bluuebunny/crossref_metadata_2025 huggingface dataset:
Fossil earthquakes preserved on fossils: New examples
Authors: Lin Jih-Pai , Tseng Chien-Chia , Chang Chung-Pai , Chen Chi-Wen
Published: March 2024

The coastal plain of Miaoli is classified as part of the Outer Foothill of the Western Foothill in Taiwan. Around six million years ago, the initiation of the Penglai Orogeny set off significant tectonic activities in the Miaoli region, resulting in the formation of numerous faults and folds. These geological structures have played a concurrent role in influencing the occurrence and preservation of fossil echinoids in the area.Unlike the commonly reported deformed fossils found in Mesozoic and older strata, this study documents new instances of deformed fossils from the Pleistocene strata in Taiwan. Through micro-CT tomographic imaging, the 3D geometry of fault planes in deformed sand dollars is revealed. Thin sections expose additional tectonic structures, including pressure solutions, box folds, and monoclines. Some deformations, both ductile and brittle, such as fractures along the taphonomically weak ossicle boundaries, may have originated from sedimentary processes. However, fault features triggered by earthquakes are unmistakably preserved in rare specimens.Notably, a thorough analysis of earthquake epicenters in Miaoli since 1997 indicates that no earthquakes occurred in proximity to the fossil localities. Consequently, it is deduced that the deformed specimens are a result of ancient or fossilized earthquakes. This study presents novel and distinctive evidence contributing to the comprehension of neotectonics regarding the collision between the Philippine Sea Plate and Eurasia Plate in Taiwan, as inferred from fossils.
Using digital technology to teach climate science
Authors: Ait Ouferoukh Lydia
Published: March 2024

Understanding contemporary climate change requires studying the climate system, how it works and evolves.Various tools, such as palynological studies, oxygen isotope ratios, numerical modelling, etc. can be used to trace the evolution of the climate. Much of this data is accessible through the publication of databases and numerical modelling. In addition, the increasingly powerful numerical tools are mainly available to classrooms: use of spreadsheets, graphs, free softwares such as SimClimat, etc.Leveraging these tools in my lessons and the training of my students seemed natural to me in a world where digital technology and information are available to all.The poster I am presenting showcases some numerical activities carried out with students from the Groupe scolaire Sainte Louise, in Paris, aimed at helping them grasp those fundamental concepts of climate system.The integration of digital technology not only enhances the dynamism of learning but also motivates students to actively participate, opening up exciting educational possibilities.
Complex dayside particle precipitation observed during the passage of solar wind discontinuities  
Authors: Berchem Jean , Wing Simon , Escoubet C. Philippe
Published: March 2024

Most studies of the geoeffectiveness of the solar wind tend to focus on coronal mass ejections (CMEs) and Corotating Interactive Regions (CIRs). By comparison, fewer studies focus on the geoeffectiveness of the solar wind directional discontinuities (DD), either tangential discontinuity (TD) or rotational discontinuity (RD).  We present two examples of solar wind DD interaction with the magnetosphere that lead to complex dayside particle precipitation structures even though the geomagnetic activities remain quiet in those two events.  In the first example, the DD leads to the formations of unusual boundary layer, overlapping mantle, and double cusp as observed by the DMSP spacecraft. The double cusp signature is consistent with simultaneous magnetic reconnection occurring at both low and high latitudes due to the dominant IMF By as confirmed in a global MHD simulation for the event. The existence of a high-latitude reconnection in this even is also supported by Cluster C2, which observes velocity fluctuations and reversals with peak-to-peak amplitudes >800 km s–1 as C2 crosses the magnetopause.  Guided by the MHD simulation, the Cluster observation can be interpreted as the spacecraft crossing reconnection outflows while moving from one side of the X-line to the other.  In the second example, the DD leads to the unusual particle precipitation structure where three distinct ion populations can be found on the same magnetic field line.  These three populations have energies of a few hundreds eVs, a few keVs, and a few tens of keVs, suggesting that ions originating from the magnetosphere, solar wind, and ionosphere, respectively, can coexist on the same field line unthermalized.  Moreover, this unusual particle precipitation region has a spatio-temporal scale of about 1 min or 500 km in the ionosphere.
Quantitative description and characteristics of submeso motion and turbulence intermittency
Authors: Ren Yan , Zhang Hongsheng
Published: March 2024

Turbulence intermittency driven by submeso motions limits the progress of turbulence theory. Field observations from the Horqin Atmospheric Boundary-Layer and Environment Experimental Station, China were used to investigate turbulence intermittency. An automated algorithm to Separate and reconstruct Submeso and Turbulent motions (SST) was improved for more accurately extraction and quantitative characterization of submeso motions. The existing intermittency intensity indices, the local intermittency strength of turbulence (LIST) and intermittency strength (IS), which are based on kinetic energy only, are revised by considering the potential energy of submeso and turbulent motions to quantify intermittency intensity more comprehensively. The analysis of eight cases revealed that turbulent intermittency events are characterized by quiescent (pulsation, material, and energy transportation are weak) and burst (pulsation, material, and energy transportation fluctuate violently) periods. The conversion of both the kinetic and potential energy of submeso to turbulent motion contributes to the transition from quiescent to burst periods. The transition always occurs after ΔTE
Impacts of wildfire on desorption of radionuclide and subsequent wash-offs in the Chornobyl Exclusion Zone
Authors: Igarashi Yasunori , Protsak Valentyn , Laptev Gennady , Maloshtan Igor , Samoilov Dmitry , Kirieiev Serhii , Onda Yuichi , Konoplev Alexei
Published: March 2024

The Chornobyl wildfires of 2020 raises concerns regarding radionuclides wash-off from post fire sites. The objective of this study is to determine the speciation of 137Cs and 90Sr in the ash and soil. And to reveal the impact of the wildfires on concentrations of 137Cs and 90Sr in river water in Chornobyl. To accomplish this objective, extraction tests were conducted using ash and soil samples collected immediately after the 2020 fires to determine the water-soluble and exchangeable fractions of 137Cs and 90Sr in the ash and soil. Long-term river-water radionuclide concentration records were also analyzed.The results showed that the solid–liquid distribution coefficient (Kd) of ash was significantly lower than that of soil for 137Cs, while for 90Sr there was no significant difference in Kd between ash and soil. Analysis of river water data indicated that 90Sr concentrations higher than the Ukrainian drinking water standard (> 2 Bq/L) were observed more frequently following wildfires in the Sakhan River catchment. The fires increased 90Sr concentrations over the following two years, particularly in the spring, when snowmelt causes substantial releases, and in the summer and autumn, when surface flows occurred. High 90Sr concentrations were observed only within the Chornobyl Exclusion Zone, so additional human uptake of or dose exposure to 90Sr from river water is not expected.The Chornobyl wildfires, which is a short period when radioactive contamination levels are elevated in the ecosystem, affected radionuclide speciation, turning the catchment into a location where radioactive contamination levels are significantly higher than in the surrounding area for the redistribution of radionuclides.
Groundwater storage change monitoring in North China Plain based on GNSS and satellite gravity
Authors: Wang Wei , Zhang Chuanyin , Yang Qiang , Zhao Tingting , Jiang Tao
Published: March 2024

The North China Plain in China is one of the areas with the scarcest water resources, and it is an area with more groundwater extraction. The form of groundwater in this area is severe, and it is necessary to monitor the changes in groundwater reserves in this area. Traditional use of groundwater wells to monitor changes in groundwater levels makes it difficult to obtain accurate changes in groundwater reserves. GRACE/GRACE-FO satellite gravity has made great achievements in the changes of land water reserves and groundwater reserves, but due to the low spatial resolution, it is not possible to obtain the changes of groundwater reserves in the North China Plain. This paper integrates GNSS and GRACE/GRACE-FO satellite gravity data, based on the load deformation theory, effectively integrates GNSS and satellite gravity data, separates groundwater balance effect and groundwater load impact, obtains the change of groundwater reserves in the North China Plain from 2018 to the end of 2021, and conducts comparative analysis on the observation data of groundwater wells and precipitation data, finding that the downward trend of groundwater level has slowed down, The groundwater reserves in the North China Plain declined as a whole, and the groundwater in some areas of Beijing rose slightly.
Impact of outer-rise slab hydration on the intermediate-depth seismicity: Evidence from near field OBS observation in the southernmost Mariana subduction zone
Authors: Chen Han , Zhu Gauhua , Yang Hongfeng , Lu Shaoping , Chen Chuanxu , Lin Jian
Published: March 2024

Intermediate-depth earthquakes (IDEs), i.e., earthquakes at depths of 70 to 300 km, have been observed in subduction zones globally and extensively investigated. However, the seismogenic mechanism of IDEs is still controversial, especially in the southern end of the Mariana Trench, where near-field observations are lacking. By using machine-learning-based methods in three sets of near-field Ocean Bottom Seismogram (OBS) network data, we detected and located more than 1,000 intraplate and interplate earthquakes. The seismogenic volumes in different regions of the subducted plate are different, showing the character of double seismogenic zones (DSZ) and single seismicity layer (SSZ). The seismicity features coincide well with the regional landform, development of outer-rise faults, and hydration scenarios, suggesting a dehydration-related mechanism for the generation of IDEs. The subducted slabs experience different degrees of slab hydration, leading to various seismic behaviors.
Reactivation of mantle lithosphere scars: deep sutures inducing shallow intraplate earthquakes? 
Authors: Heron Philip , Wan Congyi
Published: March 2024

Ancient plate tectonic processes (e.g., continental collisions) can generate deformation deep into the lithosphere, highlighted by seismological imaging showing mantle lithosphere heterogeneities (thought to be scarring from past events). As the mantle lithosphere is the largest (and often strongest) component part of a tectonic plate, it has the potential to control tectonic deformation at the surface. A number of numerical modelling studies indicate the closure of ancient plate boundaries could generate latent deep structures that could be ‘perennially’ reactivated in intraplate settings - dominating shallow geological features in activating tectonics in plate interiors. This work has often been linked to large-scale tectonic processes such as continental rifting and orogenesis. However, in order to fully understand such ‘bottom-up’ influences on plate tectonic processes, it is important to analyse such mechanisms in more ‘actualistic’ models (e.g., finding evidence in present-day tectonics) rather than applying to ancient activity (e.g., to events millions of years ago).Here, we analyse the present-day intraplate earthquake database for any scenarios where deep latent lithosphere structures could drive shallower seismic events. Case studies for intraplate earthquakes of Central China, North America, Scotland, and Africa are presented using a new visualisation software we’ve developed to handle large amounts of seismic events. A potential present-day example of this theoretical deep trigger of shallow earthquakes is examined in detail, with careful attention given to the inherent uncertainty of this work. Finally, we highlight the difficulty in understanding the rheology and composition of latent structures deep in the lithosphere, and whether they can be passive or active in present-day tectonics. 
Optimal observing strategy of GENESIS in geodetic VLBI experiments 
Authors: Schunck David , McCallum Lucia , Molera Calvés Guifré
Published: March 2024

One of the major deficiencies in the realization of the International Terrestrial Reference Frame (ITRF) stems from the combination of the four space-geodetic techniques, that are contributing: Very Long Baseline Interferometry (VLBI), Global Navigation Satellite Systems (GNSS), Satellite Laser Ranging (SLR), and Doppler Orbitography and Radiopositioning Integrated by Satellites (DORIS). The GENESIS satellite mission, a component of the European Space Agency’s (ESA) FutureNAV program, will address this problem. Scheduled for launch in 2027, the GENESIS satellite embodies a dynamic space-geodetic observatory, equipped with instruments encompassing all four space-geodetic techniques. The mission’s objective is to facilitate the in-orbit combination and co-location of these techniques in space, known as space ties. It is not yet known how GENESIS will be implemented in geodetic VLBI operations. In this talk, we will present a dedicated simulation study of VLBI observations to the GENESIS satellite. We look at the realistic observability given current and foreseeable antenna networks and session cadence. We schedule and simulate VLBI observations to the GENESIS satellite to investigate the accuracy with which VLBI antenna positions of a global network can be derived. In addition to the most common VLBI error sources, troposperic delays, clock inaccuracies, and white noise, we simulate satellite orbital errors. The observations to the GENESIS satellite are scheduled within regular, geodetic experiments. We compare different schedules varying the amount of time that is dedicated to observe the satellite. We analyse how incorporating these observations reduces the amount of time quasar sources are observed and, consequently, how fundamental geodetic VLBI observables, i.e. Earth Orientation Parameters (EOPs), are affected. We try to answer the question whether it would be necessary to include observations to the GENESIS satellite outside of regular geodetic experiments in the form of dedicated GENESIS sessions. The fact that VLBI is organized in sessions instead of continuous observing further raises the question to assess a minimal mission lifetime to achieve desired accuracies.
Reproducing computational processes in service-based geo-simulation experiments
Authors: Zhu Zhiyi , Chen Min
Published: March 2024

Geo-simulation experiments (GSEs) are experiments allowing the simulation and exploration of Earth’s surface (such as hydrological, geomorphological, atmospheric, biological, and social processes and their interactions) with the usage of geo-analysis models (hereafter called ‘models’). Computational processes represent the steps in GSEs where researchers employ these models to analyze data by computer, encompassing a suite of actions carried out by researchers. These processes form the crux of GSEs, as GSEs are ultimately implemented through the execution of computational processes. Recent advancements in computer technology have facilitated sharing models online to promote resource accessibility and environmental dependency rebuilding, the lack of which are two fundamental barriers to reproduction. In particular, the trend of encapsulating models as web services online is gaining traction. While such service-oriented strategies aid in the reproduction of computational processes, they often ignore the association and interaction among researchers’ actions regarding the usage of sequential resources (model-service resources and data resources); documenting these actions can help clarify the exact order and details of resource usage. Inspired by these strategies, this study explores the organization of computational processes, which can be extracted with a collection of action nodes and related logical links (node-link ensembles). The action nodes are the abstraction of the interactions between participant entities and resource elements (i.e., model-service resource elements and data resource elements), while logical links represent the logical relationships between action nodes. In addition, the representation of actions, the formation of documentation, and the reimplementation of documentation are interconnected stages in this approach. Specifically, the accurate representation of actions facilitates the correct performance of these actions; therefore, the operation of actions can be documented in a standard way, which is crucial for the successful reproduction of computational processes based on standardized documentation. A prototype system is designed to demonstrate the feasibility and practicality of the proposed approach. By employing this pragmatic approach, researchers can share their computational processes in a structured and open format, allowing peer scientists to re-execute operations with initial resources and reimplement the initial computational processes of GSEs via the open web.
ENIGMA: East-Asian Network Initiative for Gravity Measurement Alliance: A Proposal and Science Cases
Authors: Son Edwin J. , Kim Jeong Woo , Oh John J. , Kim Hwansun , Hwang Cheinway , Cheng Ching-Chung , Ito Yoshihiro , Tanaka Yoshiyuki , Shen Wenbin , Luan Wei , Hu Minzhang , Liu Ziwei , Sun Heping , Chen Xiaodong , Bae Sangwook , Yoon Heejun
Published: March 2024

We propose the establishment of an observational network comprising micro gravitometers across East Asia including, but not limited to Republic of Korea, Japan, Taiwan, and the Chinese mainland. The network will generate a parallel observation belt within the seismogenic zone that connects the Japan Trench, Ryuku Trenches, and Nankai Through, both constituent components of the Ring of Fire, for the detection of slight changes in micro-gravity for analyzing earthquakes of different magnitudes with different sources and depths. We will establish a data hub for sharing data, managing combined data format, and distributing computing resources for conducting collaborative research. In addition, the network measurement of micro-gravity can be used for searching the dark matter candidate inside Earth. The presentation demonstrates various science cases that could be undertaken by implementing a network of GWR Instruments Inc.’s superconducting gravimeters and a data hub within the East Asian region.
Acoustic-gravity waves generated by a point earthquake source
Authors: Gao Yongxin , Li Ting
Published: March 2024

It is reported that earthquakes can trigger coseismic ionospheric disturbances, leading to the so called Lithosphere-atmosphere-ionosphere (LAI) coupling phenomenon. The acoustic-grave wave (AGW) is an important mechanism to induce such a phenomenon. In this study, we present a semi-analytic method to calculate AGWs excited by an earthquake source in the stratified lithosphere-atmosphere model and conduct numerical simulations to investigate characteristics of the AGWs. The results show that mainly two kinds of AGWs can be generated by the earthquake source. One is the head AGWs wave generated by the Rayleigh wave propagating along the surface, which propagates upwards nearly vertically. Another one is the epicenter AGWs generated by the direct seismic waves from the source. Both the head and epicenter AGWs are sensitive to the earthquake focal mechanism and are influenced by the structures of the atmosphere and solid earth. We also apply our method to a real earthquake event and compare the synthetic signals with the observed data.
Comparing float pCO2 profiles in the Southern Ocean to ship data reveals discrepancies
Authors: Zhang Chuqing , Wu Yingxu , Brown Peter J. , Stappard David , Silva Amavi N. , Tyrrell Toby
Published: March 2024

The Southern Ocean plays a crucial role in the global carbon cycle. Recently, the utilization of biogeochemical (BGC) Argo float data has provided valuable insights into the uptake and release of carbon dioxide (CO2) by this region. However, significant uncertainty remains regarding the accuracy of pCO2 (partial pressure of CO2) values derived from float data. In this study, we compared pCO2 estimates obtained from float pH data with those from ship-collected data across the Southern Ocean, employing pCO2-depth, pCO2-O2 and CO2-O2 vssaturation plots to assess the degree of agreement between these two datasets. Our findings reveal significant systematic differences. A preliminary analysis, ignoring other factors, found that the float data is consistently higher, on average, than the ship data at equivalent depths and oxygen levels. We tested the hypothesis that inaccurate float pH data or float pCO2 correction process is the main cause of the pCO2 difference, by quantifying other factors that could produce systematic differences, including: (i) spatial sampling bias, (ii) seasonal bias, (iii) errors in estimated alkalinity, (iv) errors in carbonate system constants, and (v) higher levels of anthropogenic CO2 in float data. However, none of the other factors were found to be able to fully account for the discrepancies, suggesting issues with float pH data quality and/or the float pCO2 correction process. Additional analysis included refinements to ship-based and float-based pCO2 before intercomparison. Overall, we estimate that, in the Southern Ocean, surface pCO2 from floats is biased high by, on average, at least 10 μatm.
Spatial-temporal variation and driving factors of the gray water footprint of the Guangdong-Hong Kong-Macao Greater Bay Area, China
Authors: He Yanhu , Liu Binfen
Published: March 2024

Water resources are the foundation for socio-economic development. The grey water footprint (GWF) serves as a vital indicator that quantifies the impact of human activities on water environment and sustainable water use, and plays an important role in addressing the challenges posed by water pollution and scarcity. The Guangdong-Hong Kong-Macao Greater Bay Area (GBA), a crucial driver of China's economy, faces the dual challenges of rapidly developed economy and grappling with severe overloading of its water environment. To systematically assess the water environment of the GBA, this study utilized panel data from 2008 to 2021 to calculate the GWF of this region, considering pollution sources from agriculture, industry, and domestic activities. On this basis, spatial analysis methods and a random forest model were respectively applied to explore the spatial-temporal evolution characteristics and driving factors of GWF in the GBA. Results show that the overall GWF of the GBA initially increased, reaching its peak of 98.94 billion m³ in 2011, and subsequently declined between 2011 and 2021, with an average annual reduction rate of 5.4%. Spatially, both the overall GWF and domestic GWF exhibited an east-to-west decreasing pattern, with the agricultural GWF displaying higher values in the surrounding areas and lower values in the central region. Population and economic factors are the key driving forces of the GWF, with relative importance percentages of 18.07% and 17.55%, respectively. This study establishes a scientific basis for water resource management and sustainable water use in the GBA, providing valuable guidance to relevant government agencies.
A physics-based statistical model to predict sub-hourly extreme precipitation intensification based on temperature shifts
Authors: Marra Francesco , Koukoula Marika , Canale Antonio , Peleg Nadav
Published: March 2024

We present a new statistical method for estimating extreme sub-hourly precipitation return levels that explicitly hinges on our physical understanding of the processes. The TENAX (TEmperature-dependent Non-Asymptotic statistical model for eXtreme return levels) model is based on two modules: (i) a magnitude module describes precipitation intensities using temperature as a covariate. It includes all the information about thermodynamics and local dynamics of the processes at a given temperature; (ii) a temperature module accounts for the distribution of daily temperature during rainfall events. Using the total probability theorem, the two modules are linked to provide a physics-based estimate of the marginal distribution of the precipitation intensities. Return levels are then estimated using a non-asymptotic method. Assuming that the physics of convection remains unchanged in the future (i.e., no change in the magnitude module) and that convection remains the dominant process, the TENAX model enables to project future sub-hourly precipitation return levels only based on the projected changes in daily temperature during rainy days. We will discuss the theory behind TENAX and show it can reproduce return levels with the same accuracy as more parsimonious non-asymptotic methods. We will additionally show that the model reproduces known properties of the extreme precipitation-temperature scaling relation for which it was not explicitly designed. Last, in hindcast, we will demonstrate that TENAX trained on observations of precipitation and temperature can well reproduce “future” unseen return levels only based on projections of daily temperatures. As projections of daily temperature from climate models are more readily available and accurate than those of sub-hourly extreme precipitation, TENAX could allow one to derive future sub-hourly return levels in any location globally where observations of past sub-hourly precipitation and daily near-surface air temperature are available.
Effects of watershed subdivision based on soil and land use inputs on SWAT performance in a coastal Mediterranean catchment
Authors: Puche Mathilde , Troin Magali , Fox Dennis , Royer-Gaspard Paul
Published: March 2024

Assessing the benefits of increasing the discretization level of semi-distributed hydrological models is of great importance for hydrological applications. The impact of spatial discretization on model performance is investigated with the use of the Soil and Water Assessment Tool (SWAT) model when applied on a Mediterranean watershed (Argens, France). This study aims to explore how the spatial discretization (number of sub-basins and of hydrological response units (HRUs)) affects the model’s performance at simulating daily streamflows, and if the choice of soil and land use input datasets modifies model accuracy. Low and moderate resolution soil (5 km and 250 m) and land use (400 m and 100 m) maps are considered. Four SWAT input sets are created, each corresponding to a different combination of land use and soil datasets. Each input set is used to build 17 configurations with an increasing number of sub-basins (4, 12, and 18) and HRUs (from 4 to 320). The 68 models (4 input sets x 17 configurations) are evaluated on the 2001-2021 period using the Kling-Gupta efficiency (KGE) metric. Results indicate no influence of the number of sub-basins on SWAT performance. However, increasing the number of HRUs leads to a significant performance decrease (from 0.13 to 0.26 of KGE loss), regardless of the number of sub-basins and input datasets. The SWAT model is found to be more sensitive to soil dataset than to land use dataset. Despite significant differences in hydrological soil groups between the two soil maps, no clear impact on the derived hydrological properties is observed, such as the curve number. The observed decline in SWAT performance with an increasing number of HRUs is attributed to the calibration process rather than the soil and land use input datasets. This study suggests that, when the calibration of the semi-distributed SWAT model is not performed at the finer spatial HRU level, an increase in the spatial discretization does not lead to an improvement of the overall model accuracy.  Therefore, minimizing the number of HRUs during the watershed subdivision is recommended for getting optimal simulations of streamflow while dealing with the computational efficiency of SWAT.
Improving runoff generation knowledge through baseflow campaigns
Authors: Innocente dos Santos Camyla , Klaus Julian , Chaffe Pedro Luiz Borges
Published: March 2024

Predictions from Global Climate Models point to increasing water scarcity across the Global South. However we currently lack understanding of how these predicted changes propagate through the hydrological cycle to smaller-scale systems. This lack of understanding is due to limited knowledge of hydrological processes, which persists in tropical, subtropical, and arid environments of the Global South. Clear blueprints exist for experimental catchment setups that allow us to understand spatiotemporal catchment processes (e.g., the Long Term Ecological Research LTER, the Critical Zone Observatory network CZO, and the Terrestrial Environmental Observatories TERENO); yet, it is not feasible to maintain such dense experimental networks in the understudied Global South. Reconciling snapshot baseflow campaigns as sources of data can be an alternative to expanding hydrological observation, particularly in developing countries where long-term records are scarce and pressure on water resources is growing. Here, we present results from baseflow campaigns in small nested catchments across different landscape elements to improve a rainfall-runoff model (geomorphologic instantaneous unit hydrograph) and provide insights into spatial patterns of flow, catchment water storage, and estimates of streamflow sources. The Peri Lake Experimental Catchment (19 km²) is characterized by granite and diabase dike and covered by the Atlantic rainforest. We measured baseflow discharge and sampled isotopes (δ18O and δ2H) at 25 catchments (areas ranging from 0.02 to 5.33 km²). Through combining flow velocity and discharge, we incorporated spatial variations of velocity in the channels during runoff, using a constant relationship between velocity and celerity. The Nash values were above 0.80, and we eliminated the need for concentration time formulas, where uncertainty reaches 500%. Combining isotopes and discharge enhanced our knowledge of the role of geology, with the Spearman coefficient between the percentage of granite and specific discharge being -0.68 (p-value < 0.05). We conceptualize that the diabase dikes are shallower with greater permeability, functioning as a conductor and supplier of water during baseflow. Simulations with a 3D surface-subsurface hydrological model  verify the capacity of the observed baseflow patterns in this catchment with heterogeneous geology. The results suggest that measurements in nested catchment during baseflow conditions reflect the heterogeneity of the different sources that contribute to streamflow. Snapshot measurement and sampling  campaigns are a powerful tool to understand runoff generation patterns in subtropical and tropical catchments of the Global South where continuous monitoring is hard to implement.
Lithospheric velocity structure of South China Sea basin from ocean bottom seismometer ambient noise tomography
Authors: Cheng Liqun , Fang Yinxia , Niu Xiongwei , Li Tingzi , Dong Chongzhi , Zhao Yanghui , Hu Hao , Kong Fansheng , Tan Pingchuan , Ruan Aiguo , Lu Shaoping , Fan Jianke , Muhammad Hafeez Jeofry , Ding Weiwei , Li Jiabiao , Du Xinguang
Published: March 2024

The South China Sea (SCS) located at the intersection of the three intercontinental plates of Eurasia, IndiaAustralia, and the Pacific Oceanis, is a typical marginal sea basin formed by the seafloor spreading under the tectonic background of plate convergence. Many crustal-scale studies indicate that the SCS basin has undergone asymmetric spreading, multi-phase ridge jumps, and intense post-spreading volcanic activity. Due to the lack of seismic data in the oceanic basin of the SCS, it remainsunclear about the scale and basin control of the Zhongnan fault, the magma source depth of the SCS basin, and the transport channel after the cessation of seafloor spreading. Phase velocity derived from ambient noise surface wave tomography may provide useful information to shed light on the mechanisms of the aforementioned problems. From October 2019 to July 2020, a 3D Ocean Bottom Seismometers (OBS) passive seismic observation experiment was carried out by the Second Institute of Oceanography, Ministry of Natural Resources (SIOMNR) in a broad area of the SCS. Based on the seismic ambient noise data recorded by 16 OBSs in the SCS basin, we inverted the phase velocity images over a period range of 10–20 s using ambient noise surface wave tomography. Our results indicate that the Zhongnan fault zone is a lithospheric-scalefault, which played a regulating role in the last oceanic ridge transition of the SCS basin from the East Subbasin to the Southwest Subbasin. In addition, the low-velocity body in the north flank of the Southwest Subbasin extends from the post-spreading seamounts on the ocean crust to the uppermost mantle (i.e., about 10–30 km), which indicates an oblique magma migration during the postspreading volcanism.
 Inter-Sectoral Trade-offs in Large Scale Land Acquisitions and Implications for Household Health and Livelihood
Authors: Muller Marc , Faure Julie , Davis Kyle , Mehta Piyush , Chiarelli Davide , Rulli Cristina , D'Odorico Paolo , Dell'Angelo Jampel , Bertassello Leonardo
Published: March 2024

The recent two decades have marked a significant increase in transnational land investments, fueled by growing demands for food, water, and energy. This global land rush, primarily affecting rural areas in low and middle-income countries, where it often contributes to ongoing transitions from smallholder farming into large-scale commercial agriculture. A key aspect of this transition is the inter-sectoral trade-offs at the nexus of food, water, energy, and the environment, where global demands intersect with local health, livelihoods, and ecosystems. Most existing studies have focused on individual impacts of land acquisitions on these sectors, but a comprehensive understanding of (i) the trade-offs across sectors and (ii) their implications for household health and livelihoods is lacking. Our study addresses these gaps, using a clustering technique to analyze a unique dataset of over 160 georeferenced land deals. This method helps categorize the interplay and trade-offs between the impacts on food, energy, water, and the environment. By linking these trade-offs to specific characteristics of land deals, we identify distinct archetypes, each necessitating tailored policy responses. The extent of household health and livelihood impacts varies across these archetypes. We assess these implications using data from approximately 1.3 million households from 22  countries. This novel approach, merging a global analysis of sectoral impacts with local household effects, aims to provide insights for targeted policies to ensure a sustainable and equitable agrarian transition.
Urban Climate and CO2 Simulations with the New Atmospheric Model ICON-ART Accounting for Spatially Varying Urban Morphology and Material Properties
Authors: Dönmez Kutay , Emmenegger Lukas , Brunner Dominik
Published: March 2024

Over the last decade, numerous urban canyon schemes have been developed, aiming to reproduce the interactions between the urban surface and the atmosphere. They have either used a bulk approach, where the general urban surface characteristics are modified, or a layered approach, in which single or multiple canyon levels are adopted, taking into account the contributions of individual urban facets: such as roofs, walls, and floors. Bulk schemes have often been the preferred approach in numerical weather prediction and climate models for their cost-efficient way of representing key atmosphere-canopy interactions and other important urban characteristics.TERRA_URB is one of these bulk urban canopy models (UCM), originally developed for the COSMO atmospheric model. It has recently been integrated into the Icosahedral Non-hydrostatic Weather and Climate Model (ICON). In this study, we extended the preliminary implementation in ICON with the capability of representing morphological and material properties of the urban surfaces as spatially varying (instead of constant) fields in order to better represent the variability of energy, moisture, radiation, and momentum fluxes between the canopy and the atmosphere across a city. The spatially varying properties were derived from the Ecoclimap Second Generation (ECOCLIMAP-SG) land cover dataset, which is the latest version of ECOCLIMAP, incorporating local climate zones with a relatively high resolution of 300 meters. To assess the performance of ICON with TERRA_URB, we simulated the hot and dry summer period of mid-July to mid-August 2022 over the cities of Zurich and Basel in three configurations, (i) without TERRA_URB, (ii) with TERRA_URB in the preliminary and (iii) in the enhanced version. The three versions were compared against each other and evaluated against different types of observations, including standard weather stations, temperature sensor networks, and flux tower measurements.Overall, our results reinforce the importance of incorporating accurate characterization of urban morphological and material properties into UCMs. Going forward, we will further improve these urban parameters by incorporating local datasets not accessible to a global product like ECOCLIMAP-SG. This will include, among others, detailed 3D building information, building material properties, surface reflectance (albedo) properties derived from remote sensing, and anthropogenic heat fluxes estimated from a detailed CO2 emission inventory. Our ultimate goal is to develop a comprehensive ICON-based urban modeling system that can be run with either a bulk UCM or the multilayer UCM BEP-Tree, previously developed in our group for COSMO. This novel modeling system will allow us to study the feedback between vegetation, carbon, energy, and water cycles in the urban environment.
Supplementing rainfall simulator studies with single drop measurements
Authors: Beczek Michał , Ryżak Magdalena , Gibała Karolina , Mazur Rafał , Sochan Agata , Polakowski Cezary , Beczek Tomasz , Bieganowski Andrzej
Published: March 2024

Rainfall simulators are essential tools for geoscientific and hydrological research, e.g. water erosion processes, throughfall phenomenon, interception etc. They allow the creation of suitable and reproducible experimental conditions providing a large amount of information. However, in certain situations, e.g. the soil splash phenomenon, other research methods are needed to study the basic processes and mechanisms on a smaller scale, i.e. concerning the interaction of single drops. In such a case, single drop measurements used with raindrop generators can be a good complementary tool for rainfall simulators. They provide complete understanding and description of the investigated phenomenon.The aim of this study was to present selected measurement methods based on the single drop methodology which are used to investigate splash erosion and surface deformation, interaction of drops with leaves or conifers, and microorganism transportation. These include: a) a set of high-speed cameras with PTV (Particle Tracking Velocimetry) software used to identify, track, and characterize the splashed particles and water droplets; b) splash cup measurements for the determination of the mass ratio of splashed particles during the raindrop splash phenomenon; c) a 3D surface scanner and microtomography for the description of surface deformation after the drop impact; d) a laser diffraction method and light microscopy for the determination of the size of splashed particles; e) IRMS (Isotope-ratio mass spectrometry), i.e., deuterium-labelled water used to the define the origin of the splashed water. This work was partly financed from the National Science Centre, Poland; project no. 2022/45/B/NZ9/00605. References:Beczek M., Ryżak M., Sochan A., Mazur R., Polakowski C., Hess D., Bieganowski A.: Methodological aspects of using high-speed cameras to quantify soil splash phenomenon. GEODERMA 378, 2020Mazur R., Ryżak M., Sochan A., Beczek M., Polakowski C., Przysucha B., Bieganowski A.: Soil deformation after one water-drop impact – The effect of texture and soil moisture content. GEODERMA 417, 2022Ryżak M., Beczek M., Mazur R., Sochan A., Gibała K., Polakowski C., Bieganowski A.: The splash of a single water drop on selected coniferous plants. Forest Ecology and Management 541, 121065, 2023
Soil and plant water ages in two Pinus radiata forests with markedly different annual precipitation amounts 
Authors: Klein Lutz , Dudley Bruce , Klaus Julian , Meason Dean
Published: March 2024

Pinus radiata, which grows under a wide range of climate conditions, makes up the majority of the planted forests in New Zealand leading to concerns over the impact of this non-native species on water availability and quality. Transit times of water through the vadose zone reflect water fluxes and affect runoff chemistry. However, little is known on how vadose zone transit times differ for forests of the same species under different precipitation regimes. Our goal here is to evaluate how root water uptake (RWU), water transit times, and groundwater recharge in Pinus radiata plantations differ under variant precipitation. We investigated soil water fluxes and RWU in nine soil profiles in two Pinus radiata forests with greatly differing annual precipitation amounts (2934 mm vs. 725 mm) in New Zealand’s South Island. We estimated water age of vadose zone and xylem water using an isotope-enabled version of the one dimensional hydrological model Hydrus 1-D. We inversely derived the model parameters using a Monte-Carlo simulation with Latin hypercube sampling with times series of soil moisture and soil and xylem water stable isotopes. At the dry forest site, we found that transpiration and recharge accounted for over 80%, and around 10% of annual precipitation, respectively. At the wet forest site transpiration accounted for 24% and recharge 70% of annual precipitation. RWU at the dry forest site was nearly constantly soil moisture-limited while vapour pressure deficit was the limiting factor at the wet forest site. At the dry forest site, a large range of water ages contributed to RWU. During dry periods water age of RWU was high, but dropped sharply in surface soil layers and RWU following intense precipitation events. This was not observed at the wet forest site where soil water age and xylem water age were less variable. While at the wet forest site Pinus radiata almost exclusively relied on water from the current season for RWU, at the dry forest site significant amounts of RWU in the summer stemmed from winter precipitation.   Our results demonstrate not only greater impacts of these plantation forests on soil water balances in more arid climates, but also suggest greater susceptibility of dryland forests to variation in precipitation regimes.  
Evaluating the main drivers of ozone pollution in a typical city of the Yangtze River Delta based on machine learning
Authors: Qiu Yuqing , Li Xin , Liu Yi , Lu Sihua , Song Mengdi , Zhang Yuanhang
Published: March 2024

Ozone (O3) pollution has become more and more serious in recent years, especially in economically developed areas, such as the Yangtze River Delta region. Surface O3 is nonlinear affected by meteorological conditions, emissions of precursors and chemical reactions. Changes in atmospheric pollutants concentrations caused by emission reduction policies can be obscured by effects of dispersion and transport. Distinguish meteorological dispersion and transport from local influences is important for government to implement policy to control O3 pollution. Meteorological normalization is a technique to remove the influence of meteorological factors in the time series of pollutants concentrations. In order to better understand the local impacts on O3 production, we used random forest with meteorological normalization to remove the dispersion or transport on the concentrations of O3 and its precursors based on long-term observation data of air pollutants and meteorological parameters in Hangzhou from 2019 to 2022. After removing these meteorological effects, we found that the trend of O3 concentration was basically consistent with the observed concentration, indicating that the change of O3 in Hangzhou was mainly driven by precursor emission and chemical formation. The contribution of dispersion and transport to O3 concentration was positive in 2019 (5.2%) and 2021 (4.4%), and negative in 2022 (3.8%). Comparing the PMF results of observation and meteorological normalization, the contributions of vehicle emission and combustion to VOCs during the pollution period were underestimated, while the contributions of industry and solvent use were overestimated. Our results demonstrate that the main factors affecting local O3 generation after decoupling the effects of meteorological dispersion and transport. This work is helpful to scientifically formulate control measures of atmospheric pollution, and effectively assess the actual benefits of emission reduction policies.
Effects of changes in climatic conditions on soil water storage patterns
Authors: Ehrhardt Annelie , Groh Jannis , Gerke Horst H.
Published: March 2024

The soil water storage (SWS) defines crop productivity of a soil and varies under differing climatic conditions. Pattern identification and quantification of these variations remains difficult due to the non-linear behaviour of SWS changes over time.We hypothesize that these patterns can be revealed by applying wavelet analysis to an eight-year time series of SWS, precipitation (P) and actual evapotranspiration (ETa) in similar soils of lysimeters in a colder and drier location and a warmer and wetter location within Germany. Correlations between SWS, P and ETa at these sites might reveal the influence of altered climatic conditions but also from subsequent wet and dry years on SWS changes.We found that wet and dry years exerted influence on SWS changes by leading to faster or slower response times of SWS changes to precipitation in respect to normal years. This might be explained by a higher soil water content and the related higher soil hydraulic conductivity. Time shifts in correlations between ETa and SWS became smaller at the wetter and warmer site over time in comparison to the cooler and drier site where they stayed constant. This could be attributed to an earlier onset of the vegetation period over the years and thus to an earlier ETa peak every year and reflects the direct impact of changing climate on soil water budget parameters. 