bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluating Memory Properties in Convection Schemes Using Idealised Tests
Authors: Hwong Yi Ling , Colin Maxime , Aglas Philipp , Muller Caroline , Sherwood Steven
Published: February 2023

Two structural assumptions are frequently employed in convective parameterisation: the diagnostic and quasi-equilibrium assumptions. The former assumes an instantaneous relationship between the large-scale environment (“macrostate”) and subgrid-scale convective activity, while the latter postulates that convective processes are almost in equilibrium with slowly evolving large-scale forcing at all times. Both assumptions do not take into account the role of convective memory (“microstate” memory), which is defined as the dependence of convection on its own history. Here, we present the memory behaviour of three convection schemes by comparing their responses in two idealised RCE experiments in single-column models (SCMs) to those of a cloud-resolving model (CRM). Three main findings from these tests will be discussed. First, when the large-scale environment is held constant (“FixMacro”), precipitation remains invariant in time with the Zhang-McFarlane scheme, confirming that the scheme does not parameterise convective memory and is fully diagnostic. The org scheme (Mapes & Neale, 2011) displays similar behaviour to the CRM in that precipitation increases in the first moments after FixMacro starts, with larger entrainment rates associated with slower growth. However, its logarithmic growth shape differs from that of the CRM, which displays exponential growth, and can be explained using the scheme’s governing equations. Second, when the prognostic convective memory variable is set to zero at one time step (essentially wiping out microstate memory), the org scheme displays remarkably similar behaviour to the CRM, with precipitation dropping to zero and then recovering to its RCE value over a recovery time scale tmem. In comparison, precipitation in the LMDZ cold pool scheme (Grandpeix & Lafore, 2010) responds in the opposite direction: it grows and then falls back to its RCE value. Finally, the mean and temporal variance of the org variable were found to correlate strongly with memory strength (tmem), indicating that org has captured important aspects of convective memory. Overall, our results indicate that the org and LMDZ cold pool schemes partially, but do not fully capture CRM memory behaviour and are limited by their structural assumptions. They also demonstrate the usefulness of our simple idealised experiments to probe the memory behaviour of convection schemes. 
identification of robust predictors of tropical cyclones using causal effect network over the north indian ocean
Authors: kumar sagar Akshay
Published: February 2023

Tropical cyclone (TC) activity varies substantially yearly, and tropical cyclone-related damage also changes. Longer-term prediction of tropical cyclones plays an important role in reducing the wear and human loss caused by TCs. In this study, we have used a Causal-network-based algorithm to find the main development regions and precursors responsible for TC genesis and intensification. However, all the extreme events are interconnected through various global links. Therefore, analysis of the teleconnection and correlation of Tropical Cyclones with El Nino Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), and North Atlantic Oscillation (NAO) during the satellite era (1980-2020) over the North Indian Ocean (NIO) basins using this Causal Effect Network (CEN) based algorithms is checked. The most appropriate metric for cyclone energy is Accumulated Cyclone Energy (ACE); its correlation with the various factors are investigated. We examined the variation in TCs activity during all three phases (positive, negative, and neutral phases).The results show an increasing trend in ACE over the NIO region during that specific period. The duration of most intense cyclones is increased, but their frequency decreases in this period. A shift in ACE starts after 1997 and still rises significantly. Analysis of Sea Surface Temperature (SST), Vertical Wind Shear (VWS) between 850 and 250 hPa, mid-tropospheric (800 hPa) Relative Humidity (RH), low level (850 hPa) Relative Vorticity (RV), and Tropical Cyclone Heat Potential (TCHP) is done, and it shows positive changes and variability of ACE. These results may help get better knowledge about the atmospheric or oceanic teleconnections between the events, and improved tropical cyclone prediction can help reduce the loss caused by the TCs.        
Past black carbon deposition and sources in the European Arctic depicted from lake sediments and ice cores
Authors: Korhola Atte , Ruppel Meri
Published: February 2023

The amplified climate effect of black carbon (BC) in the Arctic is widely acknowledged. Despite this, information on its deposition patterns and particularly sources are still scarce from the area. Arctic-wide atmospheric BC monitoring show decreasing BC concentrations since the 1990s. However, increasing amounts of BC deposition records from the area show more spatial variability in long-term trends, and some records suggest deviating trends between atmospheric BC concentrations and deposition. Particularly in the European Arctic (northern Fennoscandia and northwestern Russia) BC deposition trends seem to have increased in recent decades rather than decreased as suggested by models and observed for atmospheric concentrations. Such dissimilarities between atmospheric BC concentrations and deposition trends suggest different meteorological processes and sources driving these, which need to be further studied to understand the effects of different BC emissions on the Arctic climate. Although we have quantified different BC fractions from lake sediments and ice cores in the European Arctic indicating variable deposition trends during the last 300 years, the records suggest surprisingly similar sources of the deposited BC particles. Our future endeavors lie in further illuminating the sources of deposited BC in the Arctic and particularly studying the potential significance of Russian gas flaring and increasing peatland fires.
Electron density reconstruction using fleets of LEO satellites
Authors: Schreiter Lucas , Brack Andreas , Männel Benjamin , Arnold Daniel , Jäggi Adrian
Published: February 2023

An ever-increasing fleet of low earth orbiting (LEO) satellites equipped with dual-frequency GNSS receivers can provide slant TEC observations of the topside ionosphere. If occultation measurements are included, the observed range is extended well below LEO altitude also covering the peak of the F2 layer. To reconstruct the topside electron density a large number of observations with good coverage across magnetic latitude and local time with a large variety of elevation angles are required. Apart from scientific missions like Swarm, GRACE-FO, Sentinel-1/2/3, Jason-3, and COSMIC-2 large fleets of LEO satellites operated by new-space companies like Spire Global help to increase the observation density. The Spire Lemur satellites are 3U cubesats, which carry dual-frequency GPS receivers and thus allow to compute slant TEC measurements. We will discuss the data quality of TEC measurements derived by both, the scientific and new-space cubesat satellite missions and include Spire GPS data into a three-dimensional ionospheric reconstruction together with GPS data from Swarm, GRACE-FO, Sentinel, Jason-3, and COSMIC-2. B-Splines are used to represent the electron density in magnetic latitude, magnetic local time and altitude. Code biases are co-estimated. Since the scientific satellite missions, apart from the low inclination COSMIC-2 satellites, are in polar obits, special emphasis will be put on the improvements in observation geometry provided by the Spire Lemur satellites.
NO3 reactivity in a temperate forest impacted by anthropogenic and biogenic emissions during the ACROSS campaign
Authors: Dewald Patrick , Andersen Simone T. , Tuerk Gunther N.T.E. , Schuladen Jan , Seubert Tobias , Crowley John N.
Published: February 2023

Terpenoids are readily released into the environment via biogenic emissions. One of their major nighttime oxidizing agent is the nitrate radical (NO3), which is formed from the reaction between ozone (O3) and nitrogen dioxide (NO2). The NO3-initiated oxidation of such biogenic volatile organic compounds (BVOCs) leads to the formation of organic nitrates that can deposit on particles to form secondary organic aerosols. This reaction path thus can lead to irreversible removal of NO2, usually of anthropogenic origin, from the gas phase. Alternatively, NO3 rapidly reacts with nitric oxide (NO) with reformation of NO2. Assigning the contribution of BVOCs and NO to the NO3 reactivity therefore provides insight into the fate of NOx (= NO + NO2).We used a flow-tube coupled to a cavity-ring-down spectrometer (FT-CRDS) to make direct measurements of the NO3 reactivity in air (at a height of ~ 6 m above ground level) during the ACROSS field campaign in the forest of Rambouillet in the vicinity of Paris, France. Measured reactivities ranged from < 0.006 s-1 to 2.3 s-1, with high average daytime and nighttime reactivities of 0.13 s-1 and 0.25 s-1, respectively. In addition, vertical profiles of NO3 reactivity (up to 40 m) were made and are compared to data previously observed in a boreal forest. Reactivities in Rambouillet forest were highest close the ground (0.36 s-1 at 0 m) and drastically decreased with height (0.08 s-1 at 24 m).By comparing direct NO3 reactivity measurements with those calculated from trace gas mixing ratios and their corresponding rate coefficients, we identify the contributions of BVOCs and NO to NO3 losses.
Exploiting the predictability of global teleconnections to forecast subseasonal to seasonal scale wind speeds over India
Authors: Das Aheli , Baidya Roy Somnath
Published: February 2023

This study explores the potential of slow-varying components of the earth system to predict the monthly mean wind speeds over the seven homogenous climate zones of India at subseasonal to seasonal time-scales. The following set of predictors are selected for that purpose: sea-surface temperature, mean sea-level pressure, 10 m wind speed, wind speed at 850 hPa, and geopotential height at 850 hPa. With the exception of sea-surface temperature which is obtained from HadISST, the rest of the variables are obtained from the JRA55. Besides, the popular indices such as the Nino 3.4 index and the Dipole mode index are also used as predictors. The forecasts are made at 1, 2, 3, 4, and 5 months of leadtime for the monsoon months of June, July, August, and September when the wind speeds are the highest throughout the country. The regions of significant correlations of the predictor fields with the spatially-averaged wind speeds of each homogenous region are determined using the past 6 month lagged composites. Once identified, the variables over these regions are spatially averaged and are mapped to the 10 m wind speeds from JRA55, since it is the closest representation of observed wind speeds over India. This predictor-based forecasting is carried out using the following approaches: multi-linear regression, decision tree based regression, and K nearest neighbours regression. The models use data from 1958-2018 for training and 2019-2021 for testing. The deterministic predictions are evaluated using mean absolute error (MAE) and the skill compared to a climatological forecast is estimated using the root mean squared error skill score (RMSESS). Results show that different sets of predictor combinations are responsible for giving the best forecasts for individual months and leadtimes. These forecasts have MAE of  around 0.2 m/s and RMSESS values ranging from 0.5-0.7. Although we are looking at deterministic predictions here, a combination of multiple models and predictors used above can lead to the production of ensemble forecasts as well, which will be of further added value to the wind energy sector.
Drivers of Increasing Ozone during the Two Phases of Clean Air Actions in China
Authors: Liu Yuxi , Geng Guannan , Cheng Jing , Liu Yang , Xiao Qingyang , Liu Liangke , Shi Qinren , Zhang Qiang
Published: February 2023

In response to the severe air pollution issue, the Chinese government implemented two phases (Phase I: 2013-2017, Phase II: 2018-2020) of clean air actions since 2013, resulting in a significant decline in fine particles (PM2.5) during 2013-2020, while the maximum daily 8 h average ozone (MDA8 O3) increased by 2.6 μg m-3 yr-1 during the same period. Here, we derived the drivers behind the rising O3 concentrations during the two phases of clean air actions by using a bottom-up emission inventory, a regional chemical transport model, and a multiple linear regression model. We found that both meteorological variations (3.6 μg m-3) and anthropogenic emissions (6.7 μg m-3) contributed to the growth of MDA8 O3 from 2013 to 2020, with the changes in anthropogenic emissions playing a more important role. The anthropogenic contributions to the O3 rise during 2017-2020 (1.2 μg m-3) were much lower than that in 2013-2017 (5.2 μg m-3). The lack of volatile organic compound (VOC) control and the decline in nitrogen oxides (NOX) emissions were responsible for the O3 increase in 2013-2017 due to VOC-limited regimes in most urban areas, while the synergistic control of VOC and NOX in Phase II initially worked to mitigate O3 pollution during 2018-2020, although its effectiveness was offset by the penalty of PM2.5 decline. Future mitigation efforts should pay more attention to the simultaneous control of VOC and NOX to improve O3 air quality.
In-situ hydro-mechanical responses of rainfall-induced shallow landslides
Authors: Chang Wen-Jong , Chou Shih-Hsun
Published: February 2023

Rainfall-induced shallow landslide is a coupled hydro-mechanical behavior involving the advancement of wetting fronts during the infiltration process, resulting in reducing the soil resistance from matric suction of unsaturated soil mass. The hydrologic process and mechanical response of the soil mass are coupled via the soil water characteristic curve (SWCC), unsaturated hydraulic conductivity function (HCF), and variations of effective stress of unsaturated soils. To study the coupled behavior, Internet-of-Things (IoT) based sensing modules integrated with subsurface moisture content measurement and surface inclination were developed and deployed in a high failure potential slope. The slope failed during heavy rainfall and the modules continuously recorded the advancement of the wetting front and the development of surface inclination in real time. The results agree with the integrated analysis framework by Chang et al. (2021), in which the 1D infiltration analysis is coupled with the limit equilibrium approach for infinite slopes of unsaturated soil. The technologies of in-situ monitoring and coupled analysis prove the feasibility of physics-based warning of shallow landslides. 
Fluid-assisted deformation processes at the roots of oceanic transform faults.
Authors: Bickert Manon , Kaczmarek Mary-Alix , Maia Marcia , Brunelli Daniele
Published: February 2023

Oceanic Transform Faults (OTFs) are major plate boundaries that regularly offset the axis of Mid-Oceanic Ridges and are able to generate Mw 7 earthquakes. Yet, very little is known on the evolution of fault slip mechanics at depth, mainly due to rare exposures of deep sections at the seafloor. The Atobá Ridge is one of the rare structures where the roots of an active transform fault are exposed and accessible. This transpressive ridge is part of the northern transform fault of the St. Paul transform system in the Equatorial Atlantic (Maia et al., 2016). There, ultramafic mylonites are tectonically exhumed along the inner thrust faults of a positive flower structure.Here we study the deformation mechanisms in ultramafic mylonites and ultramylonites sampled at the Atobá ridge. We show that all samples experienced ductile deformation at 750-900°C in the spinel stability field, resulting in a pervasive grain size reduction. We propose fluid-assisted dissolution-precipitation creep as the main deformation mechanism, leading to dissolution of orthopyroxene and formation of lens-shaped olivine and interstitial minor phases’ neoblasts (pyroxenes, spinel, and amphibole). Orthopyroxene neoblasts formed by this mechanism mimic the Crystallographic Preferred Orientation of the olivine neoblasts. Fluid-assisted dissolution-precipitation creep allows deformation of stiff minerals at significant lower stresses and temperatures than dislocation creep, possibly leading to an intense strain localization. This mechanism, previously reported in ophiolites and orogenic contexts (Hidas et al., 2016; Prigent et al., 2018), is described for the first time in the oceanic transform environment. Similar microstructures have been observed in mylonites from other OTFs, suggesting that this mechanism could be more widespread and could even represent one of the main deformation law in the lower oceanic lithosphere, with important implications on the mechanics and structures of (oceanic) transform faults and long-lived detachments.This work is supported by PRIN2017KY5ZX8.REFERENCESMaia, M., Sichel, S., Briais, A., Brunelli, D., Ligi, M., Ferreira, N., Campos, T., Mougel, B., Brehme, I., Hémond, C. and Motoki, A., 2016. Extreme mantle uplift and exhumation along a transpressive transform fault. Nature Geoscience, 9(8), pp.619-623.Hidas, K., Tommasi, A., Garrido, C. J., Padrón-Navarta, J. A., Mainprice, D., Vauchez, A., Barou, F., & Marchesi, C. (2016). Fluid-assisted strain localization in the shallow subcontinental lithospheric mantle. Lithos, 262(October), 636–650. https://doi.org/10.1016/j.lithos.2016.07.038Prigent, C., Guillot, S., Agard, P., & Ildefonse, B. (2018). Fluid-assisted deformation and strain localization in the cooling mantle wedge of a young subduction zone (Semail ophiolite). Journal of Geophysical Research: Solid Earth, 123. https://doi.org/10.1029/ 2018JB015492
Similarity-based storylines of future climate extremes in Switzerland
Authors: Kotlarski Sven , Mastai Alina , Wehrli Kathrin , Fischer Erich M.
Published: February 2023

The heatwave of 2003, the flooding of 2005, the drought of 2018, or the snow-scarce winter of 2019/2020 are vivid examples of extreme weather events affecting Switzerland. The CH2018 climate scenarios for Switzerland show that such kind of events will become more intense in the future, depending on the future emission pathway and the considered time horizon. So far, CH2018-based information is typically communicated as changes in the mean or extremes of a climate variable, including the uncertainty of these changes. Presenting information in this manner is scientifically correct, but not tangible for everyone. Interested stakeholders often have difficulties to imagine what the future climate, and in particular how future extreme conditions might look like.To enhance the uptake of CH2018 scenario information by stakeholders we here present a newly developed method to create similarity-based storylines and apply it to a historic heatwave event. The resulting storylines show local impacts in four different sectors at individual locations in Switzerland. In each case, the historical record-breaking heat summer of 2003 is related to a future extreme summer represented by the CH2018 scenarios assuming the RCP8.5 emission scenario. Specific indicators help to create unique heat-related storylines. In the alpine setting of Davos, the number of dry hiking weather days increases in a future extreme summer to the delight of hikers and alpine summer tourism. In contrast, the southern cities of Sion and Geneva face less favorable prospects. The fire danger massively increases in dry locations such as Sion. The population in Geneva will encounter an even stronger heat exposure compared to 2003. Finally, the living conditions for a potent agricultural pest considerably improve throughout Switzerland, threatening agriculture during a similar future extreme.The new similarity-based storylines facilitate the understanding of locally relevant processes linked to climate extremes, provide an improved insight into how extreme events quantitatively change with climate change, give examples of possible impacts, and finally try to stimulate public awareness for possible consequences of future climate change.
Measurement of the geopotential difference between two sites at Beijing and Wuhan using two hydrogen clocks via CVSTT technique
Authors: Wu Kuangchao , Shen Wen-Bin , Sun Xiao , Cai Chenghui , Shen Ziyu
Published: February 2023

Based on the gravity frequency shift equation, by comparing the frequencies between two precise clocks at two different stations at the 203 Institute Laboratory (in Beijing) and the Luojia Time-Frequency Station (in Wuhan), respectively, the geopotential difference between the two stations is determined. Here, we conduct a clock-transportation experiment for measuring the geopotential difference between the two stations by comparing two remote hydrogen atomic clocks’ frequencies via satellite links. Based on the gravity frequency shift measured between the two remote clocks at Beijing and Wuhan, the geopotential difference between the two stations was determined. Comparisons show that the experimental result deviates from the EGM2008 result by 38.5(45.7) meters in orthometric height. The results are consistent with the frequency stabilities of the hydrogen clocks (at the level of 10−15@day) used in the experiment. With the rapid development of time and frequency science and technology, the approach discussed in this study for measuring the geopotential is prospective and thus, could have broad applications. This study is supported by the National Natural Science Foundations of China (Nos. 42030105, 41721003, 41804012, 41631072, and 41874023), Space Station Project (No.2020-228), and the Natural Science Foundation of Hubei Province of China (No. 2019CFB611). 
Impact of Bay of Bengal mesoscale eddies on Indian Summer Monsoon Rainfall
Authors: Vg Kiran , A Rao Suryachandra , A Pillai Prasanth
Published: February 2023

The northern Indian Ocean serves as an ideal space to study the interaction between Ocean and atmosphere as it accommodates unique and versatile oceanic conditions and the largest monsoonal circulation in the world. The South Asian Monsoon System, the largest of its kind, directly impacts the lives and livelihoods of billions of people living in the Indian Subcontinent. Various factors that influence its strength and characteristics have been studied extensively throughout the years. But, owing to its complex and dynamic nature, a comprehensive understanding and accurate monsoon prediction remain a work in progress. Several Oceanic components that play a part in monsoon processes have been identified. Our study focuses on the Bay of Bengal, distinguished from other oceans due to its highly stratified upper layers. Through this study, we aim to understand the Impact of mesoscale eddies in the Bay of Bengal on the Indian Summer monsoon. The influence of oceanic mesoscale eddies on the circulation and precipitation directly over them has been addressed through different studies after the advent of high-resolution satellite data. The current research focuses on the large-scale influence of the eddies in the Bay of Bengal on the seasonal rainfall during the Indian summer monsoon(ISM). Indices were created using the Okubo Weiss parameter to understand the inter-annual variation of eddies (classified according to polarities and regions of occurrence). These indices correlated with the ISM system suggested that Anticyclonic eddies in the  Western Bay of Bengal strongly influenced wind and rainfall patterns over the monsoon region. The Anticyclonic Eddy activity that peaked during the El Nino years countered the suppression of rainfall by El Nino through enhanced synoptic activity in BoB. The low-pressure system formation and propagation in BoB were found to be stronger in the years having more anticyclonic eddies. The warming created by the warm-core Anticyclonic eddies initiates an Anticyclonic(Clockwise) circulation around the region, which feeds back into the existing oceanic conditions. This coupled Ocean-Atmospheric system mediated through the mesoscale eddies needs to be further analyzed through stand-alone and coupled modeling experiments. Improving the representation of the mesoscale processes in the Northern Indian Ocean can serve as a crucial step in improving the monsoon prediction systems.
Riverine Litter Flux to the Northeastern Part of the Black Sea
Authors: Pogojeva Maria , Korshenko Keka , Osadchiev Alexander
Published: February 2023

Rivers are among the main sources of marine litter, especially for semi-isolated sea areas with high population and intense economic activity. The semi-isolated Black Sea located in the Eastern Europe is one of the examples of such areas, which watershed basin is under high anthropogenic pressure. In this study, we report the results of first long-term monitoring program of floating litter at several rivers inflowing to the northeastern part of the Black Sea. We describe the main characteristics of registered marine litter including the distribution of its type and size. Based on the obtained results, we reveal the relation between river discharge rate and the litter flux for the considered rivers. Using this relation extended to all rivers of the study area, we assess the total annual flux of riverine litter to the northeastern part of the Black Sea.
An assessment of the water availability for mountain communities in the Parvati basin, Western Himalaya using a distributed hydrological model
Authors: Srinivasalu Pradeep , Kulkarni Anil , Vv Srinivas , Sk Satheesh
Published: February 2023

The impact of changing climate on the Himalayas strongly influences the amount and timing of water available in the region. Millions of people in the downstream regions of Himalayan catchments depend on streams and rivers originating from the region for domestic consumption, livelihood, agriculture, and hydropower (Immerzeel et al., 2020). Many studies have highlighted the importance of snow and glacier melt towards water availability at the basin scale (Khanal et al., 2021; Prasad et al., 2019). However, the water availability at a much finer scale (i.e., to individual mountain communities) remains unquantified. Understanding the mountain communities' water availability is imperative to mitigate climate change impacts and ensure their water and food security (Kulkarni et al., 2021). In the present study, we aim to estimate the water availability to the communities in the Parvati Basin of Western Himalaya, including the contributions of snow and glacier melt, rainfall, and groundwater to runoff. The catchment has a total area of 1754 km2 and consists of 279 glaciers which cover an area of 395.6 km2. The volume of the glaciers and their mass balance are computed to understand the present state of the glaciers. The volume of the glaciers is estimated as 21.3 ± 3.8 km3 using laminar flow and scaling methods. The mass balance of the glaciers was estimated using the improved accumulation area ratio (IAAR) method as -0.44 ± 0.23 m w.e.a−1. We simulate the daily runoff in the catchment using the Spatial Processes in Hydrology (SPHY) model, which is a fully distributed cryospheric-hydrological model. The volume and mass balance results are used to define the model's initial conditions and constrain mass loss during the simulations. Further, the study also aims to understand the role played by seasonal snow cover on the water available to the mountain communities. The outcome of this assessment would help to facilitate making informed hydrological and agricultural policies to mitigate the impact of climate change.
Optimizing Forest Management around Urban Areas for improved Cooling and Air Exchange
Authors: Bringmann Linda , Diers Marco , Weidig Johannes , Bendix Jörg
Published: February 2023

Urban areas are especially vulnerable to heat waves which are expected to occur in a higher frequency and intensity due to climate change. As a consequence, climate adaptation in these areas is crucial for the inhabitants’ health and their quality of life. Adaptation strategies relating to changes inside urban areas, such as the use of high albedo surfaces and an increase in urban vegetation, are very well studied.

In this study the cooling potential of forests surrounding these urban areas is investigated depending on silvicultural factors like tree density, tree species, forest structure, and the ratio of forest to open landscape. A focus is placed on studying the effects of these parameters on cold air drainage. For this purpose, the 3D thermodynamics version of the micro-scale urban climate model MUKLIMO_3 TD of the German Meteorological Service (DWD) is used to simulate first, the general effects of changes in silvicultural factors on idealized cities and second, the effects these changes could have on a Hessian model region.

To improve the predictive properties of these simulations, forested areas in the model are parametrized in great detail using local high resolution data provided by HessenForst.

The model performance using these datasets is investigated and discussed.

This investigation is a part of and kindly funded by the Hessian integrated Climate Programme (IKSP) and a cooperation of HessenForst and LCRS.
The characteristics of atmospheric SF6 in the Korean Peninsula during 2017-202
Authors: Lee Soojeong , Lee Haeyoung , Li Shanlan
Published: February 2023

Sulfur hexafluoride (SF6) is a most potent anthropogenic greenhouse gas with a global warming potential of 23,900 over a 100-year time horizon. There are no natural sink sources in the troposphere and they are destructed by photolysis and electron attachment in the mesosphere.  SF6 is mainly used for electrical insulation, circuit breaker, and plasma etching processes in the semiconductor industry. For monitoring changes in atmospheric SF6 in Korean Peninsula, 3 surface in-situ greenhouse gas monitoring stations, Anmyeondo (AMY), Jeju Gosan (JGS), and Ulleungdo (ULD), have been operating. AMY started its operation in 2007 and JGS and ULD followed in 2017. Due to the advantage of their locations surrounding the Korean Peninsula at the Western, Southern, and Eastern ends, they can provide information on the inflow and outflow of the SF6 in the Korean Peninsula. According to the data from 2017 to 2020, the increasing trend of background mole fraction of SF6 from the stations was in good agreement with that of the global monitoring stations, Mauna Loa and Cape Grim. Each station shows the characteristic enhancement tendency by wind direction and speed, which implies the possible influence of the regional emission source and long-range transport. In addition, based on the analysis with HYSPLIT model the central area of the Korean Peninsula is identified as an emission source region, as well as central part of China and Japan.
Estimating high resolution exposure at landscape-level – on the development of a 3‑dimensional Gaussian puff droplet drift model
Authors: Fuchs Mike , Gebler Sebastian , Lorke Andreas
Published: February 2023

Modelling environmental concentrations of pesticides at landscape-level is of growing interest for pesticide registration and product stewardship, including higher-tier studies in risk assessment, mitigation measures, monitoring support and decision making. Typically, processes such as runoff, drainage, and leaching are well represented in existing modelling concepts at point and landscape scale. However, the modelling of off-target spray drift is often neglected or simplified at the landscape-level scale due to its high computational costs. Attempts at implementing spray drift into landscape-level modelling often rely on an external calculation of drift curves with pesticide masses added directly to the channel network. Although this approach enables the estimation of drift entries based on the proximity of source areas to water bodies, it may be insufficient in representing the spatial distribution of spray drift depositions in the landscape.Our modelling approach aims to enable computationally efficient landscape-level spray drift predictions, which account for short term and local weather conditions. Therefore, a spray drift model for ground application was developed, by combining a mechanistic droplet model with a 3D Gaussian puff model. The mechanistic droplet model predicts the trajectory and mass balance of individual representative droplets, based on environmental conditions and application operations. This trajectory is then combined with a 3D Gaussian puff model to predict pesticide concentrations in the landscape, which are used to predict pesticide deposition rates. The model considers important spray drift predictors such as weather conditions, drop size distribution, physio‑chemical properties of the active ingredient, and operational conditions. The model showed realistic and expected behavior for variations in important input parameters (e.g., different nozzle types, wind speed). Furthermore, validation against two spray drift field studies showed good agreement between simulated and observed values.To increase the understanding of pesticide transport pathways at the landscape-level, it is planned to combine the spray drift model in a modular fashion with a high-resolution SWAT+ (Soil and Water Assessment Tool) model of an agriculturally dominated catchment in Germany. Moreover, the spray drift model is expected to be a useful tool in the elucidation of monitoring data and the assessment of ecotoxicological risks for non-target organisms.
Contamination and environmental risk assessment of heavy metals in coastal sediments of Ras Abu Ali Island, Saudi ArabiaKhaled Al-Kahtanya and Abdelbaset S. El-Sorogya
Authors: Alkahtani Khaled , El-Sorogya Abdelbaset S.
Published: February 2023

ABSTRACTMetal pollution is a global environmental issue and considers one of the most serious problems in coastal environments. Present work aimed to document the distribution, ecological risk, and the potential sources of heavy metals (HMs) in coastal sediments of Ras Abu Ali Island, Arabian Gulf, Saudi Arabia. V, Fe, Sr, Al, As, Hg, Sb, Cd, Co, Mn, Ni, Zn, Cr, Pb, Cu were determined in 34 coastal sediment using Inductively Coupled Plasma - Atomic Emission Spectroscopy (ICP - AES) and several pollution indices, and multivariate analysis were applied. The lower HM levels were recorded in the medium to coarse sized samples in the northern part of the study area faced to the open sea. The average values of Ni, Zn, Cu, As, Pb, and Cr were less than the sediment quality guideline (SQG) and the background continental crust. Most applied pollution indices revealed minor enrichment, low contamination and low risk for all HMs, except Sr, which indicated extremely severe enrichment and very high contamination. Sr is incorporated in calcite and aragonite of the invertebrate skeletons and sorbed in hydrated form by clay minerals. The petrochemical wastes from nearby Al-Jubail industrial city, Zn refineries, and intensive use of phosphate fertilizers might be the potential anthropogenic sources of Sr in the study area.Keywords: Heavy metals, Pollution index, Coastal sediment, Strontium, Ras Abu Ali Island. 
Impact of soil management on the quantity and quality of soil organic matter (SOM) and its microbiome.
Authors: Gismero-Rodríguez Laura , Valverde Ángel , Gómez José A. , Meurer Katharina H. E. , Knicker Heike
Published: February 2023

In the current context of global change and soil desertification, soil organic matter (SOM) plays an important role as carbon (C) sink, but also for maintaining soil fertility and soil functions. Quantity and quality of SOM depend largely upon soil management strategies that also affect microbial activity and diversity. In the present work we aim to obtain a better understanding of the interrelationship between SOM pools, microbial activity and diversity, and management of agricultural soils. To achieve this, we selected soils along a European gradient managed with and without catch crops, as well as soils with and without cover crops from an olive plantation close to Seville (Spain). The samples of the latter were taken from the top soil of the inter tree lanes managed with and without conventional tillage. For comparison, soils of the tree line treated with herbicides were also included in the study. The SOM composition of these soils will be characterized by solid-state NMR spectroscopy and related to its biochemical recalcitrance determined from the CO2 production during a controlled microcosm experiment of at least 2 month (Respicond Apparatus IV). Soil microbial biomass C and N will be analysed by the chloroform fumigation-extraction method; whereas microbial composition and biomass and microbial activity will be performed using phospholipid fatty acids (PLFA) analysis and extracellular enzymatic essays, respectively. We hypothesisized that higher plant diversity increases SOM quantity and quality, which has a positive impact on soil microbial diversity and activity.Acknowledgement: This work is financed by the project EJP Soil/Energylink, which received funding through the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 862695 and Tudi, GA 101000224, also of the H2020 program.
Energy Spectra and Cascades in the Global Ocean: Planetary Scales to Mesoscales, Surface to the Abyssal Ocean
Authors: Storer Benjamin , Buzzicotti Michele , Khatri Hemant , Griffies Stephen , Aluie Hussein
Published: February 2023

Our understanding of the ocean’s spatial scales and their coupling has been derived mostly from Fourier analysis in small "representative" regions, typically a few hundred kilometers in size, that cannot capture the vast dynamic range at planetary scales. Using coarse-graining, we analyze a 1/12-degree reanalysis dataset on a range of spatial scales spanning more than three orders of magnitude, including both mesoscales and planetary scales. We present a truly global kinetic energy wavenumber spectrum, as well as the first measurements of the cascade across this entire range of scales. This provides us with the first estimates of the global amount of energy that is transferred by the KE cascade, as well as the scale-dependent depth structure of the oceanic KE spectrum and cascade. We find that within the mesoscales, the seasonal cycles of KE at larger length scales demonstrate a characteristic lag time relative to smaller length scales. The seasonal cycle of the inverse energy cascade exhibits the same lag time but is phase-shifted to earlier times, which suggests causality.
Characteristics of cluster mode particle number concentrations in India
Authors: Sebastian Mathew , Kanawade Vijay P
Published: February 2023

The dynamics of atmospheric aerosols is governed by the spatio-temporal variability in the particle number size distributions. Atmospheric new particle formation begins with the formation of the cluster mode (sub-3nm) particle number concentrations followed by their growth to large sizes in the atmosphere. Here, we used three years (2019-2022) particle number size distribution measurements in the size range from 1 to 3 nm from nano Condensation Nucleus Counter (nCNC) in Hyderabad, India. The distinct seasonal variation was observed in size-segregated cluster mode particle number concentrations, with the highest concentrations in spring (March-May) and the lowest concentrations in winter (December-February). The seasonal variability is strongly linked to the factors affecting cluster mode formation such as planetary boundary layer evolution, temperature (oxidation extent), pre-existing particles (coagulation sink), etc. The calculated sulfuric acid proxy is strongly correlated with cluster mode particle number concentrations and formation rates, indicating the important role of sulfuric acid in aerosol nucleation. The formation rate and growth rate of cluster mode particles were also the highest during spring than winter. Our analysis further revealed that cluster mode number concentrations were the highest at low particulate matter less than 2.5 µm (PM2.5) while it was the lowest at high PM2.5 levels, indicative of the efficient scavenging of cluster mode particles by large-size pre-existing particles. We have also used PARticle Growth And Nucleation (PARGAN) inversion model to estimate the formation rate and growth rate from particle size distribution measurements in the size range from 10 nm to 560 nm. We found that the estimated formation and growth rates from PARGAN model were compared with the measured formation and growth rates from nCNC, within the uncertainty levels. This underlines the applicability of PARGAN inversion model for estimating cluster mode formation and growth rates where such measurements are not available, particularly in India.
From 3D digital outcrops to fluid flow reservoir simulations in a deltaic system: An integrated approach
Authors: Mas Perrine , Bourillot Raphaël , Brigaud Benjamin , Deschamps Rémy , Saint-Bezar Bertrand
Published: February 2023

The construction and interpretation of digital outcrop models (DOM) from outcropping reservoir analogues enable to capture and characterize reservoir heterogeneities (in terms of facies, diagenesis, and petrophysical properties) from centimeter to kilometer scales, thus allowing to improve upscaling approaches in 3D reservoir modeling. Digital outcrop models offer a reliable tridimensional representation of sedimentary heterogeneities, which can strongly impact fluid flow and therefore geothermal reservoir exploitation. The Roda Sandstones (Lower Eocene) are considered as a world-class outcropping example for deltaic sedimentary systems outcropping in the Graus-Tremp Basin (South Pyrenean Basin). Thanks to the quality of its outcrops and to the drilling of 50 to 80-meter-long cores in their vicinity, the Roda Sandstones are commonly used for educational and research purposes (Crumeyrolle et al., 1992; Martinius, 2012). Over the past 15 years, a few digital outcrop models have been published from the Roda Sandstones (Enge et al., 2007; Leren et al., 2010). These models were only constructed at a small scale (decimeter to hectometer) and did not allow to capture the large-scale architecture of the Roda fluvio-deltaic system. In this study, we built a complete photogrammetric model of one of the prograding sand wedges of the Roda Sandstones (also called Y body) from more than 11000 photos acquired by drone. The model is accurately georeferenced thanks to a dGPS campaign carried out simultaneously with the drone acquisitions. This outcrop model covers a total area of about 4km², and the pixel resolution ranges between 3 mm and 3 cm. A significant amount of quantitative and qualitative information could be extracted from this digital outcrop model, that helps at constraining the reservoir model. Its interpretation in a software dedicated to the geological interpretation of DOMs enabled to take measurements (e.g., dips, distances, etc.), to identify and to trace the main stratigraphic surfaces, locate the field observations and samples, allowing to precisely assess the architecture and the facies distribution of the Y sandbody. The results show a multiphase sandbody, made up of different prograding lobes, with variable progradation directions and a diversity of sedimentary structures formed by the competition between fluvial and tidal currents, contributing to the complexity of the sedimentary system. Paleocurrent directions, sediment thicknesses, numerical outcrops painted in facies, digitized sedimentological sections, and boreholes interpreted in facies were used as input data to build a static facies model. The geological static model was then filled with porosity and permeability properties and used as a base for fluid flow simulations in order to assess the impact of sedimentary heterogeneities in deltaic reservoirs for geothermal exploitation purposes.
Faunal and Environmental Changes Across The Cretaceous–Paleogene Boundary (KPB): Testimonials From Tethys 
Authors: Karabeyoglu Uygar , Spangenberg Jorge , Regelous Marcel , Adatte Thierry
Published: February 2023

Embracing two cataclysmic events (i.e., the Deccan volcanism and the Chicxulub impact) in a very short time, the K/Pg boundary (KPB) event has a unique standing amongst the big five major extinctions in Earth’s history. In this context, environmental and ecological outcomes of the Deccan volcanism before the Chicxulub impact require an elaborative undertaking to better comprehend the relationship between volcanic eruptions and associated environmental stress. Hence, here we documented this interplay in terms of high-resolution quantitative species analysis coupled with geochemical and isotopic data on three Tethyan localities from the Mudurnu-Göynük and the Haymana basins of central Anatolia (Turkey), and the Bottaccione section of Gubbio (Italy).

Throughout the late Maastrichtian, our δ13C measurements in the Haymana Basin show cyclical patterns highlighting the effects of precession cycles on the δ13C record. Remarkably, each cycle terminates by a less stratified ocean (i.e., similar benthic and planktonic δ13C values), and with a cooling spike (i.e., a positive shift in δ18O values).

On the other hand, we detected that an acceleration on planktonic foraminiferal species diversity loss just before the KPB during which there is a concomitant acceleration on drop of the magnetic susceptibility. These phenomena illustrate that there was an already-existed environmental stress before the KPB.

Apart from these findings, the KPB itself is characterized by a 2-3 mm-thick reddish oxidized layer hosting: a sudden annihilation of large, ornamented ecological specialists (e.g. globotruncanids, racemiguembelinids, planoglobulinids), a Hg peak, and enrichments in Ir, Te, Ba, Ni, Cr and Co. Among which Hg shows a good correlation with Te implying that the latter can be used as another proxy for volcanic activity.

Overall, our detailed paleontological, isotopic, and geochemical records show that the deteriorating effects of Deccan volcanism had already started before the Chicxulub impact which predisposed faunas to eventual extinction at the KPB.