These solutions take advantage of the boreholes’ response to different tidal phenomena, including oceanic, earth and atmospheric tides.Martinique Island, in the Lesser Antilles, is a very interesting field to study these techniques, since 16 years of piezometric level data have been recorded on this volcanic island in a monitoring network of 29 boreholes. The variety of aquifer geometry and geology enables to study different types of responses, in addition the island is submitted to seismic activity that may impact aquifers and particularly their hydraulic conductivity.The method consists in computing amplitude and phase response of aquifers to both atmospheric, earth and ocean tides. Then, the response of semi-confined aquifers to different loading sources at the tidal frequencies (between 1 and 2 cycles per day) is modelled. The model is a general and adaptable one, in order to consider the various geometries (including the presence or not of an aquitard) and aquifer boundary conditions (confined, semi-confined, connected to the atmosphere or not). Finally, a careful inversion is done to obtain the characteristics of the aquifer.Our results show that the Martinique aquifers present responses to different sources of loading. We show that using the dominant source response alone, we are able to recover aquifer or aquitard hydraulic conductivity and its evolution over the last 16 years, which we compare with pumping tests results. Using a combination of sources, we are also able to recover elastic properties like the evolution of the loading efficiency and shear modulus. Finally, comparing different sites responses, we are able to assess which aquifer is more vulnerable to pollution through vertical leakage within their aquitard.