bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of Enhanced Rock Weathering on Soil Organic Carbon Dynamics through Microbial Activity
Authors: Park Ye Lim , Hyun Junge , Ok Yejee , Yoo Gayoung
Published: March 2024

Enhanced Rock Weathering (ERW) is a method for capturing carbon dioxide from the atmosphere and turning it into inorganic carbon, which is then stored in soil or oceans. While ERW is typically acclaimed for its influence on inorganic carbon cycling, its interactions with soil organic carbon (SOC) - mainly formed through biological processes like plant and microbial activity - are less explored. This study aims to investigate the impact of ERW application on SOC dynamics, particularly through modifications in microbial activity. We tested two hypotheses: (1) The change in soil pH and micro-nutrient levels by ERW amendments could boost soil microbial activity, which then accelerate breakdown of easily decomposable SOC, and 2) Higher labile SOC content could increase SOC stabilization within soil aggregates or bound to minerals, which further contribute to an increase in long lasting SOC stock by ERW. In this study, to analyze SOC dynamics under the influence of ERW, we applied olivine, a common ERW material, to soil and conducted a four-month pot experiment with alfalfa. After experiment, soil samples from each pot were analyzed using size and density fractionation to distinguish SOC into four forms: light fraction carbon (LFC), particulate organic carbon in macroaggregates (Macro_oPOC), particulate organic carbon in microaggregates (Micro_oPOC), and mineral-associated organic carbon (MAOC). Additionally, to assess microbial activity, we measured microbial biomass carbon (MBC), extracellular enzyme activities (three hydrolases and two oxidases) associated with C decomposition, and glomalin-related soil protein (GRSP), thus providing insights into microbial processes influenced by ERW. As a result, the increased soil pH and supply of minerals from ERW are expected to boost microbial activities, potentially leading to a higher rate of labile SOC decomposition. This could result in decreases in LFC and Macro_oPOC and increases in both Micro_oPOC and MAOC. This research underscores the multifaceted role of ERW in carbon management strategies, demonstrating its potential not only in mitigating climate change through inorganic carbon sequestration but also in influencing SOC sequestration.
Differentiable modeling for global water resources under global change
Authors: Shen Chaopeng , Song Yalan , Rahmani Farshid , Bindas Tadd , Aboelyazeed Doaa , Sawadekar Kamlesh , Clark Martyn , Knoben Wouter
Published: March 2024

Process-based modeling offers interpretability and physical consistency in many domains of geosciences but struggles to leverage large datasets efficiently. Machine-learning methods, especially deep networks, have strong predictive skills yet are unable to answer specific scientific questions. A recently proposed genre of physics-informed machine learning, called “differentiable” modeling (DM, https://t.co/qyuAzYPA6Y), trains neural networks (NNs) with process-based equations (priors) together in one stage (so-called “end-to-end”) to benefit from the best of both NNs and process-based paradigms. The NNs do not need target variables for training but can be indirectly supervised by observations matching the outputs of the combined model, and differentiability critically supports learning from big data. We propose that differentiable models are especially suitable as global hydrologic models because they can harvest information from big earth observations to produce state-of-the-art predictions (https://mhpi.github.io/benchmarks/), enable physical interpretation naturally, extrapolate well (due to physical constraints) in space and time, enforce known physical laws and sensitivities, and leverage progress in modern AI computing architecture and infrastructure. Differentiable models can also synergize with existing global hydrologic models (GHMs) and learn from the lessons of the community. Differentiable GHMs to answer pressing societal questions on water resources availability, climate change impact assessment, water management, and disaster risk mitigation, among others. We demonstrate the power of differentiable modeling using computational examples in rainfall-runoff modeling, river routing, forcing fusion, as well applications in water-related domains such as ecosystem modeling and water quality modeling. We discuss how to address potential challenges such as implementing gradient tracking for implicit numerical schemes and addressing process tradeoffs. Furthermore, we show how differentiable modeling can enable us to ask fundamental questions in hydrologic sciences and get robust answers from big global data.
Evaluating Hydro Carbon Potential and Estimating Crustal Shortening in Pothohar Area, Punjab, Pakistan
Authors: Maqsood Rizwan
Published: March 2024

Abstract:
                  Geological hazards and their mitigation and search for natural resources are the two main research themes for any geo-researcher working in Pakistan. Geological hazards as October 08, 2005 great earthquake and the prevailing energy crisis in the country support the above said research themes as both the problems have crucial socio-economic impact on Pakistan.
The present study is an effort to contribute in this regard. Data for nine seismic lines were taken from Land Mark Resources, Pvt. Islamabad; the survey carried out in 1994 in Joyamir area of Chakwal, Punjab, Pakistan. Analysis and interpretation were carried out for the said data with the aim to evaluate its hydro-carbon potential and potential for future earthquakes.
Results prove the possibility of hydrocarbon existence evident from the subsurface images of structural traps, source rocks, cap rocks and thermal conditions. Results also prove the possibility of major earthquake in future due to sufficient accumulation of energy in the form of crustal shortening measured in this study. However, micro seismicity due to water and hydrocarbon extraction activities in this area is slicing the release of stored energy and diminishing the risk of major earthquake consequently.
New OBS array reveals relic slab distribution in the mantle of Southeast Asia Curved Subduction System
Authors: Li Jiabiao , Ding Weiwei , Niu Xiongwei , Kong Fansheng , Zhang Jie , Sun Qiuci
Published: March 2024

Southeast Asia is located in an important regional geodynamic intersection zone and is surrounded by inward subduction systems on three sides. It is the largest and most complicated convergent subduction system on Earth and is known as the Southeast Asia Curved Subduction System (CSS). The deep circulation and structure of the subducted slabs, especially the relic slabs within the CSS, have been an elusive scientific mystery. In this study, using an ocean bottom seismometer (OBS) array in the South China Sea in 2019-2020 and the long-term inland seismic network, we present a new seismic tomographic deep structure of the relic slabs in the CSS mantle. Both the eastern and western CSS subducting slabs exhibit high angles and pass down through the mantle transition zone (MTZ), while the southern subducting slab not only passes through MTZ but also lies flat in the lower mantle, giving rise to a very unique "dustpan"-shaped deep mantle structure. Above the "dustpan"-shaped subduction slab, a high-velocity layer located in and around the South China Sea is interpreted as a relic slab and it lies within the MTZ and continues to subduct to the north. This relic slab is broken by the low-velocity Hainan plume and may result from paleo-Pacific subduction.
Numerical simulation and dynamic analysis of ocean-continent coupling effects in Molucca Sea area, Indonesia
Authors: Fang Gui , Zhang Jian , Hao Tianyao , Dong Miao , Wang Xuefeng
Published: March 2024

The Molucca Sea area, situated on the southwestern side of the Philippine Sea in eastern Indonesia, is critical research area for the study of the ocean-continent coupling effect and subduction dynamic system of the western Pacific. Despite its significance as a research hotspot, several research gaps exist in this region. We aim to address two outstanding scientific issues: the cause of the Sangihe Forearc Thrust (SFT) in Molucca Sea, and the mechanism of volcanic discontinuity and migration of Halmahera arc. Numerical simulation is utilized to analyze these issues.
For the SFT in Molucca Sea, our results show that plate boundary stress and volcanic loading are two critical factors affecting forearc thrusting during asymmetric divergent double subduction (DDS). In the northern part of the DDS in Molucca Sea, the SFT is primarily caused by plate boundary stress. This stress is mainly generated by the southwestward subduction of the Philippine Sea Plate. In contrast, the SFT in the southern part of the DDS is mainly caused by the effects of differential volcanic loading. The effect of volcanic loading on the Halmahera forearc is considerably stronger than that on the Sangihe forearc, resulting in more severe vertical deformation and subsidence of the former. Consequently, the Sangihe forearc, which exhibits less vertical deformation, is thrust over the Halmahera forearc.
For the mechanism of volcanic arc migration in Halmahera, our results show that the dehydration depth of subduction slab and the temperature structure of mantle wedge are closely linked to the rates of subducting or overriding plates. A lower rate of subducting plate or a higher rate of overriding plate is favorable for arc magmatism. Changes in the rates of subducting and overriding plates are identified as the cause of the magmatic activity interruption and volcanic migration of Halmahera arc after the Middle Miocene. During the Miocene-Pliocene period, the rate of subducting plate was lower than the westward convergence rate of the eastern microplate, which created a high-temperature zone favorable for arc magmatism. However, starting in the Middle Pliocene, the rate of subducting plate became close to the westward convergence rate of the eastern microplate fragments due to the tilted subduction of the Philippine Plate, which was unfavorable for arc magmatism. This led to the interruption of volcanic activity and the westward migration of the volcanic arc. In the Holocene, the westward migration of Halmahera arc was blocked, leading to an accelerated convergence of the eastern microplate. As a result, the volcanic activity of Halmahera arc resumed in a new location with a high-temperature zone favorable for arc magmatism.
Agricultural Irrigation Water Allocation Planning and Economic Benefit Assessment – A Case Study of Kinmen County
Authors: Su Yi , Yu Hwa-Lung , Chang Tsang-Jung
Published: March 2024

Agricultural development in Kinmen region has long suffered from the absence of a corresponding management unit responsible for irrigation planning and infrastructure maintenance, resulting in the majority of local farmlands relying on natural rainfall for cultivation. Unfortunately, this method is highly susceptible to the impacts of climate change. To address this pressing issue, the government plans to utilize reclaimed water from domestic sources as a supplementary irrigation resource. Within this context, this study aims to devise an irrigation water allocation model to optimally harness the limited water resources.In this study, we simulate the crop rotation of local sorghum and wheat, considering soil, crop, and historical meteorological data. We calculate the variations in crop yield under different irrigation schemes. Additionally, we use historical meteorological data from Kinmen to calculate various simulated climates, testing the benefits of this irrigation plan under more extreme weather conditions. In conclusion, guided by the simulation outcomes and considerations of factors like cost and government procurement prices, we undertake a comparative analysis of the economic benefits under various scenarios and irrigation plans. This analysis aims to pinpoint the optimal irrigation water allocation plan that can be feasibly implemented by local farmers.For this study, we have chosen a 100-hectare demonstration area located in Jinsha Town, Kinmen, as our study area. We will utilize 750 tons of reclaimed water provided daily by the Ronghu Water Resources Recycling Center as the irrigation water source, and the government has already established six agricultural ponds in the area to store water. Following this, our study will proceed with the implementation of the irrigation water allocation plan in the designated demonstration area. Our ultimate aim is for this initiative to serve as a starting point, enabling the systematic expansion of the irrigation water allocation plan to other regions in Kinmen, thereby enhancing the overall irrigation quality.Keywords: Irrigation Water Allocation Model; Reclaimed Water; Rotation Irrigation; Kinmen; Sorghum
Functional organic matter components in mangrove soils revealed by density fractionation
Authors: Kida Morimaru , Hamada Kota , Ohtsuka Toshiyuki , Fujitake Nobuhide , Miyajima Toshihiro , Yokoyama Yusuke , Miyairi Yosuke
Published: March 2024

The mechanisms underlying stabilization of soil organic matter (SOM) in vegetated coastal ecosystems, including mangrove forests, are poorly understood, limiting our ability to predict the consequences of disturbances. Here, we introduce density fractionation to mangrove soils to identify the distribution and properties of the functional components of SOM with regard to degradation state, stability, and origin, namely, the free low-density fraction (f-LF), mineral-associated LF (m-LF), and high-density fraction (HF).Three 1-m soil cores were collected in the Fukido mangrove forest on Ishigaki Island, Japan, segmented into 10 cm intervals, and analyzed for C and N concentrations, stable carbon isotopes (13C), and radiocarbon isotopes (14C) followed by density fractionation. Although HF exhibited the highest abundance, the massive production of mangrove fine roots resulted in a high abundance of LFs throughout the cores, which markedly differed from terrestrial soils. The relative abundance of LFs collectively accounted for 38%–66% of total soil C. Notably, m-LF was as abundant as f-LF and 1.6 times higher in relative abundance than the global average of terrestrial soils. The C/N ratios and δ13C values exhibited a clear increase with depth in all fractions, attributed to the increased contribution from roots. A consistent pattern in Δ14C values across density fractions in the deepest section was observed, with HF exhibiting the oldest values (between -149‰ and -97‰), followed by m-LF (between -130‰ and -87‰), and f-LF (between -89‰ and 78‰). This implies that mineral association may play a pivotal role in long-term carbon storage in the mangrove mineral soil studied.A further analysis of reactive iron (Fe) and aluminum (Al) present in HF through pyrophosphate (PP) and dithionite-citrate (DC) extractions suggested that PP-extractable, organically complexed metals regulate organic carbon concentrations in HF, rather than crystalline or nano-crystalline Al and Fe phases. Our analysis successfully identified meaningful functional components of mangrove SOM, yet several questions remained unanswered, including the large variability in Δ14C values among different cores.
Response of Electric Field in Terrestrial Magnetosphere to Interplanetary Shock
Authors: Liu Wenlong , Zhang Dianjun , Li Xinlin , Sarris Theodore
Published: March 2024

Electric field impulses generated by interplanetary shocks can cause a series of dynamic processes in the Earth's magnetosphere and were previously explained by either fast-mode wave propagation or flow related to compression of the magnetopause. Based on a Space Weather Modeling Framework simulation, we suggest a new scenario in which the evolution of the impulse is due to both the propagation of the fast-mode wave and the compression of the magnetopause, which can explain the simulation and observations in previous related studies. The onset of the electric field impulse is determined by the propagation of the fast-mode wave in the magnetosphere while the peak of the impulse is determined by the propagation of the compression of the magnetopause. The new understanding of the impulse is important for the generation of subsequent ultralow frequency waves through the coupling of the fast-mode to Alfvén waves and field line resonances and related radiation-belt electron acceleration.
Interagency discrepancies in tropical cyclone intensity estimates over the western North Pacific in recent years
Authors: Bai Lina , Xu Yinglong , Tang Jie , Guo Rong
Published: March 2024

    This study investigates interagency discrepancies among best-track estimates of tropical cyclone (TC) intensity in the western North Pacific, provided by the Joint Typhoon Warning Center (JTWC), the China Meteorological Administration (CMA), and the Regional Specialized Meteorological Center (RSMC) Tokyo during 2013–2019. The results reveal evident differences in maximum wind speed (MSW) estimates, where linear systematic differences are significant. However, the Dvorak parameter (CI) numbers derived from the MSWs reported by the three agencies are internally consistent. Further analysis suggests that the remained CI discrepancies are related to differences in the estimation of intensity trends, initial intensities, and TC positions among these datasets. In addition, the CI estimates provided by the JTWC for TCs over the open ocean are generally higher than those reported by the CMA and RSMC. However, the CMA (RSMC) tends to estimate stronger intensity for TCs in the China (Japan) mainland and coastal zone than those in the open ocean with the same intensity in JTWC dataset. This pattern potentially reflects the extensive use of surface observations by these two agencies for landfalling and offshore TCs. These results may help the research community to get more accurate details about the TCs in WNP from the best track datasets of different agencies.
Evaluation of FY-4A/AGRI visible reflectance using the equivalents derived from the forecasts of CMA-MESO using RTTOV
Authors: Zhou Yongbo , Liu Yubao , Zeng Yuefei , Han Wei
Published: March 2024

The Advanced Geostationary Radiation Imager (AGRI) onboard the FY-4A geostationary satellite provides high spatiotemporal resolution visible reflectance data since March 12th, 2018. Data assimilation experiments under the framework of observing system simulation experiment have shown great potential of these data to improve the forecasting skills of numerical weather prediction (NWP) models. To effectively assimilate the AGRI data, it is important to address the quality the observations. In this study, the FY-4A/AGRI channel 2 (0.55 μm - 0.75 μm) reflectance was evaluated by the equivalents derived from the short-term model forecasts of the China Meteorological Administration Mesoscale Model (CMA-MESO) using the Radiative Transfer for TOVS (RTTOV, v 12.3). It is shown that the observation minus background (O – B) statistics could be used to reveal the abrupt changes related to the measurement calibration processes. In addition, O - B statistics are negatively biased. Potential causes include measurement errors, the unresolved processes, forward-operator errors, etc. The relative mean biases of O-B computed for cloud-free and cloudy pixels were used to correct the systematic differences for cloudy and clear pixels separately. Results indicate that the bias correction method could effectively reduce the biases and standard deviations of O-B. In addition, an ensemble forecast has advantages over a deterministic forecast in correcting the biases in FY-4A/AGRI visible reflectance data. The finding suggests an effective method to monitor the performance of FY-4A/AGRI visible measurements and to correct the biases in the observations. 
Mantle Dynamic Processes Investigation beneath the Eastern Arctic Gakkel Ridge based on Submarine Seismic Observations
Authors: Jia Yan , Li Jiabiao , Kong Fansheng , Niu Xiongwei , Ding Weiwei , Zhang Tao , Fang Yinxia , Tan Pingchuan
Published: March 2024

Mantle flow movement is one of the core aspects of the investigation of mid-ocean ridge dynamics. Previous studies have demonstrated that there are significant differences in the asthenospheric mantle flow movements as well as the patterns of magma supply and migration depending on the plate spreading rate. Compared with the fast-, middle-, and slow-spreading ridges, the mantle dynamics of the ultraslow-spreading mid-ocean ridges are less studied. The mantle dynamics of the Arctic Gakkel Ridge, which has the slowest spreading rates on Earth, have almost no relevant studies because of the constraints imposed by harsh weather and dense ice cover. In this study, we used approximately 300 teleseismic data collected from 42 OBS deployed during the 12th Chinese Arctic Scientific Expedition to establish the anisotropic structure of the upper mantle in the eastern part of the Gakkel Ridge based on the shear wave splitting method. A total of ~100 pairs of splitting parameters and 6 null measurements were obtained, showing complex anisotropy patterns along the Gakkel ridge axis and on both sides near the axis beneath the North American and Eurasian plates. The results may reflect the horizontal complicated mantle flows along and normal to the mid-ocean ridge and a vertical upwelling mantle flow, revealing a three-dimensional model of distinctive upper mantle dynamic processes of the slowest-spreading Gakkel Ridge.
Spatio-temporal clustering of storm surges along the global coastline
Authors: Wahl Thomas , Enriquez Alejandra , Martin Ariadna
Published: March 2024

When storm surges often affect the same coastline stretches simultaneously (i.e., they cluster in space, leading to spatial compounding) or if they occur in close succession (i.e., they cluster in time, leading to temporal compounding), the impacts are often greatly amplified. Hurricanes Irma and Maria in 2017 in the eastern Caribbean and Hurricanes Ian and Nicole in Florida were recent reminders how back-to-back storm surges affecting long coastline stretches can cripple economies and societies which are still in recovery mode. This can be a significant burden for the (re-)insurance industry and government budgets, as has been shown for the case of river floods (Jongman et al., 2014). Despite many examples where spatial or temporal compounding effects worsened coastal flooding impacts, developing appropriate tools to incorporate such events into present-day and future coastal flood impact assessments and hazard mitigation planning is still at its infancy. This presentation will showcase a novel algorithm to identify independent storm surge events and preliminary results from applying it to a global tide gauge data set to detect hotspots of temporal storm surge clusters at different time scales and different levels of extremeness. Results from identifying spatial storm surge footprints along the global coast and associated non-stationarity (for selected coastline stretches) will also be presented. The latter will be linked to large-scale weather patterns causing shifts in the spatial footprints at seasonal to decadal time scales. The results can inform the development of flexible statistical models capable of capturing both spatial and temporal dependences to overcome existing limitations in flood risk assessments where this is typically ignored.
Remote Sensing of Atmospheric Temperature, Water Vapor, Trace Gases, Cloud, and Surface Properties on Daily and Decadal Time Scales
Authors: Liu Xu
Published: March 2024

Hyperspectral IR sounders such as AIRS on Aqua, CrIS on S-NPP, NOAA20 and JPSS-2, IASI on Metop A, B, and C provide high-quality atmospheric temperature, water, vapor, and greenhouse gas vertical profiles.  Additionally, they provide atmospheric cloud properties, surface emissivity, and surface skin temperatures.  We have developed two algorithms which can consistently derive these products from multiple IR sounders.  The first one is a Single Field-of-view Sounder Atmospheric Product (SIFSAP) algorithm and the second one is a Climate Fingerprinting Sounder Product (ClimFiSP) algorithm.  The SiFSAP algorithm performs one retrieval for each FOV using an all-sky optimal estimation approach. The core of the SiFSAP algorithm is an accurate and fast Principal Component-based Radiative Transfer Model (PCRTM), which can calculate hyperspectral radiance spectra under both clear and cloudy conditions. The PCRTM was developed in the past decade using consistent reference line-by-line radiative transfer model and spectroscopy for hyperspectral sounders such as AIRS, CrIS, IASI, NAST-I, and S-HIS.  The ClimFiSP algorithm, which performs retrievals from spatiotemporally averaged L1 hyperspectral radiances directly, will be orders of magnitude faster than traditional method. he ClimFiSP algorithm uses consistent radiative kernels and a robust spectral fingerprinting method. It provides accurate data climate data fusion products from multiple satellite sensors. Both SiFSAP and ClimFiSP will be available at NASA GES DISC data center for public access. 
Mesophyll largely contributes to the historical increase in isotope discrimination of C3 plants and implications for water use efficiency
Authors: Lai Jiameng , Sun Ying
Published: March 2024

Much information of photosynthesis and carbon cycling was embedded in the stable carbon isotope, as plants discriminate against heavier carbon isotope. The process of isotope discrimination has been implemented in most terrestrial biosphere models (TBMs), mainly following the standard equation by Farquhar et al. With National Center for Atmospheric Research (NCAR) Community Land Model (CLM5), we found this standard equation cannot reproduce the historical long-term increase of isotope discrimination as deduced from atmospheric 13C/12C measurements. We attributed such a mismatch to the missed representation of photorespiration and mesophyll diffusion. Updating the discrimination equation by leveraging a mechanistic mesophyll diffusion model developed by Sun et al. (2014), we reproduce the trend towards a larger discrimination under higher CO2 levels: globally the trend is 0.013‰ ppm−1, consistent with atmospheric measurements. Mesophyll effects significantly contribute to this global trend, with the largest contribution in natural ecosystems. Moreover, we found that an explicit consideration of mesophyll conductance can lead to a higher response of historical water use efficiency to climate and environmental changes. Our results have implications for advanced modeling of isotopic discrimination and therefore for a better understanding of the coupled carbon-water cycle under changing climate. References:Farquhar, G. D., Ehleringer, J. R., and Hubick, K. T.: Carbon isotope discrimination and photosynthesis, Annu. Rev. Plant Phys., 40, 503–537, (1989).Sun, Y. et al. Impact of mesophyll diffusion on estimated global land CO2 fertilization. Proc. Natl. Acad. Sci. U. S. A. 111, 15774–15779 (2014).
Causal methods for climate extremes
Authors: Engelke Sebastian
Published: March 2024

The talk discusses a critical topic in climate science: understanding how interventions on our climate system influence the likelihood of extreme events. The focus is on methodologies that enable causal attribution of such events to specific drivers, rather than merely predicting their occurrence. We discuss common practices and highlight the use of recent statistical methods that are applicable when only observational data is available, as opposed to model-based data. The talk defines the concept of a causal effect of a treatment (such as changes in flood infrastructure or increased CO2 emissions) on extreme outcomes (like a one in 100 year flood). We also cover the estimation of these effects amidst confounding factors and the assessment of associated uncertainties. Finally, we discuss the inherent challenges of applying causal inference to extreme climate events. 
Thermospheric wind response to the annular solar eclipse on 21 June 202
Authors: Wang Jin , Sun Yang-YI
Published: March 2024

The sudden cutoff of solar radiation caused by the solar eclipse could cause significant changes in the thermosphere and ionosphere, considering the fact that the solar radiation plays a significant role in their dynamical processes. In this study, the thermospheric neutral wind recorded by the Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI) on the Ionospheric Connection Explorer (ICON) spacecraft and metero radar were analyzed to examine the variations in thermospheric wind during and after the 21 June 2020 annular solar eclipse over the East China area. The neutral wind observations showed direct evidences that the solar eclipse disturbed the mesosphere and low thermosphere for more than 10 hours. The clear enhancement of the meridional wind during the moon obscuration and sharply decreased meridional wind after local sunset suggested that a large-scale oscillation was caused by the solar eclipse, which persisted from daytime to nighttime.
Exploring changes of precipitation extremes under climate change through global variable-resolution modeling
Authors: Sun Wei , Li Jian , Yu Rucong , Li Nina , Zhang Yi
Published: March 2024

Understanding the responses of precipitation extremes to global climate change remains limited owing to their poor representations in models and complicated interactions with multi-scale systems. Here we take the record-breaking precipitation over China in 2021 as an example, and study its changes under three different climate scenarios through a developed pseudo-global-warming (PGW) experimental framework with 60–3 km variable-resolution global ensemble modeling. Compared to the present cli- mate, the precipitation extreme under a warmer (cooler) climate increased (decreased) in intensity, cov- erage, and total amount at a range of 24.3%–37.8% (18.7%–56.1%). With the help of the proposed PGW experimental framework, we further reveal the impacts of the multi-scale system interactions in climate change on the precipitation extreme. Under the warmer climate, large-scale water vapor transport con- verged from double typhoons and the subtropical high marched into central China, enhancing the con- vective energy and instability on the leading edge of the transport belt. As a result, the mesoscale convective system (MCS) that directly contributed to the precipitation extreme became stronger than that in the present climate. On the contrary, the cooler climate displayed opposite changing characteris- tics relative to the warmer climate, ranging from the large-scale systems to local environments and to the MCS. In summary, our study provides a promising approach to scientifically assess the response of pre- cipitation extremes to climate change, making it feasible to perform ensemble simulations while inves- tigating the multi-scale system interactions over the globe.
Deformation characteristics and evolution of Rakhine Basin, Bay of Bengal 
Authors: Wang Xuefeng , Fan Guozhang , Ding Liangbo , Ma Hongxia , Yang Zhili
Published: March 2024

We analyzed the structural characteristics and tectonic evolution of the Rakhine Basin based on 2D seismic data and well data．The Basin is located at accretionary wedge with trench setting of active continental margin, and have experienced embryonic stage (Late Cretaceous-Paleocene)，collision stage (Eocene- Oligocene ) and quick collision stage (Miocene- Pliocene). Rakhine Basin can be sub-divided into Marine plain and Rakhine fold belt. The Rakhine fold belt is consisting of Northern compressing fold belt and southern strike slip belt. Northern compressing fold belt developed a lot of NNW-trending linear folds that can be subdivided into steep folds with high amplitude caused by intensive tectonic deformation from East to West. Southern strike slip belt formed some anticlines along strike-slip fault and unambiguous flower structures. Evolution of regional section suggested that the deformation began in the late Miocene, and became intensive from later Pliocene to Quaternary; Structures in eastern part are older and more intensive than the Western part, due to the regional contraction is from East to west and deformation propagated westward. The deposition center migrated from East to West after Miocene formation deposited. All characteristics of the Rakhine Basin are mainly controlled by different stress patterns caused by the arched boundary of subduction formed between Indian-Australia plate and the Eurasia plate.
Strong ice-ocean interaction drives and enhances calving of Antarctic ice shelves
Authors: Liu Yan , Cheng Xiao , Liu Jiping , Moore John , Li Xichen , Cook Sue
Published: March 2024

Since 2015, there has been a significant increase in iceberg calving rates from Antarctic ice shelves. It is crucial to comprehend the climate-related reasons for this enhanced iceberg calving to improve coupled simulations with the ice sheet and predict their future effects on sea-level rise. Based on continuous observations of iceberg calving around Antarctica over 15 years, we demonstrate that sea ice extent is the primary control on iceberg calving rates in Antarctica, regardless of ice shelf size, location, or ocean regime. The recent increase in calving rates coincides precisely with a significant reduction in sea ice area in most sectors around the continent. We propose a calving model, where iceberg calving is dominated by ocean-wave induced flexure and basal shear and enhanced by ice-shelf basal melt. We also find links between iceberg calving rate and El Niño/Southern Oscillation (ENSO), which are particularly strong in East Antarctica. Given that further decreases in sea ice extent and increases in extreme ENSO events are predicted in future, we raise concern that previously stable East Antarctic ice shelves may soon begin to retreat, with potential to trigger significant mass loss from this massive ice sheet.
Abovyan – an enigmatic Kiruna-type apatite-magnetite deposit in Armenia
Authors: Nekrylov Nikolai , Hovakimyan Samvel , Moritz Robert , Bergemann Christian , Hambaryan Karen , Meliksetian Khachatur
Published: March 2024

The Abovyan deposit in Armenia represents a unique example of relatively young, Late Miocene age Kiruna-type apatite-magnetite mineralization in the region. Initially identified in 1947 by a team of Armenian geologists, based on the well-pronounced magnetic anomaly, it remains largely obscure outside the confines of Soviet-era scholarly literature. This deposit resides within a magmatic formation predominantly of intermediate composition, comprising andesites and dacites, and characterized by disseminated and massive magnetite ores and transitional varieties between them. The deposit is fully covered by several dozens of meters of younger, Pliocene-Quaternary volcanic rocks, so the samples for our study were collected from drill cores. These specimens, encompassing both host rocks and ores, retain critical insights into the processes governing ore segregation and accumulation, despite having a large influence of the autometasomatic alteration. The young age (~6-7 Ma, K-Ar, Sarukhanyan, 1969) and, consequently, the absence of later metamorphic events in the area is the main advantage of the Abovyan deposit over the majority of Kiruna-type deposits around the world in terms of preservation of the initial textures and other mineralogical and petrological features. Several generations of the magnetite-apatite ores could be clearly distinguished in the ores, which include (1) magnetite melt-like droplets in the host-rocks, (2) massive magnetite apatite ores, (3) magnetite-hosted breccias of the altered host-rocks and (4) several generations of late hydrothermal veins. Notably, the apatite within these ores exhibits a remarkable enrichment in light rare earth elements (REEs), reaching concentrations as high as 4 wt.%. This level of enrichment is notably higher than that observed in other Kiruna-type deposits (Frietsch, Perdahl, 1995) and is accompanied by the other critical metals’ mineralization (e.g., Th). Ongoing research on the geochemistry and geochronology of the Abovyan deposit may be a key to understanding the formation of the Kiruna-type deposits and their REE potential, in particular.This study was funded by the Science Committee of RA (Research projects №23PostDoc-1E001 and  № 22IRF‐08), and by the Swiss National Science Foundation (grant 200021_188714).Frietsch, R., Perdahl, J. A., 1995. Rare earth elements in apatite and magnetite in Kiruna-type iron ores and some other iron ore types. Ore Geology Reviews, 9, 6, 489-510.Sarukhanyan, L.B., 1969. Some questions about the genesis of the Abovyan apatite-magnetite deposit. Proceedings of the Armenian SSR Academy of Science, Earth Sciences, 3, 40-49 (in Russian)
Estimation of unknown source term based on radioxenon observations with the presence of background signal
Authors: Tichý Ondřej , Šmídl Václav , Mácha Václav , Kuśmierczyk-Michulec Jolanta , Sommerer Wolfgang , Tipka Anne
Published: March 2024

The identification of a sample associated with a nuclear test is a challenging task for the CTBTO because of the presence of a noble gas background in the constant evolving atmosphere. This background is caused by nuclear power plants, nuclear research reactors, and medical isotope production facilities and contributes to samples collected by the noble gas systems of the International Monitoring Stations (IMS). Because of that background, standard linear inverse model applied to Xe-133 measurements is prone to substantial errors. To address this problem, we investigate possible methods for separation of the background signal and any signal from a nuclear explosion, which is further processed for estimation of the Xe-133 source term.We assume that the observed unknown point release of Xe-133 can be modeled as a linear model y=Mx, where y is the vector of observations, M is source-receptor sensitivity (SRS) matrix, and x is the temporal profile of the unknown release from a nuclear explosion, i.e. its source term. Since the signal in the observation vector is most probably mixed with civilian emitters, we test methods for separation of the contributions from the unknown signal and the background. We compare various approaches, ranging from simple model calibration, to simulated background term and their combinations with anomaly detection. The results are demonstrated on the data from the 1st Nuclear Explosion Signal Screening Open Inter-Comparison Exercise 2021 where advantages and disadvantages of studied methods are discussed and results are evaluated with the use of ground truth information on temporal and spatial location of the Xe-133 source.Acknowledgment: This research has been supported by the Czech Science Foundation (grant no. GA24-10400S). The work was performed under the CTBTO awarded contract for ”Provision of Software Engineering Services for the Scientific Development of a Source Term Estimator Tool (STE)” under funding from the European Union Council Decision VIII.
Assessing Surface Drainage Efficiency in Urban Pluvial Flood Hazard and Risk Mitigation: A Case Study of Braunschweig City
Authors: Khosh Bin Ghomash Shahin , Apel Heiko , Schroeter Kai , Steinhausen Max
Published: March 2024

Due to rapid urbanization and the increase of extreme precipitation events driven by climate change, urban areas have experienced more frequent and severe pluvial floods in recent years. This trend is anticipated to continue in the future. One of the causes of flooding in these urban zones is the limited effectiveness or temporary reduction in surface drainage capacity, even when storm sewers adhere to technical standards. A notable instance was the June 2023 flooding in Braunschweig, situated in Lower Saxony, Germany, where the city received 60 liters per square meter of rainfall within a short time span, largely excessing sewer system capacity and leading to widespread inundation.This research investigates the impact of implementing diverse strategies aimed at expanding urban drainage capacity to mitigate pluvial flood risk in Braunschweig. To accomplish this, a moderately detailed hydrodynamic model for the city was set up using the RIM2D hydrodynamic model, allowing for quick computational processing times which enabled the exploration of various measures through sensitivity analysis. The setup involved employing a high-resolution digital elevation model and various remote sensing data for land classification. The model incorporated high-resolution precipitation radar data from the 2023 event and additional precipitation scenarios of varying occurrence probabilities. Validation of the model against available event data and existing flood hazard maps specific to Braunschweig was conducted.The validated model was then utilized to assess the effectiveness of different surface de-sealing scenarios within the city. These scenarios aim to enhance drainage capacity by means of increased infiltration to complement the existing sewer drainage system. The evaluation of these de-sealing scenarios focused on reducing surface inundation and anticipated damage, serving as a foundational aspect for conducting a cost-benefit analysis and detailed planning. This analysis can contribute to future-oriented urban pluvial flood risk management plans for the city.
Spatial distribution of fallout 137Cs and 239+240Pu in Equatorial and Southern Hemisphere soils
Authors: Dicen Gerald , Guillevic Florianne , Chaboche Pierre-Alexis , Meusburger Katrin , Sabatier Pierre , Evrard Olivier , Alewell Christine
Published: March 2024

Past nuclear weapons testing and nuclear power plant accidents resulted in the ubiquitous deposition of radionuclides in the environment. While the risks associated with radionuclide contamination are apparent, these fallout radionuclides (FRNs) provide the privileged markers (“golden spikes”) of the Anthropocene stratigraphic layers. The onset of their emissions in the 1950s coincided with the “Great Acceleration”, which is characterized by large-scale shifts in the biophysical and socio-economic aspects of the Earth System, including an increase in soil degradation, triggered mainly by land-use change. Among the host of FRNs deposited globally, 137Cs has been the most commonly used and 239+240Pu is a new emerging tracer and chronological marker to assess soil erosion and/or chronology of sediment deposition.In this meta-analysis, we compiled existing 137Cs and 239+240Pu data analyzed from undisturbed soils in the literature to get an overview of the spatial distribution and constraints of fallout 137Cs and 239+240Pu in Equatorial and Southern Hemisphere soils, as well as the possible sources of these FRNs through their isotopic ratios. A database composed of 1087 reference cores was built from the literature published on Equatorial and Southern hemisphere soils.Aside from the cores collected from the north equatorial regions, high 137Cs inventories were also found in reference soils collected at the 40-50° S latitudinal band, which were mostly from South America. On the other hand, high 239+240Pu inventories were found at the 20-30° S latitudinal band, but this was influenced by the unusually high inventories measured from the French Polynesia, where many nuclear weapons testing occurred. The 240/239Pu atomic ratios indicated that sources other than the global fallout (240/239Pu = 0.18) contributed to the reference inventories in the Southern Hemisphere. As some areas lacked measurements, specific points where additional data could be obtained were identified through a GIS-based approach to represent the entire land surface areas of interest adequately. Together with new measurements, the compiled reference soil data will be used to construct a detailed baseline map of 137Cs and 239+240Pu fallout mainly for regional soil erosion assessments.
Testing tomography-based plate reconstructions from a paired, inverse-forward closed-loop experiment in a mantle circulation model
Authors: Chen Yi-Wei , Bunge Hans-Peter , Stotz Ingo , Wu Jonny
Published: March 2024

Global plate reconstructions that constrain the surface plate motions provide crucial boundary conditions for mantle circulation models. Earth-like plate kinematics could reduce the impact of the uncertain mantle initial conditions and generate slab structures in the mantle that are comparable with seismic tomographies. However, due to the subduction of the oceanic plates, uncertainty increases in global plate reconstruction over time. Here, we utilize a novel slab unfolding technique to retrodeform mantle slabs imaged in the MITP08 seismic topography back to the pre-subduction states at Earth’s surface. Such a technique provides additional constraints on plate reconstructions, especially in regions dominated by intra-oceanic subductions, such as Southeast Asia.Our reconstruction shows a significant trench retreat along Southeast Asia and Northern Australia between 90 and 65 Ma that opened a gigantic, >3,000 km wide backarc basin. This basin, named the East Asian Sea plate, was later consumed by the west-moving Philippine Sea plate and North-moving Australian plate in the Cenozoic. We then embed our reconstruction in a mantle circulation model, TERRA, testing the fidelity of the reconstruction in a closed-loop experiment.We found that fragmented, sub-horizontal East Asian Sea slabs can be reproduced in the mantle circulation model. These slabs lying underneath the current Philippine Sea plate and northern Australia are similar to the MITP08 tomography on which the reconstruction is built. Moreover, these slabs at 800-1000 km depths result in a more negative dynamic topography on the present Philippine Sea plates comparable with the observed residual topography. On the contrary, the traditional, Andean-style reconstruction can only produce positive dynamic topography. Other Mesozoic, intra-oceanic subductions in NE Asia and western North America embedded in our reconstruction also produce negative, yet smaller magnitude, dynamic topography, possibly due to the older subduction history and deeper slabs. We conclude the negative dynamic topography within the present Pacific plate is the result of ancient intra-oceanic subductions. 