bluuebunny/crossref_metadata_2025 huggingface dataset:
Neural Networks for Surrogate Models of the Corona and Solar Wind
Authors: Barros Filipa , Lima João José Graça , F. Pinto Rui , Restivo André
Published: March 2024

In previous work, an Artificial Neural Network (ANN) was developed to automate the estimation of solar wind profiles used as initial conditions in MULTI-VP simulations. This approach, coupled with profile clustering, reduced the time previously required for estimation by MULTI-VP, enhancing the efficiency of the simulation process. It was observed that generating initial estimates closer to the final simulation led to reduced computation time, with a mean speedup of 1.13. Additionally, this adjustment yielded a twofold advantage: it minimized the amplitude of spurious transients, reinforcing the numerical stability of calculations and enabling the code to maintain a more moderate integration time step.However, upon further analysis, it became evident that the physical model inherently required a relaxation time for the final solution to stabilize. Therefore, while refining initial conditions offered improvements, there was a limit to how much it could accelerate the process. Consequently, attention turned towards the development of a surrogate model focused on the upper corona (from 3 solar radii to 30 solar radii). This range was chosen because the model can avoid learning the initial phases of wind acceleration, which are hard to accurately predict. Moreover, in order to connect the model to heliospheric models and for space weather applications, more than 3 radii is more than sufficient and guarantees that the physics remain consistent within the reproducible domain.This surrogate model aims at delivering faster forecasts, with MULTI-VP running in parallel (eventually refining the solutions). The surrogate model for MULTI-VP was tested using a heliospheric model and data from spacecraft at L1, validating its efficacy beyond Mean Squared Error (MSE) evaluations and ensuring physical conservation principles were upheld.This work aims at simplifying and accelerating the process of establishing boundary conditions for heliospheric models without dismissing the physical models for both extreme events and for more physically accurate results. 
Ground-based radar observations of deep convective clouds over Naqu, Qinghai–Tibet Plateau
Authors: Zheng Dong , Fan Penglei , Zhang Yijun , Yao Wen
Published: March 2024

The analysis of deep convective clouds (DCCs, with 20 dBZ echo tops exceeding 14 km) and intense DCCs (IDCCs, with 40 dBZ echo tops exceeding 10 km) over Naqu, a city featuring the most active thunderstorm and lightning in the central Qinghai–Tibet Plateau (QTP), was carried out using data collected from the Naqu C-band radar within a 100 km radius. This approach stands in contrast to previous studies that heavily depended on satellite-based radar data. The geographical distribution of DCCs appears to be influenced by the topography. Regions characterized by the highest frequency of DCCs align with specific hilly areas, while the ratio of IDCC to DCC is higher in certain flat areas. This phenomenon could be attributed to the hilly topography favoring the initiation of convection but hindering to the full accumulation of unstable energy. The DCCs (IDCCs) display average 20, 30, and 40 dBZ echo tops at approximately 15.8 (16.5), 12.3 (14.1), and 9.9 (11.3) km, respectively. The average areas of regions featuring composite reflectivity greater than 20, 30, and 40 dBZ measure approximately 120.3 (196.1), 37.4 (75.3) km², and 9.2 (14.6) km², respectively. The maximum reflectivity and horizontal extents of 20 and 30 dBZ radar echoes tend to occur at levels around –20 ℃. Remarkably, the average horizontal extent of the 20-dBZ area for DCCs is one order of magnitude lower than the value suggested by satellite-based radar data. In the diurnal variations of vertical and horizontal extents of DCCs, parameters associated with 30 dBZ exhibit slower increases and more rapid decreases than those linked to 20 dBZ in the afternoon. This phenomenon is attributed to the generally weak convection characteristics of DCCs in Naqu. A supplementary analysis of lightning data using a local 3-D total lightning location array indicates that the horizontal extent of lightning channels approximately matches the equivalent diameter of the area with radar echoes surpassing 30 dBZ. This observation resonates with our experience conducting lightning observation experiments in Naqu and lends support to the earlier speculation that the charge region within QTP thunderstorms should maintain a relatively intact distribution rather than being fragmented.
Impact of pre-existing structures on the emplacement and post-intrusion deformation of the Late Jurassic rift-related Notre Dame Bay Magmatic Province, Newfoundland, Canada
Authors: Keefe Emma , Peace Alexander , Guna Ai Gusti , McCausland Philip
Published: March 2024

In this field-based study, we investigate the Notre Dame Bay Magmatic Province (NDBMP) located in the Dunnage Zone, north-central Newfoundland, Canada. The NDBMP is a collection of rift-related intrusions dated at ca. 148 Ma (Late Jurassic, Tithonian), including the gabbroic Budgell Harbour Stock (BHS) and an associated lamprophyre dyke swarm. The host rock, composed of Ordovician-aged sedimentary and volcanic back-arc sequences, is metamorphosed to greenschist and locally amphibolite facies. The host rocks were deformed during the Ordovician-Silurian closure of the Iapetus Ocean. The primary Iapetus suture divides peri-Laurentian and peri-Gondwanan terranes in the Newfoundland Appalachians, and forms a Z-shaped flexure across the study area.Our research focuses on three primary aspects: 1) investigating the relationship between pre-existing orogenic structures and rift-related magmatism, 2) assessing the impact of this magmatism on the host rock, and 3) analysing the post-intrusive deformation of lamprophyres. The dataset includes 178 structural measurements of lamprophyres, and host rock structures, petrographic analysis of thin sections of the BHS, lamprophyres, and host rocks, and 3D structural models created from drone-based photogrammetry for selected outcrops.Our findings indicate that structures dating from the Ordovician to Silurian, associated with the Iapetus suture and Notre Dame Bay oroclinal flexure, significantly impacted the location and pathways of magmatism. This influence occurred at local scales, where dykes were deflected along bedding, foliation, and fold hinges, and on a larger scale along the Iapetus Suture. Additionally, multiple instances of magmatism affecting the host rock, including fracturing occurring subparallel to dykes, hydrothermal alteration, and brecciation were observed. Our investigation also identified three instances where dykes underwent brittle and ductile deformation due to the reactivation of pre-rift south-east dipping thrust faults with an oblique dextral motion towards the northeast. This movement is consistent with the direction of extensional forces the region experienced during Mesozoic rifting.Preliminary findings suggest that the reactivation of these Ordovician-Silurian thrust faults reflect larger scale transtensional reactivation of the Iapetus suture zone during Mesozoic rifting and opening of the Atlantic Ocean. These results enhance our understanding of structural inheritance, which is essential for accurately modelling rifting processes and reconstructing the opening of the North Atlantic Ocean.
Simulating Atmospheric Dust With a Global Variable-Resolution Model: Model Description and Impacts of Mesh Refinement
Authors: Feng Jiawang , Zhao Chun , Du Qiuyan , Xu Mingyue
Published: March 2024

In this study, a global variable-resolution modeling framework of atmospheric dust and its radiative feedback is established and evaluated. In this model, atmospheric dust is simulated simultaneously with meteorological fields, and dust-radiation interactions are included. Five configurations of global mesh with refinement at different resolutions and over different regions are used to explore the impacts of regional refinement on modeling dust lifecycle at regional and global scales. The model reasonably produces the overall magnitudes and spatial variabilities of global dust metrics such as surface mass concentration, deposition, AOD, and radiative forcing compared to observations and previous modeling results. Two global variable-resolution simulations with mesh refinement over major deserts of North Africa (V16km-NA) and East Asia (V16km-EA) simulate less dust emissions and smaller dry deposition rates inside the refined regions due to the weakened near-surface wind speed caused by better resolved topographic complexity at higher resolution. The dust mass loadings over North Africa are close to each other between V16km-NA and the quasi-uniform resolution (~120km) (U120km), while over East Asia, V16km-EA simulates higher dust mass loading. Over the non-refined areas with the same resolution, the difference between global variable-resolution and uniform-resolution experiments also exists, which is partly related to their difference in dynamic time-step and the coefficient for horizontal diffusion. Refinement at convection-permitting resolution around the Tibetan Plateau (TP) simulates less dust due to its more efficient wet scavenging from resolved convective precipitation around the TP against coarse resolution.
A Multiscale Analysis of a Nocturnal Extreme Rainfall Event of 14 July 2017 in Northeast China 
Authors: Wang Gaili
Published: March 2024

A Multiscale Analysis of a Nocturnal Extreme Rainfall Event of 14 July 2017 in Northeast China  Gaili Wang1, Da-Lin Zhang2,1, and Jisong Sun11State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Science, Beijing, China46 South Street Zhongguancun, Beijing, China 1000812 Department of Atmospheric and Oceanic Science, University of Maryland, College Park, College Park, Maryland AbstractA multiscale observational analysis of a nocturnal extreme rainfall event that occurred at Changtu in Northeast China on 14 July 2017 is performed using global analysis, automated surface observations, Doppler radar, rawinsonde and disdrometer data. Results show that the large-scale environment was characterized by high convective available potential energy and precipitable water, moderate convective inhibition, and a southwesterly low-level jet (LLJ) capped by an inversion layer. The first and subsequent convective cells developed along a quasi-stationary surface convergence zone in a convection-void region of a previously dissipated meso-a-scale convective line. Continuous convective initiation through backbuilding at the western end and the subsequent merging of eastward-moving convective cells led to the formation of a near-zonally oriented meso-b-scale rainband, with reflectivity exceeding 45 dBZ (i.e., convective core intensity). This quasi-stationary rainband was maintained along the convergence zone by the LLJ of warm-moist air, aided by local topographical lifting and convectively generated outflows. A maximum hourly rainfall amount of 96 mm occurred during 0200-0300 BST as individual convective cores with a melting layer of >55 dBZ reflectivity moved across Changtu with little intermittency. The extreme-rain-producing stage was characterized with near-saturated vertical columns, and rapid number concentration increases of all raindrop sizes. It is concluded that the formation of the meso-b-scale rainband with continuous convective backbuilding, and the subsequent echo-training of convective cores with growing intensity and width as well as significant fallouts of frozen particles accounted for the generation of this extreme rainfall event. This extreme event was enhanced by local topography and the formation of a mesovortex of 20~30 km in diameter.
Parameterization Solutions for Basal Melting at the Grounding Line in Ice Flow Models
Authors: Wang Yu , Zhao Chen , Gladstone Rupert , Zwinger Thomas , Galton-Fenzi Ben , Christoffersen Poul
Published: March 2024

Recent studies have indicated that the migration of grounding line is extremely sensitive to basal melt in the grounding zone. Different representations of melting at the grounding line introduce significant uncertainties in predictions of ice mass loss and global sea level rise. However, there remains an absence of targeted, systematic studies grounded in real-domain, and robustly representing melt in partially floating cells of ice sheet models remains a pressing technical challenge. This study delves into four distinct melt schemes at the grounding line within the Wilkes Subglacial Basin (WSB) model, focusing on their impact on ice loss predictions. Specifically, we analyse the No Melt Parameterization (NMP), Full Melt Parameterization (FMP), and two variants of the Sub-Element Melt parameterization (SEM1, SEM3) as applied to partially floating elements at the grounding line. We found that both the SEM and NMP schemes outperform FMP in terms of convergence with finer mesh resolution, with each exhibiting varying advantages over the other.  Notably, the discrepancies in results attributed to various melt schemes are significantly amplified when high melt rates are applied near the grounding line. Our results consistently suggest that the FMP should be avoided under all circumstances due to its poor convergence and substantial overestimation of ice mass loss. We recommend that future ice sheet models carefully evaluate the choice between NMP and SEM in their specific model contexts.
Response of the Yellow and East China Seas ecosystems to two typhoons with different translational speeds in the northwestern Pacific
Authors: Wang Yucheng , Zhang Jing
Published: March 2024

The Yellow and East China Seas (YECS) are semi-enclosed marginal seas that are one of the most vulnerable regions to typhoons in the world. Frequent typhoons can significantly change the temperature, nutrients, and phytoplankton biomass in the YECS. The oceanic response to typhoons is usually influenced by the features of the typhoon, among which, the translational speed is of critical importance. Using a high-resolution coupled physical-ecological model, we investigated the response of the YECS to two typhoons with different translational speeds, Muifa in August 2011 and Bolaven in August 2012, during their northward translation in the YECS. The results show that the typhoon with slower translational speed uplifts more deep water in the YECS, leading to a more significant response of the ocean. The effects of horizontal convection on ecological elements during typhoons should not be ignored. Horizontal advection caused the flow of nutrients in the surface and bottom layers in opposite directions, but the flow of chla in the same direction. At the same time, the flux of nutrients in the bottom layer is more than that in the surface layer, while the opposite is true for chla. These phenomena are closely related to the spatial distribution of nutrients and chla. Further studies have shown that the degree of ocean response to typhoons is also highly correlated with the initial levels of physical and ecological elements of the ocean before the typhoon, as well as with ocean structure. Pre-typhoon initial levels of ocean physical and ecological elements, mixed layer depth (MLD) and Potential Energy Anomaly (PEA) can all alter the degree of typhoon-induced ocean response. This study emphasizes the important roles of the translational speed of typhoons and the initial oceanic condition in the oceanic response to typhoons.
Late Neogene hydrothermalism in the Central Oman Mountains
Authors: Scharf Andreas , Bolhar Robert , Uysal Tonguc , Mattern Frank , Callegari Ivan , Bozkaya Gülcan , Baublys Kim
Published: March 2024

The Jabal Akhdar Dome of the Central Oman Mountains provides insights into the autochthonous Neoproterozoic to Cretaceous Arabian rocks. A superbly exposed outcrop of the dark carbonate Ediacaran Hajir (or Khufai) Formation displays NW/SE-trending, non-plunging tight folds and SW thrusts. As the Permo-Mesozoic rocks lack this deformation pattern, the folds/faults are inferred to have formed during the Infracambrian Cadomian Orogeny. White calcite veins in fold hinges and within faults/calcmylonites provide U-Pb ages of 8.95 ±0.92, 7.71 ±1.44, 5.91 ±2.92, 4.89 ±6.1, 2.41 ±1.46 and 2.03 ±0.78 Ma (all 2 SE). These ages do not match the field observation, indicating that pre-existing Cadomian(?) calcite veins were overprinted at a later stage. Geochemically, almost all carbonates from the veins display strongly positive Eu values in shale normalization ([Eu/(0.5*Sm+0.5*Gd]MUQ=1-8.4) indicative of precipitation from hydrothermal fluids at temperatures >200-250°C under non-oxidizing conditions. The δ13C and δ18O values of the limestone host rocks range between +3.93‰ to +5.93‰ and between +19.8‰ to +23.3‰, respectively. In contrast, vein calcites show considerably higher δ13C values, varying between +5.85‰ to +7.01‰ and slightly lower δ18O values from 16.5‰ to 20.7‰. Fluid inclusion homogenization temperatures of vein calcite suggest two phases of precipitation, with values of 125-150°C and 160-260°C. Based on fluid inclusion data, two phases of fluid entrapment can be discerned, consistent with two different calcite generations or recrystallization events. Stable isotope data seem to be a product of one calcite precipitation or recrystallization event, rather than a mixture of two different generation, because δ18O values of vein calcites define a fairly narrow range, requiring precipitation from fluids at similar temperatures and oxygen isotope compositions, during a time of similar palaeohydrological conditions. Fluid inclusions from primary inclusions in calcite indicate relatively high temperatures (at ~225°C) and are possibly a product of the fluid-flow event in response to the Cadomian Orogeny. Since the U-Pb isotopic system of the calcites was reset, providing late Cenozoic ages (
Investigation of natural hydrogen and helium in the Bohai Bay Basin, China: insights from Earth's spheres interactions
Authors: Wei Yongbo , Liu Quanyou
Published: March 2024

Non-alkane gases such as H2, He, CO2, and H2S were often found in natural gas exploration in the lithospheric surface layer. Among them, H2 and He are widely distributed in deep and shallow geologic systems of the earth as green energy and scarce strategic resources, respectively. Undoubtedly, their resources are huge, and their exploration and development are getting more and more attention recently. However, natural H2 and He resources in the Earth's tectonically active regions are rarely mentioned. Considering the origin of H2 and He, the study of H2 and He resources in geological systems needs to explore the formation and distribution regularities from the perspective of the Earth's inner-spheres interactions, and to select favorable exploration areas. The Bohai Bay Basin is located at the subduction front of the Western Pacific Plate, with frequent interactions between the Earth's inner spheres, and shows H2 and He resources. It was found that the He-rich reservoirs in the Bohai Bay Basin are of crust-mantle complex genesis and have a sizeable contribution of mantle-sourced He (maximum 82.06%). The release of He from the deep mantle source into the shallow basin accumulation resulted in the highest He content (30,800 ppm) in the Huagou area. Natural H2 from the Bohai Bay Basin has a complex genesis and may be mainly produced by the serpentinization of mafic-ultramafic rocks from within the crust. Hydrogen isotope thermometer demonstrates that the temperature range of H2 formation is wide, ranging from 10 to 165°C, encompassing H2 from all over the world with a variety of genesis. Boxing Sag in the Bohai Bay Basin is a potential resource distribution area for H2 and He (especially 3He) due to the high frequency of deep magmatic volcanism, the development of deep faults, and superior preservation conditions. This work is important for the investigation of natural H2 and He resources in the tectonically active regions of the Earth, where there is frequent material-energy communication between the deep and the shallow.
Defining Arctic Stratospheric Polar Vortex Intensification Events
Authors: Huang Jinlong , Hitchcock Peter
Published: March 2024

 Using the ERA5 reanalysis data, we identify seven easily calculable indices of the strength of theArctic stratospheric vortex: zonal winds at 10 hPa and temperature or height anomalies at 10 , 50, and 100 hPa.We then compare the climatological statistics and meteorological properties of strong and weak events basedon these indices. We particularly consider the sensitivity of the event statistics to the choice of thresholds, theuse of these indices in capturing stratosphere–troposphere coupling, and meteorological conditions relevant tochemical ozone depletion. The frequency, seasonal distribution, and interdecadal variability of strong eventsis more sensitive to threshold or index choice compared to weak events. Composites of polar-cap geopotentialheight anomalies are found to differ significantly based on the choice of index. In particular, height-basedevents reveal a strong and immediate barotropic response near the central date due to surface pressurefluctuations, making it more difficult to regard central dates of height-based events as purely stratosphericin origin. We further characterize the relationship of all indices to conditions relevant to chemical ozonedepletion, finding that temperature-based indices in the lower stratosphere perform best. Finally, we presentfour dynamical benchmarks used to assess and compare the representation of strong events in climate models.Our results highlight the challenges in determining the optimal definition for strong events and emphasizethe implications of different choices, providing valuable insights for guiding future studies in defining strong events. 
Long-term changes and impacts of nutrient addition to vegetation and CO2 fluxes at ombrotrophic Mer Bleue Bog, Canada
Authors: Larmola Tuula , Bubier Jill , Liski Eero , Kostensalo Joel , Moore Tim , Antila Jani , Humphreys Elyn , Juutinen Sari
Published: March 2024

To study long-term impacts of nutrient addition on carbon sequestration capacity, we investigated changes in vegetation and ecosystem CO2 exchange at Mer Bleue Bog, Canada in plots that had been fertilized with nitrogen (N) or with N plus phosphorus (P) and potassium (K) and in non-fertilized control plots for 13-18 years. The vegetation structure and species composition were measured in all treatments mid July 2001-2018 (14 measurement years) using a point intercept method. Gross photosynthesis, ecosystem respiration, and net CO2 exchange were measured weekly during June–August 2001-2016 (7 measurement years, usually every two years) using climate-controlled chambers. Using Bayesian approach, we analyzed whether there were changes over time in vegetation and ecosystem CO2 exchange and whether those trends differed between treatments. We found that shrubs had become taller and more abundant at the unfertilized plots during the 18 study years likely owing to warmer summers and a drying trend that favor shrubs. At the fertilized plots, the increase in shrub height was greater and faster than in unfertilized plots, and the addition of PK with N further accelerated growth of the shrub canopy. Among the dwarf shrubs, only Chamaedaphne calyculata benefitted from the fertilization. No change towards more gramineous vegetation was observed. Because the plants at the bog are N-P co-limited rather than N-limited, PK addition alleviated growth limitation. Sphagnum cover decreased with the increasing nutrient load. Ecosystem respiration increased in all treatments, but it increased faster and more in fertilized plots than in unfertilized plots. In all treatments, increases in ecosystem respiration resulted in less net CO2 uptake during the recent ten years (since 2008), because gross photosynthesis rates did not compensate for increases in ecosystem respiration. In general, the magnitude of this trend of reduced net C sink potential did not differ markedly in unfertilized from fertilized plots. These CO2 flux trends could be explained by changes in nutrient availability, a larger proportion of nongreen biomass in dense stands and enhanced peat decomposition. Our long-term field experiment revealed that ecosystem responses to the combination of nutrient addition and drying must be considered when evaluating the impact of climate change on the carbon sink potential of peatlands.
Imaging of Main Himalayan Thrust in Central Seismic Gap using seismic interferometry  
Authors: Ali T S Saneesh , Gupta Sandeep , Kumar Sudesh , Sivaram Krishnavajjhala , Rawat Vishal
Published: March 2024

The Main Himalayan Thrust (MHT) demarcates the boundary between the underthrusting Indian Plate and the overriding Himalayan orogeny. Stress accumulation on the MHT due to the underthrusting of the Indian Plate leads to the occurrence of bigger earthquakes in the Himalayas. It is, therefore, imperative to understand the MHT's geometry in different Himalayan segments. Furthermore, how this geometry varies along the Himalayan arc while taking into account the uneven distribution of earthquakes offers a comprehensive insight into earthquake nucleation in the region. The central seismic gap is one of the most significant segments of the Himalayas, which is considered a potential region for the proposed great earthquake in the future. This study focuses on defining the MHT geometry by constructing a 3-D model within the central seismic gap using the seismic interferometry technique.  We analyzed the data sets obtained from 159 broadband stations spread across the area to construct a comprehensive three-dimensional geometry of MHT. The different arc normal cross-sections highlight variations in the MHT's geometry along the arc in the central seismic gap.Keywords: Main Himalayan Thrust, seismic interferometry, central seismic gap, crustal imaging.
Introduction of ATES and its Activities 
Authors: Ai Likun
Published: March 2024

Ancient Silk Road was a network of trade routes from Central China to the Pamir, through Central Asia and Arabia to India and Rome. Silk Road has served as a bridge fostering the exchange of diverse civilizations between the West and East across Eurasia. Stretching over 6,400 kilometers, the Silk Road covers vast terrains of the Gobi deserts, oases, high mountains, basins, forests, and steppes across Eurasia. The natural characteristics of the Silk Road render it one of the most vulnerable regions to climate and human-induced changes. The Asscoiation for Trans-Eurasia Exchange and Silk Road Civilization Development (ATES) was launched in 2019 to deepen understanding of the interaction between environmental changes, long-term trans-Eurasia exchanges and Silk Road civilization, by promoting interdisciplinary research of natural sciences, social sciences, and humanities across Eurasia. The interdisciplinary  study promoted by ATES will provide valuable insights into environmental, social and economic interactions, that can support the national and local climate change adaptation strategies, and build a climate resilience society from comprehensive historical, cultural and environmental viewpoints.
 
The strength and soil water characteristics for subsurface clays under low suction
Authors: Dafalla Muawia
Published: March 2024

A firm standing ground is always required for vehicles to move around in areas of green parks or vegetations zones where access is needed. Expansive soils or landfill cover materials include smectite-rich mineral soils which are sensitive to water. Saturated and near-saturated soils are normally of low shear strength and may not be capable of supporting pavements or traffic loads. The type and constituents of soil play a significant role in determining the appropriate top layer to be used for this purpose. Granular components which include sand and fine gravel play a significant role in providing the required subgrade strength. Soil water characteristic curves predicted for Tabuk clays are compared to the clay slurry behaviour under low suction. Clay sand mixtures compaction characteristics were examined to establish the maximum dry density and optimum moisture content. Stress partitioning between clay and sand concept is used to recommend an appropriate clay sand mixture for top layers or access roads over muddy ground. Landfill cover layers are generally intended to support plants, grass and shallow root vegetation. When water is introduced in a flooding mode to a landfill cover or a top clayey ground, it is likely to cause the fine material to lose strength, wash away or show excessive settlement.
The competing effect of aerosols on stratiform mixed-phase clouds
Authors: Villanueva Diego
Published: March 2024

Due to limited in-situ observations, spaceborne retrievals of cloud top phase are often used to study the behaviour of mixed-phase clouds and their sensitivity to aerosols. By stratifying 35 years of cloud observations by temperature and cloud thickness, we gained valuable insights into the interplay between aerosols and mixed-phase clouds.First, there is evidence that the ice-to-liquid frequency (ILF) is dominated by two sources of cloud ice: For thin clouds, a cirrus-origin due to ice sedimentation from temperatures colder than -38 dgC, and for thick clouds, a glaciation-origin due to aerosol-driven droplet freezing. These different sources of ice may explain differences in the ILF from different retrieval methods. For example, active instruments, which are more sensitive to thin cirrus, may estimate a higher ILF compared to passive instruments, which are more sensitive to thick clouds.Second, we find that in extratropical thick mixed-phase clouds, aerosols have two dominant effects on the ILF: For liquid clouds, aerosols increase cloudiness at warm temperatures, but they decrease cloudiness at cold temperatures. Our results suggest that precipitation inhibition (by increasing the number of droplets) and enhanced cloud glaciation (by increasing the rate of droplet freezing at cold temperatures) can explain this behaviour. As a result, we find that the indirect effect of aerosols through mixed-phase clouds is strongly temperature dependent.Third, at cold temperatures, both dust aerosol and organic aerosols are temporally correlated with higher ILF on a monthly basis. Spatially, this correlation coincides with regions downwind of deserts and highly biologically productive regions in the ocean. We also find that the ILF increases logarithmically with increasing aerosol concentrations, at a rate consistent with the behaviour reported from laboratory studies. Thus, for the first time, we provide a link between laboratory studies of droplet freezing and space-based studies of cloud glaciation.
Trends and drivers of the soil organic carbon stocks along the urban-rural gradients globally
Authors: Xu Fangjin , Li Shuangcheng
Published: March 2024

The land use changes and environmental pollution brought by urbanization are important aspects of global change. Cities provide a unique "natural laboratory" for people to understand the impact of human-nature composite ecosystems on global change and their response processes. Unlike natural soils, human activities during urbanization directly or indirectly affect the formation and development of soils. Generally, urban soils have a higher organic carbon content compared to agricultural soils and some natural soils, making them an important carbon reservoir in urban ecosystem carbon cycles. The urban-rural gradient method based on urbanization intensity provides a possibility for studying the response of Soil Organic Carbon (SOC) storage to urbanization on a global scale. Here, we define Urban Intensity (UI) as the proportion of impervious surface area within each 1x1 square kilometer (ranging from 0 to 100%). We first analyzed the trends of SOC storage along the UI gradient globally and in different climate zones, distinguishing the contributions of natural and socio-economic factors through multiple linear regression and residual quantification. The study found that as UI increases, SOC storage undergoes phased changes, with natural and socio-economic factors contributing differently in each urbanization stage and climate zone. For example, globally, when UI is low (UI ≤ 0.25) and high (0.75 < UI ≤ 1), SOC storage tends to decrease with increasing UI, while at medium intensity (0.25 < UI ≤ 0.75), SOC storage shows an increasing trend. Globally, changes in socio-economic factors (population, GDP) are the main drivers of SOC storage changes during urbanization. Particularly at low and medium urbanization intensities, socio-economic contributions reach 98% and 89%, respectively. However, as urbanization intensity increases, the driving role of natural factors becomes more apparent, contributing over 40% in areas of high urbanization intensity.
North Atlantic subtropical mode water formation controlled by Gulf Stream fronts
Authors: Yu Jingjie , Gan Bolan , Wu Lixin , Danabasoglu Gokhan , Small R. Justin , Baker Allison H. , Jia Fan , Jing Zhao , Ma Xiaohui , Yang Haiyuan , Chen Zhaohui
Published: March 2024

The North Atlantic Ocean hosts the largest volume of global subtropical mode waters (STMWs), serving as heat, carbon, and oxygen silos in the ocean interior. STMWs are formed in the Gulf Stream region where thermal fronts are pervasive with strong feedbacks to atmosphere. However, their roles in the STMW formation have been overlooked. Using eddy-resolving global climate simulations, we find that suppressing local frontal-scale ocean-to-atmosphere (FOA) feedback leads to STMW formation being reduced almost by half. This is because FOA feedback enlarges STMW outcropping, attributable to the mixed layer deepening associated with cumulative excessive latent heat loss due to higher wind speeds and greater air-sea humidity contrast driven by the Gulf Stream fronts. Such enhanced heat loss overshadows the stronger restratification induced by vertical eddy and turbulent heat transport, making STMW colder and heavier. With more realistic representation of FOA feedback, the eddy-present/rich coupled global climate models reproduce the observed STMWs much better than the eddy-free ones. Such improvement in STMW production cannot be achieved even with the oceanic resolution solely refined but without coupling to the overlying atmosphere in oceanic general circulation models. Our findings highlight the need to resolve FOA feedback to ameliorate the common severe underestimation of STMW and associated heat and carbon uptakes in earth system models.
Developing an African Climate Intervention Research Coalition
Authors: Lennard Chris , Abiodun Babatunde , Parker Andy
Published: March 2024

With the 1.5oC global warming target set to be breached in the next decade, and as the impacts of this warming across the world become more deleterious, Climate Intervention (CI) and in particular Solar Radiation Modification (SRM) will become the subject of global political discussion. While low latitude, developing countries have the most to gain or lose from CI and SRM, they are underrepresented in current discussions, however, decisions regarding development and implementation/rejection of SRM require that these countries be at the center of such conversations.Preparing the African voice for this discussion is essential and requires a well-resourced and well-connected African research community that understands the regional impacts of global warming and how CI may mitigate or exacerbate these impacts. While there are many SRM research projects around Africa facilitated by the DEGREES Initiative, a coordinated CI research community does not yet exist.Here we present results from a project that aims to transition the current loose research network into a well-structured CI and SRM research coalition, nurturing an expert SRM community in Africa over the next 5-10 years.The main component of the project is a workshop that will bring together African CI and SRM researchers alongside representatives of the World Climate Research Programme, the Coordinated Regional Downscaling Experiment (CORDEX-Africa) and International African research institutions. The workshop will discuss how to build, grow, and sustain a coalition of African SRM researchers, considering its research and capacity-building activities, its initial composition, and its structure. The workshop will also develop an initial roadmap of activities for the coalition and consider potential funding sources to support it. Furthermore, we will explore using a research hub model as a vehicle through which the coalition, its activities and growth is supported.The insights and outcomes from these discussions will be synthesized into a white paper outlining the goals and principles of the coalition, with concrete recommendations for next steps. Key messages of the white paper will be presented in this session.The work is pioneering and entrepreneurial and we know of no other efforts like this. In fact, we believe this would be the first continental scale SRM research coalition in the world, let alone in the Global South.
Magnitude correlation exposes hidden short-term earthquake catalog incompleteness
Authors: Corrado Paola , Herrmann Marcus , Marzocchi Warner
Published: March 2024

Current models used for earthquake forecasting assume that the magnitude of an earthquake is independent of past earthquakes, i.e., the earthquake magnitudes are uncorrelated. Nevertheless, several studies have challenged this assumption by revealing correlations between the magnitude of subsequent earthquakes in a sequence. These findings could significantly improve earthquake forecasting and help in understanding the physics of the nucleation process.We investigate this phenomenon for the foreshock sequence of the first 2019 Ridgecrest event (Mw6.4) using a high-resolution catalog; choosing this foreshock sequence has been guided by a low b-value (~0.68 ± 0.06 after converting local magnitudes to moment magnitudes) and a significant magnitude correlation, even when considering only earthquakes above the completeness level estimated with different methods. To disregard incomplete events in the b-value estimation, we apply the b-positive approach (van der Elst 2021), i.e., using only positive magnitude differences; those magnitude differences are uncorrelated and we obtain a markedly higher b-value (~0.9 ± 0.1). Apparently, the foreshock sequence contained substantial short-term aftershock incompleteness due to a Mw4.0 event.We observe a similar behaviour for whole Southern California after stacking earthquake sequences. Finally, we generate synthetic catalogs and apply short-term incompleteness to demonstrate that common methods for estimating the completeness level still result in magnitude correlation, indicating hidden incompleteness.Our findings highlight that (i) existing methods for estimating the completeness level have limited statistical power and the remaining incompleteness can significantly bias the b-value estimation; (ii) the magnitude correlation is the most powerful property to detect incompleteness, so it should supplement statistical analyses of earthquake catalogs.
Effects of Water Stress on Spectral Reflectance of Potato Crop Grown in Open Field Conditions 
Authors: Maurya Alok Kumar , Pathak Amey
Published: March 2024

Potato belongs to the Solanaceae family, which is known for being highly susceptible to abiotic stress, particularly related to water. Understanding how and to what extent potato plants respond to different wavelengths of light is essential for gaining insights into soil water and plant water status, chlorophyll levels, and optimal timing for watering. Studying the spectral response of potato plants before and after irrigation, particularly focusing on agricultural management, resource optimization, and enhancing crop output. This study aimed to investigate the spectral characteristics of potato plants before and after irrigation, while plants are under varying soil-water conditions. This was achieved by implementing different irrigation schedules that maintained soil moisture levels at 25%, 50%, 65%, and 85% of the Maximum Allowable Depletion (MAD) of Available Soil Moisture (ASW). The plants' spectral responses were measured using a portable spectroradiometer. During the vegetative stage of the potato crop, plants treated with MAD50 and MAD25 experienced a slightly higher spectral reflectance in the green band spectrum before irrigation indicating healthy plants (Chlorophyll abundance). In general, MAD50-treated plants showed a higher spectral reflectance than plants treated with MAD25, MAD65, and MAD85 in the red-edge band (730-750nm) and NIR band spectrum. Furthermore, MAD85-treated plants exhibited higher spectral reflectance in all spectra than MAD65, MAD50, and MAD25-treated plants after irrigation. However, the red band (around 680nm) was almost saturated for all plants treated with MADs before and after irrigation, except MAD85-treated plants, after irrigation.  In addition, we have found the least variations in spectral reflectance of the MAD25 and MAD50-treated plants prior and post-irrigation. Whereas, MAD65 shows a spectral reflectance increase of +1.54-2.97% in the green band and +2.23-12.18% in the red-edge and NIR band after irrigation. Similarly, MAD85 exhibits a reflectance increase of +3.56-6.29% in the green band and +4.24-19.73% in the red-edge and NIR band after irrigation.  These findings highlight that optimum soil moisture is required for plants to be effective in MAD25 and MAD50 compared to the other delayed irrigation conditions. This research suggests an effective irrigation schedule to adapt in situations where adverse impacts of climate change, such as unpredictable water supply, water scarcity, and decreased irrigation expenses affects production. Assessing the baseline spectral response of crops before irrigation aids in detecting indications of water stress, while post-irrigation assessment helps determine whether the provided water has relieved stress and promoted robust plant development.Keywords: Potato crop, Spectral response, Handheld Spectroradiometer, Water-stress, Irrigation 
Estimating the Energy Flux of Internal Tides in the Northern South China Sea Using Underwater Gliders
Authors: Gao Zhiyuan , Chen Zhaohui , Huang Xiaodong , Yang Haiyuan , Wang Yanhui , Ma Wei , Luo Chenyi
Published: March 2024

The character of internal tides energy flux in the northern South China Sea (SCS) is explored through an analysis of a fleet of underwater gliders. It is found that the lower mode diurnal internal tides with ~300 km wavelength in the middle basin originate predominantly at the Luzon Strait (LS) and propagate over 1000 km to the western SCS. The semidiurnal internal tides, however, originate from multiple regions, including the LS, the continental shelf, and the islands in the west part. The energy flux of the mode-1 diurnal internal tides attenuated rapidly within 450 km of the LS and was less pronounced after that. The estimated dissipation rate based on the mode-1 energy flux is about 10-8 W/kg, underling the significant role of mode-1 diurnal internal tides in bolstering far-field mixing. This study provides a unique view of the spatial pattern, energy flux, and energy sink of the internal tides in the northern SCS, which could supplement the altimetry-based results and improve the parameterization in ocean models. 
Evaluating the efficacy of multitemporal TLS and UAS surveys for quantifying wind erosion magnitudes of sand dune topography
Authors: Bertalan László , Négyesi Gábor , Szabó Gergely , Túri Zoltán , Szabó Szilárd
Published: March 2024

Wind erosion constitutes a prominent land degradation process in regions of Hungary characterized by low annual precipitation. In these areas, it poses significant challenges to agricultural productivity and adversely impacts soil and environmental quality. Presently, human activities exert a more pronounced influence on the endangered areas of Hungary in comparison to climate-related factors. It is noteworthy that the wind erodibility of Hungarian soils not only poses a soil conservation challenge but also gives rise to economic ramifications, such as nutrient loss, as well as environmental and human health concerns. Within agricultural landscapes, wind erosion contributes to the removal and transportation of the finest and biologically active soil fractions, rich in organic matter and nutrients.High-resolution topographic surveys have become integral for assessing volumetric changes in sand dune mobility and mapping wind erosion. While Unmanned Aerial Systems (UAS) surveys have been extensively employed for erosion rates exceeding the decimeter scale, Terrestrial Laser Scanning (TLS) surveys have demonstrated efficiency in capturing more extensive negative erosional forms, even in a vertical orientation. To enhance the field of view, a mounting framework can be implemented to elevate the TLS. However, determining centimeter-scale material displacement in flat terrain conditions remains challenging and requires an increased number of scanning positions.To identify optimal settings for surveying centimeter-scale wind erosion magnitudes, we conducted combined multi-temporal TLS and UAS surveys at the Westsik experimental site near Nyíregyháza during the spring of 2023. This site features dune topography with a height of 6 meters. Our investigations encompassed various UAS image acquisition modes, involving different flight altitudes and camera settings, utilizing a DJI Matrice M210 RTK v2 drone and a Zenmuse X7 24 mm lens. Additionally, we generated diverse point clouds through various scanning scenarios using a Trimble X7 TLS device. In the data processing phase, we explored multiple co-registration algorithms to address the challenge of larger Root Mean Square Error (RMSE) in Digital Terrain Models (DTMs) from UAS Structure from Motion (SfM) compared to the actual wind erosion rates.---The research is supported by the NKFI K138079 project.
Teleseismic Traveltime Tomography of Sulawesi, Indonesia
Authors: Kesumastuti Lintang , Pilia Simone
Published: March 2024

Located in the eastern region of Indonesia, Sulawesi exhibits a distinctive K-shaped configuration due to the Cretaceous to present day tectonic interaction of the Indian-Australian, Sunda, and Philippine plates. This tectonic interaction has delineated two main tectonic provinces of Sulawesi: the Western Sulawesi Province, including the South and North Arms with large plutono-volcanic rocks generated during the Paleogene, and the Eastern Sulawesi Province, comprising the East and Southeast Arms characterized by the ophiolite complex and metamorphic belt emerging after the Early Miocene collision between the northern part of the Australian continental plate and the North Arm of Sulawesi. The present configuration of Sulawesi is attributed to the Sulawesi Orogeny, the attachment of eastern Sulawesi and Buton-Tukang Besi as well as Banggai-Sula Islands by subduction, accretion, and collision that led to the development of two major active tectonic structures in Sulawesi: the left-lateral Palu-Koro strike-slip fault to the west and the Celebes Sea subduction zone to the north.We present preliminary P-wave tomographic images of the crust and upper mantle beneath Sulawesi, obtained by exploiting teleseismic earthquake data. Passive-seismic data are recorded by approximately 89 seismic stations of the Agency for Meteorology, Climatology, and Geophysics (BMKG) network running from January 2020 to July 2023. We employ an adaptive stacking technique to extract relative P-wave traveltime residuals from nearly a thousand teleseismic events recorded across the network. The relative arrival-time residuals from first-arriving, core and reflected P phases are then utilized to map 3-D P-wave perturbations using an inversion technique implemented in FMTOMO.The final tomographic model reveals several distinct features, including a south-dipping, high-velocity anomaly beneath northern Sulawesi that we associated to the subducting slab of the Celebes Sea. 