bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing the impact of mobility on heat exposure
Authors: Lin Guo-Shiuan , Manoli Gabriele
Published: March 2024

Higher temperatures are linked to elevated mortality risk and reduced economic productivity. In urban centers, human mobility and the urban heat island effect generally result in higher population density and increased temperatures. Yet, existing studies on urban heat exposure rely on static residential population data, thus neglecting population dynamics and their covariation with the spatial distribution of urban temperatures. Here, we evaluate how seasonal and daily mobility modify heat exposure and risk across 80 European cities by combining monthly daytime and nighttime population estimates with high-resolution urban climate simulations. Our findings reveal that, on a daily scale, mobility increases population and summer heat exposure in most cities due to daily commuting behavior. Conversely, commuting to warmer city centers (from colder rural areas) may be advantageous in winter. On seasonal timescales, summer populations decrease in most cities as urban residents travel outward for holidays but heat exposure increases significantly in touristic destinations where population peaks during the June-August period. These results emphasize the significant impact of mobility on the space-time distribution of heat exposure in cities and offer valuable insights for mitigating temperature-related risks in diverse climatic and urban contexts.
Comparison of direct and indirect approaches for mapping soil organic carbon stock
Authors: Chen Zhongxing , Shuai Qi , Shi Zhou , Arrouays Dominique , Richer-de-Forges Anne , Chen Songchao
Published: March 2024

Soil organic carbon (SOC) is a critical factor influencing global carbon cycling. Accurate estimates of its spatial distribution are essential for addressing global climate change. Digital soil mapping has demonstrated significant potential in providing precise and high-resolution spatial information about SOC across various scales. We conducted an evaluation of two soil mapping approaches for SOCD estimates in France: the direct approach (calculate-then-model) and the indirect approach (model-then-calculate). Our study utilized 916 topsoil samples (0−20 cm) from the LUCAS Soil 2018 dataset and 24 environmental covariates. We employed a random forest model and forward recursive feature selection to build spatial predictive models of SOCD using both the direct and indirect approaches. The results revealed that, with the random forest model and full covariates, both approaches demonstrated moderate performance (R2 = 0.28−0.32). Through the use of forward recursive feature selection, the number of predictors was reduced from 24 to 9, leading to enhanced model performance for the direct approach (R2 of 0.35), while no improvement was observed for the indirect approach (R2 of 0.28). The mean SOCD of French topsoil was estimated at 5.29 and 6.14 kg m−2 using the direct and indirect approaches, respectively, resulting in SOC stocks of 2.8 and 3.3 Pg, respectively. Notably, the indirect approach exhibited better performance in estimating high SOCD. These findings serve as a valuable reference for SOCD mapping.
Quantifying and modelling feedbacks between forest structure, light, microclimate and carbon cycling in temperate forests
Authors: Van de Walle Emma , De Hertog Steven , Meunier Félicien , Calders Kim , De Frenne Pieter , Yang Zhizhi , Stock Michiel , wyffels Francis , Terryn Louise , Sanczuk Pieter , Verhelst Tom E. , Verbeeck Hans
Published: March 2024

Studying the feedback between forest structure and the environment, particularly below canopies, is crucial for sustainable forest management, biodiversity conservation, and climate mitigation. Advanced vegetation models play a key role in unraveling the complex interaction between forest composition and environmental conditions, as these allow to understand the dynamics of ecosystems by simulating the interactions between plant species and their environment. An essential aspect necessitating refinement in these models is understanding how radiation interacts with intricate structures like forest canopies.In this study, we employ advanced terrestrial laser scanning techniques, distributed fiber-optic, and microclimate sensors to investigate the relationships between light, microclimate, carbon cycling, and forest structure in temperate forests. In a temperate forest in Belgium, we implemented a sensor setup since March 2023. It comprises a Distributed Temperature Sensing (DTS) fiber, Temperature and Moisture Sensor (TMS) microclimate loggers, SurveyTag microclimate loggers, Photosynthetic Active Radiation (PAR) sensors, and pyranometer (direct/diffuse) light sensors along a 135 m long transect from forest edge to core. Monthly 3D terrestrial laser scanning (TLS) of the transect allowed us to quantify forest structure with high spatiotemporal resolution.Preliminary results reveal distinct microclimate gradients along the transect and seasonal changes in forest structure in 3D space, including budding and changes in canopy volume. These findings will be used to calibrate and improve existing radiative transfer models (RTMs) to be further implemented in vegetation models. Integrating observations and model parameters in a common framework will provide breakthrough insights into the feedbacks between light, forest structure, microclimate, and their impact on the carbon cycle in temperate forests.
Adaptive soil moisture bias correction in the ECMWF land data assimilation system
Authors: Weston Peter , de Rosnay Patricia , Fairbairn David
Published: March 2024

Bias-correction (BC) is typically needed prior to the assimilation of satellite-derived soil moisture (SM) observations in land surface models. Active ASCAT and passive SMOS satellite-derived SM observations are assimilated in the ECMWF integrated forecasting system (IFS). Prior to assimilation, the ASCAT SM observations are bias-corrected using a seasonal rescaling technique. SMOS level 1 observations are converted to level 2 SM via a neural network, which is trained on the global ECMWF operational SM analysis. However, neither of these techniques allow for non-stationary biases and the globally trained SMOS neural network is affected by local biases. In this presentation a two-stage filter is employed in the ECMWF IFS to dynamically correct biases in the SM observations, whilst allowing the assimilation to correct sub-seasonal scale errors. Over a 3-year test period this adaptive BC approach leads to (i) reduced observation-model biases, (ii) slight improvements in SM analysis performance against in situ data and (iii) reduced mean errors in relative humidity forecasts near the surface in the northern hemisphere midlatitudes. This will benefit the development of a unified coupled land-atmosphere data assimilation system in the context of the CERISE European project (Copernicus Climate Change Service Evolution). Furthermore, it is expected that the assimilation of non-biased ASCAT SM observations will improve the root-zone SM products for the hydrological satellite applications facility (H SAF).  
Rifting in the presence of accreted terranes – a numerical modelling study
Authors: Erdős Zoltán , Buiter Susanne , Tetreault Joya
Published: March 2024

Many rifted margins have formed in areas that have previously experienced subduction and orogenesis, completing the Wilson cycle of closing and opening oceans. Often the subduction phase is accompanied by the accretion of bathymetric highs, such as oceanic plateaus, continental fragments, seamounts and microcontinents. Such accretionary orogeneses result in a more complex structural, rheological and thermal inheritance than continent-continent collision without terranes. Here we use 2D thermo-mechanical numerical models to investigate how accretionary, rather than collisional orogens, affect a subsequent phase of continental rifting. Our models build an orogen through subduction, terrane accretion and collision before the onset of rifting. We examine the structure of the resulting rifted margins and the degree in which inherited compressional structures are utilized.For rifting of collisional systems without terrane accretion, we find that there is a competition between structural and thermal inheritance that has a first order control on rifted margin architectures. For smaller, colder collisional systems, localized reactivation of the old subduction interface promotes the formation of narrow margins. Conversely, in larger, hotter collisional orogens, wide margins develop through distributed extension, initiating away from the inherited suture in the hot, weak regions of the pre-rift orogen. This dynamic persists even in the presence of accreted terranes, where the orogens preserve multiple suture-zones that dissect the lithosphere. In smaller orogens, the optimally oriented, steepest and as a result shortest, and hence weakest suture experiences the highest degree of inversion, localizing the rifting.. In larger, hotter accretionary orogens, deformation is not primarily focused on inherited shear zones but is instead concentrated in the thickest, hottest part of the orogen. We interpret this as thermal inheritance dominating over the influence of structural inheritance. Depending on the pre-rift lithosphere configuration, accreted terranes can be preserved in one or both rifted margins. Our results show that the size of the accretionary orogen prior to extension has the strongest influence on the style of the resulting rifted margins and that the presence of multiple sutures between the accreted terranes plays a smaller role in localizing extension.Our experiments demonstrate that a wide range of features such as continental fragments, allochthons or hyper-extended segments that can form in the presence of inherited compressional structures and emphasize the importance of the deformation history in the evolution of continental rifting. These results can be further used to understand how various stages of the Wilson cycle affect each other. 
Salting out, non‑ideality and synergism enhance surfactant efficiency in atmospheric aerosols
Authors: El Haber Manuella , Ferronato Corinne , Fine Ludovic , Girroir-Fendler Anne , Nozière Barbara
Published: March 2024

The surface tension of sub-micron aerosol particles is expected to affect their efficiency in becoming cloud droplets. Over the last years the role of surfactants in the activation of atmospheric aerosols into cloud droplets has received a growing interest. However, most of the investigations have focused on mixtures containing only one surfactant, while the composition of atmospheric aerosol is complex. Until now, there was little experimental information on the surface properties of mixtures of surfactants with other aerosol components. In this work pendant droplet tensiometry was used to determine the adsorption isotherms and cmc of aqueous mixtures of amphiphilic surfactants (SDS, Brij35, TritonX100, TritonX114, and CTAC) with inorganic salts (NaCl, (NH4)2SO4) and soluble organic acids (oxalic and glutaric acid). Interestingly, inorganic salts and organic acids systematically enhanced the efficiency of the surfactants by further lowering the surface tension and, in some cases, the CMC. Furthermore, all the mixtures studied were strongly non-ideal, some even displaying some synergism, thus demonstrating that the common assumption of ideality for aerosol mixtures is not valid. The molecular interactions between the mixture components were either in the bulk (salting out), in the mixed surface monolayer (synergy on the surface tension) or in the micelles (synergy on the CMC) and need to be included when describing such aerosol mixtures.Figure 1: Evolution of the minimal surface tension for mixtures of amphiphilic surfactants and organic acids (left) and two amphiphilic surfactants (right).
Assessment of the Impact of Coarse and Fine Dust on Solar Devices in the Middle East
Authors: Mostamandi Suleiman , Stenchikov Georgiy , Balawi Ahmed , Shevchenko Illia , Kabakebji Dania , Altmann Thomas
Published: March 2024

Dust in the Middle East (ME) significantly impacts regional climates and negatively affects the operation of solar farms in the ME region. Suspended dust particles attenuate downward short wave (SW) radiation, while dust deposited on the solar devices decreases effectiveness. This study theoretically assesses dust's attenuation and soiling effects on solar panels within the ME, employing a Weather Research Forecasting Model coupled with the aerosol-chemistry module, WRF-Chem, constrained by observed dust depositions. By analyzing the size distribution of dust deposition samples, we found that a major part of the deposited mass resulted from the deposition of dust particles with radii > 10 um. However, the models usually consider only particles with radii < 10 um. We corrected this deficiency and conducted a year-long simulation using WRF-Chem. We found that the dust (primarily fine particles with radii < 3 m) reduces the downward SW radiation near the surface by 5-10%. Meanwhile, dust deposition (mostly coarse dust particles with radii > 6 m) imposes soiling losses of 12 to 36 % in different parts of the ME, assuming a weekly cleaning cycle.Our findings unveil a complex interplay between dust size and its multifaceted impact on solar energy production. This novel insight could lead to optimized maintenance strategies and novel mitigation approaches tailored to the unique dust burden of the Middle East. Ultimately, this study aims to advance solar energy resource assessment and pave the way for enhanced photovoltaic efficiency in dust-prone regions.
Assessing Marine Heatwave Variability in the Luzon Strait
Authors: Macagga Rose Angeli , Hsu Po-Chun
Published: March 2024

The Luzon Strait, a 350-km wide channel located between Taiwan and the Philippines, connects the West Philippine Sea and the north Pacific Ocean. Multiple factors affect the circulation in the Luzon Strait, such as the Kuroshio Current, monsoon, and the West Philippine Sea circulation. Discrete periods of extreme ocean warming events, also known as marine heatwaves (MHWs), have been occurring longer and more frequently across the globe. Anomalous temperature events can cause drastic changes in the biogeochemical processes and trigger adverse effects on marine ecology in the surrounding areas. This study aims to understand the variation in MHWs in the study area (16-24°N, 115-126°E), focusing on the Luzon Strait, using a daily global 5-km sea surface temperature (SST) product from 1985 to 2022. Four points of known coral reef areas were also chosen to further assess the MHWs and their possible effects on marine ecology.  Six MHW indices were utilized to describe the frequency, duration, and intensity of MHW events. The highest frequency of 17 MHWs in a year occurred in 1998, while the longest duration per event of 144 days and the total duration in a year of 308 days were recorded in 2020 and 2021, respectively. The highest values for all three intensity parameters were recorded in 2021, with mean, maximum, and cumulative intensities reaching 2.62°C, 3.86°C, and 227.42°C-days, respectively. The spatial distribution of monthly SST and ocean current profile showed thermal areas and helped identify high-risk areas. Climate variations, such as El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO), were also explored as physical drivers of MHW in the study area. It has been observed that most of the years featuring MHW events at the four coral reef points occurred during the La Niña phase of ENSO, in conjunction with the negative phase of PDO, including 1998, 2010, and from 2020 onwards. Additionally, from 2016 to 2019, MHWs were observed at the same points during the positive phase of PDO, in conjunction with El Niño, La Niña, or Neutral phases of ENSO.
Impact of CO2 Permeation on Inter-layers and Reservoir Cap-rock Sealing Efficiency
Authors: Alsayah Ali
Published: March 2024

The need to find sufficient capacity for geological storage of carbon dioxide (CO2) to meet demand means less-than ideal, heterogeneous reservoirs need to be considered. Many such reservoirs are apparently compartmentalised by inter-layers, which may help, or hinder, CO2migration and storage capacity, depending upon their nature. The impact of shale inter-layers of thicknesses below seismic resolutions are generally neglected in plume migration simulations, but have been shown here to be important. Only simulations of plume migration that include the full coupling of all three of mass transport, geo-chemical and geo-mechanical processes together provide proper prediction of the barrier efficiency of relatively thin shale inter-layers. A series of feedback inter-actions, between these three process types, has been studied in detail, and, for example, leads to the unexpectedly higher barrier efficiency of relatively thin inter-layers compared to slightly thicker inter-layers. The results showed that changes to the capillary breakthrough pressure, together with diffusion processes, played the vital roles in enhancing the migration of the CO2 plume via the thicker shale inter-layers towards the overburden. This presentation identifies significant research gaps regarding the effects of complicated, intricate processes affecting shale inter-layer (or seal) integrity under realistic reservoir conditions.
Effect of Uncertainty in Water Vapor Continuum Absorption on CO2 Forcing, Longwave Feedback, and Climate Sensitivity
Authors: Roemer Florian E. , Buehler Stefan A. , Kluft Lukas , Pincus Robert
Published: March 2024

We assess the effect of uncertainty in water vapor continuum absorption on CO2 forcing F, longwave feedback λ, and climate sensitivity S at surface temperatures Ts between 270K and 330K. We calculate this uncertainty using a line-by-line radiative-transfer model and a single-column atmospheric model, assuming a moist-adiabatic temperature lapse-rate and 80% relative humidity in the troposphere, an isothermal stratosphere, and clear skies. Emulating continuum uncertainty in observations, we hold total continuum absorption fixed at room temperature, but change its components: We assume a 10% decrease in self continuum absorption, which comprises interactions between water molecules, and a spectrally varying increase in foreign continuum absorption, which comprises interactions between water and non-water molecules. We find that continuum uncertainty mainly affects S through its effect on λ. Continuum uncertainty primarily impacts the surface feedback at Ts290 K. Under present-day conditions, those two effects have opposite signs and thus largely cancel each other, therefore the effect of continuum uncertainty on S is negligible (0.02K). At Ts>300K, however, the effect on S is much stronger (>0.2K). This is because at those Ts, the effects on λ of decreasing the self continuum and increasing the foreign continuum have the same sign. These results highlight the importance of a correct partitioning between self and foreign continuum to accurately determine the temperature dependence of Earth’s climate sensitivity.
A Global Database of quality-controlled Crowd Weather Station Data
Authors: Bechtel Benjamin , Kittner Jonas , Fenner Daniel , Demuzere Matthias
Published: March 2024

Privately-owned weather stations, Crowd Weather Stations (CWS), offer high spatial and temporal density in many urban regions across the globe, and therefore have been used in a variety of urban climate studies, mostly focusing on single cities. One challenge in crowdsourcing CWS data lies in the fact that the link between measured atmospheric data and (historic-) metadata is often lost due to the limited metadata available from popular CWS networks. This poses challenges in retrieving and analyzing data, as, e.g., past changes in CWS location remain undetected, introducing incorrect data, thus reducing data integrity.We developed an end-to-end workflow for consistently collecting and checking CWS (meta-)data in 257 areas worldwide, covering over 500 urban regions since 2019. The workflow automatically adds newly set-up CWS to the database, as well as consistently handling changes in CWS location. Until now, the database includes over 310,000 CWS with 7 Billion hourly observations of air temperature and relative humidity (mean, maximum, minimum). Over 65,000 changes in CWS location have been detected since 2019. This highlights the importance of continuous metadata updates for this dynamic data source, further enabling the use of the measurements for different applications. Within the database, CWS are linked to additional metadata, including a global digital elevation model, a global Local Climate Zones map, and the Global Human Settlement Layer Urban Center Database.The database was developed using open data and open-source software, combining PostgreSQL, PostGIS, and Timescale, which allows us to manage billions of measurements efficiently. All air-temperature measurements are consistently and continuously quality controlled using the state-of-the-art open R-Package CrowdQC+. The result is a dataset of consistently-processed metadata and measurements with potential for global-scale (intra-)urban climate studies and in-depth city analyses.[MD1] [DF2] 
The 1928 – 1937 Oaxaca Earthquake Sequence (Mexico)
Authors: Nunez-Cornu Francisco J , Nunez Diana
Published: March 2024

Oaxaca is the most seismically active region in Mexico and one of the most studied using different methodologies. This seismic activity is due to the subduction of the Cocos Plate beneath the North American Plate, which is considered an anomalous subduction zone since it is a truncated continental margin. Seventy-four earthquakes (M> 7.0) have been identified in the last 510 years, which is an average of one earthquake every 6.8 years. The seismic sequence occurred between 1928 and 1937 is the key to understand the regional seismotectonics. The locations of these nine events (M>7.0) reported by different authors differ by more than 100 km for the same earthquake. We relocated the aftershocks of these earthquakes using the seismograms from TAC (Tacubaya) and VCM (Veracruz) stations available at the Seismological Seismic Network (Mexico) archive reading pre-phases S-P.  To calibrate these readings, we relocate the seismicity in the region between 1950 and 1982 with the JHD Method using 1978, 1982, 1965 and 1968 earthquakes as Master Events. We look from this catalog the earthquakes registered in TAC and VCM in the period 1950 - 1982 and whose seismograms were in the archive were selected. The S-P prephases in TAC and VCM were read with the same criteria used previously. With these data we fitting a time-distance curve for each station. These curves were used to obtain more reliable aftershock area for each of the coastal earthquakes occurred during the 1928 – 1937 sequence.
The occurrence and distribution of Scandium resources in the world-class Bayan Obo REE-Nb-Fe deposit, China
Authors: Liu Shuangliang , Wang Mingshi , Gao Zhaoyang , Liu Xuan , Fan Hong-Rui , Butcher Alan , Lahaye Yann , Michallik Radoslaw , Jolis Ester , Lukkari Sari
Published: March 2024

Scandium (Sc) is famous as a rare-scattered element in nature but can be anomalously enriched by the carbonatite system, especially in the Bayan Obo deposit (~0.14 Mt). However, the Sc distribution of Bayan Obo deposit is rarely revealed, which hinders resource utilization and the understanding of Sc mineralization. Thus, we comprehensively analyze the occurrence and distribution characteristics of Sc resources of Bayan Obo deposit, from deposit scale to mineral scale, based on 236 samples and 13 representatives. In the deposit scale, the Sc contents are 301-2 ppm (banded/massive type ores), 273-91 ppm (vein-type ores), 77-17 ppm (ore-hosting dolomite), and 281-1 ppm (slate/schist) for different rock types, respectively. Among them, the high-Sc rocks usually occur in the vicinity of the contact zone between the H9 slate/schist and the ore-hosting dolomite, which represents the most intently fenitization area in Bayan Obo. In the rock scale, Sc is heterogeneously scattered in rock with a small volume ratio (less than 0.1‰) of extremely high-Sc domains (Sc contents >0.3 wt. %). In contrast, Sc resources are more commonly found in aegirine and Na-amphibole, ranging from hundreds to thousands of ppm, sometimes reaching several weight percent, of banded/massive type ores and vein-type ores, and in biotite and titanite of altered slate/schist, typically in dozens of ppm. Notably, in the mineral scale, three types of individual Sc minerals are first distinguished in the Bayan Obo carbonatite deposit, that is thortveitite, aegirine-jervisite solid solution, and bazzite. Their metasomatism texture and mineral associations record two Sc migration and precipitation events in this deposit. These new reports reveal that the hydrothermal process is the main controlling factor of Sc resources in the Bayan Obo carbonatite system, and provide a scientific basis for the rational and effective utilization of Sc resources in this deposit.
Microplastic Contamination of a Benthic Ecosystem in a Deep-Sea Hydrothermal Vent
Authors: Park Byeongyong , Cho Boongho , Cho Jaemin , Kim Seungho , Kim Tae Won
Published: March 2024

Plastic contamination is a global pervasive issue, extending from coastal areas and open oceans to polar regions and even the deep sea. Microplastic contamination in hydrothermal vents, which are known for their high biodiversity even under their extreme conditions, has remained largely unexplored. Here, we present, for the first time, microplastic pollution in a deep-sea hydrothermal vent at one of the pristine biodiversity hotspots—the Central Indian Ridge. Not only the environment, (seawater: 2.08 ± 1.04 MPs/L, surface sediments: 0.57 ± 0.19 MP/g) but also all six major benthic species investigated were polluted by microplastics.  Microplastics mainly consisted of polypropylene, polyethylene terephthalate, and polystyrene fragments ≤ 100 µm, and were characterized as being either transparent or white in color. Remarkably, bioaccumulation and even biomagnification of microplastics were observed in the top predators of the ecosystem, such as squat lobsters (14.25 ± 4.65 MPs/individual) and vent crabs (14.00 ± 2.16 MPs/individual) since they contained more microplastics than animals at  lower trophic levels (e.g. mussels and snails, 1.75 ~ 6 average MPs/individuals). These findings reveal microplastic contamination of an ecosystem in a hydrothermal vent, thereby suggesting that their accumulation and magnification can occur in top-level animals even within remote and extreme environments.
The daily growth bands pattern of Tridacna - evidence from culture experiments.
Authors: Yang Haotian , Yan Hong , Liu Chengcheng
Published: March 2024

Biogeochemical archive such as tree rings, corals, and stalagmites have proven effective in reconstructing past paleoclimate patterns at year-month resolutions. However, they are not suitable for investigating weather changes on a day-hour scale. Tridacna, the largest bivalve in the world, which inhabits the Tropical-subtropical Pacific-Indian Ocean area, exhibits unique daily growth bands ranging from 5 to 60μm. This characteristic grants Tridacna the potential to reconstruct extreme weather events in the past, thus paving the way for paleoweather studies. Tridacna engages in symbiosis with zooxanthellae and relies on photosynthesis for energy. The growth rate and pattern of its daily growth bands correlate with diurnal alternations. Currently, the utilization of Tridacna daily growth bands and high-resolution geochemical element ratios holds potential for establishing a daily resolution biogeochemical proxy. However, the precise mechanism of the circadian rhythm during Tridacna's growth period in natural conditions remains unclear. Consequently, our comprehension of the pattern exhibited by Tridacna's daily growth bands is limited, impeding progress in the development of hourly scale paleo-weather analysis. In this study, a 30-day artificial experiment was conducted on Tridacna derasa to investigate the significance of shell daily growth bands and hourly element ratios in reflecting environmental conditions. The results of calcein labeling revealed that the wide dim areas in the daily growth bands corresponded to daytime and exhibited valley values in Sr/Ca ratio, while the narrow bright areas corresponded to nighttime and showed peak values in Sr/Ca ratio. At the daily-hourly scale, when the water temperature remained constant, the Sr/Ca daily variation showed potential for recording the light daily cycle. However, it is important to note that the influence of the light daily cycle on the Sr/Ca variation may be indirect. As a result, a hypothesis was proposed: the Sr/Ca variation is directly controlled by the internal regulation of Tridacna. During the daytime, the Sr/Ca ratio was primarily regulated by physiological activities. Due to light stimulation, the activity of certain enzymes in the inner mantle was enhanced, leading to an increase in Ca2+ concentration and a decrease in Sr/Ca ratio. During the nighttime, the Sr/Ca ratio was mainly regulated by organic matrices. In the extrapallial fluid (EPF), the presence of high Sr2+-selective organic matrices promoted the incorporation of Sr2+ into the shell, resulting in a higher Sr/Ca ratio.
A Detailed Analysis of the Diahaline Overturning Circulation in a Marginal Sea
Authors: Henell Erika , Burchard Hans , Gräwe Ulf , Klingbeil Knut
Published: March 2024

We apply a local water mass transformation framework to quantify and decompose the exchange flow associated with diahaline mixing. As a realistic example we analyze two years of numerical model results for the Baltic Sea, which serves as a natural laboratory for processes relevant on the global scale. Despite this regional focus, the diagnostic methods of this study are applicable to diverse regions, as well as for other tracers than salinity, e.g. temperature. We verify relations between local diahaline volume and diffusive salt fluxes, and local diahaline mixing, and present them as maps on chosen isohaline surfaces. In this way, hot spots for mixing and the diahaline circulation are visualized. Two dominant types of diahaline exchange flow are analyzed. First of all there is a large scale overturning circulation with inflow at places where the isohaline surface is close to the bottom and with outflow at places where the isohaline is surfacing. Secondly, there is the well-known small-scale overturning circulation localized inside the bottom boundary layer over sloping bathymetry, driven by boundary mixing. One major result is that about 50% of the simulated diahaline exchange flow is generated by numerical mixing caused by the truncation error of the advection scheme, despite the fact that an anti-diffusive advection scheme and vertically-adaptive coordinates are used. We also demonstrate how model ensembles can be used to study short-term episodic and local events.
Assessment of Future Precipitation Changes in Mediterranean Climate Regions from CMIP6 ensemble
Authors: Tarín-Carrasco Patricia , Petrova Desislava , Chica-Castells Laura , Lukovic Jelena , Rodó Xavier , Cvijanovic Ivana
Published: March 2024

Previous studies have indicated a large model disagreement in the future projections of precipitation changes over the regions featuring Mediterranean climate. Many of these highly populated regions have been experiencing major droughts in the recent decades, raising concerns about future precipitation changes and their impacts. Here we investigate precipitation projections across five Mediterranean climate regions in the CMIP6 ensemble, and study their respective model agreements on the sign of future precipitation changes. We focus on the period 2050-2079 relative to 1970-1999, and consider two climate change scenarios (ssp2-4.5 and ssp5-8.5) over the Mediterranean Basin (MED), California (CAL), the central coast of Chile (SAA), the Cape Province area of South Africa (SAF) and southwest Australia (AUS).The CMIP6 ensemble mean suggests that annual mean cumulative precipitation will decrease over all the regions studied with the exception of northern California. In most cases, this decline is primarily attributed to a reduction in winter precipitation, except over the Mediterranean Basin, where the most significant decrease occurs in autumn. The model agreement on the sign of future precipitation changes is generally high over the regions and seasons where the ensemble mean indicates the precipitation decline in the future, and low over the regions showing the precipitation increase or no change. Specifically, the model agreement is low in southern California during all seasons, in northern Mediterranean during winter and autumn, and in southwest Australia during austral summer and autumn. CMIP6 ensemble means also indicate that the consecutive dry days (CDD) will increase in the future in all regions, but again the model agreement on this increase is low over southern and central California, the southern Mediterranean, and parts of southwest Australia. Similarly, the ensemble mean of consecutive wet days (CWD) indicate a decrease in all regions, with weak model agreement on the sign of future changes over CAL, northeast AUS and part of the MED region. The ensemble mean maximum one-day precipitation increases over all the regions, the most over the parts of southwest Australia and the Mediterranean.We conclude that despite substantial improvements to the new CMIP6 generation of models, the intermodel differences in future projections of precipitation changes continue to be high across parts of California, the Mediterranean Basin and southwest Australia. Impact studies need to account for these uncertainties and consider the whole intermodel range of projected precipitation changes.
Variability of the North Atlantic westerlies during MIS 31-16 (1.1- 0.65 Ma) from SW Iberian margin records
Authors: Quan Xiaowen , Sanchez Goñi Maria Fernanda , Moal-Darrigade Paul , Yin Qiuzhen , Polanco-Martinez Josue
Published: March 2024

The driving mechanisms of the middle Pleistocene Transition (MPT) are still unclear but the most likely hypotheses are related to ice-sheet dynamic feedbacks, such as ice albedo, precipitation at the ice margins, elevation-temperature and the regoliths. Here we focus on the “precipitation at the ice margins” hypothesis. To test this hypothesis, we have analysed the pollen content of SW Iberian margin sedimentary sequences that document changes in the direction and intensity of the westerlies during the MPT. In my presentation I will show the pollen-based vegetation and winter rainfall changes in the adjacent landmasses of the southwestern Iberian margin during the MPT. Changes in the reconstructed vegetation from IODP Site U1386 (1.2-0.8 Ma), combined with IODP Site U1385 (0.8-0.67 Ma), and their comparison with changes in the North Atlantic Ocean thermal gradient reveal the variability in the intensity and position of the westerlies and in the position of the moisture source, respectively. Preliminary pollen results reveal a long-term decreasing trend in the Mediterranean forest cover during MIS 31-20 (1.1-0.8 Ma), associated with long-term southward migration of the thermocline water source. This trend abruptly shifted northward at 0.8 Ma, and probably was related to progressive northward shift of the westerlies that bring moisture to the margin of the ice sheets feeding the ice caps, and leading to the shift of the dominant ice sheet cyclicity from 41 kyrs to 100 kyrs.
Communicating seismic risk: experiences from launching the Swiss and the European seismic risk models
Authors: Marti Michèle , Valenzuela Nadja , Philippe Roth , Irina Dallo , Helen Crowley , Laurentiu Danicu , Stefan Wiemer
Published: March 2024

Seismic risk describes the potential consequences of future earthquakes in terms of human and financial losses. As such, seismic risk models provide information that is crucial for earthquake mitigation and emergency response. For these models to be effective, their results must be accessible and comprehensible to a wide range of stakeholders including the general public. To achieve this, we applied a transdisciplinary approach to design and evaluate key outreach materials including seismic risk maps, scenario and rapid impact information. We conducted two representative online surveys with the general public (N1=580; N2=593), an online survey with students of European universities (N3=83), seven interviews with experts developing rapid impact assessments, and three workshops with about 150 representatives from cantonal authorities, first responders, and civil protection.Although the initial product designs were well received by the target groups, which we attribute to the close interdisciplinary collaboration during the design process, they have been significantly improved based on user feedback. This enhanced stakeholders’ understanding and the usability of the products. For example, the insights from the user testing led to a new preferred colour scheme and legend for the seismic risk map and in a new standard for displaying loss distributions in rapid impact assessments. In this talk, we will present the strategy elaborated for designing useful seismic risk information and provide insights to key findings from our accompanying research using the examples of the Swiss and European seismic risk model releases in 2022 and 2023.
Connection among meteorological observations,columnar aerosol properties and urban heat island during nighttime extreme heat events in the uRban hEat and pollution iSlands inTerAction in Rome and possible miTigation strategies(RESTART)project
Authors: Campanelli Monica , Di Bernardino Annalisa , Brattich Erika , Argentini Stefania , Barbano Francesco , Casasanta Giampietro , Cecilia Andrea , Di Sabatino Silvana , Erriu Margherita , Falasca Serena , Maestri Tiziano , Siani Anna Maria
Published: March 2024

The “uRban hEat and pollution iSlands inTerAction in Rome and possible miTigation strategies” (RESTART) is a 2-years project, funded by the Italian Ministry for University and Research as a Project of National Interest (PRIN2022).RESTART aims to explore the interaction between the Urban Heat Island (UHI) and the Urban Pollution Island (UPI) in Rome (Italy),providing a series of mitigation strategies, including tailored Nature-Based Solutions, and ready-to-use guidelines for the improvement of well-being and liveability in urban environments. The connection between UHI and UPI is investigated by inspecting quality-checked datasets of meteorological trace gases and aerosol observations, provided by local and international observatories and dense networks of instruments in Rome.Specifically,the UHI is studied by examining the time series of atmospheric near-surface temperature (average, minimum, maximum daily), relative humidity, pressure, and wind speed, while the UPI is characterised by the observations of trace gases (e.g., NO, NO2, O3, CO), particulate matter (PM10, PM2.5),aerosols optical properties (e.g., aerosol optical depth, AOD, Ångström exponent, single scattering albedo, SSA, particle volume size distribution) in terms of surface and columnar contents and vertical profiles, based on the availability of measurements.The city of Rome (Lat. 41.90 °N, Lon. 12.54 °E) is the most populous and extended Italian city and the third most densely populated metropolis in Europe. Rome is located in the central region of the Italian Peninsula, about 27 km inland from the Tyrrhenian coast. Due to its position in the middle of the Mediterranean Basin and the complex orography of its surroundings, the city is frequently subjected to the advection of Saharan dust in the case of persistent southerly winds, and to the sea breeze regime from the southwest, the latter particularly evident during summertime under anticyclonic conditions. In recent years, the city has experienced significant atmospheric warming and a substantial intensification of extreme weather events, such as heat waves, tropical nights, and droughts.This work explores the connection among some meteorological observations (near-surface temperature and relative humidity) from weather stations, columnar aerosol properties (AOD and SSA) from Skynet and AERONET international networks, and UHI intensities during heat waves, paying particular attention to nighttime. During the selected events, the synoptic weather conditions affecting the interaction between the UHI and the aerosol properties, are discussed.
Behaviour Of Temperature During Wintertime Reversal Of Zonal Wind 
Authors: Ramatheerthan Sunil Kumar , Kozubek Michal , Laštovička Jan
Published: March 2024

Climatologically, the wintertime-evolved stratospheric polar vortex comprises zonal wind, which is westerly. During extreme events like Sudden Stratospheric Warming (SSW), the polar vortex disrupts, showing easterly wind at stratospheric altitudes. Defining extreme events in the stratosphere, like SSW at a definite pressure scale, depends on the region explaining its effects. For instance, the standard definition of SSW is 10 hPa pressure suites primarily for the lower atmosphere. SSW's current definition is unsuitable for the upper atmosphere, especially the ionosphere. So, with this viewpoint, we study the fundamental behaviour of the zonal mean of temperature during the reversal of the zonal mean of zonal wind by using superposed epoch analysis. We use the MERRA2 dataset for this analysis. From MERRA-2, we analyse the zonal mean of temperature and zonal wind from 1980 – 2022 northern hemispheric winters. The analyses are done at 10 hPa, where the standard definition of SSW is defined, and at 1 hPa, 0.5 hPa and 0.1 hPa. Temperature behaviours at different reversal periods are studied at various latitudinal values, starting at 60oN and ending at 90oN. With this analysis, a more general picture of the temperature–wind relation can be understood, which will help to understand and define SSW in a much better way for upper atmospheric studies.
A new radiodont from the lower Cambrian (Series 2 Stage 3) Chengjiang Lagerstätte, South China informs the evolution of feeding structures in radiodonts
Authors: Wu Yu , Pates Stephen , Zhang Xingliang , Fu Dongjing
Published: March 2024

Radiodonts, a diverse clade of early Palaeozoic stem-group euarthropods, have provided critical information on early euarthropod evolution, and were important constituents of early animal ecosystems. The well-known Chengjiang Lagerstätte (Cambrian Stage 3, c. 518 Ma) has yielded the highest known diversity of radiodonts of any Cambrian Konservat-Lagerstätten, and represents a crucial deposit for radiodont research. One important but generally overlooked Chengjiang radiodont taxon, previously identified as Anomalocaris sp. or Radiodont C, is herein designated as the type species of a new monotypic genus, Shucaris ankylosskelos gen. et sp. nov. based on dozens of specimens. Shucaris is distinctive for its combination of several characters, including the strong curvature of frontal appendage, presence of two pairs of endites on proximalmost claw podomere, posteriorly-inward curved endites on proximal five claw podomeres, and most strikingly the coexistence of gnathobase-like structures and oral cone. Phylogenetic analysis retrieves Shucaris as either an early diverging member of Anomalocarididae or as sister to the clade Anomalocarididae + Amplectobeluidae. Moreover, our phylogenetic analysis also supports the divergence between hurdiid and non-hurdiid radiodonts. This study not only illuminates the early diversification of Radiodonta, but also provides new insights into the radiodont systematics and phylogeny.
Exploring the climate change influence on short-duration convective precipitation extremes in the southeastern Alpine forelands
Authors: Haas Stephanie , Kirchengast Gottfried , Fuchsberger Jürgen
Published: March 2024

Short-duration extreme convective precipitation events (SDECPEs) are increasingly altered by climate change. Considering their severe risk, and high impact on our everyday lives, a profound understanding of such extreme precipitation is crucial. For their investigation we can leverage a newly developed class of Threshold-Exceedance-Amount (TEA) metrics, which enable the detection and tracking of weather and climate extremes. The compound indices based on these TEA metrics have proven to be a useful tool to investigate changes of different characteristics of temperature and precipitation extremes, both in isolation and in combination.It is challenging, however, to perform such an analysis for SDECPEs, since their short durations of only about one to three hours and their highly localized character make them very weakly detectable in reanalysis datasets like ERA5-Land, with a spatial resolution of the order of 10 km (0.1° x 0.1° grid). High resolution datasets like from the WegenerNet climate station network in southeast Austria (100 m x 100 m, 5 min) and GeoSphere Austria’s INCA dataset (1 km x 1 km, 15 min) are far better suited for this purpose but offer only data over the most recent two decades. To our knowledge, there is currently no dataset that on its own fulfills all three key requirements (high spatial resolution, high temporal resolution, long data record) for the analysis of SDECPEs over time.To get observations-based insight into the influence of climate change on SDECPEs in the southeast Alpine forelands, in particular their possible amplification, we aimed to bypass and overcome the weaknesses of any single dataset by a study consisting of two parts: (1) the high-resolution exploration of SDECPEs in the well-observed most recent two decades. Here we investigate the relationship between maximum hourly precipitation and average hourly precipitation on SDECPE-days and complement our findings with information about the temperature increase in the study region. (2) We perform a longer-term assessment of the development of SDECPEs based on reanalysis data. Using the knowledge gained from (1), we are able to model maximum hourly precipitation data and compare the changes in event characteristics to the ones of daily precipitation sums.We show that our approach does reveal some evidence for a climate change induced amplification of SDECPEs in the southeast Alpine forelands. At the same time, the results vary strongly within the study region, mainly due to high natural variability.
Hydrogeological Characterisation of Sherwood Sandstone using BNMR and Geophysical Logs
Authors: Oguntade Sodiq , Ofterdinger Ulrich , Comte Jean-Christophe , Gee Ryan , Kynaston Myles , Raine Robert
Published: March 2024

The Sherwood Sandstone is an important aquifer for geothermal energy in Northern Ireland. The Northern Ireland Government has identified geothermal energy, including aquifer thermal energy storage (ATES) systems, as a viable green energy source. This study investigates the hydrogeologic characteristics of the Sherwood Sandstone, with a focus on its porosity, using borehole nuclear magnetic resonance (BNMR) and geophysical models (Archie and Waxman-Smits).BNMR and geophysical logging were done inside three borehole installations drilled into the Sherwood Sandstone aquifer at a depth of about 100 m. The data (BNMR, resistivity log, EC log, temperature log, and natural gamma log) obtained from this exercise were analysed using WELLCAD.The results of the processed data showed that the porosity calculated from the BNMR and the two petrophysical logs are similar, demonstrating the relationship between nuclear magnetic resonance and petrophysical-derived porosity. The average porosity of the Sherwood Sandstone at this location ranges between 19.9% and 14.5%, the minimum ranges between 2.1% and 9.9% and the maximum ranges between 42.5% and 30.2%.This study confirmed the viability of Sherwood Sandstone for ATES systems, and further hydrogeologic characteristics such as hydraulic conductivity, transmissivity, and structure delineation are needed before its installation.