bluuebunny/crossref_metadata_2025 huggingface dataset:
Unraveling secondary ice production in winter orographic clouds through a synergy of in-situ observations, remote sensing and modeling
Authors: Georgakaki Paraskevi , Billault-Roux Anne-Claire , Perrin Eliot , Foskinis Romanos , Sotiropoulou Georgia , Vogel Franziska , Gini Maria , Eleftheriadis Konstantinos , Moehler Ottmar , Takahama Satoshi , Berne Alexis , Nenes Athanasios
Published: February 2023

The representation of orographic clouds in numerical weather prediction models remains a great challenge, as a consequence of our incomplete understanding of the microphysical processes acting on them and the complex interactions between the large-scale and orographic flow dynamics. Mixed-phase conditions are frequently occurring in orographic clouds, highlighting the importance of correctly simulating the microphysical evolution of ice- and liquid-phase hydrometeors. In this study we employ the mesoscale Weather Research and Forecasting (WRF) model to investigate the drivers of intense snowfall events observed during the Cloud-AerosoL InteractionS in the Helmos background TropOsphere (CALISHTO) campaign, that took place from Fall 2021 to Spring 2022 at Mount Helmos in Peloponnese, Greece. Vertical profiles of reflectivity, Doppler velocity, as well as full Doppler spectra measured by a vertically pointing W-band (94 GHz) Doppler cloud radar, in synergy with Doppler and aerosol depolarization lidar data, help gain insight into the snowfall microphysics involved and set the basis for evaluating the performance of the WRF model. A radar simulator coupled with WRF enables the direct comparison between the mesoscale simulations and remote sensing products, and allows us to find the optimal model set-up that minimizes deviations from the observations. Comparing the modeled ice crystal number concentrations (ICNCs) with the Ice Nucleating Particles (INPs) measured in-situ at the Helmos High Altitude Monitoring Station (2314 m, 42°N 05' 30'', 34°E 14' 25'') by the Portable Ice Nucleation Experiment (PINE) instrument, we seek to quantify the ice enhancement factors due to secondary ice production (SIP) or seeding ice particles and their potential role in enhancing orographic precipitation. The synergy between high-resolution modeling and radar observations gives us the opportunity to infer SIP signatures from remote sensing observations, which is an important outcome given the abundance of the latter.
A seamless coastal to global ocean pCO2 and pH reconstruction at a 0.25-degree resolution with extrapolation to the near future
Authors: Chau Thi-Tuyet-Trang , Chevallier Frédéric , Gehlen Marion
Published: February 2023

Observational networks monitoring marine carbon variables are established to meet the critical need to estimate ocean CO2 uptake, as well as assessing its consequences on ocean health through changes in carbonate chemistry (ocean acidification). Despite considerable efforts over the past decades, data coverage is still sparse over large ocean regions, prompting the implementation of mapping methods to gap-fill carbon datasets over the globe. Different statistical approaches have been proposed with the aim to generate reconstructions of the complete marine CO2 system at high spatial-temporal resolutions. Following this goal, we first introduce a global reconstruction of surface ocean partial pressure of CO2 (pCO2) at monthly and 0.25-degree resolutions over the period 1985-2021. This high-resolution pCO2 product is derived from ensemble neural network models interpolating monthly gridded observation-based data from Surface Ocean CO2 ATlas (SOCAT). We will assess the ability of the proposed pCO2 ensemble (1) to derive long-term time series of pCO2 and associated 1-sigma uncertainty per 0.25-degree grid cell for each month, (2) to reproduce temporal and horizontal gradients of coastal pCO2 observations in comparison with a coarser spatial resolution, (3) to estimate surface ocean pH and air-sea CO2 fluxes. Furthermore, we will present an extension of the ensemble neural network models, which is referred to as a new module extrapolating pCO2 to several years ahead. The extended ensemble-based approach will ultimately be used to project global ocean CO2 uptake and ocean acidification with low latency.
Climate warming by open-top chambers enhances the flowering and fruit development of bog cranberry (Vaccinium oxycoccos L.)
Authors: Antala Michal , Juszczak Radosław , Stróżecki Marcin , Rastogi Anshu
Published: February 2023

Changes in plant phenology belong to the important consequences of climate change. Earlier start of the bud bursting, leaf development, or root growth are reported for many species, including those growing in northern peatlands. The next generation of plants depends on the production of generative organs; therefore, flower and fruit development are essential stages of ontogenesis, which are strongly regulated by ambient temperature. In this work, we focused on the generative organs’ development of bog cranberry (Vaccinium oxycoccos L.) under climate manipulation. The study was carried out in a nutrient-poor fen located in Western Poland, where two climate manipulation sites with different hydrology and vegetation composition were established in 2017. The site with a more stable water-table depth (WTD) and higher abundance of Carex spp. is named CL, and the site with a more fluctuating WTD and lower abundance of Carex spp. is named CR. Each site consists of three control (C) and six manipulated (M). The climate manipulation was induced by open-top chambers with the addition of 100 W infrared heaters that were switched on during nighttime. This manipulation resulted in an average annual increase of the air temperature 30 cm above ground in the period April-June of the studied year 2022 by 0.44°C at the CL site and 1.07°C at the CR site. The flower and fruit appearance and the flowering dynamics were analyzed from high-resolution images. We observed that flowering in M plots started on average 3.5 days sooner at CL and 14.5 days sooner at the CR site compared to respective Cs. The peak of flowering in warmed plots occurred 7.5 and 14 days earlier for CL and CR sites, respectively. The first fruit developed on average 11 days sooner in M plots of the CL site and 19 days sooner in M plots of the CR site than in respective Cs. In addition to the shifts in phenophases, the flowering dynamic was changed. The slow flower opening at the beginning and the faster opening towards the peak of flowering in C were changed to the fast opening at the beginning and slower towards the peak in M plots.Our results show the earlier onset of the generative stages of bog cranberry with the warming climate. Additionally, a comparison of the two vegetation sites suggests that the vegetation community mediates the magnitude of the climate manipulation impact. The Research was co-founded by the National Science Centre of Poland (NCN) within grants No. 2016/21/B/ST10/02271 and 2020/37/ B/ST10/01213. 
Dust Interaction with Charged Particles in Laboratory
Authors: Pavlů Jiří , Nouzák Libor , Wild Jan , Šafránková Jana , Němeček Zdeněk
Published: February 2023

Dust in space is subject to various interactions of photons and charged particles. Whereas photoemission is rather well understood, the charging of dust grains due to the interaction with charged particles has many variations and was not study in detail so far. We report the first laboratory experiment dealing with some less pronounced and often neglected secondary processes, e.g., secondary electron emissions due to ion, electron or positron impacts. We employed a quadrupole trap to store a single micrometer-sized silicate dust grain and measure variations of its charge with an accuracy of one elementary charge. The determined yields of secondary processes exhibit surprisingly large values. We discuss the experimental results and formulate possible consequences for space dust charging.
Up-scaling approach to monitor pests in Alpine forests: A case study in Vinschgau, South Tyrol, Italy.
Authors: Mejia-Aguilar Abraham , Theofanidis Alexandros , Dorigatti Emilio , Sonnenschein Ruth , Chuprikova Ekaterina , Meng Liqiu
Published: February 2023

Endemic pests are a fundamental part of forest ecosystems, they provide key ecosystem services such as nutrient cycling and support biodiversity. Still, massive outbreaks of these pests, triggered by events such as drought, windthrows, and snow breaks, can limit the provisioning of ecosystem services that are key for human populations such as water cycle regulation and, which can eventually trigger natural hazard events (e.g. landslides).Unmanned Aerial Vehicles (UAVs) and miniaturized optical sensors can be used to support foresters in detecting, identifying, and quantifying pests and their diffusion by exploiting multispectral imagery at high resolution. Such platforms are especially suited for monitoring areas in mountain regions that are difficult to access.This study focus on the pine processionary (Thaumetopoea pityocampa) and European bark beetle (Ips typographus) that affect many forests in the Province of South Tyrol, Italy. Here, we present an up-scale strategy that first identifies the presence of a pest at the centimeter level (ground and close-range scale) based on UAV-derived products on a plot level. We conducted three UAV-flight campaigns during the year corresponding to the insect-life cycle. Then, on the one hand, using simple RGB and NDVI mosaics the system delineates the trees, identifies nests (processionary) and quantifies their impact. On the other, using the NDVI time series collection the system classify healthy, infested or dead tree linked to the presence of bark beetle. The system classifies and quantifies its presence by presenting graduated symbol maps widely used by foresters. Then, we scale up to meter resolution (remote sensing scale) to detect changes due to certain conditions of stress that can link to the presence of the studied pests. The final aim is to create high-quality training datasets that will be exploited by remote sensing products (Sentinel) to study and cover wider areas.
Evolution of temporal seismic velocity changes and earthquake source mechanisms during the 2021 Fagradalsfall dyke intrusion
Authors: Cubuk Sabuncu Yesim , Rodríguez Cardozo Felix , Geirsson Halldór , Jónsdóttir Kristín , Hjörleifsdóttir Vala , Lecocq Thomas , Caudron Corentin , Mordret Aurelien
Published: February 2023

Late February 2021, the Reykjanes Peninsula in southwest Iceland experienced severe seismicity associated with the development of a 9 km long dyke. Eight earthquakes of magnitude M≥5  were registered in the vicinity of Fagradalsfjall from February 24 until the onset of the Fagradalsfjall eruption in mid-March, which lasted for six months. Here, we analyze the temporal variations in crustal seismic wave velocities and the source characteristics of earthquakes during the dyke formation phase (February-March 2021).We apply ambient-noise seismic interferometry and compute seismic noise cross-correlations using the MSNoise software. Cross-wavelet analysis, a powerful technique that allows us to obtain frequency-dependence of velocity change, is used to investigate relative variations in seismic wave velocities (dv/v). Along with our wavelet-based dv/v results, we also present the stretching-based dv/v time-series that were calculated in real-time for volcano monitoring during the unrest. The Fagradalsfjall dyke intrusion induced temporal variations in seismic velocities and strong decorrelation that were picked up by the entire network across the peninsula. Beginning abruptly with the increased seismic activity, velocities at nearby seismic stations decreased by 1.5 percent. The amount of dv/v change was noticeably less than 1 percent at distant stations (15-30 km). The regional time-domain moment tensor inversion method (TDMT_INVC) was also applied to obtain earthquake mechanism solutions. Source parameters of 50 moderate-sized events with magnitudes Mw≥4.0 revealed predominantly normal and strike-slip faulting. We compare these to the deformation, dv/v and modeled Coulomb stress changes and present a joint interpretation.We provide a summary of the complex spatial and temporal evolution of crustal seismic velocity changes in the weeks preceding the effusive eruption. The understanding of the pre-eruptive geophysical signatures of the Fagradalsfjall volcano will contribute to better predict future volcanic activity in the area.
The San Bartolo lava flow field, Stromboli volcano, Italy: Simulation of the most recent historic flank eruption (2 kyr) affecting the inhabited area aimed at hazard assessment
Authors: Ganci Gaetana , Bilotta Giuseppe , Cappello Annalisa , Calvari Sonia
Published: February 2023

The San Bartolo eruption is the last flank eruption occurred at Stromboli volcano about 2 ka ago on the NE flank of the island. Despite its importance in being the most recent example of flank activity outside the barren Sciara del Fuoco slope, where the recent activity concentrated, some important volcanological data, such as the duration and lava volume have not yet been provided. Here, we present a new simulation of the San Bartolo eruption carried out using a combination of field analyses and numerical modelling. In particular, we used the CL-HOTSAT satellite monitoring system to estimate the effusion rate and erupted volume of the 2002-03 eruption, which formed a similar lava flow field extending from about 600 m in elevation to the coast. These were used as input of the physics-based model GPUFLOW to reproduce the emplacement dynamics of the San Bartolo lava flow. The aim is to reconstruct the sequence of events and infer a possible duration and impact of the eruption. Our results can provide a useful scenario should a flank eruption occur in the future, a possibility that was close to happening in 1998, when the ground deformation stations revealed a lateral intrusion in the shallow supply system of the volcano.
Cenozoic bryozoan biota: their palaeoecology and climatic environmental significance in Antarctic ecosystems
Authors: Hara Urszula
Published: February 2023

The distribution of the bryozoans in the shallow-marine-estuarine sediments of the late Early–Late Eocene La Meseta Formation, Seymour Island shows a sharp decline in bryozoan biodiversity between the lower, basal transgressive facies of Telm1 and upper part of the formation (Telm6-7) at the end of Eocene (Hara 2001). In the lowermost part of LMF (Telm1) the cheilostome bryozoans, preserved as internal moulds systematically belonging to buguloids and catenicelloideans, at the present day are widely distributed in the tropical-warm temperate latitudes and deposited in the shallow-water settings (Hara 2015). Within a 2 meters thick interval of the basal transgressive facies of Telm1 unit, the most common are multilamellar colonies, showing a great variety of shapes dominated by celleporiforms and cerioporids.The middle part of (LMF, Telm4-5) reveal a presence of the microporoideans and disc-shaped lunulitiform - warm-loving, free-living bryozoans. Environmentally, Recent, lunulitids are known to occur in warm, shallow-shelf conditions, at temperatures of 10-29˚C, on coarse, sandy to muddy bottom, what suggest the shallow-water setting for the middle part of the LMF.10 million years older, the Cape Melville Formation on King George Island dated as Early Miocene is dominated by the infaunal bivalves, which provide a unique fossil record in the Antarctic Peninsula region during the latest Oligocene to earliest Miocene interglacial to glacial transition. Only one bryozoan was described identified as Aspidostoma melvillensis (Hara and Crame, 2004).The shallow-marine, pectinid-rich biofacies of the Pecten Conglomerate of CIF, Cockburn Island, taxonomically shows the mosaic pattern in occurrence of bryozoan taxa, which are known from the Middle and Late Cretaceous, another originated in the Paleogene, as well as those which are solely common in the Neogene. Exclusively encrusting colony growth-form of the Pliocene biota suggests sedimentation in the shallow-water environment and indicates an interglacial palaeoenvironment of the CIF Formation (Hara & Crame, in revision).The cold-water geographical distribution of the Recent bryozoans with dominant Neocheilostomatina of Buguloidea and the ascophoran lepraliomorphs of Smittinoidea and Schizoporelloidea, shows a dynamic history of this highly endemic fauna, which evolved over long period of time.Hara, U. 2001. Bryozoa from the Eocene of Seymour Island, Antarctic Peninsula. Palaeontologia Polonica, In: Palaeontological Results of the Polish Antarctic Expeditions, Part III, 60, 33-156.Hara U., 2015. Bryozoan internal moulds from the La Meseta Formation (Eocene) of Seymour Island, Antarctic Peninsula. Polish Polar Research, 36: 25-49.Hara and J. A. Crame 2004. A new aspidostomatid bryozoan from the Cape Melville Formation (lower Miocene) of King George Island, West Antarctica. Antarctic Sciences, 16, 319-327.
  
The growth of Turkish – Iranian Plateau and comparative models for understanding the deformation on the overriding plate during plateau formation
Authors: Çetiner Uğurcan , van Hunen Jeroen , Gogus Oguz H. , Allen Mark B. , Valentine Andrew P.
Published: February 2023

The Arabia-Eurasia collision, which started during Late Eocene (~35 Ma) or afterward across the Bitlis-Zagros suture, resulted in the formation of the Turkish – Iranian Plateau. Even though the average elevation throughout the plateau is around 2 km, the lithospheric structures between East Anatolian and the Iranian parts may be different. For instance, seismological studies suggest that East Anatolia is underlain by anomalously low-speed anomalies/hot asthenosphere whereas the Iranian part is associated with a rather thick (>200 km in some places) and strong lithosphere. Therefore, the area may be regarded as two distinct regions, namely, the East Anatolian Plateau and the Iranian Plateau. The growth of the plateau is mostly attributed to slab break-off combined with crustal shortening. Other processes often associated with the collision are lithospheric delamination and tectonic escape of microplates. These hypotheses suggested for the growth of the plateau are yet to fully explain the dualistic nature of the lithosphere in a region where elevations are roughly similar. In this work, by using 2D numerical experiments we aim to investigate the physical, geometric, and rheological parameters affecting the deformation of the plate during pre-, syn-, and post-collision. Our preliminary model results show an extension (up to ~70 km) on the terrane that is dragged behind the subducting plate, while the overriding plate undergoes shortening during the collision. The collision results in ~100 km of underthrusting in 50 Myrs which is in the range for the measured amounts of underthrusting across the plateau. We aim to expand the study by creating comparative model sets (i.e., models representing East Anatolia vs. models representing Iran) with a parameterization of varying lithospheric structures (e.g., different crust and mantle thicknesses), and strength profiles, which will help us to understand the kinematics and dynamics of such orogenic growth.
Fram Strait Marine Cold Air Outbreaks and associated surface heat fluxes in the ERA5 & CARRA reanalyses
Authors: Slättberg Nils , Maturilli Marion , Dahlke Sandro
Published: February 2023

The rapidly transforming Svalbard and Fram Strait region is characterised by strong air-sea exchanges and represents a major gateway of oceanic and atmospheric transport between the Arctic and lower latitudes. In winter, Marine Cold Air Outbreaks (MCAOs) extract large amounts of energy from the ocean in the form of surface sensible and latent heat fluxes. We investigate how the spatiotemporal variability in Fram Strait MCAOs affects the heat fluxes in ERA5 and the novel Arctic reanalysis CARRA over ocean, sea-ice and land during November-March 1991-2020.

We find that the daily mean heat fluxes are strongly correlated with the MCAO index and that wind speed only plays a large role for the heat fluxes when the MCAO index is positive. The sensible heat flux from the surface to the atmosphere reaches greater values in CARRA than in ERA5 while the opposite is true for the latent heat flux. The difference between the reanalyses scale with the magnitude of the heat fluxes, leading to large disagreement over ice-free ocean, where the fluxes have their highest values. When accounting for the differences in magnitude, we find the largest disagreement between the reanalyses over sea ice. 

In addition, we find that although sea ice loss drives positive ocean-to-atmosphere heat flux trends around much of Svalbard, negative trends in the monthly mean heat fluxes are seen in Fram Strait during the winter, especially in January. These negative trends reflect the decline in the surface-atmosphere potential temperature difference which forms the basis for the MCAO index. 

Finally, we examine the vertical structure of the atmosphere during MCAOs and find anomalously northerly winds, low temperature and low specific humidity throughout the troposphere. The specific humidity anomalies are strongest at low altitudes over the ice-free ocean in southern Fram Strait, while the temperature anomalies reach their maximum in the vicinity of the ice edge. Over the ice-free ocean, where the heat fluxes warm the air from below, the strongest temperature anomalies are found around the altitude of the 800 hPa level.
A 3-D numerical investigation of the impact of buoyant features on subduction dynamics and stress
Authors: Suchoy Lior , Goes Saskia , Chen Fangqin , Davies D. Rhodri
Published: February 2023

The subduction of positively buoyant features has been suggested to cause flat or shallow dipping slabs, the formation of cusps in trench geometry and periods of reduction or full cessation of arc magmatism. Additionally, recent earthquake data indicates that the subduction of the Hikurangi plateau near New Zealand causes a rotation of intraplate stresses. In this study, we present a series of multi-material 3-D simulations of free subduction to investigate how subduction of buoyant elongated features, or ridges, impact downgoing plate velocities, trench motions, slab morphology and intraplate stress regime. We examine how these parameters are affected by the age of the subducting plate and the relative buoyancy and position of the buoyant ridge. We find that buoyant ridges change slab sinking and trench retreat rates and locally rotate intraplate stresses. These, in turn, modify the evolution of slab morphology at depth and trench shape at the surface, as trench retreat is reduced, or switches to trench advance, where the ridge subducts. These effects depend strongly on downgoing plate age: on young and weak plates, the change in trench shape is more localised than on old and strong plates. We observe slab shallowing around the ridge only in young plates, while the stronger pull by the more negatively buoyant old plates causes slab steepening near the buoyant ridge. Buoyant ridges on old plates which are located near stagnating or advancing regions, typical in wide slabs, modify trench behaviour more strongly than ridges in other regions of the trench. Bending-related intraplate earthquakes are more likely in older plates where higher stress is accumulated and the rotation due to the buoyant ridge is more widespread than for younger plates. The combined effects of buoyant feature location, subducting plate age and overriding plate properties can result in a range of responses: from mainly trench deformation, through local slab shallowing, to the formation of a flat slab, a variation in expressions also observed on Earth.
Multi-modal data assimilation of sea surface currents from AIS data streams and satellite altimetry using 4DVARNet
Authors: Benaïchouche Simon , Le Goff Clément , Boussidi Brahim , Rousseau François , Fablet Ronan
Published: February 2023

Over the last decades, space oceanography missions, particularly altimeter missions, have greatly advanced our ability to observe sea surface dynamics. However, they still struggle to resolve spatial scales below ~ 100 km. On a global scale, sea surface current are derived from sea surface height by a geostrophical assumption. While future altimeter missions should improve the observation of sea surface height, the observation of sea surface current using altimetry techniques would remains indirect. In the other hands, recent works have considered the use of AIS (automated identification system) as a new mean to reconstruct sea surface current : AIS data streams provide an indirect observational models of total currents including ageostrophic phenomenas. In this work we consider the use of the supervised learning framework 4DVARNet, a supervised data driven approach that allow us to perform multi-modal experiments : We focus on an Observing System Simulation Experiment (OSSE) in a region of the Gulf-Stream and we show that the joint use of AIS and sea surface height (SSH) measurement could improve the reconstruction of sea surface current with respect to product derived solely from AIS or SSH observations in terms of physical and time scale resolved. 
Cyclonic development in the Mediterranean Basin in CMIP6 models using a neural network approach
Authors: Blougouras George , Philippopoulos Kostas , Tzanis Chris G. , Cartalis Constantinos
Published: February 2023

The Mediterranean basin is located between the subtropical high-pressure belt and the mid-latitude westerlies and is characterized by complex topography. Its orography, the relatively warm Mediterranean Sea, which is a source of energy and moisture, and the land-sea interactions result in significant cyclonic behavior in the synoptic and sub-synoptic scales. Due to its high sensitivity to climate change forcings, the Mediterranean region is considered a climate change hot spot, with impacts, such as the decline in the projected precipitation, leading to increasing aridification in an already water-stressed area. The above highlight the importance of examining the cyclonic development in the area and assessing the respective changes under different climate change scenarios. In this research, unsupervised machine learning algorithms are used in order to objectively identify cyclonic development in the Mediterranean basin using CMIP6 data for a subset of the different shared socio-economic pathways (SSP) that explore a wide range of possible future outcomes. In more detail, Sea Level Pressure from selected CMIP6 models is used as an input in a Self-Organizing Map (SOM) which is trained to identify the cyclone activity in the Mediterranean Basin for the 1981-2010 reference period. The ability of the network in terms of identifying effectively cyclogenesis regions and the transition probabilities is evaluated. The trained SOM is used to classify CMIP6 mid-century (2031-2060) projections and changes in the frequencies of occurrence of cyclonic development. These are evaluated in terms of physical drivers and regionally specific mechanisms. Examining the responses of cyclonic development to different forcing scenarios will not only shed light on the physical and dynamical processes that govern these circulations but will also allow identifying high–risk regions with potential socio-economic impacts.
Territorial climate change: understanding, mitigating and adapting
Authors: Breton Florentin
Published: February 2023

Territories are complex environments with many issues at stake. The issues of human health and energy consumption for instance are linked to local weather and climate change. Despite the scientific and societal developments of the last decades, some of the physical and social processes of territorial climate change are still not well understood, and the implementation of mitigation and adaptation is slow. The following studies address these aspects of processes, mitigation, and adaptation, based on different methods in climate and social sciences.The first study investigates the seasonality of weather conditions in Europe by using classification approaches (weather types, local analogues) on climate observations, simulations and projections. Simulations are close on average to the observed variability, winter conditions decrease while summer conditions increase, and Mediterranean seasonality expands Northwest while Scandinavian seasonality declines. The second study investigates the social perception of climate change and the acceptability of territorial options (mitigation, adaptation) by inhabitants and decision-makers, based on field interviews and foresight activities in the Gulf of Morbihan (France). A strong territorial seasonality (climate, socio-economy) and a complex role of climate change are found, as well as general agreement between local experiences and scientific knowledge. Despite divergent visions among inhabitants, two long-term scenarios and about twenty short-term actions emerged from foresight activities.A third study investigates the effect of urban parameters on city temperature, and how urban planning options can optimize thermal comfort and reduce energy consumption and GHG emissions, based on urban climate observations and simulations. The city size drives urban warming, followed by urban fraction but building heights can cool the city depending on the season. Model adjustment and sensitivity simulations are presented for the urban planning approach.
A fractal approach to document the Wave-Influenced Boundary Layer in the Large Air-Sea Interaction Facility of Luminy, Marseille
Authors: Bourras Denis , Luneau Christopher , Chemin Rémi , Bruch William , Benjeddou Saïd , Fraunié Philippe
Published: February 2023

The study of the relationship between wind speed, altitude, and the geometric properties of the ocean surface (characteristics of dominant waves, surface roughness, see the wave-breaking rate) is a central topic both (1) for the representation of the transfer of momentum at the ocean-atmosphere interface in weather, ocean, wave growth forecasting models, and in coupled models, from sub-meso-scale to climate and paleoclimatic scales, and (2) for spaceborne remote sensing of the wind speed at the surface of the oceans, either in microwaves (mainly scatterometers and radiometers) or in visible wavelengths (observation of foam lines). Our study is focused on the surface air layer that is directly influenced by the presence of waves, which is so-called Wave-influenced Bounday Layer (WBL). After a survey of the existing relations found between wind, momentum, and the surface geometry in gradually increasing wind conditions, we will attempt to relate the results of ongoing fractal analyses based on (1) wind field deduced from PIV technique, (2) horizontal wave slope images from light refraction technique, and (3) Laser slice, in a controlled environment.
Suitability of near-real time precipitation products for Flood Risk Forecasting
Authors: Salinas Illarena Jose Luis , Nicotina Ludovico , Li Shuangcai , Hilberts Arno
Published: February 2023

Accurate real and near-real time forecasting of extreme flood events has lately become more and more important for the insurance and re-insurance industry (e.g., for claims allocations, Insurance Linked Securities and Catastrophe Bonds…). Examples of such events triggering significant losses in recent years are low-pressure system Bernd (July 2021, eastern Belgium, western Germany, and north-eastern France), hurricane Ida (August-September 2021, Louisiana and Northeastern United States), or hurricane Ian (September 2022, Florida). In order to estimate overall flood risk and flood losses in near-real time, a precipitation product released with a short latency is necessary.This study analyses the use of the near-real time precipitation products NOAA’s Climate Prediction Center (CPC) and Multi-Radar/Multi-Sensor System (MRMS) for flood forecasting, the latter having a higher spatial and temporal resolution than the former. We investigate and compare their different rainfall characteristics in terms of their ability to capture rainfall extremes, their suitability as input for hydrological/inundation models, and the effect that they have on overall economic losses for a series of selected historical events over the Conterminous United States. Finally, we include in the comparison the more stablished, long-latency dataset North American Land Data Assimilation System (NLDAS), more frequently used for event reconstruction c.a. 1 week after the event.
An improved MSG SEVIRI wet-dry product based on a convolutional neural network
Authors: Wiegels Rebecca , Wagner Andreas , Polz Julius , Glawion Luca , Chwala Christian
Published: February 2023

Adequate spatial coverage of precipitation measurements is not available for large regions. Many countries are only equipped with networks of meteorological stations to measure precipitation based on sparse point measurements. Attenuation data from commercial microwave links (CML) allow precipitation estimates over existing networks, such as the cellular network. However, the processing of the data requires a distinction between wet and dry. Here, satellite data in countries of the Global South play a significant role, as they can be used in place of conventional reference data to distinguish between dry periods and precipitation events.Deep Learning (DL) can be used to develop a dry indicator based on geostationary satellite data that can be applied for dry-wet classification in CML processing. A convolutional neural network is used to process visual and infrared cloud information from geostationary satellites and to create a dry indicator. Satellite derived products exist, such as the NWC SAF products PC and PC-Ph, and are utilized as baseline products. The baseline products and the DL based dry indicator developed in this work (DL product) are evaluated with radar and station data in Germany.The evaluation shows that the developed DL product improves the performance at day and especially at nighttime. Limitations in detecting the correct rain field area is reduced by the DL product. In total the DL product improves the Matthews Correlation Coefficient value by about 0.05 compared to the PC-Ph product. 
8O Analyses of bulk lipids as a novel palaeoclimate tool in loess research - a pilot study
Authors: Zech Michael , Labahn Jakob , Bittner Lucas , Roettig Christopher , Burghardt Diana , Markovic Slobodan , Glaser Bruno
Published: February 2023

The analysis of the stable oxygen isotopes 18O and 16O has revolutionised palaeoclimate research since the middle of the last century. Particularly, 18O of ice cores from Greenland and Antarctica is used as a palaeotemperature proxy and 18O of deep-sea sediments is used as a proxy for global ice volume. Important terrestrial archives to which 18O as palaeoclimate proxy is successfully applied are speleothems, lake sediments or tree rings. By contrast, 18O applications to loess-palaeosol sequences (LPSs) are scarce, despite for instance a compound-specific 18O analytical tool for sugar biomarkers was developed and presented already years ago (Zech et al., 2014). Here we present a first continuous 18O record (n=50) for the LPS Crvenka in Serbia, SE Europe, spanning the last glacial-interglacial cycle. From a methodological point of view, we took advantage of a recently proposed palaeoclimate/-hydrological tool/proxy based on bulk 18O analyses of plant-derived lipids. The 18O lipid values range between −10.2‰ and +23.0‰ and are systematically more positive in the interglacial and interstadial (paleo-)soils compared to the loess layers. In our presentation, we compare our 18O lipid record from the LPS Crvenka with the marine oxygen-isotope stages as well as with the Greenland 18O ice core records revealing the famous Dansgaard-Oeschger events (stadials and interstadials). Concerning the interpretation of our LPS 18O lipid record, we will discuss several influencing factors, such as temperature-control on 18O, evaporative leaf water enrichment, post-sedimentary effects and pool-effects.ReferencesLabahn, J., Bittner, L., Hirschmann, P., Roettig, C., Burghardt, D., Glaser, B., Marković, S. and Zech, M., 2022. 18O analyses of bulk lipids as novel paleoclimate tool in loess research – a pilot study. E&G Quaternary Science Journal 71, 83-90.Zech, M., Mayr, C., Tuthorn, M., Leiber-Sauheitl, K. and Glaser, B., 2014. Reply to the comment of Sternberg on "Zech et al. (2014) Oxygen isotope ratios (18O/16O) of hemicellulose-derived sugar biomarkers in plants, soils and sediments as paleoclimate proxy I: Insight from a climate chamber experiment”. GCA 126, 614-623. Geochimica et Cosmochimica Acta 141, 680-682.
Variable Hydroclimate in the Suguta-Turkana Valley, Kenya during the Early Middle-Pleistocene Transition
Authors: Robakiewicz Elena , Owen R. Bernhardt , Deino Alan , Trauth Martin , Junginger Annett
Published: February 2023

The Early Mid-Pleistocene Transition (EMPT) between 1,200–700 ka represents a major global climate transition from dominantly 41,000-year to 100,000-year glacial cycles. The forces and mechanisms behind this transition, and the response of African environments, is not well understood. The active volcanism and tectonics of the East African Rift System (EARS) add complexity to environmental systems and can erase important proxy records, inhibiting studies of lacustrine dynamics. As a result, there is minimal understanding of how this transition impacted the region’s lake systems, with implications for hominin migration. At paleolake Suguta in the northern Kenya Rift, however, flood basalts cap lacustrine EMPT-aged deposits and help preserve these strata and their valuable paleoenvironmental record. This research presents a high-resolution reconstruction of hydrological change from approximately 930 to 830 ka during the EMPT at the Suguta-Turkana Valley in the northern Kenya Rift. Paleolake dynamics are reconstructed from a 41 m sedimentary section using diatom morphology, sedimentology, and x-ray fluorescence analysis. Lake levels varied during the EMPT, particularly from ~885–830 ka, ranging from deep stratified lakes, shallow, well-mixed lakes, and complete desiccation. This record identifies hydroclimate variability at several thousand year-resolution within the Suguta-Turkana Valley during the EMPT, illuminating a period where generally little is known about terrestrial environmental change.
A multi-stage analytical framework for the integration of Nature-based Solutions into climate risk management and adaptation
Authors: Furlan Elisa , Allegri Elena , Simeoni Christian , Simide Remy , Perez Geraldine , O'Leary Bethan , Fonseca Catarina , Critto Andrea , Marcomini Antonio
Published: February 2023

Climate change and environmental degradation are severely affecting marine and coastal systems and the innumerable ecosystem goods and services on which people rely. As result, biodiversity loss and reductions in ecosystem functioning have been recorded across marine and terrestrial systems. A transformative change in the way we adapt to climate change is needed, centered around preserving and restoring nature. Nature-based Solutions (NbS), an umbrella term for conservation, restoration and other management measures (e.g., regulation law implementation), offer an opportunity to transform climate adaptation pathways while providing environmental and societal benefits. They can act as risk reduction measures and address ecological, political, societal, economic issues at multi-level from individual targeted local interventions to collective regional upscaling.To facilitate the adoption of evidence-informed NbS responding to environmental targets as posed by relevant EU acquis (e.g., Marine Strategy Framework Directive) and specific contexts, in the frame of the MaCoBioS project, a harmonized modeling framework has been developed. It brings together risk assessment approaches, NbS suitability mapping and a decision-support system guiding the selection of most appropriate NbS in marine and coastal ecosystems. In particular, following a progressive analytical process, Machine Learning techniques and GIS are exploited to recognize risk-prone areas against the combined effect of human and climate-related pressures, while identifying suitable areas for marine-coastal NbS implementation today and into the future. Drawing on this, the designed decision-support system offers a portfolio of potential actionable interventions based on a variety of factors (e.g., from ecological to socio-economic) that will need to be considered during NbS planning and implementation. It allows practitioners an overview of NbS approaches that are best suited to addressing societal challenges, also linked to climate-related risks, thereby potentially helping to achieve value for money from the often-limited resources available for environmental conservation and management.Overall, the proposed multi-stage analytical framework aims to provide evidence-based guidance on the inter-relations between climate change, biodiversity and ecosystem services, offering a basis for strategic discussions and better alignment of marine-coastal NbS with respect to societal challenges. Its adoption by marine-coastal managers can facilitate an effective pathway towards NbS adoption that enhances the adaptation and resilience capacity of marine-coastal ecosystems.
Morphology, distribution and origin of soil biogenic carbonates “queras” presents in Loess-palaeosols of Ebro Valley
Authors: Alvarez Daniela , Torres-Guerrero Carlos A. , Poch Rosa M. , Preusser Frank
Published: February 2023

Several types of secondary carbonate accumulations have been reported, but some of them are not completely well defined in the field due to unclear nomenclature. This is the case of the “queras”, reported in several Loess-palaeosol sequences of the Ebro Valley, which have often been described as pseudomycelia. Micromorphologically, they are complex pedofeatures (including calcified root cells, infillings and hypocoatings of carbonates and a decarbonated zone), resulting from calcification/decalcification processess at a microscale. They are composed of a central channel (1-2 mm wide and 2-3 cm long) filled with biosparite crystals (Herrero et al., 1992). The study of these secondary carbonate bioaccumulations are important archives for climatic reconstructions in terrestrial environments and can be used for paleoenvironmental reconstructions. The aims of this research are the characterization (morphological, optical and isotopically) of the biocalcifications present in Loess-palaeosols sequences, OSL-dated, to determine the main factors that originate them and their possible use as a palaeoenvironmental proxy. We collected soil samples from seven profile of Loess-palaeosols where the presence of these biocalcifications was recorded. We isolated and manually cleaned complete fragments of queras to describe them and to determine their isotopic composition. For that purpose, we used the queras fraction (sieved fraction of bulk soil between 100-250 µm) removing the residues of micrite with a buffer solution and manually separating the quera fragments with the help of a stereoscope. Thin sections were made to analyse the micromorphology in a petrographic microscope and cathodoluminescence techniques to determine the origin of the calcite. The micromorphology of these biocalcifications is similar in most cases: they present the same number of rows around the central channel (4 to 5), and a decarbonated hypocoating around it, supporting the hypothesis that their origin is derived from the calcification of cells of the root tips as a strategy to acidify the soil surrounding to absorb nutrients. Under cathodoluminescence biosparite has a different behaviour than non-biological calcite crystals. The age of the queras was similar in most horizons and their formation is independent of the age of the loess deposit. The isotopic composition of δ13C correspond mainly to CAM plants and the temperatures of precipitation calculated correspond to a Mediterranean template climate (Cerling and Quade, 1993), implying that the biocalcifications developed in warm environments. Finally, we hope to gain some more certainty of their origin and formation processes from the ongoing analyses of DNA sequencing and pollen recording.
Pure compaction bands in the naturally deformed flysch sandstones of the Silesian Nappe (SE Poland): early markers of tectonic shortening
Authors: Strzelecki Piotr , Świerczewska Anna
Published: February 2023

Deformation in sandstones often takes the form of tabular strain localization structures known as deformation bands. To date, only a few localities have been documented with naturally occurring deformation bands that primarily localize compactant failure i.e. pure compaction bands (PCBs).The PCBs are found in the Oligocene flysch sequence of the (Lower) Krosno beds within the Otryt sandstones of the Silesian Nappe, the Outer Carpathians (SE Poland). The PCBs are perpendicular to the bedding planes and occur within the folded strata. The PCBs were formed in very fine-grained to very coarse-grained sandstones of moderate or poor sorting. The spacing of PCBs is on average 7 mm and the average thickness of a band is 0.7 mm. The PCBs’ microstructures originated due to a range of mechanisms which include pore collapse resulting in compact grain packing and disaggregation, including kinking and cataclasis. The type of resultant microstructure shows a strong relationship with the textural parameters of the host rock. The frequency of cataclasis increases with grain size, whereas kinking is related to the moderate sorting of the host rock. The structural restoration of beds to the primary horizontal position indicates that the PCBs formed prior to the folding and recorded the SW-NE directed shortening which is consistent with the subsequent folding. The results of the mechanical modelling and stratigraphic constraints suggest that the PCBs formed under shallow burial depths <1 km.The occurrence of hydrocarbons and calcite veins within some fractured PCBs shows that the PCBs might have played an important role in fluid transport during the subsequent evolution of the fold-and-thrust belt of the Outer Carpathians.Acknowledgements: This research was funded by National Science Centre, Poland (grant number: 2018/31/N/ST10/02486).