bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of the diurnal evolution of flower cloud organization in multi-day Lagrangian large-eddy simulations based on EUREC4A against GOES satellite data
Authors: Ghazayel Salima , Neggers Roel
Published: February 2023

The subtropical marine stratocumulus-to-cumulus cloud transition and associated cloud size distributions are studied using Large-Eddy Simulations based on EUREC4A data. The simulations with the DALES code follow a Lagrangian trajectory from initially overcast stratocumulus to the tropical shallow cumulus region at the HALO flight site near Barbados, covering four days and three complete diurnal cycles. Mean state and bulk properties for different domain sizes are evaluated against aircraft data. In addition, time-continuous high-frequency data from Geostationary Operational Environmental Satellite (GOES) are used to investigate the evolution of cloud size distributions, focusing on the diurnal evolution of mesoscale cloud features. TOA brightness temperature data from GOES is used at a spatial resolution of 2x2 km2 to characterize cloud populations and cloud morphology. These are compared to TOA brightness temperatures calculated from DALES output using the RRTOV simulator, as applied to subdomain-averages of similar dimensions. We find that the simulation with the largest domain size (100x100 km2) best reproduces the observed boundary layer and cloudy states at the HALO target site. The same applies to the amplitude and evolution of cloud cover as detected by GOES. The upstream nocturnal flower cloud organization is also reproduced, albeit with a slight time delay. 
Garnet in metarodingites: composition, chronology and link to dehydration/hydration reaction during subduction
Authors: Piccoli Francesca , Rubatto Daniela , Millonig Leo J. , Gerdes Axel
Published: February 2023

Metarodingites are metasomatized mafic dykes that are embedded within serpentinized mantle rocks and commonly contain garmet. Garnet in this rock type has the potential to preserve compositional and chronological information of the entire metamorphic-metasomatic evolution, from the ocean floor to deep subduction. In this study, we investigate the chemical and chronological record of garnet from chloritized metarodingites and garnet veins, from the Zermatt-Saas unit (Unter Theodulgletscher unit and Pfulwe pass). Compositional major and trace element maps reveal that a first generation of Ti-rich garnet is consumed during chloritization, while a second generation of Ti-poor garnet grows in textural equilibrium with chlorite and titanite. In both metarodingite and garnet vein, garnet rim displays an enrichment in Cr, suggesting that late garnet records the infiltration of fluids equilibrated with serpentinites. Fluids liberated from dehydrating serpentinites infiltrate the metarodingite leading to the first garnet generation dissolution, chloritization and titanite crystallization. To validate this hypothesis, we performed LA-ICPMS U-Pb dating of garnet, titanite and zircon. U-Pb dating of garnet core and rim, returned overlapping ages between ca. 44 and 46 Ma, which coincide with previous estimation of peak metamorphic conditions. Titanite from the metarodingite samples yields an age of ca. 45 Ma, which indicates that fluid release and chloritization occurred indeed at peak conditions. Garnet veins cutting across the foliation of the metarodingite and associated titanite are instead resolvably younger and yield ages of ca. 38-39 Ma and ca. 36 Ma, respectively. Zircon in chloritized mafic dykes from Pfulwe pass consists of a Jurassic magmatic core and a metamorphic rim of ca. 47 Ma, confirming that the major fluid-release event and related metasomatism occurred between 45-47 Ma. Rutile yields a younger age of ca. 34 Ma, probably linked to re-setting during exhumation. In conclusion, we show how garnet from metarodingites preserves the metamorphic-metasomatic history and can be used to gather information on (de)hydration reactions during subduction. The consistency of our multi-mineral geochronological data further indicates that petrochronology of garnet from metarodingites is a robust way to track in time metasomatic events in the subducted oceanic lithosphere.
Appropriate solar park management enhances bumble bee populations under different land use scenarios
Authors: Blaydes Hollie , Gardner Emma , Whyatt Duncan , Dunford Robert , Potts Simon , Armstrong Alona
Published: February 2023

Land use change for solar parks could provide a unique opportunity to support insect pollinators, such as bumble bees, if located and managed appropriately. Vegetation management can provide floral and nesting resources for bumble bees and well managed solar parks could safeguard suitable bumble bee habitats for up to 40 years. Understanding the potential for solar parks to contribute to bumble bee conservation is growing, but the longer-term roles of solar parks have not yet been considered. To address this knowledge gap, we used a geographic information system (GIS) and a process-based pollinator model to quantify the impact of solar park management on bumble bee density in present day Great Britain and in 2050. Future landscapes were based on state-of-the-art UK-SCAPE CRAFTY-UK scenarios that represent how land use responds simultaneously to climatic and social change. Scenarios range in levels of sustainability and therefore deliver contrasting landscapes that impact bumble bees in both solar parks and the surroundings. In the present day, solar parks managed with resource-rich wildflower margins approximately doubled bumble bee density compared to those managed as turf grass. Moreover, bumble bee density was higher in solar parks surrounded by more floral resources. In future scenarios, the impact of solar park management differed depending on how the surrounding landscape changed. Our findings suggest that solar parks could contribute to bumble bee conservation both now and in the future, potentially becoming more or less valuable habitats depending on land use change.
Air pollution over Romania: spatial relationship betweensocio-economic indicators and air pollutants using univariate and bivariate local indicators
Authors: Chiritescu Robert Valentin , Iorga Gabriela
Published: February 2023

AbstractIt has been proven that air pollution is closely related to the level of socio-economic development of a country. Various levels of development generate different level of by-products, including air pollution, deteriorating therefore the air quality at regional levels in peculiar ways. Romania is the largest country in southeastern Europe with a very complex economic development level and air pollution disparities among cities.This paper aims to study main socio-economic indicators (as measures of the effect of human activities on air pollution and climate) for over 30 cities in Romania with diferent levels of economic development, to determine the relationship between these variables and air pollution condition. We focused on the spatial relationship between main gaseous air pollutants and the following indicators GDP, GDP/capita, resident population, number of private vehicles and life expectancy.In this research we created two data sets as follow: first one consists of daily values of air pollutant (CO, NO2, O­­3, SO2) mass concentrations extracted from the Romanian National Air Quality Network and the second set consists of socio-economic indicators (GDP, GDP/capita, resident population, number of private vehicles and life expectancy) obtained from Romanian National Institute of Statistics. The study was conducted over five years, from 01.01.2016 to 31.12.2020 using yearly means of air pollutants from the first dataset in all selected urban areas in the Romanian territory and corelate them with the socio-economic indicators from the second data set using univariate LISA and bivariate LISA statistical analysis methods.The analysis demonstrated the correlation of socio-economic indicators with the increase of the air pollution in the study area. Other highlights of the study: (a) Range of major air pollutant levels in 30 urban agglomerations across Romania from 2016 to 2020 was assessed (b) Maps of interpolated mass concentrations reveal regional significant differences with pollutant-specific hot- and cold-spots in Romania. Regional significant differences can be observed; (c) Results show pollution decreases for most pollutants in most cities in 2020 due to pandemic restrictions.The results of present study can be beneficial to local authorities in order to help them in their decisions for abatement pollution strategies at the country scale combined with regional measures. AcknowledgmentThe research leading to these results has received funding from the NO Grants 2014-2021, under Project contract no. 31/2020, EEA-RO-NO-2019-0423 project. Data regarding ground-based air pollutants were extracted from the Romanian National Air Quality Database, www.calitateaer.ro. Economy indicators were provided by National Institute of Statistics http://statistici.insse.ro:8077/tempo-online/. Databases were last accessed in December 2022.
Theoretical and observational evidence for climate tipping points
Authors: Boers Niklas
Published: February 2023

Some components of the Earth system could change their state abruptly in response to a warming atmosphere and associated changes in climate conditions. This possibility has been recognized as one of the greatest potential threats associated with anthropogenic climate change. Examples  include the Atlantic Meridional Overturning Circulation, the polar ice sheets, the Amazon rainforest, and possibly the tropical monsoon systems.  The empirical evidence for abrupt climate transitions comes from paleoclimate proxy records, but also in observational records, signs of stability loss for some of the major tipping elements have been suggested. Here we explain some of the key theoretical concepts suggesting that tipping events may happen under ongoing climate change and summarize the empirical evidence for stability loss in some Earth system components with focus on candidates for future abrupt transitions. We argue that the critical forcing levels and rates are subject to large uncertainties and hence difficult to prdict. Improvements will require combining information from paleoclimate records, simulations with a hierarchy of models, and from observation-based data.
Flood Occurrences in Tropical Coastal Intensified by Exacerbating Extreme Weather Events
Authors: Zhang Wenxin , Park Edward , Ynag Xiankun
Published: February 2023

Extreme weather events attributed to global climate change brought disasters into view, the 2021-2022 Malaysian Flash Flood that crushed eight states across the peninsula astonished the world. With a death toll of 56 and total damage of $14,600,000, western Peninsular Malaysia, which has withstood acute and large amounts of precipitation in a short time, suffered the worst flood since the one that occurred in 2014. This study combined recorded sociological statistics with remote sensing data, specified the historical extreme rainfall and flash flood events since 1981 in Peninsular Malaysia, including the 2021-2022 Malaysian Flash Flood, to explicit and compare the temporal and spatial characteristics of these events. Study found since 2000s flood events occurred frequency has significantly increased, including flash floods. In addition, precipitation ditribution in Peninsular Malaysia expreienced a spread to western from concentrating in east coast. A series of factors might have exacerbated flood vulnerability of this tropical peninsular coast under the intensified extreme rainfall events in the 40 years are disscussed. 
Verification of reproductivity of 137Cs activity concentration in the database by an ocean general circulation model
Authors: Tsumune Daisuke , Bryan Frank , Lindsay Keith , Misumi Kazuhiro , Tsubono Takaki , Aoyama Michio
Published: February 2023

Radioactive cesium (137Cs) is distributed in the global ocean due to global fallout from atmospheric nuclear tests, release from reprocessing plants in Europe, and supply to the ocean due to the Fukushima Daiichi Nuclear Power Plant accident. In order to detect future contamination by radionuclides, it is necessary to understand the global distribution of radionuclides such as 137Cs. For this purpose, the IAEA is compiling a database of observation results (MARIS). However, since the spatio-temporal densities of observed data vary widely, it is difficult to obtain a complete picture from the database alone. Comparative validation using ocean general circulation model (OGCM) simulations is useful in interpreting these observations, and global ocean general circulation model (CESM2, POP2) simulations were conducted to clarify the behavior of 137Cs in the ocean. The horizontal resolution is 1.125° longitude and 0.28° to 0.54° latitude. The minimum spacing near the sea surface is 10 m, and the spacing increases with depth to a maximum of 250 m with 60 vertical levels. Climatic values were used for driving force. As a source term for 137Cs to the ocean, atmospheric fallout from atmospheric nuclear tests was newly established based on rainfall data and other data, and was confirmed to be more reproducible than before. Furthermore, the release from reprocessing plants in Europe and the leakage due to the accident at the Fukushima Daiichi Nuclear Power Plant were taken into account. 2020 input conditions were assumed to continue after 2020, and calculations were performed from 1945 to 2030. The simulated 137Cs activities were found to be in good agreement, especially in the Atlantic and Pacific Oceans, where the observed densities are large. On the other hand, they were underestimated in the Southern Hemisphere, suggesting the need for further improvement of the fallout data. 137Cs concentrations from the Fukushima Daiichi Nuclear Power Plant accident in March 2011 were generally in good agreement, although the reproducibility remained somewhat problematic due to insufficient model resolution. In other basins, the concentration characteristics were able to be determined, although the observed values were insufficient. Radioactivity concentrations of atmospheric nuclear test-derived 137Cs may continue to be detected in the global ocean after 2030. The results of this simulation are useful for planning future observations to fill the gaps in the database.
Biogeochemical consequences of agricultural soil contamination with Sulfamethoxazole (SMX)
Authors: Menyailo Oleg , Deroo Heleen , Eichinger Corinna , Dercon Gerd
Published: February 2023

Agricultural soils are increasingly polluted by antibiotics, and this makes them a source of antimicrobial resistance (AMR). However, antibiotics may also change microbial communities in soils, and so alter microbiological processes. Given the knowledge gap on how antibiotics affect soil functioning, in particular soil organic carbon (C) cycling, we conducted an experiment to investigate how different concentrations of the model antibiotic sulfamethoxazole (SMX) alter soil heterotrophic respiration (C mineralization) and priming of soil C.  We collected Austrian soils rich and poor in soil organic C from Seibersdorf and Grabenegg, respectively. After the samples were sieved at 2 mm, we incubated 80 g of soil in 100 mL jars at room temperature for 30 days. SMX was added at day 1, at six rates (0; 0.01; 0.1; 1; 10 and 100 mg.kg-1) in water solution. Soil moisture was kept constant at 45% of the soil water-filled pore space throughout the incubation experiment. The flux of CO2 and isotopic composition of C in respired CO2 were determined with a Picarro 2201-i laser isotope analyzer using Keeling plots.In general, SMX negatively affected the CO2 production rate. The negative effect was larger with a higher SMX concentration. The inhibitory effect of SMX followed a logarithmic function, after excluding outliers. The fitted equations may be used to predict how much the microbial activity is inhibited if the concentration of SMX in soil is known. However, it was also observed in our study that when the antibiotic concentration increases, the marginal toxic effect declines at some specific concentrations, and even a stimulation of CO2 production could be found. This observed increase can be related to the following processes: it may be concentration-dependent AMR, or SMX may act as a C source, but the most likely explanation is that bacterial growth is inhibited. This last suggested process may then reduce competition, so that other microbial groups may proliferate and actively decompose soil organic matter.    The estimated priming of soil C was positively related to SMX concentration. When readily available C source (glucose) was added, mineralization of soil C increased and this effect was accelerated with an increase in SMX concentration. Overall, the incubation experiment with different concentrations of SMX provided important insights on the toxicological effects of SMX on soil microbial life and the soil C cycle in agricultural soils. The SMX was shown to inhibit soil heterotrophic activity, but would increase losses of soil C in the presence of readily available C. 
Addressing the chemical composition of secondary organic aerosol in the rural/ urban Paris area
Authors: Pereira Diana L , Gratien Aline , Giorio Chiara , Noyalet Gael , Chevaillier Servanne , Bertin Thomas , Mebold Emmanuelle , Cantrell Christopher , Michoud Vincent , Di Biagio Claudia , Picquet-Varrault Bénédicte , Hawkins Lelia , Favez Olivier , Garret Olivier , Pronovost Drew , Di Antonio Ludovico , F. de Brito Joel , Riffault Véronique , Yu Chenjie , Formenti Paola
Published: February 2023

Organic aerosol (OA) from natural or anthropogenic origin can be directly emitted into the atmosphere (primary organic aerosols, POA) or formed by secondary processes via the oxidation of volatile organic compounds (VOC). However, the formation pathways and their chemical composition of these secondary organic aerosols (SOA), which may contribute up to 90% of the OA mass, are not well understood to date, which is problematic due to the relevance of SOA on climate. To address this issue, this study uses a tracer-based approach to identify and quantify the contribution of different anthropogenic/biogenic VOCs precursors to the SOA formation. To do so, we combine experiments in a large scale atmospheric simulations chamber, CESAM (which means Multiphase Atmospheric Experimental Simulation Chamber), and field measurements during the ACROSS (Atmospheric ChemistRy Of the Suburban foreSt) campaign conducted in the Paris area in summer 2022. This approach provides both a mechanistic study of the oxidation of targeted VOCs in simulated and controlled rural/urban atmospheres and the identification of targeted tracers in the real atmosphere, to quantify their concentrations in ambient air.The ACROSS dataset consists in atmospheric samples of submicron aerosols collected twice a day (day and night) in the urban area of Paris and the Rambouillet forest on the south-west of Paris, as well as samples collected onboard the Safire ATR-42 research aircraft on low-level flights targeting the  evolution and dilution of the Paris urban plume. The CESAM chamber dataset consists in samples of SOA generated by the OH oxidation of toluene/ m-xylene in various conditions.Filters are analyzed to provide with the chemical composition at the molecular scale by SFE-GC-MS (Supercritical Fluid Extraction Gas Chromatography- Mass Spectrometry) and UPLC-QTOF-MS (Ultra Performance Liquid Chromatography Time of Flight Mass Spectrometry). The organic mass and chemical speciation are obtained by aerosol mass spectrometry and the organic carbon (OC) concentrations by thermal-optical analysis.The first results of the ambient samples of Paris revealed that the OC concentration varied between 0.69 ± 0.07 and 9.48 ± 0.51 µgC/m3, which correspond to the 28% and 53% of the total mass of the submicron aerosols, for background and polluted (fire) conditions, respectively. These diverse conditions are favorable to trace the compounds identified during the simulation chamber experiments, such as benzoic acid, succinic acid, and 2-methyl-4-nitrophenol. These attempts will be presented and discussed in order to determine the contribution of specific precursors to SOA formation.
Fast spin-up of geochemical tracers in ocean circulation and climate models
Authors: Khatiwala Samar
Published: February 2023

Ocean geochemical tracers such as radiocarbon, protactinium and thorium isotopes, and noble gases are widely used to constrain a range of physical and biogeochemical processes in both the present-day and past ocean. However their routine simulation in global ocean circulation and climate models is hindered by the computational expense of integrating them to a steady state. Here, a new approach to this long-standing ``spin-up'' problem is introduced to efficiently compute equilibrium distributions of such tracers in seasonally-forced models. Based on ``Anderson Acceleration'', a sequence acceleration technique developed in the 1960s to solve nonlinear integral equations, the new method is entirely ``black box'' and offers significant speed-up over conventional direct time integration. Moreover, it requires no preconditioning, ensures tracer conservation and is fully consistent with the numerical time-stepping scheme of the underlying model. It thus circumvents some of the drawbacks of other schemes such as matrix-free Newton Krylov that have been proposed to address this problem. An implementation specifically tailored for the batch HPC systems on which ocean and climate models are typically run is described, and the method illustrated by applying it to a variety of geochemical tracer problems. The new method, which provides speed-ups by over an order of magnitude, should make simulations of such tracers more feasible and enable their inclusion in climate change assessments such as IPCC.
Open Science: How Open is Open?
Authors: Stall Shelley , Vrouwenvelder Kristina
Published: February 2023

Open science is transformative, removing barriers to sharing science and increasing reproducibility and transparency. The benefits of open science are maximized when its principles are incorporated throughout the research process, through working collaboratively with community members and sharing data, software, workflows, samples, and other aspects of scientific research openly where it can be reused, distributed, and reproduced. However, the paths toward Open Science are not always apparent, and there are many concepts, approaches, tools to learn along the way.  Open Science practices are along a continuum where researchers can make incremental adjustments to their research practices that may seem small but can have valuable benefits. Here we will share the first steps in a researcher’s open science journey and how to lead your own research team in adopting Open Science practices.
Formation and evolution of inversely-zoned “complex feldspar” in the lower crust
Authors: Dunkel Kristina G. , Jamtveit Bjørn
Published: February 2023

Within and near lower crustal shear zones, plagioclase grains frequently exhibit a peculiar compositional zonation: Albite-rich single crystals contain anorthite-rich lamellae and smaller, polygonal grains show an increase in anorthite-content from core to rim. This is the opposite of the zonation that develops during fractional crystallization in magmatic systems. Both the changes in plagioclase compositions and associated grain size reductions may affect rock rheology. Therefore, these microstructures may potentially provide valuable information about shear zone development and the behaviour of plagioclase-rich lower crustal rocks during an orogeny.Next to shear zones in gabbronorites of the Ramberg section (Lofoten, Northern Norway), we observe both endmember microstructures (anorthite-rich inclusions in larger single crystals and zoned polygonal grains) as well as transitions between them. These were investigate in detail with scanning electron microscopy, including electron backscatter diffraction, and transmission electron microscopy.The microstructures range from isolated, anorthite-rich lamellae in the host albite-richer plagioclase, via connected networks of anorthite-rich plagioclase within plagioclase single-crystals, to polygonal plagioclase grains with anorthite-rich rims close to the shear zones. These grains occur in clusters of similar orientation (presumably representing pre-existing larger grains). Preliminary work suggests that the plagioclase experienced an overall enrichment in Ca, which implies that fluid introduction played an important role during the reaction. The orientations of the anorthite-rich lamellae do not appear to be influenced by the crystallography of the host grain. Additionally, the density of the lamellae is highest in areas between grains of other phases than plagioclase, suggesting a stress-control on the reaction.Ongoing transmission-electron microscopy work will help to understand whether the transition between the different microstructures is only spatial, or also temporal: Did the polygonal microstructure develop from the lamella-type microstructure, or are they expressions of the same event at different stress levels and/or fluid contents?
From Fieldwork to Publication with AusGeochem: An Open end-to-end Solution for managing FAIR Sample Based Geoscience Data
Authors: Theile Moritz , Noble Wayne , Beucher Romain , Bedoya-Mejia Alejandra , Boone Samuel , Kohlmann Fabian
Published: February 2023

Here we introduce the AusGeochem platform enabling geoscientists to manage and publish sample based geoscience data in a consistent and FAIR way. The AusGeochem data platform has been built by the AuScope Geochemistry Network (AGN) and Lithodat Pty Ltd as part of a national digital infrastructure project to facilitate the sharing of data produced by geochemistry laboratories across Australia. In order to improve national geochemical facility data management, the AusGeochem platform uses detailed structured and standardized method specific data models for collating, preserving, and disseminating geochronology and isotopic data. AusGeochem provides researchers with a solution to record and utilize all of this information, while streamlining their workflow from collection to publication. Here we will give an overview of a typical sample workflow. The demonstrated workflow contains the following steps: Storing all sample details on-the-fly during sample collection with the field app. Managing the data by logging into the AusGeochem website. Adding subsequent geochemical analyses to the sample. Visualizing the data using analytic dashboards and graphs. Sharing the data with a team of collaborators. And finally, making the data referenceable by minting DOIs and IGSNs.Manifold data is produced and captured along this process of collecting, analyzing and publishing. This is not confined to just the analytical results, but also a lot of meta information, such as involved people, instruments, funding sources, grant numbers, laboratories and institutions. Being rich in such metadata opens up the path to interesting new functionality, e.g. in the space of structured quantification and quality assessment of research projects.The AusGeochem platform is of great help for a single researcher or a team of researchers by providing them with the means and tools to make their work more efficient and productive. However, the real benefit comes by having an access control layer, so data from multiple institutions can be  stored on one single platform. Since the data is now all stored in one detailed model, it gives researchers the possibility to apply analysis across data from all contributing institutions on the fly.  This means, no downloading of data from multiple sources required. And most importantly, no difficult and often impossible data preprocessing required.How to cite: Theile, M., Noble, W., Beucher, R., McMillan, M., Boone, S., and Kohlmann, F.: From Field Application to Publication: An end-to-end Solution for FAIR Geoscience Data, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11980, https://doi.org/10.5194/egusphere-egu22-11980, 2022.
Key drivers and pressures of water scarcity at global hotspots
Authors: Leijnse Myrthe , Droppers Bram , Bierkens Marc , Wanders Niko
Published: February 2023

Although global freshwater resources are vital to the livelihood of humanity and all other life on Earth, 10% of the global population lives in regions with high to critical levels of water stress. In many of these regions the freshwater resources risk depletion of surface water or groundwater resources due to unsustainable use. Such regions are considered as the “hotspots of water scarcity”. Understanding how these hotspots have evolved over time towards their current state of water scarcity, provides important insights for decision-making and implementation of mitigation and water regulation policies.We present a global intercomparison of the key drivers and pressures causing water scarcity at these hotspots around the world. For our analysis we have applied a Driver-Pressure-State-Impact-Response (DPSIR) framework to a literature search of >175 case studies of the hotspot regions. In this framework natural, social and economic information is combined to identify driving forces and resulting pressures that have deteriorated the state (quality or quantity) of the water resources. The DPSIR literature analysis is supported by observational data analysis to study the temporal evaluation for each hotspot.We identify the key drivers and pressures to be: hydroclimatic changes (78%), population growth (28%) and agricultural (93%), municipal (54%), and industrial water demand (37%). Subsequent impacts on society are less homogeneous between the hotspots, with damage to ecosystems (25%) and reduced agricultural production (16%) as main impacts. Responses also vary greatly. While some have a positive impact on alleviating water scarcity (e.g. increased storage capacity (25%) or water treatment (23%)), others are ineffective in attempting to alleviate water scarcity or even worsen water scarcity problems (e.g. lack of groundwater regulation policies (12%) or unfair distribution of water rights (12%)).These outcomes of the DPSIR analysis provide valuable information for constructing causal networks representative to water scarcity problems at the hotspots. Such a causal network will serve as the basis of a conceptual model that represents human-water interactions at the hotspots, thereby providing a better understanding of trade-offs and synergies in different human-water systems around the world.
Refractory black carbon aerosols in rainwater in the summer of 2019 in Beijing: Mass concentration, size distribution and wet scavenging ratio
Authors: Lei Shandong , Pan Xiaole
Published: February 2023

Black carbon (BC) aerosols in the atmosphere play a significant role in climate systems due to their strong ability to absorb solar radiation. The lifetime of BC depends on atmospheric transport, aging and consequently on wet scavenging processes (in-cloud and below-cloud scavenging). In this study, sequential rainwater samples in eight rainfall events collected in 2 mm interval were measured by a tandem system including a single particle soot photometer (SP2) and a nebulizer. The results showed that the volume-weighted average (VWA) mass concentrations of refractory black carbon (rBC) in each rainfall event varied, ranging from 10.8 to 78.9 μg/L. The highest rBC concentrations in the rainwater samples typically occurred in the first fraction from individual rainfall events. The geometric mean median mass-equivalent diameter (MMD) decreased under precipitation, indicating that r BC with larger sizes was relatively aged and preferentially removed by wet scavenging. A positive correlation ( R2 = 0.73) between the VWA mass concentrations of rBC in rainwater and that in ambient air suggested the important contribution of scavenging process. Additionally, the contributions of in-cloud and below-cloud scavenging were distinguished and accounted for 74% and 26% to wet scavenging, respectively. The scavenging ratio of rBC particles was estimated to be 0.06 on average. This study provides helpful information for better under-standing the mechanism of rBC wet scavenging and reducing the uncertainty of numerical simulations of the climate effects of rBC.
New insights of the East Asian summer monsoon variability over the past 800 kyr from a transient simulation with CLIMBER-2
Authors: Jin Liya , Ganopolski Andrey , Willeit Matteo , Lu Huayu , Chen Fahu , Zhang Xiaojian
Published: February 2023

The East Asian summer monsoon (EASM) is a major component of the global climate system with its variability closely associated with regional changes of rainfall, impacting the lives of over one sixth of the global population strongly. Understanding the periodicities of summer rainfall influenced by the EASM is beneficial to its future projections. However, the mechanism of the response of the EASM associated summer rainfall fluctuations to orbital-scale forcing during the late Pleistocene remains far from being well understood. Here, we provide an 800-kyr long series of EASM rainfall variations by extracting data from multiple transient simulations of CLIMBER-2 over the past 3 million years. Despite a coarse model resolution, the CLIMBER-2 captures a realistic spatial distribution and magnitude of present-day summer (June-July-August) rainfall, especially in East Asia. The CLIMBER-2 model simulates correct magnitude and timing of the last eight glacial cycles in respect to both global ice sheet volume (expressed in δ18O) and CO2 concentration. Both the simulation and reconstructions reveal predominant 100-ky and 41-ky cycles of global ice sheet volume and CO2 concentration, although precession (23- and 19-kyr) bands dominate high-latitude summer insolation. The EASM intensity is traditionally measured by the monsoonal circulation, i.e. the low-level southerly winds in summer over East Asia. Cross-spectral analysis confirms high coherence between model and proxy at 19-kyr and 41-kyr bands implying a strong low-latitude process modulated by precession. Unlike the EASM circulation from the CLIMBER-2, simulated boreal summer rainfall in East Asia, denoted as “EASM rainfall” shows pronounced 41- and 100-kyr cycles, resembling the loess record over the past 800 kyr. The simulation results reveal a decoupling between EASM rainfall and EASM circulation, which probably is a reasonable explanation for the conflicts in proxy records, and also reflects complicated mechanisms of the EASM system on glacial–interglacial timescales.
Coseismic slip of the 2020 Mw 6.4 Petrinja earthquake (Croatia) from dense geodetic benchmarks, optical image correlation and InSAR data
Authors: Henriquet Maxime , Kordić Branko , Métois Marianne , Hollingsworth James , Lasserre Cécile , Cavalié Olivier , Benedetti Lucilla , Baize Stéphane , Špelić Marko , Vukovski Matija , Gold Ryan
Published: February 2023

The Mw 6.4 Petrinja earthquake (2020, Croatia) is among the strongest continental earthquakes that occurred in Eastern Europe for decades. In such low-strain contexts, the sparse terrestrial-monitoring (few seismic and geodetic stations) of rare but strong earthquakes often prevents a detailed analysis of their seismic source. Here, we take advantage of > 160 geodetic benchmarks and optical image correlation to obtain a dense near-field coverage of the coseismic surface displacements. The geodetic dataset is obtained by repeated measurements of benchmark networks designed for civilian purposes and constitutes a unique dataset of coseismic displacements in the near-field of the fault. The optical image correlation is based on pre-earthquake (December 2017) WorldView and post-earthquake (February 2021) Pleiades satellite images with a 50 cm resolution. We also complete these displacement fields with unwrapped coseismic interferograms based on Sentinel-1 products, except in the near field affected by decorrelation. These displacement fields are consistent and thus suitable for modeling the slip distribution of the Petrinja earthquake. The elastic inversion of the geodetic benchmarks revealed interesting characteristics of this event: the rupture occurred on a near-vertical strike-slip fault, at a shallow depth (< 10 km), with significant slip reaching the surface. It also suggests that the deformation was partly accommodated by a subparallel strand 2.5 km from the main source northward. The aim of this research is to improve the source model of Petrinja 2020earthquake sequence, with a joint inversion of the geodetic benchmarks, optical image correlation, and InSAR data. Nevertheless, the comparison of the geodetic and coseismic offsets measurement on the field, shows that > 70% of the slip is likely distributed at the surface. Moreover, the coseismic strain maps derived from the unique benchmark data set helped us to identify zones where deformation appears distributed. Finally, the new data raises questions about whether such moderate earthquakes are accompanied by subsurface off-fault deformation or residual elastic strain.
Use of Long-Short Term Memory network (LSTM) in the reconstruction of missing water level data in the Seine River.
Authors: Janbain Imad , Deloffre Julien , Jardani Abderrahim , Vu Minh Tan , Massei Nicolas
Published: February 2023

Missing data is the first major problem that appears in many database fields for a set of reasons. It has always been necessary to fill them, which becomes unavoidable and more complicated when the missing periods are longer. Several machine-learning-based approaches have been introduced to deal with this problem. 

The purpose of this paper is to discuss the effectiveness of a new methodology added prior to the LSTM deep learning algorithm to fill in the missing data in the hourly surface water level time series of some stations installed along the Seine River in Normandy-France. In our study, due to a lack of data, a challenging situation was faced where only the water level data in the same station, which contain many missing parts, were used as input and output variables to fill the station itself in a self-learning approach. This contrasts with the common work on imputing missing data, where several features are available to take advantage of in a multivariate and spatiotemporally way, e.g.: using the same variable from other stations or exploiting other physical variables and metrological data, etc. The reconstruction accuracy of the proposed method depends on both the size of the available/missing data and the parameters of the networks. Therefore, we performed sensitivity analyses on both the properties of the networks and the structuring of the input and output data to better determine the appropriate strategy. During this analysis process, a data preprocessing method was developed and added prior to the LSTM model. This data processing method was discovered by presenting many scenarios, each of which was an updated version of the last one. Along with these scenarios, limitations were also addressed and overcome. Finally, the last model version was able to impute missing values that may reach one year of hourly data with high accuracy (One-year RMSE = 0.14 m) regardless of neither the location of the missing part in the series nor its size.  
Indo-Pacific teleconnection changes during the Holocene: model-proxy comparison
Authors: Abdelkader Di Carlo Isma , Braconnot Pascale , Elliot Mary , Marti Olivier
Published: February 2023

The teleconnections between the Indian and Pacific Oceans are very complex, involving multiple modes of variability and phenomena such as the El Niño-Southern Oscillation, Indian Ocean Dipole, Indian Ocean Basin mode, and the Asian monsoon. Their interactions are complex because changes in one of these phenomena affect the others. Insufficient agreement exists on the predicted evolution of mean states of both basins and the impacts of climate variability in this region in response to increasing CO2 emissions. To better constrain Indo-Pacific interactions, we have studied the Holocene period. We consider four transient simulations from three General Circulation Models (GCM) and a collection of paleo-archives from the Holocene in the Indo-Pacific region. Our study allows us to put into perspective the links between long-term changes in variability and in the mean state. The main driver is insolation and trace gases (CO2) that have increased the mean sea surface temperature of the tropical ocean over the last 6,000 years. Our first results show that modeled trends in the regional long-term variability are in agreement, but differences are observed when we analyze the data at shorter interannual timescales. We also explain why the simulations differ or agree with the paleoclimate reconstructions. One way is to look at the relative role of temperature and salinity in determining the changes in δ18O recorded by the various climate archives. 
The International Soil Moisture Network - a global interoperable data center for in situ soil moisture observations
Authors: Böhmer Fay , Olarinoye Tunde , Korres Wolfgang , Kramer Kasjen , Dietrich Stephan , Zink Matthias , Himmelbauer Irene , Schremmer Lukas , Petrakovic Ivana , Aberer Daniel , Sabia Roberto , Crapolicchio Raffaele , Goryl Philippe , Scipal Klaus , Dorigo Wouter
Published: February 2023

Soil moisture is recognized as an Essential Climate Variable (ECV), because it is crucial to assess water availability for plants and hence food production. Having long time series of freely available and interoperable soil moisture data with global coverage enables scientists, farmers and decision makers to detect trends, assess the impacts of climate change and develop adaptation strategies.The collection, harmonization and archiving of in situ soil moisture data was the motivation to establish the International Soil Moisture Network (ISMN) at the Vienna University of Technology in 2009 as a community effort. Based on several project funding periods by the European Space Agency (ESA), the ISMN became an essential means for validating and improving global land surface satellite products, climate and hydrological models.Permanent funding for the ISMN operations was secured through the German Government (Ministry of Digital and Transport) and therefore the ISMN has successfully migrated at the end of 2022 to its new host the International Centre for Water Resources and Global Change (ICWRGC) and the German Federal Institute of Hydrology (BfG). Furthermore, the ISMN was recognized by WMO in their latest State of Global Water Resources report.To improve the data service delivery, ISMN users can now benefit from a newly developed dataviewer which features functionalities such as data archives and advanced filter options (e.g. for climate and landcover types, for data quality) developed in synergies with the ESA project Fiducial Reference Measurements for Soil Moisture (FRM4SM). This presentation aims at showcasing these latest upgrades as well as new network contributions to the ISMN.
Towards a general constitutive model for snow
Authors: Vallero Gianmarco , Barbero Monica , Barpi Fabrizio , Borri-Brunetto Mauro , De Biagi Valerio
Published: February 2023

Reproducing the mechanical behaviour of snow is a challenging task for many different application fields (e.g., Civil and Environmental Engineering, Physics, etc.) and can be useful to study many topics, such as: the stability of mountain snowpacks, the safety of structures and infrastructures in cold environments, the social and physical risk for people and goods in snow covered areas.The available constitutive models for snow generally use the elasto-plastic (EP) theory to reproduce different and complex items of this peculiar material with reference to both laboratory and on-site conditions. Nevertheless, these models are often related to some specific types of snow (i.e., rounded grains, faceted crystals, etc.) and cannot be used for general purposes. Moreover, many models do not consider viscosity, rate-sensitivity, bonding effects, etc.In this work, we introduce the theoretical bases of our proposal for a new and improved constitutive model for snow. The model is based on the theory of visco-plasticity for finite element applications with an implicit integration scheme, and can reproduce both qualitatively and quantitatively the findings of some literature experimental data. For instance, promising results are obtained for the following tests: triaxial compression and relaxation, volumetric compression, and creep. Finally, we suggest possible improvements of the model to include important snow features not considered so far, such as: the collapse in compression of the weak layer (anticrack), the change in shape of snow grains, the ductile-to-brittle transition of the material, etc.
Spatial and temporal distribution of organic matter in central Arctic: Insights from biomarker proxy
Authors: Singh Akanksha , Ho Sze Ling , Löwemark Ludvig
Published: February 2023

Studies have shown that Arctic sea-ice conditions influence the earth’s energy budget by affecting its albedo and global ocean circulation. It also exerts a strong control on the local primary productivity. In addition, by drifting sea ice, it facilitates the transport of sediment and organic matter (OM) from marginal seas across the Arctic Ocean. Over the past decades, there have been several studies on sediment cores from Central Arctic where the major source of OM was shown to be terrigenous. The presence of this elevated terrigenous OM is driven by the transport of sediments and OM from marginal seas to the Central Arctic via drifting ice. However, our understanding of the processes involved in the transport of OM to the central Arctic is still limited. In this study, in order to better understand the pathways of OM transport, we examine spatial and temporal variations in OM flux to the central Arctic. We use organic carbon and biomarker proxies, namely n-alkanes and Glycerol dialkyl glycerol tetraether (GDGT) to explore the spatial and temporal (Marine Isotope Stage 1, 2 and 3) variation of terrigenous input versus marine primary productivity in the central Arctic. To understand the transport of OM in the Central Arctic, biomarkers in 100 samples collected from 9 central Arctic cores were investigated. The presence of terrestrial organic matter in the central Arctic region was confirmed by the high values of the BIT index, which virtually all reached above 0.5 with a maximum of 0.9. The spatial pattern of both terrestrial and marine OM showed higher concentrations at the central Lomonosov ridge and reduced values towards the Lomonosov Ridge off Greenland, with lowest concentrations from the cores located at Morris Jesup Rise (MJR). The pattern of declining terrestrial biomarker concentrations from the central Arctic to MJR, which is closer to the Fram Strait and marks the exit of the Arctic Ocean, are likely caused by sea-ice drift patterns. The sea ice would have been transported by the Transpolar Drift, which allows terrigenous material entrained in the dirty sea ice to get transported towards central Arctic. This spatial pattern remains same for all three studied Marine Isotope Stages. Looking at the temporal variation of the OM into the central Arctic, compared to MIS 3 and MIS 2, TOC as well as both marine and terrestrial biomarkers show enhanced concentration during MIS 1 all over the central Arctic. These increased biomarker concentrations reflect that MIS 1 was warmer with less extensive sea-ice cover than MIS 2 and MIS 3.