bluuebunny/crossref_metadata_2025 huggingface dataset:
Rupture-mode preferences of crustal earthquakes in Japan
Authors: Shibata Ritsuya , Aso Naofumi
Published: February 2023

Fault rupture has various complexity in space and time. The temporal complexity could be expressed by the radiated energy enhancement factor (Ye et al., 2018), which is the ratio of the radiated energy to its theoretical minimum value. Regarding the spatial complexity, the rupture directivity has been well investigated from small scales (Boatwright 2007; Kane et al., 2013; Ross and Ben-Zion, 2016) to large scales (e.g. Ide and Takeo, 1997; Ruiz et al., 2016) by investigating the azimuthal dependency of dominant frequency or estimating the source process. While these studies focus on the spatiotemporal complexity of the entire fault rupture, the mesoscopic scale rupture complexity also exists through the rupture propagation, which is an important perspective of the rupture mechanics. Specifically, we can classify the rupture propagation into two endmembers: mode-II and -III ruptures. In this regard, we focused on the rupture propagations at the scale of subfault extracted from the waveform inversion.In this study, we analyzed multiple M6-class inland earthquakes in Japan using waveform inversion with the radiation-corrected empirical Green’s functions (Shibata et al., 2022), which enable us to estimate slip distributions with slip directions by synthesizing the EGF waveforms for any focal mechanisms. Then, we introduced rupture-mode intensity to evaluate the rupture-mode preferences by comparing the rupture propagation direction with the slip direction for each earthquake. As a result, we confirmed that the rupture preferentially propagated parallel (mode II) or perpendicular (mode III) to the slip direction, which is expected from the fracture mechanics. In addition, the characteristic of rupture propagation at the early stage was similar to that during the entire rupture, implying that most rupture characteristics are determined at the early stage.
The subsoil horizons are the preferential location for organic carbon stabilization in chestnut forests
Authors: De Feudis Mauro , Falsone Gloria , Trenti William , Vianello Gilmo , Vittori Antisari Livia
Published: February 2023

Forest soils are recognized to be important organic carbon storage, but the role of surface and subsurface soil horizons on such function and its drivers are still field of debate. In this context, we examined the dynamics of soil organic carbon (SOC) for a chestnut forestry system in a temperate area of northern part of Apennine mountain range in Italy. Specifically, we questioned: what are the main i) SOC forms both in mineral surface and subsurface soil horizons? ii) factors affecting SOC stabilization?. Soil samples were collected by horizon and SOC was separated into organic C of the particulate organic matter (POM_C), sand–size aggregates (sand_C) and the mineral–associated organic C (MAOM_C). The easily oxidizable C (EOC), water–soluble organic C (WSOC), the microbial biomass–C and its respiration, and the total and easily extractable glomalin–related soil protein (T–GRSP and E–GRSP, respectively) were also estimated. Then, the E–GRSP–to–T–GRSP and E-GRSP–to–SOC ratios, the metabolic (qCO2) and microbial (qMIC) quotients were calculated. The POM_C, sand_C and MAOM_C showed the highest concentrations in A horizon (26.5, 14.6 and 13.9 g kg–1, respectively) highlighting the importance of the litter floor on the organic matter pools quantity in the topsoil. Further, the A horizon was enriched of the most labile organic C forms (i.e., EOC and WSOC) indicating the key role of A horizon for the development and growth of chestnut forest ecosystems. In fact, the labile organic C forms provide several ecosystem services, such as plant growth and yield. Unlike A horizon, the subsurface horizons preserved SOC mostly in the most stable form (63.8 %, on average). Because of the role of fungal biomass and its exudates to increase SOC capture and stabilization, the great potential of the subsurface horizons to store MAOM_C can be attributed both to the higher release of exogenous GRSP (higher E–GRSP–to–T–GRSP ratio) by mycorrhizal fungi and fungal mycelium expansion (higher E-GRSP–to–SOC ratio) within such horizons (0.504  and 0.061, respectively) compared to the A horizon (0.244 and 0.034, respectively). Therefore, the subsurface soil horizons seemed to have more favourable conditions for microorganisms compared to surface one as shown by the lower qCO2 and the higher qMIC values found in the former than in the latter. Overall, the present investigation highlighted the importance of subsurface soil horizons of chestnut forests on C stabilization processes compared to the A horizon likely due to the better edaphic conditions for the microbial communities. Thus, our results pointed out the key role that the subsurface soil horizons of chestnut forests could have for mitigating the current climate change.
The use of regional climate models for estimating past and future precipitable water vapor and extreme precipitation over Ethiopia
Authors: Van Schaeybroeck Bert , Kawo Abdisa , Van Malderen Roeland , Pottiaux Eric
Published: February 2023

There exist well known relations between Precipitable Water Vapor (PWV) and extreme rainfall which are of prominent importance in the context of climate change. These relations, however, are mostly established in mid-latitudes and for flat terrain. Ethiopia, however, is located in the tropics and features a complex orography, both of which may modulate these relations. We investigate PWV and extreme precipitation over Ethiopia by use of Regional Climate Models (RCMs) from the Coordinated Regional Climate Downscaling Experiment (CORDEX). We first evaluate the RCMs by comparing their annual PWV cycles with the ones obtained from Global Positioning System observations and reanalysis in the past. Additionally, we focus on the behaviour of PWV before and after a heavy-rainfall event. It is found that there are two characteristic timescales, both for the build-up and for the decline around the event of the heavy precipitation: a timescale of about 2 days and a longer timescale that extends beyond ten days which seems unreported in the literature. The RCMs are capable of reproducing the PWV annual cycle and the spatial variability. However, there is a predominantly dry bias that strongly increases with elevations. The RCMs reproduce well the spatial differences of the PWV anomaly peak during a heavy-rainfall event but overestimate the timescales of build-up and decline. Future PWV-changes scale linearly with the near-surface temperature changes at a rate of 7.7% per degree warming and locally increase up to 40% for the end-of-the-century RCP8.5 scenario. Changes in rainfall extremes, on the other hand, do not follow this trend especially in north-western Ethiopia, potentially caused by an overall decrease in rainfall in that region.
Paleoclimate and paleoenvironment reconstructions from Middle Eocene successions in Egypt: Geochemical and micropaleontological approaches
Authors: Mohamed Sayed Mostafa , Heinz Petra , Mohamed Abd El-Gaied Ibrahim , Wagreich Michael
Published: February 2023

Forty-three rock samples have been collected from two sections, exposed at south east Beni-Suef area, Egypt. These samples showed richness in benthic foraminiferal assemblages and only rare occurrences of index planktonic foraminifera. The studied outcrops were lithologically subdivided into two Middle Eocene rock units named from base to top as follow: (1) the Qarara Formation (Lutetian) and (2) the El Fashn Formation (Bartonian). The investigated rock samples yielded 160 foraminifera species and subspecies which belonging to 4 suborders, 19 superfamilies, 34 families and 59 genera. The stratigraphic distribution of the identified species allowed us to construct four local benthic biozones which are: (1) Bolivina carinata Lowest Occurrence Zone (Lutetian), (2) Bulimina jacksonensis Lowest Occurrence Zone, (3) Nonion scaphum Lowest Occurrence Zone and (4) Brizalina cooki / Nonionella insecta Concurrent-Range Zone (Bartonian). These biozones were described and discussed in detail and correlated to equivalents recorded before in Egypt. The rareness of index planktonic foraminifers through the studied sections did not allow a biozonation. The shale samples showed low TOC values which may be related to high sediment influx and/or subjected to oxidation conditions. Bulk rock geochemistry, consistend with the benthic foraminifera ecological preferences, showed that the studied sections were deposited in moderate to high oxygen levels, warm climatic conditions and typical shelf marine settings. The identified species showed strong similarities with southern Tethys areas such as Libya, reflecting migration via trans-Sahara seaway, and minor similarities with those identified from the northwestern Tethys (Italy, France, Spain, England) province attributed to the benthic nature which limit their ability to move for a long distance and related to cooler, latitudinal zoned climatic conditions which was unsuitable for their biological demands.
Observing System Simulation Experiment for designing a monitoring network in urban areas using the GRAMM/GRAL model
Authors: Maiwald Robert , Vardag Sanam Noreen
Published: February 2023

Urban areas and cities play a crucial role in mitigating climate change. First, a large share of greenhouse gases (about 60%) is emitted in urban areas. Second, city networks have formed to implement climate change mitigation measures at the local level. Therefore, cities have great potential to significantly reduce greenhouse gas emissions.Realizing this potential requires solid knowledge of local greenhouse gas sources, which can be obtained through robust measurements of greenhouse gases in an urban network. These measurements can then serve as a starting point for quantifying and thus verifying local emissions. In order to optimize the investment in a measurement network and maximize the knowledge gained from these measurements, several parameters need to be considered, such as the number and location of nodes, the uncertainty of the measurements, and the co-measured species.These parameters can be evaluated and optimized in an Observing System Simulation Experiment (OSSE). In our study we perform a high-resolution OSSE using the atmospheric transport model GRAMM/GRAL. We first feed a high-resolution anthropogenic emission inventory into the model and simulate CO2 concentration in the urban atmosphere on 10 m resolution in a 12 km x 12 km domain. Next, we approximate CO2 fluxes on neighborhood scale using an inverse framework. We test different configurations of possible measurement networks to assess under which circumstances and how well we can estimate CO2 fluxes. We find that the accuracy of the estimated fluxes increases with node number and precision, reaching a mean error reduction of about 50 % for 16 nodes and a precision of 1.0 ppm in the best configurations. Sources emitted on ground level can be successfully estimated on hourly resolution, but the measurement stations are not sensitive enough to detect sources emitted from tall emission stacks in the vicinity of the measurement nodes. We further discuss the advantages of using CO as an additional tracer in the inversion with respect to measurement precision and sectoral source disaggregation. The framework developed allows for the planning of an optimal measurement network and can thereafter be used to derive fluxes and associated uncertainties in urban areas. This allows for verification of emissions and targeted monitoring of mitigation measures at the local scale.
The bow shock and magnetosheath responses to density depletion structures
Authors: Lu Xi , Zhang Hui , Otto Antonius , Liu Terry , Chen Xingran
Published: February 2023

Hot flow anomalies (HFAs) are typical and important foreshock transients characterized by large flow deflection and plasma heating. HFAs can deform the Earth’s bow shock by dynamic pressure perturbation resulting in disturbance in the magnetosphere and ionosphere. Traditionally, HFAs are believed to be associated with discontinuities. But recently, HFA-like structures were simulated by an magnetohydrodynamics (MHD) model without the discontinuity prerequisite. In this study, we give three HFA examples to verify this MHD formation mechanism. For the first event, we use multi-points observation from the THEMIS mission to track the formation of the HFA accompanying with a density depletion upstream. For the other two events, we compare observations from the MMS mission and the ARTEMIS mission with the MHD simulation results using density depleted solar wind flux tubes to investigate the physical process of HFA formation. The comparison of simulation and observation shows general agreement particularly in the presence of a core with strong heating and velocity deflection, and two compression regions (shocks) with clear maxima in the ram pressure with a strongly inclined normal boundary at the leading edge and moderately inclined at the trailing edge. Agreement was better when the MHD simulations used a transient change to quasi-parallel solar wind magnetic field during the events. Result suggests that ram pressure may be an excellent diagnostic for HFAs both in the solar wind and in the magnetosheath.
High accuracy doesn’t prove that a deep learning model is accurate: a case study from automatic rock classification of thin section photomicrographs
Authors: Zheng Dongyu , Cao Zhisong , Hou Li , Ma Chao , Hou Mingcai
Published: February 2023

As deep learning (DL) is gathering remarkable attention for its capacity to achieve accurate predictions in various fields, enormous applications of DL in geosciences also emerged. Most studies focus on the high accuracy of DL models by model selections and hyperparameter tuning. However, the interpretability of DL models, which can be loosely defined as comprehending what a model did, is also important but comparatively less discussed. To this end, we select thin section photomicrographs of five types of sedimentary rocks, including quartz arenite, feldspathic arenite, lithic arenite, dolomite, and oolitic packstone. The distinguishing features of these rocks are their characteristic framework grains. For example, the oolitic packstone contains rounded or oval ooids. A regular classification model using ResNet-50 is trained by these photomicrographs, which is assumed as accurate because its accuracy reaches 0.97. However, this regular DL model makes their classifications based on the cracks, cements, or even scale bars in the photomicrographs, and these features are incapable of distinguishing sedimentary rocks in real works. To rectify the models’ focus, we propose an attention-based dual network incorporating the microphotographs' global (the whole photomicrographs) and local features (the distinguishing framework grains). The proposed model has not only high accuracy (0.99) but also presents interpretable feature extractions. Our study indicates that high accuracy should not be the only metric of DL models, interpretability and models incorporating geological information require more attention.
Immediate and carry-over effects of late spring frost and growing season drought on forests in the Northern Hemisphere
Authors: Chen Liang
Published: February 2023

Forests are increasingly exposed to extreme global warming-induced climatic events. However, the immediate and carry-over effects of extreme events on forests are still poorly understood. Using eddy covariance data from 34 forest sites in the Northern Hemisphere, we analyzed the responses of ecosystem gross primary productivity capacity under light saturation (GPP2000) of forest ecosystems to late spring frost (LSF) and growing season drought. The immediate and carry-over effects of frost and droughts on needle-leaf (NF) and broadleaf (BF) forests were analyzed. Path analysis was applied to reveal the plausible reasons behind the varied responses of forests to extreme events. The results show that LSF had clear immediate effects on the GPP2000 of both NF and BF. However, GPP2000 of NF was more sensitive to drought than that of BF. There was no interaction between LSF and drought in either NF or BF; instead, drought effects were masked by the LSF effect in NF. Path analysis further showed that the response of GPP2000 to drought differed between NF and BF, mainly due to the difference in the sensitivity of canopy conductance. Moreover, LSF had a more severe and long-lasting carry-over effect on forests compared to drought. These results enrich our understanding of the mechanisms of forest response to extreme events across forest types. 
Understanding drought conditions and impacts on key ecosystem services in a low-mountain watershed in Germany
Authors: Al-Qubati Abdulhakeem Amer Abdulhafed , Zhang Lulu , Pyarali Karim
Published: February 2023

Europe has experienced increasing frequency of climate extremes which caused negative impacts on the ecosystems and various socioeconomic sectors. In this research, we examined the drought conditions and impacts in Weisse Elster, a low-mountain watershed, in Central Germany. First, we studied the temperature and precipitation trends in the watershed. We found that seasonal and annual temperatures had an increasing trend. Precipitation had a decreasing trend during summer and an increasing trend in the winter and annual scales. By using drought indices, namely standardised precipitation-evapotranspiration index (SPEI) and standardised precipitation index (SPI), we found that drought conditions have been worsening. We used the Water Supply Stress Index (WaSSI), an integrated ecosystem services model developed by U.S. Forest Services, to simulate two key ecosystem services: surface water flow and carbon sequestration. The model showed satisfactory performance when evaluated against discharge, evapotranspiration and gross primary productivity (GPP) observations. To understand the drought vulnerability of different areas and ecosystems, we compared water yield (WY), net ecosystem productivity (NEP), and soil moisture (SM), averaged for the five most intense drought events, to the averages of the total study period (57 years). We found that droughts caused a significant reduction in WY (54%), NEP (18%), and SM (13%) in the region, with some areas being more affected than others. Urban landcover saw a 41% reduction in water flow, while agriculture and grasslands landcovers experienced significant reductions in generated water flow (63% and 60%, respectively). Deciduous forests had a 53% reduction in water flow and coniferous forests experienced a loss of around 37%. All landcover types saw a similar impact on carbon sequestration during droughts. Coniferous forests sequestered 21% less carbon while deciduous forests, grasslands, and agriculture landcover sequestered 18%, 17%, and 17% less carbon, respectively. We emphasise that there is an urgent need to improve climate resilience in the region and to reduce drought risks in different sectors to adapt to climate change.
Uncertainty research of landslide susceptibility mapping based deep ensemble learning: different basic classifier and ensemble strategy
Authors: Zeng Taorui , Yin Kunlong , Wu Liyang
Published: February 2023

The Jurassic red-strata of the Three Gorges Reservoir Area in China is interbedded of thick siltstone and thin sandy-mudstone and contains many clay minerals, such as montmorillonite and illite, which is water sensitive, weak and expansive, and easy to decompose by water weathering. In particular, due to the seasonal rainfall, development of settlements, and large-scale reservoir impoundment, many slow-moving landslides (e.g., deep rotation and planar landslides) often occur. Notwithstanding, the reconnaissance, updating, and mapping of kinematic features of township area landslides lack the appropriate attention of the government and researchers. Landslide susceptibility mapping is necessary prerequisites for landslide hazard and risk assessment. But a certain proportion of unpredictability is always closely related to modeling. The main objective of this work is to introduce deep ensemble learning into landslide susceptibility assessment to improve the performance of maximum likelihood models. Therefore, the current model construction has focused on three basic classifiers: decision tree, support vector machine, multi-layer perceptron neural network model, and two homogeneous ensemble models: random forest and extreme gradient boosting. Two prominent ensemble techniques—homogeneous/heterogeneous model ensemble and bagging, boosting, stacking ensemble strategy—were applied to implement the deep ensemble learning. Then, thirteen influencing factors were prepared as predictors and dependent variables. The landslide susceptibility maps were validated by the area under the receiver operating characteristic curve. The results of validation showed that the ensemble model shows that the ROC/AUC value is higher than 0.9, which is improved compared with the basic classifiers. Deep ensemble learning focuses more on detecting the landslide susceptibility area with the highest probability of occurrence. The Stacking based RF-XGBoost model obtained the best verification score (AUC=0.955). The comparison between the susceptibility map and landslide inventory data is encouraging as most of the recorded landslide pixels (about 83.3%) are at a high susceptibility level. Besides, from the information gain rate, we found that the Yangtze River and human engineering activities mainly affect the results, which is consistent with the current situation in the study area. The research results in the township-level landslide susceptibility map can also be extended to other urban and rural areas affected by landslides to reduce the landslide disaster risk and formulate further development strategies.
Including Ice-Cloud Longwave Scattering and Surface Spectral Emissivities in Climate Models Leads to More Impacts on Mean-State Climate than Climate Feedbacks
Authors: Fan Chongxing , Chen Yi-Hsuan , Chen Xiuhong , Lin Wuyin , Huang Xianglei , Yang Ping
Published: February 2023

Climate models often ignore cloud scattering and surface emissivity in the longwave (LW) for computational efficiency. Such approximations can cause biases in radiative fluxes and affect simulated climate, especially in the Arctic because of its large sensitivity to perturbations. We implemented treatments to both physics into the Energy Exascale Earth System Model (E3SM) version 2 by DoE and assessed their impacts on the simulated mean-state global climate as well as climate feedback and sensitivity.By turning on and off the switches in the modified E3SMv2 model, we studied the changes in mean-state climate due to cloud LW scattering and surface emissivity effects by comparing four 35-year fully-coupled simulations. Cloud LW scattering warms the entire global troposphere by ~0.4 K on average; the warming is stronger in the Arctic (~0.8 K) than in the tropics, which is a manifestation of the polar amplification phenomenon. When realistic emissivity is incorporated into the model, the surface skin temperature increases by 0.36 K instantaneously on a global average, especially in the Sahara Desert (~0.7 K) where the surface emissivity is low. Surface skin temperature, as well as surface air temperature and tropospheric temperature, further increases by 0.19 K due to the inclusion of surface spectral emissivity. The mean-state climate changes due to both effects are linearly additive. The latitudinal and seasonal pattern of surface air temperature warming resulting from both effects is very similar to the response due to CO2 increase in the standard E3SMv2 model.We also carried out four 35-year simulations under the abrupt 4xCO2 scenario, with cloud LW scattering and/or surface emissivity effects on and off. Based on standard radiative kernel analysis, we found that total global-mean climate feedback does not change significantly after including either or both physics. Nevertheless, lapse rate feedback, water vapor feedback, and cloud feedbacks in the tropics have changes by up to 10%. They are primarily associated with high cloud fraction response in the upper troposphere. Our study suggests that both the cloud LW scattering effect and the surface spectral emissivity effect should be included in climate models for a faithful representation of the radiative process in the atmosphere, especially at regional scales.
The Color Diversity of Kuiper Belt Objects
Authors: Kaiser Ralf
Published: February 2023

Objects in the Kuiper Belt exhibit the reddest known surfaces and reveal a wider range of colors than any other Solar System population. The origin of this extraordinary color diversity is unknown, but likely the result of the prolonged irradiation of organic materials by Galactic Cosmic Rays (GCRs). However, laboratory experiments simulating irradiation processes have provided conflicting results and are highly dependent on the assumed initial composition, GCR flux, and exposure time. Here, we combine ultrahigh vacuum irradiation experiments with comprehensive spectroscopic analyses to examine the GCR processing of simple hydrocarbon surfaces of methane and acetylene under Kuiper Belt conditions. This study efficiently replicates the color diversity shown by Kuiper Belt Objects located at distances from 39 to 44 AU from the Sun such as Makemake, Orcus, and Salacia, and indicates effective exposure ages of at least 1,100 million years. Aromatic structural units carrying up to three rings as in phenanthrene (C14H10), phenalene (C9H10), and acenaphthylene (C12H8), of which some carry structural motives of nitrogen bases of DNA and RNA connected via unsaturated linkers, play a key role in producing the reddish colors. These studies demonstrate the level of molecular complexity synthesized by GCR processing and hint at the role played by irradiated ice in the early production of biological precursor molecules. Extrasolar counterparts to the Kuiper belt are known in the population of debris disks such as those around Fomalhaut and Vega, where these processes must also be relevant.
Global high-resolution climate change projection and its impacts on global hydrology and hydrological extremes
Authors: Gebrechorkos Solomon Hailu , Leyland Julian , Darby Stephen
Published: February 2023

Hydroclimate extremes have a large societal impact if not appropriately monitored and if site-specific adaptation measures are not developed and modified. The impact of hydroclimate extremes such as floods is projected to increase in the future, demanding site-specific adaptation measures to reduce the impacts. Assessing historical and future changes in local scale hydroclimate extremes and estimating trajectories of change requires higher resolution climate projections than those output from Global Climate Models (GCMs). To improve the coarse resolution and bias of climate data from GCMs, we used a statistical downscaling model. The statistical downscaling model, Bias Correction/Constructed Analogues with Quantile mapping reordering (BCCAQ), provides high-resolution climate data suitable for hydrological extremes. Here, we downscaled seven variables (air pressure, precipitation, air temperature, relative humidity, and maximum and minimum temperature) from 18 CMIP6 GCMs under three SSPs (Shared Socioeconomic Pathways). The downscaled global high-resolution climate data is available at The Centre for Environmental Data Analysis (CEDA, https://catalogue.ceda.ac.uk/uuid/c107618f1db34801bb88a1e927b82317).We used the global hydrological model, WBMsed, with the downscaled climate data and future population projections and dam scenarios to assess changes in hydrology. The downscaling model is calibrated at 0.25° resolution during the historical period (1981-2014) using a high-resolution climate dataset (e.g., MSWEP for precipitation) and showed a strong correlation (>0.85) for monthly climatology of the seven downscaled variables. The climate data used to calibrate the downscaling models, particularly for precipitation, is selected after a comprehensive evaluation of multiple precipitation datasets for simulating river discharge globally. Based on data from ~2400 stations, MSWEP was found to outperform other precipitation datasets in most of the stations.  The results, based on the downscaled data and WBMsed model, shows a mixed change in river discharge in the future; an increase in the Middle East, Africa, Central and South-Eastern USA and a decrease in parts of Europe, South-western USA, and Northern South America) in the 2050s and 2080s. The global average annual river discharge will be higher than the reference period (1981-2014) in the periods 2015-2040, 2041-2070 and 2071-2100 by more than 6%, 9%, and 13%, respectively. Sediment flux, on the other hand, shows a high spatial variability dominated by a decrease in larger rivers and an increase in smaller rivers. Overall, this high-resolution global scale impact assessment study will help identify potential and risk areas for different sectors and allow the development of climate change adaptation measures at a local scale to minimize the impacts of future changes.  
Reliability-Based Approach to Hyporheic Zone Depth Delineation for Groundwater Remediation Strategy
Authors: Kim Heejung , Yang Jae E , Lee Minha
Published: February 2023

Natural phenomena like hyporheic zone depths show intrinsic statistical behavior due to large variability of related parameters. In the previous researches, authors proposed a deterministic method to delineate hyporheic zone depth using a simple field temperature measurement, and studied a probabilistic method to present a proper statistical distribution model for hyporheic zone depth. As a next step forward, this research proposes remediation strategies on contaminated groundwater system in relation to hyporheic zone depth management. Primarily, demand of hyporheic zone depth to achieve a required recovery ratio is predetermined. The field hyporheic zone depth is, then, changed according to each strategies. The two probabilistic variables, demand and field values, are modified such that the difference are reduced. The index applied to evaluate each strategy in this paper was adopted from the concept of reliability index. This approach is frequently used in many fields of science and engineering, including a safety design of structures. The key point of safety design involves sufficiency of safety margins between a strength criterion and the requirements, and this is what the reliability index evaluates. The paper is structured to introduce reliability-based approach in terms of general concept and hyporheic zone depth management first, and proceeds to a development of index. The paper concludes with performance evaluation of strategies. This paper is of value because a combination of the previous research on the probabilistic property extraction of hyporheic zone depth and the presented approach of performance evaluation has potential to offer another useful tool to the remediation of contaminated groundwater.Acknowledgement: This research was funded by the Korea Ministry of Environment through the strategic EcoSSSoil Project at the Korea Environmental Industry and Technology Institute (grant no. 2019002820004) and National Research Foundation of Korea (NRF), funded by the Ministry of Education (grant numbers 2019R1I1A2A01057002 and 2019R1A61A0303
A system dynamics simulative modeling framework to assess bioaccessibility of lead and facilitate lead reduction in the urban environment
Authors: Yu Danlin
Published: February 2023

Lead (Pb) exposure to residents of impacted communities depends on the environmental concentrations of lead that is potentially bioaccessible. Such concentrations are the result of a complex array of interactive factors that influence one another through direct or indirect linkages. Current models to predict the health impact of Pb exposure often do not consider the complexity from a system perspective. Therefore, there exists a great need to develop a holistic modeling strategy to simulate the risk to Pb exposure and resulting blood Pb concentrations based on bioaccessible Pb concentrations in the environment and how socioeconomic status, policy/ scholarly intervention, and collective community behaviors influence that concentration. Our study attempts to develop a grey system integrated system dynamics simulative modeling framework to simulate general Pb bioaccessibility in the environments and how it transmits from the soil, the water, the house, and the general environment to human bodies. The study aims to predicting risk of Pb exposure in the long run in a community/neighborhood, especially the risk to vulnerable populations, such as young children and the aged population. The model also aims to identify the most effective ways to curb human exposure to bioaccessible Pb. This is the first stage of a multi-stage research activity. In this stage, the study focuses on developing a theoretical and empirical modeling framework of the simulative model, and the data structure. In this study, we take a macro perspective to treat a neighborhood/community, a city, or a designated area as an integrated and dynamic system in that it is composed of many interrelated, feedback-linked components. Each component exists and acts because of its interaction with other system components, both observable and hidden. The integrated mutual interaction and multiple components collectively determine how the system will change and evolve in the future, manifested as the change and evolution of the various system components. Bioaccessible Pb in the neighborhood’s environment is our key system component. The grey system and system dynamic simulative model attempts to analyze the potential interactive co-variations among different system components, or the changing and/or evolving trend a system component demonstrates over time. By establishing the interactive feedback loops that connect all the observable system components with sufficient data, the model will be able to simulate the dynamics of the system to predict its behavior and manifestation in the future. Since the simulative model is built upon the interactive feedback loops among all system components, the model will produce simulated results for all observable system components as well. Our goals in later stages are to predict the potential damage to human bodies that will be the basis for Pb reduction and removal related policies at the macro management levels.
Towards a method of rapid flood scenario mapping using hybrid approaches of hydraulic modelling and machine learning
Authors: Pozo Andrea , Wilson Matthew , Lane Emily , Méndez Fernando , Katurji Marwan
Published: February 2023

Floods are the most common hazard in New Zealand, the second most costly and they will change rapidly in frequency and intensity, become more extreme as the impacts of climate change become realized. At the same time, we are undergoing an intense urban development and growing population lives in floodplains, increasing the risk for people’s households and wellbeing. Additionally, computers have limited power and capacity, so there is a limitation in the number of flood scenarios that can be assessed and in the complexity of the hydrodynamic modelling process. This research project, which is part of the 5-year multi-stakeholder research programme “Reducing flood inundation hazard and risk across Aotearoa/New Zealand”, supported by the New Zealand Government and led by the National Institute of Water and Atmospheric Research (NIWA); investigates the feasibility of using a hybrid hydrodynamic/machine learning model to reduce the numerical modelling load and enable probabilistic modelling. The study site is the Wairewa catchment (Little River, Canterbury, New Zealand), working closely with the Wairewa Rūnanga based there. A sample of flooding scenarios is constructed based on the characteristics of the main inundation driver (spatial and temporal characteristics of rainfall extreme events) and other inundation drivers (lake level and antecedent conditions in the catchment). Selected scenarios from this sample will be modelled through a previously calibrated hydrodynamic model and the resultant inundation maps (maximum water depth map for each event) will be used to train a machine learning algorithm to produce the maps for the remaining events. The hybrid model would provide for any flooding scenario (defined by a specific number of variables) the corresponding inundation map in a fast and accurate way, avoiding the hydrodynamic modeling process (very time and computationally expensive). Results from this research will be used to develop a Mātauranga Māori approach to flood resilience and flood related policies by the local and central governments.
Seismic constraints on the nature and geometry of the downwelling Indian crust beneath Sikkim Himalaya
Authors: Singh Arun , Kumar Gaurav , Singh Chandrani , Kumar M. Ravi , Uthaman Mita , Saikia Dipankar , Dubey Arun Kumar
Published: February 2023

  The exact role of subducting Indian continental crust in the formation of Himalaya-Tibet collision zone remains enigmatic. The mass budget estimates describing shortening across the orogen is partly derived from the observations made from seismic imaging of deep earth. Here using data from 38 broadband seismic stations covering Sikkim Himalaya, we produce high resolution seismic images in order to fill the crucial gaps in our understanding of the formation of Himalayan collision zone. We have used 11,594 high quality receiver functions using earthquakes of magnitude >5.5 in the distance range of 30-100°. Our data demonstrates a highly imbricated and heterogeneous crust beneath Sikkim Himalaya. The Main Himalayan thrust responsible for large scale earthquakes in the Himalayan collision zone is not so vivid in the migrated images, but is observed intermittently. The main cluster of earthquakes at shallower depths linked to the Main Himalayan thrust is marked by low amplitude arrivals. Overall trend suggests a gently dipping Moho attaining crustal depths of ∼60 km beneath Higher Himalaya compared to ∼40 km in the Himalayan foredeep. Moho as we see in this segment of Himalaya is with possible offsets and overlapping segments. Imbrication is well reported in the Himalayan orogenic wedge forming upper crust, we also observe this in the lower crust indicating lithospheric imbrication in response to collision. Interestingly, the lower crustal clusters of earthquakes fall at the juncture of offsets in the Moho. The offset positions at lower crustal depths seem more prone to earthquakes in response to active shortening. Seismic images reveal differences in amplitude of receiver functions and presence of conversions at deeper depths in the lithospheric mantle across Dhubri-Chungthang Fault Zone, possibly related to the segmentation of Himalaya.  
Evaluation of daily average OLR retrieved jointly by FY-3 multiple satellites
Authors: Zhang Wanchun
Published: February 2023

Outgoing longwave radiation (OLR) of the atmosphere top (TOA) is an important component of the radiation energy balance of the TOA. The Medium Resolution Imaging Spectrometer (MERSI) carried by the FY-3D and FY-3E satellites can be used for OLR calculation. This paper described the algorithm of MERSI OLR, and the consistency and accuracy of FY-3D MERSI and FY-3E MERSI instantaneous OLR were evaluated based on AQUA CERES OLR. The inspection results showed that the FY-3D and FY-3E MERSI OLR accuracy were basically consistent. And there was uniformly negative deviation compared AQUA CERES instantaneous OLR, the average deviation was about -3 W m-2, and the RMSE was about 6-7 W m-2. On this basis, the ability of daily mean OLR retrieved from FY-3D MERSI and FY-3E MERSI was discussed. The results showed that the accuracy of OLR from four-time observation per day was higher than that from two-time observation per day. The average OLR of the four-time observation per day could be better represent the diurnal variation of that, and the diurnal variation characteristics of OLR also was provided with seasonal changes. In general, the OLR retrieval capabilities of FY-3D and FY-3E satellites are equivalent, and the joint use of them is better on daily mean OLR retrieval. This study can provide a basis for users to analyze OLR data of Fengyun satellites. 
Impact of changes in the cloud amount due to condensation processes on precipitation forecasting on the Korean Peninsula during the summer in the Korean Integrated Model
Authors: Park Yeseo , Lim Jeong-Ock , Choi Hyun-Joo , Cho Kyoungmi , Baek Seon-Kyun , Cheong Seong-Hoon
Published: February 2023

In numerical models, the amount of clouds affects atmospheric temperature through interaction with radiation. In the Korean Integrated Model (KIM), which has been in operation at the Korea Meteorological Administration since April 2020, the amount of clouds is determined from prognostic equation consisting of source and sink terms  by  physical processes such as planetary boundary layer (PBL) mixing, convection, advection, condensation, and evaporation. In the control KIM version, the temperature forcing used for calculating the rate of changes in time of saturation specific humidity which determines formation of cloud area due to condensation is calculated by considering those from all physical processes, such as radiation, cumulus convection, and turbulence, as well as cloud microphysical processes. However, we found the inconsistency between the cloud fraction and mixing ratio by using the methodology, so in this study, we modify the temperature forcing from all physical processes into that only due to the microphysical process. It is confirmed that the change in the amount of clouds changes the temperature and humidity of the atmosphere through the interaction between physical processes such as radiation, which also affects precipitation. In this study, to examine the effect of changes in cloud cover on precipitation in the Korean Peninsula, we perform one case study July 4, 2021 when precipitation in Gangwon occurs due to the convergence of air currents caused by east wind of high pressure in the eastern of Korea. Up to 172.5 mm of daily maximum precipitation was reported in the Gangwon region. In the 3-day forecast of the case, the control KIM  underestimates inland precipitation. But the trend of under-estimation is improved by increasing the amount of precipitation when the cloud amount is modified. The increase in precipitation mainly occurs in the large-scale precipitation due to the microphysical process. This is because the cloud amount generally increases in the Asian area including the Korean Peninsula, which makes the environment favor to the precipitation, by decreasing the temperature through the radiative cooling, in turn resulting the decrease in saturation vapor pressure. For the statistical evaluation of the precipitation performance, precipitation verification is also performed for one month in July, and it is found that ETS (Equivalent Threat Score) performance against the  reanalysis data on the Korean Peninsula is also improved.
The Dynamics of the El-Niño Southern Oscillation (ENSO) Diversity
Authors: Priya Priyamvada , Dommenget Dietmar , McGregor Shayne
Published: February 2023

This study investigates the observed El-Niño Southern Oscillation (ENSO) dynamics for the eastern Pacific (EP) and central Pacific (CP) events. Here we use the recharge oscillator (ReOsc) model concept to describe the ENSO phase space, based on the interaction of sea surface temperatures in the eastern equatorial Pacific (T) and thermocline depth (h), for the different types of ENSO events. We further look at some important statistical characteristics, such as power spectrum and cross-correlation, as essential parameters for understanding the dynamics of ENSO. The results show that the CP and EP events are very different in the ENSO phase space and less well described by the ReOsc model than a T index-based model. The EP events are closer to the idealised ReOsc model, with clear propagation through all phases of the ENSO cycle and strongly skewed towards the El-Niño and subsurface ocean heat discharge states. The CP events, in turn, do not have a clear propagation through all phases and are strongly skewed towards the La-Nina state. Also, the CP events have a slower cycle (67 months) than the EP events (50 months). Further, the CP events collapse after the La-Nina phase, whereas the EP events appear to collapse after the discharging phase. The characteristics out-of-phase cross-correlation between T and h is nearly absent for the CP events, suggesting that the interaction between T and h is not as important as for the EP or the canonical ENSO events. Furthermore, the coupling factor of T and h is smaller for the CP events than the EP events, implying that the CP events are not influenced much by T and h interactions. This study will provide new insight to understand these events by developing a dynamical approach to explain the observed ENSO dynamics for the EP and CP events in the ReOsc model framework.
Middepth Zonal Velocity in the Southern Tropical Indian Ocean: Striation-Like Structures and Their Dynamics
Authors: Xia Yifan , Du Yan
Published: February 2023

The middepth zonal velocity resembles a system of eastward/westward jets with a considerably smaller width than the larger-scale ocean surface circulation. Such a phenomenon always occurs in a turbulent ocean that presents eddy or eddy–mean flow interactions. In this study, the upper-ocean absolute geostrophic currents in the southern Indian Ocean are constructed using Argo temperature and salinity data from the middepth (1000 m) zonal velocity derived from the Argo float trajectory. The results reveal alternating quasi-zonal striation-like structures of middepth zonal velocity in the equatorial and southern tropical Indian Ocean, with a meridional scale of 300 km. The triad of baroclinic Rossby wave instability plays a significant role in near-equatorial striations. In the south, the  unstable vertical structure leads to strong baroclinic instability, which increases the eddy kinetic energy in the middepth layer, thus contributing to a turbulent PV gradient. The convergence/divergence of the eddy PV flux generates the quasi-zonal striations. The meridional scale of the striations is controlled by the most unstable wavelength of baroclinic instability, which explains the observations.
Geodetic measurements of the gravity potential difference to validate a 1000-km scale optical lattice clock comparison in Japan - preliminary result
Authors: Tanaka Yoshiyuki , Sakaue Hiromu , Tamura Yoshiaki , Aoki Yosuke
Published: February 2023

Advances in the developments of optical clocks have enabled 10-18-level frequency comparisons between fibre-linked clocks. This leads to chronometric leveling on the Earth’s surface with an uncertainty on the order of 1 cm, based on the observation of the gravitational red shift. Since measurement uncertainty does not deteriorate with increasing fibre length, applications of chronometric leveling in geodesy, particularly unification of height reference systems, have been actively studied. When the uncertainty of chronometric leveling reaches a few cm in height, uncertainties in the verification by geodetic survey must be carefully evaluated. In a previous study, we determined the height difference between two clock sites approximately 100 km apart in the Tokyo area, based on geometric leveling and estimated its uncertainty to be roughly 2 cm. Comparison with chronometric leveling using optical lattice clocks is currently underway. In addition to this, frequency comparison between the clock sites in Tokyo and the Mizusawa VLBI observatory 400 km apart is under preparation. In this study, we will report preliminary results on the geodetic determination of the height difference between the latter two sites. Due to the long distance, we combine so called GNSS-geoid method and local geometric leveling. In this approach, the largest uncertainty comes from the error of the geoid model, precluding a few cm-level verification. Confirmation by geometric leveling over 400 km distance should be considered. Uncertainties in the determination of not only static but also dynamic height difference due to tides etc. are discussed, for future repeated frequency comparison experiments to detect tectonic gravitational potential change due to the postseismic relaxation caused by the M9 Tohoku earthquake in 2011.