bluuebunny/crossref_metadata_2025 huggingface dataset:
Climate change is not the primary cause of extreme monsoons in Pakistan
Authors: Ashfaq Moetasim , Johnson Nathaniel , Kucharski Fred , Diffenbaugh Noah , Abid Adnan , Evans Katherine
Published: March 2024

Monsoons have been frequently severe in Pakistan in the last few decades, leading to extreme droughts and floods of unprecedented proportions. The wide belief is that these changing precipitation patterns are mainly due to climate change. However, considering this region's long history of floods and droughts, it is unwise to rule out the role of natural climate variability without a careful diagnosis. This study examines the contribution of oceanic and atmospheric variability to unusual precipitation distributions in Pakistan. We find that variations in sea surface temperatures in the tropical Pacific and northern Arabian Sea and internal atmospheric variability related to the circumglobal teleconnection pattern and the subtropical westerly jet stream account for 74% of monthly summer precipitation variability in the 21st century. Several of these forcings have co-occurred with record strength during episodes of extreme monsoons, compounding the overall effect. Climate change may have contributed to increased variability and the in-phase co-occurrences of the identified mechanisms, but further research is required to confirm any such connection.
Inversion and Evaluation of anthropogenic CO2 emissions based on 4Dvar method and the ratio of NOx-to-CO2
Authors: Hu Yiwen , Zang Zengliang , Li Yi , You Wei , Liu Lang , Liu Ning
Published: March 2024

Anthropogenic carbon dioxide (CO2) emissions are one of the most important source of greenhouse gases that driver climate change. However, there are still large uncertainties persist in the anthropogenic CO2 emissions and and no global observing system exists to monitor emissions from localized CO2 sources with sufficient accuracy. Combined nitrogen oxides (NOx) and CO2 observations showed the potential to constrain the identification of the locations and strength of anthropogenic CO2 emissions. In this study, a four-dimensional variational assimilation (4Dvar) system was developed to estimate high-resolution inversion of CO2 fluxes based on a regional chemical transport model WRF-Chem combined multiple observations. The ratios of NOx-to-CO2 from the TROPOspheric Monitoring Instrument (TROPOMI) and Orbiting Carbon Observatory 2 (OCO-2) satellite observations were applied to distinguish the enhancements of CO2 concentration from anthropogenic CO2 emissions. The gridded data set of monthly anthropogenic emissions (GCP-GridFED version 2022.2) was considered as the priori emission. The posterior CO2 emissions over China during April and September 2021 were estimated to reduce the influence of terrestrial ecosystem carbon sources and sinks. The posterior CO2 anthropogenic emissions reproduced the daily and hourly variation effectively, demonstrating the ability to fully absorb observations and the potential of applying NOx-to-CO2 ratio to estimate CO2 emissions. Two sets of forecast experiments were conducted to evaluate the prior and posterior CO2 simulations with independent surface observation data. Our results provide the basic data for carbon emissions reduction policies and may be helpful for accurate estimating carbon sinks, achieving carbon neutrality. The advanced data assimilation systems are beneficial to better quantify and characterize uncertainty for large carbon sources and sinks. 
Impacts of anthropogenic land use and land cover change on climate extremes based on CMIP6-LUMIP experiments
Authors: Zhang Meng , Gao Yanhong
Published: March 2024

Assessing the impacts of anthropogenic land use and land cover change (LULCC) on climate extremes is of public concern, calling for the use of state-of-the-art experiments and datasets to update our knowledge. Here, we used the CMIP6-LUMIP experiment results to depict the realistic LULCC effects on extreme temperature and extreme precipitation over both historical and future periods. We pointed out some interesting findings over the historical period: Approximately 1oC decrease in the maximum temperature, and up to nearly 2oC decrease in the minimum temperature in the mid-high latitude of the North Hemisphere. About 10 annual heatwave days can be avoided by LULCC effects in 10% of specific LULCC-intense regions. Three LULCC-intense regions in the North Hemisphere have experienced cooling effects in intensity, frequency, and duration aspects. The precipitation displayed a clear contrast change between the North Hemisphere (wetter) and the South Hemisphere (drier), especially on light rainy days (R1mm). Results of the future period indicate that the tropical deforestation regions are projected to induce a remarkably hotter and drier trend. However, the climate responses averaged globally to deforestation have no obvious changes due to the colder and wetter compensation responses in other regions. The maximum temperature increase in deforestation regions is prominent in intensity, frequency, and duration aspects, while the drought is mainly manifested by frequency and duration reduction of precipitation. Seasonal cycle of changes in temperature indices can be discovered in the North Hemisphere mid-latitude deforestation region, tropical region shows year-round consistency. Changes in LULCC induced climate extremes are more obvious under the low-emission scenario in general. Our work is devoted to portraying the latest and more realistic picture of LULCC impacts on climate extremes and gives early warning information to policymakers and the public.
Subducting seafloor anomalies promote porphyry copper emplacement
Authors: Mather Ben , Müller Dietmar , Alfonso Christopher , Wright Nicky , Seton Maria
Published: March 2024

The oceanic seafloor is scarred by fracture zones, seamounts, and large igneous provinces (LIPs) which record tectonic deformation and plume impingement through deep time. The subduction of these seafloor anomalies has been speculated to localise slab tearing, enrich the mantle wedge in volatile elements, or trigger flat slab subduction. However, the association between these subducting seafloor anomalies and the emplacement of mineral deposits in the overriding plate is poorly understood. Using a tectonic plate reconstruction of the last 170 million years paired with a machine learning model trained on the location and age of known porphyry copper deposits, we find that the subduction of seafloor anomalies is highly predictive of mineral emplacement, particularly along the American Cordillera. The subduction of fracture zones and seamounts are consistently within the top 10 highest ranked features after the crustal thickness of the overriding plate and the plate convergence velocity. We propose that fracture zones, seamounts, and LIPs have higher degrees of hydrothermal alternation and serpentinization compared to regular seafloor which oxygenates the sub-arc mantle upon their subduction, leading to more fertile conditions for porphyry copper emplacement in the overriding plate. These findings have significant implications for the discovery of new porphyry copper deposits to power the renewable energy transition.
Substantial increase in future fluvial flood risk projected in China's major urban agglomerations
Authors: Jiang Ruijie , Lu Hui , Yang Kun , Chen Deliang , Zhou Jiayue , Yamazaki Dai , Pan Ming , Li Wenyu , Xu Nan , Yang Yuan , Guan Dabo , Tian Fuqiang
Published: March 2024

Floods are one of the most destructive natural disasters and projecting future flood risk is essential for protecting lives and livelihoods. China is in the process of rapid urbanization, and most of the urban agglomerations are distributed on floodplains, facing high fluvial flood risk. The effect of urban spatial expansion, instead of densification of assets within existing urban cells, on flood risk has rarely been reported. Here, based on the latest projected urban land data and bias-corrected CMIP6 outputs, we project the future flood risk of seven urban agglomerations in China, home to over 750 million people. The inundated urban land areas in the future are projected to be 4 to 19 times that at present, with southern China facing the greatest increase. Although climate change is the main driver for this strong projected rise in flood risk, the inundated urban land areas will be underestimated by 10-50% if the urban spatial expansion is not considered. Urban land is more likely to be inundated than non-urban land, and the newly-developed urban land will be inundated more easily than the historical urban land due to the marginal expansion of urban land. The results demonstrate the urgency of integrating climate change mitigation, reasonable urban land expansion, and increased flood protection levels to minimize the flood risk in urban land.
Augmenting WRF with PDAF for an Online Localized Ensemble Data Assimilation
Authors: Shao Changliang
Published: March 2024

Data assimilation is a widely used method for estimating the state and associated uncertainties in numerical models. While ensemble-based approaches are common, their computational expense arises from necessary ensemble integrations. This study improves the Weather Research and Forecasting–Advanced Research WRF (WRF-ARW) model by integrating it with the Parallel Data Assimilation Framework (PDAF) in a fully online mode. Through minimal modifications to the WRF-ARW code, an efficient data assimilation system is developed, leveraging parallelization and in-memory data transfers to minimize file I/O and model restarts during assimilation. The clear separation of concerns between method development and model application, facilitated by PDAF's model-agnostic structure, is an advantage. Evaluating the assimilation system through a twin experiment simulating a tropical cyclone reveals improved accuracy in temperature, U and V fields. The assimilation process incurs minimal overhead in run time compared to the model without data assimilation, demonstrating excellent parallel performance. Consequently, the online WRF-PDAF system proves to be an efficient framework for high-resolution mesoscale forecasting and reanalysis.
Mechanical interactions between the underthrusting Indian crust and overlying Tibetan crust: insight from 2D numerical modeling
Authors: Pang Yajin
Published: March 2024

The Tibetan Plateau has been characterized by orogen-wide crustal thickening and surface uplift, partially attributed to the underthrusting Indian model. In addition, the underthrusting Indian crust has been proposed to promote the predominant E-W extension and N-S rifting in southern Tibet. However, the influence of the underthrusting processes of the Indian crust on crustal deformation in the Tibetan Plateau remains debated. Here, we construct a series of 2D thermo-mechanical models to investigate the mechanical interactions between the rigid underthrusting Indian lower crust and its overlying Tibetan crust. The preliminary results show that pronounced decrease in N-S compressional rates in the upper crust above the front edge of the underthrusting Indian lower crust, which moves northwards with the northward slab indentation. In contrast, the shear tractions on the overlying upper crust from the interior of the underthrusting plate, alleviating the N-S compression, are relatively slight. Therefore, the numerical results indicate locally accelerated extension in the middle-upper crust of the southern Tibet in response to the northward indentation of the Indian lower crust.
Earth structure from P-wave coda autocorrelation using particle swarm optimization
Authors: Zhou Jinju , Tkalčić Hrvoje
Published: March 2024

Teleseismic P-wave coda autocorrelation has been increasingly applied to subsurface structure detection and has shown potential for inverting subsurface velocity models. However, it has yet to be extensively investigated in terms of inversion and practical field data application strategy and initial model dependence. Compared with the receiver function, teleseismic P-wave coda autocorrelation can be used to invert the subsurface velocity model using only single-component data. This will significantly improve the application areas and reduce the costs of passive source seismology methods. Here, we propose a new inversion scheme for teleseismic P-wave coda autocorrelation based on the particle swarm optimization. The teleseismic P-wave coda autocorrelations are binned according to the ray parameters and then stacked to construct the observed waveforms. Our featured method, the particle swarm optimization, is then used to find the velocity model that minimizes the fitting error to the observed waveforms. It is a global optimization algorithm that simulates the feeding of a natural population. Each particle in the population has two parameters: position and velocity. The optimization space is a multi-dimensional space comprising various stratum thicknesses and velocities. Thus, a particle's position in the optimization space represents a set of parameters for the subsurface velocity distribution. We assume that the maximum number of layers within the crust above the mantle (a homogeneous half-space) is 10. The thickness of each layer ranges from 0 to 10 km, and if the thickness of a layer is 0 km, this corresponds to a reduction of one layer. The method thus allows the number of layers within the crust to be obtained by inversion without a priori information. Together with the P-wave velocity of each layer (including the mantle), the optimization space is 21-dimensional. While we still assume horizontal layers, our method is capable of inverting a wide range of crustal models, including those containing surface sedimentary layers, upper crustal low-velocity layers, and lower crustal low-velocity layers, among others. Notably, the method does not require prior knowledge of the number of layers in the model, making it highly robust. Furthermore, field data tests demonstrate the method's potential for practical application.
Simulating aerosol-radiation effect on subseasonal prediction in a coupled Unified Forecast System and CCPP-Chem: prescribed aerosol climatology versus dynamic aerosol model
Authors: Sun Shan , Grell Georg , Zhang Li , Henderson Judy , Li Haiqin
Published: March 2024

This study examines the impact of aerosol-radiation interation on subseasonal prediction using the Unified Forecast System (UFS) coupled to an ocean and an aerosol component. The aerosol component is from the current NOAA operational GEFS-Aerosols model, which includes the GOCART aerosol modules, simulating sulfate, dust, black carbon, organic carbon, and sea-salt aerosols. The modeled aerosol optical depth (AOD) is compared to reanalysis from Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA2) and observations from Moderate Resolution Imaging Spectro-radiometer (MODIS) satellite. Despite AOD bias primarily in dust and sea salt, good AOD agreement is achieved. The simulated radiative forcing (RF) from the total aerosol at the top of the atmosphere is approximately -2.5 W/m2 or -16 W/m2 per unit AOD globally. This is consistent with previous studies.In parallel simulations, the dynamic prognostic aerosols are replaced with modeled climatological aerosol concentrations in the UFS. While regional differences in RF are noticeable in some special events between these twin experiments, the resulting RF, surface temperature, precipitation and geopotential height at 500 hPa, show similarity over multi-years in subseasonal applications. This suggests that replacing the costly chemistry module with the modeled aerosol concentration climatology is a possible alternative in the subseasonal applications.
Exploring the impact of soil warming on methane uptake at different soil depths in a subtropical forest: unraveling the role of decreased water content
Authors: Zhang Lei , Lin Weisheng , Guo Jianfen
Published: March 2024

Global warming can significantly impact soil CH4 uptake in subtropical forests due to changes in soil moisture, temperature sensitivity of methane-oxidizing bacteria (MOB), and shifts in microbial communities. However, the specific effects of climate warming and the underlying mechanisms on soil CH4 uptake at different soil depths remain poorly understood. To address this knowledge gap, we conducted a soil warming experiment (+4°C) in a natural forest. From August 2020 to October 2021, we measured soil temperature, soil moisture, and CH4 uptake rates at four different soil depths: 0-10 cm, 10-20 cm, 20-40 cm, and 40-60 cm. Additionally, we assessed the soil MOB community structure and pmoA gene (with qPCR) at the 0-20 cm depth. Our findings revealed that warming significantly enhanced soil net CH4 uptake rate by 12.28%, 29.51%, and 61.05% in the 0-10, 20-40, and 40-60 cm soil layers, respectively. The warming also led to reduced soil moisture levels, with more pronounced reductions observed at the 20-40 cm depth compared to the 0-20 cm depth. At the 0-10 cm depth, warming increased the relative abundance of upland soil cluster α and decreased the relative abundance of Methylocystis, but it did not significantly increase the pmoA gene copies. Our structural equation model indicated that warming directly regulated soil CH4 uptake rate through the decrease in soil moisture, rather than through changes in the pmoA gene and MOB community structure at the 0-20 cm depth. In summary, our results demonstrate that warming enhances soil CH4 uptake at different depths, with soil moisture playing a crucial role in this process. Under warming conditions, the drier soil pores allow for better O2 and CH4 penetration, thereby promoting more efficient activity of MOB. This increased CH4 uptake in subtropical forests has the potential to mitigate the effects of global warming.
Quantifying the impact of urbanization on regional climate based on a partial differential method: a case study of vapor pressure deficit
Authors: Gong Siqi , Xia Jun , She Dunxian
Published: March 2024

The rapid development of urbanization has significant impacts on regional climate, and thereby affects the hydrological characteristics of urban areas. Urban hydrological models have been mainly focused on the changes in hydrological response caused by complex urban underlying surfaces and urban pipe network construction in previous studies, while there is a need to strengthen research on the climate change patterns caused by urbanization. Vapor pressure deficit (VPD) is a key indicator for studying water cycle in climate system, and it has a close relationship with hydrological processes such as precipitation, evapotranspiration, and surface water transport. However, as a meteorological indicator affected by multiple factors, a deep understanding of the quantitative analysis method for the contribution of different factors to VPD changes is still lacking. This study uses a urban-rural station pairing method to analyze the impact of urbanization and proposes a method based on partial differential equations to quantitatively explore the contribution of different factors to urban-rural VPD difference. Taking daily-scale data of urban-rural paired stations in mainland China as an example, the study finds that urbanization significantly increases VPD in the core urban areas, and the urban-rural VPD difference gradually expands over time, showing significant seasonal and geographical variations. The method based on partial differential equations can effectively capture the trend of the urban-rural VPD difference, thereby confirming the validity of the derived method for evaluating the contributions. Relative humidity is the main factor contributing to the urban-rural differences in VPD in most regions, but shows a different pattern in some plateau continental climate regions. This study establishes a framework for analyzing the impact of urbanization on specific meteorological indicators, especially providing a way to quantify the contribution of factors causing urban climate change, which is of reference value for further considering the uniqueness of urban climate in the construction of urban hydrological models.
A Study on Correction Technique for Temporal Rainfall Distribution of Numerical Weather Prediction
Authors: Hwang Seokhwan , Yoon Jungsoo , Kang Narae
Published: March 2024

In small basins such as upstream basins, sub-basins, or drainage basins, the arrival time is usually less than 1 hour, so it is very difficult to secure the advance time necessary for response through flood forecasting. Therefore, the use of precipitation forecasts is very important for flood forecasting in such small-scale areas. However, because predicted precipitation involves spatial and temporal uncertainty, quantitative spatial and temporal errors occur between observed and predicted flood amounts in predicted floods. If the quantitative error is small, advance flood forecasting is possible using predicted precipitation, but if the error is large, it can greatly reduce the reliability of the flood forecast. In the case of Numerical Weather Prediction (NWP), the temporal resolution is usually more than several hours and the spatial resolution is more than a dozen kilometers. Therefore, there are limits to reproducing precipitation that occurs quickly locally. In other words, the peak of heavy rain concentrated over a short period of time is often predicted to be flat compared to observations. Recently, localized heavy rainfall has been increasing, but the problem of spatial and temporal resolution is making it difficult to properly predict peak inflow for river or basin flood management. Therefore, in this study, we developed a technology to correct the peak of precipitation in digital meteorological predictions using Korea's representative time distribution. As a result of correcting the daily forecast rainfall for the 2022 Typhoon Hinnamno attack, the accuracy was found to improve from 68% of the actual rainfall before correction to 85% due to improvement in the peak. 
Acknowledgments
This research was supported by a grant(2022-MOIS61-002(RS-2022-ND634021)) of Development Risk Prediction Technology of Storm and Flood for Climate Change based on Artificial Intelligence funded by Ministry of Interior and Safety(MOIS, Korea).
 
 
In-situ and real-time detection of micro/nanoplastics in water: Combining laboratory experiments and modelling studies for plastic life cycle analysis
Authors: Wang Zi , Pal Devendra , Pilechi Abolghasem , Fok Cheung Maïline , Ariya Parisa
Published: March 2024

Maritime micro/nanoplastic research provides valuable insights into oceanic plastic waste remediation. Yet, there is a notable disparity, with micro/nanoplastic research in freshwater being ~ 85% less extensive than that in seawater. Observational studies suggest that over 1000 rivers contribute to ~ 80% of the global riverine plastic input into the oceans. Understanding the presence of micro/nanoplastics in freshwater systems is essential for unraveling the global micro/nanoplastic cycle.In our laboratory, a cutting-edge nano-digital inline holographic microscope (nano-DIHM) was developed for real-time and in-situ micro- and nanoplastic research, including physicochemical characteristics, coatings, and dynamic behaviours in freshwater systems. The nano-DIHM data revealed distinct intensity and optical phase patterns of various types of single particles and clusters of micro/nanoplastics (PE, PP, PS, PET, PVC, and PUR), along with other organics (oleic acid), inorganics (magnetite), and biological materials (phytoplankton). We further incorporated a deep neural network functionality to nano-DIHM for rapid micro/nanoplastic detection in real-environmental waters. With its 4D (3D + time) tracking capability, we utilized nano-DIHM to measure the sedimentation (settling and floating) velocity of plastics in two size categories in water. The experimental results were subsequently integrated into a numerical model (CaMPSim-3D) developed at the National Research Council Canada to simulate the transport of plastic particles in Canadian rivers. Complementary modelling results demonstrated distinct distribution and accumulation patterns of macro-, micro-, and nanoplastic particles in aquatic systems, establishing nano-DIHM a powerful approach for plastic life-cycle analysis.
A New Global Color Image Dataset and Reference Frame for Mars by Tianwen-
Authors: Yan Wei , Liu Jianjun , Ren Xin , Chen Wangli , Zeng Xingguo , Wen Weibin , Li Chunlai , Geng Yan , Li Jiawei
Published: March 2024

Global-scale Mars remote-sensing image datasets with accurate and consistent spatial positions contain a wealth of information on its surface morphology, topography, and geological structure. These data are fundamental for scientific research and exploration missions of Mars. Prior to China's first Mars exploration mission (Tianwen-1), none of the available global color-image maps of Mars with a spatial resolution of hundreds of meters were true-color products. On the other hand, there is currently a lack of global optical image datasets on a scale of several tens of meters with high-precision positioning and consistency that can be served as a reference frame for Mars.Global remote sensing of Mars is one of the primary scientific goals of Tianwen-1. As of July 25, 2022, The Moderate Resolution Imaging Camera (MoRIC) onboard the orbiter has obtained 14,757 images, which have allowed acquiring global stereo images of the entire Martian surface. Additionally, the Mars Mineralogical Spectrometer (MMS) has returned 325 strips of visible and near-infrared spectral measurement data. These measurement data have laid the foundation for the development of a high-resolution global color-image map of Mars with high positioning accuracy and internal consistency. After processing of radiometric calibration (atmospheric correction, photometric correction and color correction), geometric correction (global adjustments and orthorectification) and global image cartography (global color uniformity, mosaicking and subdivision), the development of the Tianwen-1 Mars Global Color Orthomosaic and datasets based on these data was completed, with a spatial resolution of 76m and a planar position accuracy of 68m (a root mean square (RMS) residual of 0.9 pixels for tie points). This is currently the highest resolution global true color image map of Mars in the world, which can be served as a new Mars geodetic control network and reference frame. It can provide crucial foundational data for Mars scientific research and engineering implementation.
Unraveling the Preparatory Processes of the 2023 Kahramanmaraş MW7.8-7.6 Earthquake Doublet
Authors: Yin Fengling , Jiang Changsheng
Published: March 2024

Within a span of 9 hours on February 6, 2023, two significant earthquakes, with magnitudes of Mw7.8 and Mw7.6, struck the southeastern part of Türkiye and the northern region of Syria, resulting in significant casualties and widespread economic losses. The occurrence of such intense earthquakes in rapid succession on adjacent faults, especially within a highly complex intraplate region with a multi-fault network, poses a rare phenomenon, presenting new challenges for seismic hazard analysis in such areas. In order to investigate whether the preparatory processes for the Mw7.8-7.6 earthquake doublet could be identified on a large spatial scale prior to the seismic events, we employed a data-driven approach for b-value calculation. The difference in b values from the background values (Δb) in a reference period were used as inputs, and the Cumulative Migration Pattern (CMP) method, quantitatively describing the migration of seismic activity, was utilized to calculate the corresponding probability distributions. The results indicate a widespread phenomenon of decreasing b-values in the study area over a decade before the occurrence of the earthquake doublet, revealing a significant enhancement of differential crustal stress over a large region. Additionally, despite not being the region with the most pronounced decrease in b-values, there is a distinct high probability distribution of CMP near the nucleation points of the earthquake doublet, indicating a spatial and temporal "focus" of increased crustal differential stress in the study area, unveiling the preparatory process of the earthquake doublet. This study reveals quantifiable migration patterns over a long-time scale and a large spatial extent, providing new insights into the evolution and occurrence processes of the 2023 Kahramanmaraş Mw7.8-7.6 earthquake doublet. Moreover, it offers potential clues for seismic hazard analysis in such intraplate regions with multiple fault systems.
Fostering Urban Agriculture in Chinese Cities: Strategies for Enhanced Food Security and Sustainable Development
Authors: Zhu Zhe , Chan Faith Ka Shun , Li Gang , Xu Mengxia , Feng Meili , Zhu Yong-Guan
Published: March 2024

Rapid urbanization globally has set food security under the spotlight, with urban agriculture emerging as a pivotal strategy to address the challenge. In the context of Chinese cities, urban agriculture is revealed in three distinct forms: small-scale, capital-intensive, and tourism-oriented agricultural practices, each influenced by the local socio-economic milieu and governmental directives. This paper examines the multifaceted benefits of urban agriculture, which include supporting social cohesion, advancing public health, fostering environmental stewardship, and creating economic avenues. Despite its numerous advantages, urban agriculture in China contends with obstacles such as land scarcity, capital acquisition, market access, and require more supportive government frameworks. The study delves into the ongoing evolution of the Nature-Based Solutions in urban agricultural practices in China, examining the existing barriers and proposing robust strategies to address them. Drawing upon successful models from the Global North, exemplified by initiatives in the United States, the United Kingdom, France, Spain, and Singapore, the paper outlines a comprehensive set of recommendations aimed at integrating urban agriculture in Chinese cities. The recommendations span four key areas: the integration of agricultural spaces within urban areas, innovative approaches to land and resource utilisation, enhanced governmental support and policy-making, and the establishment of effective planning and regulatory mechanisms. The implementation of these strategies promises to elevate the quality of life for Chinese urban dwellers, pave the way for eco-friendlier urban landscapes, and fortify food security. The ultimate goal is to cultivate a healthier urban future and a resilient agricultural framework that reaps enduring benefits for the populace of China.
Deep borehole based subsurface geophysical monitoring network: TELLUS Project
Authors: Jo Yeonguk , Park Sehyeok , Lee Changhyun
Published: March 2024

We introduce a comprehensive strategy to monitor subsurface fault behavior and associated geophysical environment (e.g., micro-seismicity, stress, groundwater), using a deep borehole based monitoring system. This study provides an in-depth overview of the TELLUS (The Earth Login Leverage for Underground Signal) project, with its individual monitoring system tracking subsurface fault movements with high precision by deploying borehole seismometers, and gathering important data on various geophysical properties.This paper details site selection process and characterizations, the operational framework on monitoring system installations, and the potential of deep borehole monitoring approach in advancing subsurface-related geophysical studies. We conducted extensive review of the distributions of major fault systems in the south-eastern part of South Korea. Subsequently, we strategically selected and arranged candidates for monitoring system installations. Total of six TELLUS deep borehole monitoring systems were installed in the vicinity of the major faults (Yangsan and Ulsan fault).In the TELLUS observatories, preliminary monitoring data is being collected in real time, and this is establishing a foundation for a more precise understanding of the behavior of subsurface faults and the related geophysical environment. It would be expected that the comprehensive analysis of these datasets will further elucidate the intricate subsurface geophysics. This enhanced understanding promises to contribute substantially to our seismic risk assessment capabilities and to the broader field of geoscience research, offering new insights into earthquake prediction and geophysical phenomena.
Projected changes in mean temperature, precipitation and extreme snowfall events over the Tibetan Plateau based on a set of RegCM4 simulations
Authors: Tang Xianbing , Fu Yuanhai , Gao Xuejie
Published: March 2024

Tibetan Plateau (TP, with the height > 3000 m) is a region with complex topographical features and a large diversity of climate both in space and time. Future climate change over TP and the surrounding areas is investigated based on the ensemble of a set of the 21st century climate change projections using a regional climate model, RegCM4. The model is driven by five different GCMs at a grid spacing of 25 km. Results show the RegCM4 greatly improves the temperature and precipitation simulations by providing finer scale spatial details of them over the region. The topographic effects are well reproduced by RegCM4 but not the GCMs. General warming and increase in precipitation are found in both GCM and RegCM4 simulation, but with substantial differences in both the spatial distribution and magnitude of the changes. For temperature, RegCM4 projected a more pronounced warming in DJF over TP compared to its surrounding areas. The increase of precipitation is more pronounced and over the basins in DJF for RegCM4. For the extreme indices of snowfall, RegCM4 generally reproduces the spatial distributions although with overestimation in the amount. General decreases in SNOWTOT and S1mm, with greater magnitude over the eastern part are projected. Both S10mm and Sx5day show decrease over the eastern part but increase over the central and western parts. Notably, S10mm shows a marked increase (more than double) with high cross-simulation agreement over the central TP. Significant increases in all four indices are found over the Tarim and Qaidam basins, and northwestern China north of the TP. The projected changes show topographic dependence over the TP in the latitudinal direction, and tend to decrease/increase in low-/high-altitude areas.
δ13C of bulk leaf matter and cellulose reveal post-photosynthetic fractionation during ontogeny in C4 grass leaves
Authors: Yu Yong Zhi , Schäufele Rudi , Tcherkez Guillaume , Schnyder Hans , Gong Xiao Ying
Published: March 2024

The 13C isotope composition (δ13C) of leaf dry matter is widely employed as an index of physiological characteristics. δ13C of leaf carries integrated signatures of 12C/13C discrimination occurring during and after photosynthesis. The former is well-understood, and models have been developed to infer physiological processes and key parameters in C3 and C4 photosynthesis. However, much less is known about the downstream post-photosynthetic fractionation (∆post) processes. Several mechanisms have been hypothesized, such as isotope fractionation during respiration and the export of photosynthetic products. ∆post could cause the isotopic difference between newly fixed carbon and leaf biomass and thus complicates the interpretation of physiological responses based on isotopic records.We investigated the effects of ∆post on δ13C of mature leaves of Cleistogenes squarrosa, a perennial C4 grass, in controlled experiments with different levels of vapour pressure deficit and nitrogen supply. We measured the 12C/13C fractionation of leaf organic matter relative to the δ13C of atmosphere CO2 (ΔDM) and that of cellulose (Δcel) along leaf age category. With the increase of leaf age classes, ΔDM increased while Δcel was almost constant. Also, ΔDM of young leaves and Δcel had similar responses to vapour pressure deficit and nitrogen treatments. The divergence between ΔDM and Δcelincreased with leaf age classes with a maximum value of 1.6‰, indicating the accumulation post-photosynthetic fractionation. Applying a new mass balance model that accounts for respiration and export of photosynthates, we found an apparent 12C/13C fractionation associated with respiration of –0.7 to –1.1‰ and carbon export of –0.5 to –1.0‰. Furthermore, different 12C/13C fractionation among leaves, pseudostems, daughter tillers and roots indicate that ∆post happens at the whole-plant level.In summary, our study confirmed that leaf became increasingly 13C-depleted during ontogeny and respiration and carbon export are the driving mechanisms. Compared with ΔDM of old leaves, ΔDM of young leaves and Δcel are more reliable proxies for predicting physiological parameters due to the smaller sensitivity to post-photosynthetic fractionation and the similar sensitivity in responses to environmental changes.
How deep is deep enough: disambiguating the acceptable depth for cosmogenic isochron burial dating
Authors: Ma Yan , Pang Jianzhang , Zheng Dewen
Published: March 2024

Cosmogenic 10Be/26Al isochron burial dating is an effective way to accurately determine the depositional time of fluvial sediments that were shallowly buried without requiring any information on post-burial nuclide production and time-dependent burial history. The apparent differences in measured 10Be and 26Al concentrations among a sample assemblage, which derives from the differential erosion in provenance, plays a crucial role in building the isochron. While, when the burial depth is too shallow and/or the amounts of post-burial produced nuclides constitute a main part of total nuclide inventories in samples, the concentration differences among samples would be overwhelmed by the analytical uncertainties of measured 10Be and 26Al concentrations in samples, especially for the old sediments, and it thus leads to a large uncertainty in obtained burial age or destroys totally the isochron. As a result, in the situation of shallow outcrops, a compromise needs to be done between time consumption to dig few meters for sampling and the attainable dating precision. Furthermore, in the cases of shallowly deposited river terraces, especially in the southeastern margin of Tibetan Plateau where the surface erosion is fast and sediments preserved are commonly thin, there is no alternative deeper-buried sediments, and the dilemma between dating but without acceptable uncertainty and not dating has to face. Therefore, the question of how deep is deep enough has to be weighed when sampling. Here, we proposed that the sampling depth of sediments in isochron burial dating should be a flexible standard depending on the isochronicity of the sample assemblage, the predicted burial duration, local geomorphic conditions, and the probably analyzed uncertainties. We try to plot the correlation of predicted age uncertainties with sampling depth, burial ages, as well as the geomorphic parameters, to disambiguate the acceptable depth in the isochron dating for the required dating precision. 
Trace organic compounds in wastewater-loaded lowland River Erpe – Key findings from 12 years of research
Authors: Lewandowski Jörg , Höhne Anja , Jäger Anna , Kronsbein Anna Lena , Meinikmann Karin , Müller Birgit M. , Posselt Malte , Reith Christoph J. , Schaper Jonas , Schulz Hanna , Villa Arroyave Maria Alejandra , Arnon Shai , Horn Marcus A. , Krause Stefan , McCallum James L. , Nützmann Gunnar , Putschew Anke , Spahr Stephanie
Published: March 2024

Increasing concentrations of trace organic compounds (TrOCs) in water bodies worldwide are of great concern. In addition to a general load reduction and a better understanding of the ecotoxicological effects of TrOC cocktails, it is important to better understand the pathways and fate of this large group of compounds in the environment. The lowland River Erpe (Berlin/Brandenburg, Germany), which receives treated wastewater from an urban wastewater treatment plant, is an excellent site for such research, as TrOC concentrations are exceptionally high compared to other German rivers, allowing reliable process studies without much analytical effort such as prior enrichment steps of water samples. In addition, the river system offers a variety of reaches that differ in hydrology and streambed morphology, allowing for different types of investigations. Over the past 12 years, more than 100 researchers have been involved in several large and numerous smaller studies on the River Erpe. Topics have included the role of hyporheic zones in the self-purification capacity of streams with respect to TrOCs, seasonal changes, interactions between easily degradable organic matter and TrOC attenuation, the importance of identifying flow paths for understanding biogeochemical processes, the effects of management actions such as macrophyte removal on the fate of TrOCs, the effects of losing conditions on TrOC input to aquifers and bank filtration systems, the effects of discharge of treated effluent from a large new industrial site on river water composition, and the identification of microbial key players associated with TrOC removal, and much more. Ongoing research includes topics such as bioremediation, the effects of migrating bedforms on the fate of TrOCs, and the effects of droughts on water quality at bathing sites in the receiving River Spree. Research highlights and future directions are presented.
Antarctic total ozone longitude–latitude dependence on sudden stratospheric warmings
Authors: Grytsai Asen , Yu Ruixian , Burmay Alina , Milinevsky Gennadi , Evtushevsky Oleksandr , Klekociuk Andrew , Poluden Oleksandr , Wang Xiaolong , Shi Yu , Ivaniha Oksana
Published: March 2024

We use Multi-Sensor Reanalysis and ground-based total ozone content (TOC) data to study total ozone variations in Antarctica near the dates of sudden stratospheric warmings (SSW). Three events were analyzed, including the warmings in 1988, 2002 (major warming), and 2019. All of them occurred in September, during the period of ozone hole development. Total ozone over stations with different latitudes and longitudes was considered to understand the properties of its variations in different parts of the stratospheric polar vortex and over the surrounding area. The 1979–2022 TOC climatology was obtained from the Multi-Sensor Reanalysis data. The multi-year mean shows a main total ozone minimum in September–October with values lower than 200 Dobson Units (DU) in the Atlantic longitudinal sector (Rothera, Faraday/Vernadsky). The annual TOC maximum of 280–300 DU occurs at the Antarctic stations, mainly in December. The exception is Dumont-d’Urville, located in the zonal maximum region and characterized by higher ozone levels of about 340 DU, which are reached in October–November. Composite analysis is carried out to study the interrelation between SSW events and total ozone variations. We considered a time range covering 60 days before and 60 days after an SSW. Of course, three events do not allow proper statistical material, but some tendencies can be traced. Preliminarily, there is a TOC increase by ~100 DU at Amundsen-Scott (located at the South Pole) near the SSW date. The corresponding increase in the Atlantic longitudinal sector (Rothera, Faraday/Vernadsky, and even mid-latitude Ushuaia station) occurred several days later. It is noticed that after several weeks, TOC values in the Atlantic sector become lower than climatological ones, which a partial recovery of the polar vortex can cause. In the opposite Australian longitudinal sector, TOC values are maintained over the climatological level by tens of DU at least 30–40 days before the SSW. Consequently, the SSW events seem to be prepared by stratospheric processes connected with the intensification of the TOC zonal maximum.This work was partly supported by the projects of the Australian Antarctic Division and by the International Center of Future Science, Jilin University, under Grant No G2023129024.
Forest Ecosystem on the Edge: Mapping Forest Fragmentation Susceptibility in Tuchola Forest, Poland
Authors: Dutt Sanjana
Published: March 2024

Amidst the growing urgency to sustain forest ecosystems, this study presents a crucial analysis of forest fragmentation susceptibility in Poland's Tuchola Forest—a region recurrently devastated by windstorm events. Our research aims to innovatively harness remote sensing technologies for a comprehensive assessment of forest fragmentation from 2015 to 2020. The study primarily revolves around three objectives: selecting the most suitable remote sensing dataset for monitoring fragmentation, identifying key contributing factors to forest fragmentation, and developing a susceptibility map to illustrate the forest’s fragmentation dynamics.Employing a comparative analysis with the GTB tool, we scrutinized the capabilities of PALSAR (25m resolution) and Dynamic World (10m resolution) datasets. Our findings highlighted PALSAR's superior proficiency in detecting rare-patchy fragments, despite its marginally higher resolution. To construct a forest fragmentation susceptibility map, we used fragmented patches observed over the last six years as indicators of regions prone to intense fragmentation. These patches were further analyzed through the Weight-of-Evidence (WOE) method, where causative factors were normalized and scrutinized using a Correlation matrix.The results indicate a heightened vulnerability of forest areas proximal to agricultural lands (
Emulators for Predicting Tsunami Inundation Maps at High Resolution
Authors: Gibbons Steven J. , Briseid Storrøsten Erlend , Ramalingam Naveen , Lorito Stefano , Volpe Manuela , Sánchez-Linares Carlos , Løvholt Finn
Published: March 2024

Predicting coastal tsunami impact requires the computation of inundation metrics such as maximum inundation height or momentum flux at all locations of interest. The high computational cost of inundation modelling, in both long term tsunami hazard assessment and urgent tsunami computing, comes from two major factors: (1) the high number of simulations needed to capture the source uncertainty and (2) the need to solve the nonlinear shallow water equations on high-resolution grids. We seek to mitigate the second of these factors using machine learning. The offshore tsunami wave is far cheaper to calculate than the full inundation map, and an emulator able to predict an inundation map with acceptable accuracy from simulated offshore wave height time-series would allow both more rapid hazard estimates and the processing of greater numbers of scenarios. The procedure would necessarily be specific to one stretch of coastline and a complete numerical simulation is needed for each member of the training set. Success of an inundation emulator would demand an acceptable reduction in time-to-solution, a modest number of training scenarios, an acceptable accuracy in inundation predictions, and good performance for high impact, low probability, scenarios. We have developed a convolutional encoder-decoder based neural network and applied it to a dataset of high-resolution inundation simulations for the Bay of Catania in Sicily, calculated for almost 28000 subduction earthquake scenarios in the Mediterranean Sea. We demonstrate encouraging performance in this case study for relatively small training sets (of the order of several hundred scenarios) provided that appropriate choices are made in the setting of model parameters, the loss function, and training sets. Scenarios with severe inundation need to be very well represented in the training sets for the ML-models to perform sufficiently well for the most tsunamigenic earthquakes. The importance of regularization and model parameter choices increases as the size of the training sets decrease.