bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the thermodynamic characteristics of heavy rainfall events in the southern Korean Peninsula
Authors: Kim Yoo-Jun , Lim Byunghwan
Published: February 2023

This study investigated the impacts of low-level thermodynamic structure and water vapor on heavy rainfall events in the southern Korean Peninsula during the 2016 summer intensive observation period. An intensive dataset of mobile observation vehicle (MOVE), with high temporal resolution rawinsonde soundings and global navigation satellite system (GNSS) observations in Geochang (GC) supersite, was used. We divided study events into two heavy rainfall cases to compare the characteristics of representative summer heavy rainfall with different synoptic conditions. Case 1 has localized heavy rainfall associated with the Changma (summer monsoon) and Case 2 has convective instability. The temporal behavior of precipitable water vapor (PWV) retrieved from the MOVE-GNSS data demonstrated that during Case 1, heavy rainfall events experience a steep decrease after a long increasing trend. However, the most intense rainfall events occurred after a rapid increase in PWV during Case 2. In Case 1, the mean static stability at >2 km altitude was variable for all periods (in the order of after > before > during rainfall), whereas in Case 2, this was less variable with time and had generally higher convective instability close to the surface, compared with Case 1. In addition, Case 1 demonstrated the progression of a vertical wind structure connected with a quasi-stationary frontal passage (e.g., veering winds at low levels before rainfall), whereas Case 2 demonstrated a nearly homogeneous southwesterly wind from the surface to an altitude of 5 km.
Reduction in ENSO variability during the mid-Holocene: a multi-model perspective
Authors: Tiwari Shivangi , Pausata Francesco S. R. , LeGrande Allegra N. , Griffiths Michael L. , Beltrami Hugo , de Vernal Anne , Tabor Clay R. , Litchmore Daniel , Chandan Deepak , Peltier W. Richard
Published: February 2023

Paleoclimatic reconstructions have suggested a reduction inthe variability of the El Niño Southern Oscillation (ENSO) during the mid-Holocene (MH). Model simulations have largely failed to capture thisreduction, potentially due to the inadequate representation of the Green Sahara.The presence of a vegetated Sahara has been shown to have significant impacts on both regional and remote climate but remains inadequately addressed in Paleoclimate Modelling Intercomparison Project / Coupled Model Intercomparison Project (PMIP/CMIP) boundary conditions. Specifically, the incorporation of a Green Sahara has been shown to impact ENSO variability through perturbations to the Walker Circulation. In this study, we evaluate the MH (6,000 years BP) ENSO signatures of simulations from four models, namely —EC-Earth 3.1, iCESM 1.2, University of Toronto version of CCSM4 and GISS Model E2.1-G. Two simulations are considered for each model—a standard PMIP simulation (MHPMIP) with the mid-Holocene orbital parameters and greenhouse gas concentrations with vegetation prescribed to preindustrial conditions, as well as a Green Sahara simulation (MHGS) which additionally incorporates factors such as enhanced vegetation, reduced dust, presence of lakes, and land and soil feedbacks. All models show a reduction in ENSO variability due to the incorporation of Green Sahara conditions. This variability is interpreted in the context of perturbations to the Walker Circulation, triggered by the strengthening of the West African Monsoon.
Contrasting patterns in the temperature dependence of wetland CH4 and CO2 emissions across globally geographic climate gradients
Authors: Chen Hongyang , Zhou Xuhui
Published: February 2023

Determining the temperature dependence of wetland CH4 and CO2 emissions is critical for predicting the impacts of climate change on greenhouse gas (GHGs) emissions in wetland ecosystems. However, the spatial variation for temperature dependence of wetland CH4 and CO2 emissions is poorly understood, especially at the global scale. Here, we investigate the temperature dependencies of wetland CH4 and CO2 emissions across large-scale climatic gradients using 56,271 daily paired observations of ecosystem-level CH4 and CO2 emissions in 45 widely distributed wetlands from the FLUXNET-CH4 database. The temperature dependencies of CH4 and CO2 emissions show contrasting spatial patterns across globally geographic climate gradients. Specifically, the temperature dependence of CH4 emissions  increased with increasing mean annual temperature (MAT), but the opposite was true for that of CO2 emissions. The ratio of CH4 to CO2 emissions was positively dependent on temperature when only MAT and mean annual precipitation were greater than 4.7 °C and 483 mm, respectively. Our results imply that the relative contribution of CH4 to total GHG emissions increases with ambient temperature increases in a warmer and wetter climate region and could act as a positive feedback mechanism in the future. 
What explains the population of daytime, optically-thin clouds below one km in the marine trade wind region?
Authors: Zuidema Paquita , McCoy Isabel , Perez Michael , Baidar Sunil
Published: February 2023

The cloud fraction of shallow non-precipitating cumulus residing at the lifting condensation level (LCL) increases in the afternoon, most evident in airborne lidar observations from EUREC4A. Observations from the HALO platform and from the R/V Ronald H. Brown are used to articulate the responsible process. Three hypotheses are investigated: 1) afternoon increases of the ocean sea surface temperature help support buoyancy fluxes that lift air parcels to saturation, as seen in tropical regions under low wind speeds; 2) shortwave absorption of the sub-cloud layer helps deepen the sub-cloud layer, so that its mixed-layer height can reach the LCL; 3) clouds form where the cloud layer is already moist. We invite the reader to take a moment here to choose which hypothesis you think is correct.Analysis to date suggests #3 is the correct explanation. If so, then the next question is to identify why the daytime cloud layer is more or less moist in some places and times. Ideas for this can either be moisture redistribution from shallow circulations occurring at scales of approximately 200 km, or, moisture transport occurring at larger scales. These will be explored prior to the meeting, as well as ramifications for the diurnal cycle.
Revegetation impacts on moisture recycling over Loess Plateau in China
Authors: Cao Mingzhu , Wang Weiguang , Wang-Erlandsson Lan , Fetzer Ingo
Published: February 2023

Moisture recycling of local water sources through evaporation allows a region to maintain precipitation in the same region. Many studies have shown that deforestation can reduce evaporation and downwind rainfall, and it has been suggested that reforestation conversely increase evaporation and downwind rainfall. Precipitation has been observed to increase over China’s Loess Plateau over the past two decades, coinciding with the start of the Grain for Green project - the largest active revegetation programme attempted in the world. However, the contribution of revegetation to the increase in precipitation is yet unknown. Here, we aim to quantitatively analyze the relationship between revegetation, evaporation, and locally recycled moisture. Based on the ERA5 reanalysis data, we used the modified Water Accounting model-2 layers (WAM-2layers) to track the recycling moisture over the Loess Plateau. Preliminary results indicate that local recycling moisture (Er) accounted for almost one-tenth of the annual precipitation, and seems to have a decreasing trend, which was more evident after 2000. Meanwhile, the contribution of local evaporation to local precipitation appears to decrease during both 1982-1999 and 2000-2015, while the decreasing trend has been slightly amplified after the revegetation. Spatially, Er over the Loess Plateau showed a decreasing trend from southeast to northwest. Significant increasing trend of Er can be identified in the northern part of the plateau during 1982-1999. However, after the implement of the Green for Grain Project, most area over the Loess Plateau showed a decreasing trend, which is significant in the east. Thus, contrary to popular wisdom, the revegetation appears to have led to a decrease in evaporation and subsequent recycling, and the increase in precipitation seems to have other causes. These results are subject to high data uncertainty, and further research is needed to better understand the hydroclimatic effects of revegetation projects under climate change.
Reassessing post-eruption precipitation anomalies in the context of natural variability
Authors: McGraw Zachary , Polvani Lorenzo
Published: February 2023

Several studies have reported anomalous precipitation in the years that follow large volcanic eruptions. Here we assess precipitation anomalies in post-eruption years according to their rarity in non-volcanic periods. Using global simulations of climate over the last millennium, we reevaluate the response of precipitation to volcanic aerosols in terms of novel metrics. In this approach, the magnitude of the precipitation response is contextualized through comparisons to internal variability. We also examine the connections between global and regional-scale precipitation anomalies. Finally, we assess to what extent a unique ‘fingerprint’ of eruptions can be seen in the observational precipitation record in spite of concurrent internal variability.
The effect of water-repellent soil-induced preferential flow on the spatial distribution of nutrients and salts in the soil profile of a commercial orchard
Authors: Wallach Rony
Published: February 2023

Treated wastewater (TWW) has gained recognition as an alternative source for freshwater irrigation and is steadily expanding worldwide, particularly under the current climate change. Beyond its many advantages, it has been found that prolonged use of TWW renders the soil water-repellent to certain degrees. The flow in these soils has been known to take place in preferential flow pathways (unstable flow). This lecture presents the results of a study performed in a commercial citrus orchard grown on sandy-loam soil in central Israel that has been irrigated with TWW. Electrical resistivity tomography (ERT) surveys revealed that water flow in the soil profile is occurring along preferential flow paths, leaving behind a considerably nonuniform water-content distribution. The preferential flow in the soil profile led to uneven distribution of salts and nutrients, with substantially high concentrations in the drier spots and lower concentrations in the wetter spots along the preferential flow paths. The chemical's pore concentration, which depends on the local soil water content, is higher than paste-measured concentrations and may even reach toxic values. This could partially explain the negative effect that prolonged TWW irrigation has on soil and trees. The relationship between water-repellent soils and the spatially nonuniform distribution of nutrients and salts in the root zone was verified in a consecutive in-situ study where soil water repellency was eliminated by surfactant application to the soil. Repeated ERT surveys and chemical concentration measurements in disturbed soil samples along transects revealed that the surfactant application diminished the preferential flow pathways and rendered the soil water and dissolved chemicals uniformly distributed. The preferential flow elimination and increased chemical distribution uniformity result in a yield increase compared to the surfactant-untreated soil. The different aspects of the results will be further presented and discussed. 
The power low in information geometry: Attempt from the viscoelastic relaxation of rock
Authors: Hirano Mitsuhiro , Nagahama Hiroyuki
Published: February 2023

It is known that power law exists in the background of various natural phenomena. One example is the viscoelastic behavior of rocks. In the flow laws of high temperature of rocks, strain rate is in proportion to the power of stress. It can be replaced by the one that relaxation modulus (the ratio of stress to strain) is in proportion to the power of time with fractal dimension as power exponent. From Laplace transform for the relaxation modulus, the distribution of relaxation time (relaxation spectrum) with the power of relaxation time is derived. It indicates the existence of fractal distribution of different relaxation times in material elements in rocks. On the other hand, these strain-relaxation modulus-stress relations can be recaptured as the input-response-output relation in an ideal complex system with the power law of component. When input and output are stochastic with probability functions, the response corresponds to the change in differential geometric structure on a statistical manifold with a point as a probability function. Although previous studies suggested the correspondence between the power exponent (fractal dimension) and the constant (alpha) characterizing invariant geometric structure (alpha-connection), its details have not been discussed yet. In this presentation, we would reveal the correspondence between the power exponent (fractal dimension) and the constant (alpha) based on q-exponential family in information geometry, which is a more general exponential family.
Attribution and projection of the summer 2022 compound dry and hot extreme in the Northern Hemisphere
Authors: Meng Yu , Hao Zengchao
Published: February 2023

Under the context of global warming, climate and weather extremes (e.g., droughts, high temperature extremes) take a heavy toll on natural and human systems. It has been reported that the concurrence of droughts and hot extremes (CDHEs) in summer 2022 in the Northern Hemisphere (NH) have led to reduced water resources/crop yield and increased health risks. While assessments of droughts and heatwaves in summer 2022 have been noted, the assessment of these extremes from a compound event perspective is still limited. In this study, we analyzed the rarity of CDHEs in summer 2022 across the NH, detected anthropogenic influence on CDHEs area, and projected the likelihood under different warming levels based on observations from ERA5 and simulations from the Sixth Phase of the Coupled Model Intercomparison Project (CMIP6). Our results illustrate that severe CDHEs in summer 2022 across the NH mainly occur in central North America, Europe, and south China. Event attribution analysis shows that CDHEs area in summer 2022 in the NH would not have occurred without anthropogenic global warming. The CDHEs area like 2022 is projected to occur more likely, particularly under SSP585 in a 4°C warming world. This study provides useful insights for advancing our understanding of compound extremes during summer 2022 across the NH.
A study on input ground motion processing platform for evaluating seismic fragilities using Deep Learning Phase Determination Model
Authors: Lee Jin Koo , Seo JeongBeom
Published: February 2023

The 9.12 Gyeongju earthquake(Sep. 12, 2016, Ml 5.8) and the Pohang earthquake(Nov. 15, 2017, Ml 5.4) have occurred in the Korean Penisula, resulting in emphasizing the stability of nuclear power plants. For safety evaluation, it is necessary to study the earthquake vulnerability caused by input ground motion. The input ground motion can be obtained from the earthquakes, and it is essential to acquire good quality and many samples input ground motion database for accurate evaluation. In this study, we tried to develop a platform that can automatically generate a ground motion database from past or real-time waveforms. To determine the detailed time window for data processing, deep learning-based earthquake detection, and phase-picking models were used. A voting method was conducted on these models to increase reliability in various environments. The platform produces a RotD50 5% damped pseudo-spectral acceleration, peak ground acceleration, and meta information related to site, hypocenter, and path. It also provides a web service to confirm generated data and meta information. The database generated by the platform could be used as input ground motion data to evaluate the safety of operating power plants and could be applied as fundamental data for the seismic design of planned nuclear power plants.
Seasonal Variation of the Martian Inner Hot Oxygen Exosphere Observed by EMM/EMUS
Authors: Deighan Justin , Chaffin Michael , Chirakkil Krishnaprasad , Al Matroushi Hessa , Lillis Robert , Fillingim Matthew , England Scott , Jain Sonal , Holsclaw Greg , Lootah Fatma , Al Mazmi Hoor , Raghuram Susarla , Eparvier Frank , Thiemann Ed , Chamberlin Phil , Curry Shannon
Published: February 2023

One of the primary objectives of the Emirates Mars Mission (EMM) is to study the seasonal variation of the upper atmosphere of Mars and associated changes in the escape of atmosphere to space. Here we present a preliminary analysis of the oxygen population in the inner exosphere (1.06-1.6 Martian radii) with nearly-contiguous sampling across all Martian seasons from early MY 36 to early MY 37. This oxygen is thought to be a non-thermal photochemically generated population driven by solar EUV, which can produce energetic atoms with sufficient velocity to escape Mars’ gravity. The observations are made by measuring the atomic oxygen emission at 130.4 nm using the Emirates Mars Ultraviolet Spectrometer (EMUS). We compare the brightness of the exospheric oxygen population with the thermospheric population ( < 1.06 Mars radii, or < 200 km) and find that the exosphere is much more responsive to seasonal variations in solar energy input. The seasonal variations cannot be explained by modulations in solar irradiance at 130.4 nm alone, and are consistent with the expectation that the extended oxygen exosphere at Mars is generated by a photochemical source.
Characteristics of Volcanic Lightning Distribution Generated by Hunga Tonga–Hunga Haʻapai on January 15th, 2022
Authors: Lin Yu-Cheng , Chen Alfred
Published: February 2023

    Existing literature indicates that volcanic lightning occurs during a devastating volcano eruption. However, it is still limited to understanding the volcanic electrification mechanism in nature because of the rarity of the explosive volcano eruption and visible spectrum obstacles from plumes full of dirty ashes. The eruption of the Hunga Tonga–Hunga Haʻapai (HT-HH) submarine volcanoes in the Lau Basin, South Pacific, had an extremely violate surtseyan type eruption on January 15th and generated numerous volcanic lightning. This eruption event provides a great opportunity to explore the electrification and evolution of volcanic lightning.     In this work, more than 40,000 lightning events were detected by the World Wide Lightning Location Network (WWLLN) during the primary eruption on January 15th. At the first stage of the eruption, the geographic distribution of lightning strikes expanded rapidly and isotropically while the eruption column reached a specific altitude. Then a lightning tranquility period occurred subsequently, implying explosive erupting was intermittent. Several explosive sub-eruptions were detected from 04:00Z to 07:00Z, and sub-eruptions' timestamps are highly consistent with seismic data analysis from IRIS. Lightning footprint provided evidence that the HT-HH eruption was a surtseyan eruption unsteady with several quiescent phases separating the explosive stages.    HT-HH is one of the most powerful eruptions of the 21st century and provides a favorable environment for volcanic lightning research. The result of this work can track the immediate eruption by using lightning activities. Moreover, volcanic lightning has a different charging mechanism than general tropospheric lightning. Therefore, many interesting issues can be discussed, such as the volcano eruption's contribution to global electrical circuits or whether volcanic lightning can generate other atmospheric electricity events like TLEs or TGFs.
The critical state behavior of saturated glacial till
Authors: Chen Leilei , Zhou Gordon G.D. , Fang Yingguang , Xie Yunxu , Cui Kahlil F. E.
Published: February 2023

A large number of glacial tills are distributed in the high and cold mountainous areas of the Qinghai-Tibet Plateau. Recently, climate change compounded by many other factors, promote the instability of glacial tills resulting in more frequent mountain disasters. Although the physical properties of glacial tills have been extensively studied in previous works, there are relatively few works that have focused on their shear behavior and critical state for different water contents. To understand the failure mechanisms, it is necessary to study the effects of water content on the shear behavior and critical state characteristics of glacial tills. This work discusses and studies the significance of compression, shear, and dilatancy of glacial tills in landslide prediction. The experimental results in this study are aimed to provide a basic understanding of the underlying failure mechanisms of glacial tills. Reconstituted specimens are studied through an oedometer, isotropic compression, and consolidated undrained shear tests. We compared the compressibility and shear behavior of glacial tills with three other types of weathered soils in Hong Kong: Lateritic soil (LAT), completely decomposed granite (CDG), and volcanic soils (CDV). Test results reveal similarities and differences between the tested soils. Through one-dimensional consolidation and triaxial compression tests, we find that the compressibility of glacial till is the lowest. Secondly, the stress-strain relationship exhibited by the glacial till is inconsistent with those of the other tested soils. Our test results showed that upon increasing the applied stress, glacial tills first softened and then hardened. Stress path analysis further showed that glacial tills first dilated and then shear contracted indicating a phase transition. In comparison, the other weathered soils consistently all shrink and eventually reach a critical state. The processes between soils are more complex. The slope and friction angle of the critical state line of glacial tills is significantly higher than that of CDG and CDV, but lower than that of LAT. This might be due higher large particle content of glacial tills and the difference in mineral composition.
Numerical study of 2018 Baige landslides induced geohazards chain and dynamic proesses
Authors: Xie Yunxu , Zhou Gordon G.D. , Chen Leilei , Cui Kahlil F. E. , Lu Xueqiang
Published: February 2023

Geohazards chain in watershed contains a landslide, which contributes to the propagation on the slope, intruding into river channels forming a landslide dam, a subsequent dam breach, and outburst flooding. Since the sub-process belonging to one chain are all coupled, one or several sub-processes can be the triggering factors of the subsequent one. They can generally own a larger space and time scale than that of a single disaster resulting in greater destructive power and amount of impact area. In this study, the most recent geohazard chain event that happened in the 2018-Baige landslide in Sichuan province, China is adopted for a numerical case study. This event can be divided into several sub-processes according to the coupling order within the chain process. The first landslide generates a landslide dam followed by another landslide and landslide dam sharing the same location. The second landslide overlapped with the first one forming a higher landslide dam. A larger-scale dam breach and resulting outflow occurred eventually. For solving this, a series of validated depth-averaged containing models for geohazards chain is adopted to simulate the whole coupling sub-processes, as well as, the standard LxF central differencing scheme is adopted for retaining high resolution and avoiding Riemann characteristic decomposition. The numerical study simulates the landslide propagation process using a viscos-inertial friction law. The numerical prediction is verified by values from field measurement in the literatures, indicating the feasibility of the (K) viscos-inertial rheology in simulating the large-scale landslide and the landslide dam formation. The overtopping failure process of the two overlapping landslide dams and the outburst flooding is numerically modeled by the proposed model. The results of maximum discharge illustrate the proposed model for landslide dam failure can simulate the interaction process of dam breach and outburst flood. The numerical results, validated by the literature provide reliable assessment and emergency relief support of the actual event. This proposed modeling framework is expected to improve mitigation strategies for geo-hazard chain hazards.
Estimation of raindrop size distribution from polarimetric radar measurements at C-band
Authors: Adachi Ahoro , Kobayashi Takahisa , Umehara Akihito
Published: February 2023

Many studies have proposed methods to estimate the raindrop size distribution (DSD) parameters from polarimetric radar data as a part of rain attenuation correction and/or rainfall rate estimation algorithms, in which a modified gamma distribution model has been often used to characterize the natural variation of DSD. The parameters that determine the modified gamma DSD are a shape parameter μ, median volume diameter D0 or slope parameter Λ, and a number concentration N0 or its normalized version NW. While D0 (or Λ) and NW can be retrieved relatively straightforward from the polarimetric radar measurements, estimation of shape parameter is not an easy task. Instead, empirical relations including μ-Λ and/or μ-D0 relations derived from surface measurements of DSD are widely used to estimate μ implicitly.   Adachi et al. (2015) proposed a method to estimate the three parameters of the DSD from polarimetric radar data without any assumptions of relationship among the parameters. In that method, they assumed a constant shape parameter in a range profile. However, this assumption may not be satisfied if the radar is sampling mixed convective/stratiform echoes that simultaneously exist in a single profile. Theoretically, on the other hand, a shape parameter can be estimated from a correlation coefficient ρHV at each range gate (e.g., Thurai et al. 2008). However, to estimate shape parameters with a method of this kind, it is necessary to obtain a correlation coefficient with quite high accuracy, for which a very long sampling time is needed to apply it to radars to satisfy this condition for most radar measurements. The MRI C-band polarimetric radar is equipped with solid-state transmitters, which enable the radar to make observations of correlation coefficient with high accuracy in a relatively short time, especially in high-SNR regions. Thus, we have developed an algorithm to estimate a shape parameter at each range gate both from correlation coefficient and differential reflectivity along with D0 and NW, and compared it with surface measurements.
Investigation of TC track uncertainty using multiple ensembles for the official TC forecast
Authors: Kim Jinyeon , Kim Dongjin , Kim Daejoon , Son Joohyung , Ham Dong-Ju
Published: February 2023

The official tropical cyclone information in Korea includes a deterministic forecast position of TC center and its uncertainty with the 70% probability circle, which is statistically determined by previous 3 year’s operational track errors. Therefore, the current probability circle does not represent situational uncertainty. In this study, it is investigated for using an ensemble prediction system (EPS) to represent the TC position uncertainty with three different methods: circle (CIR), ellipse with an along-track and a cross-track axes (EAC), ellipse with eigenvector axes (EEV). Five single EPSs, ECMWF, NCEP, UKMO-UM, JMA and KMA-UM, and two multiple ensembles, a simple one (SME) and a calibrated one (CME) which coincides the ensemble means, were evaluated. The methods and the ensembles were verified for 5 days with the hit rate which is defined as the percentage of the observed TC central positions within circles or ellipses.In order to verify the new probability areas as well as the operation, the hit rate which is defined as the percentage of the observed TC central positions within 70% probability circle or ellipses were used. The operational radii have over 70% hit rate, around 0.8 for all forecast times. It means that the official forecast skill is getting better year by year and the current circle is overestimated. EPS based circle or ellipse showed better performance apart from the EAC. In more detail, the CME for both circle and ellipse method outperformed the operational method until 48 forecast hours. Since the five single EPSs were under-spread at this time, the multiple ensembles could overcome this shortage. After 72 forecast hours, SME and CME are too overspread, so that a single EPS is more likely to be consistent with the 70% probability area.Although it is definitely sure that the EPS based one is better, there are still limitations to use them. It is difficult to say which method is the best because performance of methods is different according to the forecast time and to get other organizations’ EPS data in real time. Nevertheless, utilizing ensemble for TC track is valuable information since EPS can provide the best method for estimating uncertainty. 
Understanding long-term carbon dioxide (CO2) variability and its link with ENSO and climate parameters over India using satellite retrievals
Authors: Das Chiranjit , Kunchala Ravi Kumar
Published: February 2023

India is primarily concerned with comprehending regional carbon source-sink response in tandem with changes in atmospheric carbon dioxide (CO2) concentrations or human-caused anthropogenic emissions. Atmosphere CO2 is the most significant greenhouse gas contributing to climate change and global warming. To develop a countrywide mitigation policy, it is therefore critical to identify underlying source-sink locations and their mechanisms at various temporal scales and regional levels. To better understand the variability of CO2 and its relationship with the climate variables requires long-term observations. Recent advancements in high-resolution satellite measurements provide a viable opportunity to examine CO2 variability at a regional level. In this work, we presented the long-term variations and growth rates of the Greenhouse Gas Observing Satellite (GOSAT) and Orbiting Carbon Observatory-2 (OCO-2) satellite retrieved column-averaged dry-air mole fraction of CO2 (XCO2 ) and the relationship of XCO2 growth rate with ENSO and climate parameters (temperature, precipitation, soil moisture, and NDVI) over India for the period 2010 to 2021. Results revealed an increase of 2.54 (2.43) ppm/yr of XCO2 in GOSAT (OCO-2) retrievals during overlapping measurement period (2015-2021). In addition, a wavelet analysis shows an increase in XCO2 every year for GOSAT; however, OCO-2 decreases and increases in XCO2 every 5-6 months. This is attributable to high resolutions measurements of OCO-2 favouring better capture of source (high XCO2)-sink (low XCO2) signal than GOSAT. The Principal Component Analysis (PCA) analysis on XCO2 anomalies showed EOF-1 contributed mainly by the south and southeast of India. Further analysis demonstrated that the trend and seasonal cycle of XCO2 regulates the variability. The XCO2 growth rates strongly correlate with ENSO and NDVI (clear during major ENSO events), whereas precipitation and temperature show a weak correlation. Further, lag correlation analysis reveals that ENSO and climate parameters precede the GOSAT XCO2 growth rates, with soil moisture, NDVI, and ENSO having a good correlation with 8,4 and 3 months of leads, respectively.
Experiment on the benefits of natural-based solutions for debris flow mitigation using synergistic eco-geotechnical measures
Authors: He Songtang , Chen Xiaoqing , Wang Daojie , Qi Yuchao , Li Yong , Pei Zengli , Zhao Peng
Published: February 2023

With the growing development of nature-based solutions (NBS) for debris flow hazard mitigation, the eco-geotechnical coupled technical system has drawn public concern. While the scheme of debris flow prevention and control are constantly improved, the current collaborative patterns, mechanism, and effects on debris flow interception are not clear. In this study, a new synergistic mitigation methodology of reducing debris flow impact risk coupling tree-shrub mixed vegetation filter stripes (T-SMVFS) in S-shape flow paths and dams was proposed. Four efforts were achieved stepwise: 1) the optimal row and stem spacing of T-SMVFS were determined by the overspread T-SMVFS type; 2) set “S-shape” flow path parameters: width ratio (30%, 45%, 60%, 75%); 3) Comprehensively compared the effects of synergistic measures and single measures (ecological or geotechnical measure) on debris flow reduction; 4) Calculation equation of flow reduction considering the influence of topographic features (channel width, roughness), vegetation planting pattern (stem spacing and row spacing), physical properties of debris flow (capacity, mass) was constructed. The results showed that the overspread T-SMVFS with the row spacing of 10cm and stem spacing of 6cm, respectively presented the best reduction effects with energy regulation reaching 43%, flow regulation reaching 46%, and flow rate being close to 40%, respectively. As the flow path widths of the S-shape vegetation filter strips increased (0%-75%), the flow reduction rate (≈45-8%), flow reduction rate (≈58-13%), and sediment interception rate (≈78-5%) decreased sequentially, but the transport capacity increased. Synergistic measures achieved 60% energy reduction, which was better than pure geotechnical (8.9-23.6%) and pure biological (11.56-52.72%) measures, and 70% sediment interception, and were also much higher than single measures. In the comparison of multiple synergistic approaches, the coupled s-shape vegetated filter strip with a 45% proportion of flow path and beam dam is more effective in synergistic hazard reduction. The synergistic eco-geotechnical mitigation measures proposed in this study are a pattern and an attempt to mitigate disasters based on the concept of NBS and provide a reference for subsequent more optimal mitigation solutions.
GIS‐based multi-criteria decision analysis for suitable locations of landfills and protection of peri-urban groundwater catchments: a case study in northeastern Brazil
Authors: Leal Luiz , Purificação Carlos , Klammler Harald , Hatfield Kirk
Published: February 2023

Groundwater located in peri-urban areas may be impacted by many pollutants from different types of point or diffuse sources. About 40% of Brazil's waste is disposed of inappropriately in open dumps and constitutes a risk of contamination for aquifers. In the metropolitan region of the city of Salvador in northeastern Brazil, approximately 9,800 tons of solid waste are generated daily. This research aimed to delineate areas for the implementation of landfills and protection of peri-urban groundwater in Salvador and other catchments in northeastern Brazil. An integration of Boolean and fuzzy logic was performed using GIS, while the Analytic Hierarchy Process was used in a Multi Criteria Decision Analysis technique to generate the weights of the factors and criteria for the fuzzy model. From this methodology, two preliminary models were generated, one using the Boolean logic and the other the fuzzy logic. The first used restrictive criteria established by Brazilian legislation applied to fifteen factors/themes. In the second model, non-restrictive criteria were applied to eleven factors/themes based on technical knowledge and literature. The integration of the maps and the crossing of the models demonstrates that 6% of the studied areas are classified as highly adequate; 16% as adequate; 8% not suitable; and 70% are areas with total restrictions for locations of landfills and protection of aquifers.
Exploring the interplay between continent formation, surface erosion, and the evolution of plate tectonics on Earth
Authors: Jain Charitra , Sobolev Stephan
Published: February 2023

In this work, we test the hypothesis of surface-erosion controlled plate tectonics preceded by plume-induced retreating subduction tectonic regime on Earth proposed by Sobolev and Brown (2019) using 2D global compressible convection models. To simulate the effect of increased sediment supply as a result of surface erosion after the emergence of continents in the late Archean and after the Neoproterozoic "snowball Earth" glaciation, we decrease the effective frictional strength of the oceanic lithosphere in models spanning the age of the Earth. These StagYY models self-consistently generate oceanic and continental crust while considering both plutonic and volcanic magmatism (Jain et al., 2019). Pressure-, temperature-, and composition-dependent water solubility maps calculated with Perplex (Connolly, 2009) are also utilised, which control the ingassing and outgassing of water between the mantle and surface (Jain et al., 2022). The core cools with time and different initial mantle potential temperature values are tested within the range of 1750-1900 K (Herzberg et al., 2010; Aulbach and Arndt, 2019).Models that consider a more realistic upper mantle rheology (diffusion creep and dislocation creep proxy) show higher recycling of denser basaltic-eclogitic (oceanic) crust, efficient cooling of the planet, and higher mobilities (ratio of surface to mantle rms velocities) (Tackley (2000); Lourenço et al. (2020)). These models exhibit intermittent episodes of long-lasting mobile-lid regime and short-lived plutonic-squishy-lid regime in the Hadean and the early Archean accompanied by extensive subduction leading to rapid production and recycling of the continental crust. Models that consider adaptive frictional strength (to mimic sedimentation post glaciation and continental emergence) predict the transition to continuous plate tectonics in the late Archean, reproduce features of supercontinent cycles, and appear to be consistent with cooling history of the Earth inferred from petrological observations (Herzberg et al., 2010). The thermo-compositional evolution can vary between models due to the inherent randomness arising from the initial thermal perturbations and the initial positions of the tracers/particles. Accordingly, we intend to run multiple instances of every model considered in our parameter space to present statistically robust results. We also aim to test more realistic models where the lithospheric frictional strength adapts with the surface topography.
Intercomparison of air quality simulations in 2019 using three chemical transport models
Authors: Kim EunRyoung , Kim Hyeon-Kook , Oak Yujin J. , Park Rokjin J. , Kim Ganghan , Lee Myong-In , Song Chang-Keun
Published: February 2023

Strong air pollution control policies have been implemented to reduce health damage from heavy air pollution, but the PM2.5 concentration level is still high in Southeast Asia. This study aims to identify the causes of air pollution in East Asia using chemical transport models (CTMs). Using three CTMs (CMAQ, WRF-Chem, and GEOS-Chem), air quality was simulated by season in 2019 in Northeast Asia including China and Korea. The prediction performance of PM2.5 and its major components was evaluated, and the causes affecting the difference between CTMs were analyzed, and ways to improve the prediction performance were considered. The 2019 emission inventory updated to reflect recent changes in air pollution emissions was used in common for all three models.As a result of analyzing the total mass concentration of simulated PM2.5 and major chemical components, the performance of each model was different for each season. CMAQ in January, WRF-Chem in July, and GEOS-Chem in October tended to overestimate the PM2.5 concentrations. For CMAQ, secondary organic aerosol (SOA) was produced by semivolatile/intermediate-volatility organic compounds (S/IVOC), and PM2.5 concentrations was high in winter. This is because CMAQ includes a new pathway for potential combustion secondary organic aerosol (pcSOA). Also, WRF-Chem simulated a particularly high concentration of sulfate because it affected the scavening function according to the aqueous phase chemistry.These multi-model intercomparison of air quality simulations will be helpful in future research to increase understanding of the differences between CTMs in Northeast Asia and to identify the causes of air pollution.
Non-contact Entropy-based flow Estimation in Himalayan Rivers
Authors: Kumar Abhishek , Jain Manoj Kumar
Published: February 2023

Rapidly collected river discharge data can be used for flood forecasts, hydraulic structure design, and impromptu response during floods. This calls for the monitoring of both water level and velocity at the same time, which is not feasible using conventional invasive methods. Non-contact techniques like doppler radar and satellite remote sensing techniques are the sole options. Doppler radar sensors are gaining popularity in the recent decade due to their accuracy and user-friendly operation. The study was conducted using data collected at two gauging sites at Devprayag on Bhagirathi and Ganga, two significant Himalayan Rivers. This study compares the observed discharge measured using a current meter and ADCP with the entropy-based discharge estimated using radar telemetry data for water level and surface velocity. Radar-derived water level and one-point surface velocity observations were used to estimate the discharge using probability-based Shannon and Tsallis Entropy laws. The discharge varied from 77.09 to 4265.4 cumec, while the surface velocities ranged from 0.283 to 8.35 m/s. The estimated discharges using radars were compared with observed discharges using Goodness-of -fit statistics which showed a good agreement between observed and estimated discharges as well as velocities, suggesting that radars can be effectively used to estimate real-time discharge for its improved applications in Himalayan mountainous rivers.
Model studies on transport of microplastics from a leak accident
Authors: Zhang Chen
Published: February 2023

We investigated an unexpected microplastic (MP) leakage event that occurred along the coastline of Yantai in January 2021. Sediment samples were collected from three zones on 9 beaches. MPs were identified with an average abundance of 247.6±125.6 items/m2 on 7 beaches. The total amount of MPs from the leak accident was estimated to be 1.50×107 items (514.67 kg). The MPs were identified as polyethylene (PE), polypropylene (PP), and PP/PE blends using μ-FT-IR analysis. By utilizing a numerical model, the transmission process and potential source of MPs were demonstrated. The modeling results showed that the MPs might originate from the central and western part of the Bohai Sea and be driven to the beaches of Yantai by northwest wind and wind-induced surface current. However, due to the absence of direct evidence, the simulation results might only indicate the range of the leaking source, which was the movement trajectory of MPs.
A tale of two orogens- Taiwan and Mindoro
Authors: Lee Yuan-Hsi , Mesalles Lucas , Bacolcol Teresito
Published: February 2023

The Taiwan and Mindoro islands are located on the northern and southern ends of the Malina trench, and both orogens result from the deformation of the continental margin of the Eurasia plate. Comparing the exhumation histories of both orogens allow us to discuss the mechanism of mountain building of two orogens.In Taiwan orogen, the timing of the mountain building starts from ca. 6-8 Ma, which can be identified using ZrnFT, Ar-Ar, and the timing of the developing foreland basin. For Mindoro island, we combine with ZrnFT, ApaFT, and ZrnHe to constrain the timing of the exhumation. It shows oldest ZrnFT ages are ca. 6-7 Ma. We further constrain that the latest stage of granite age in the rifted continental crust is ca. 13Ma indicating the collision should be later than this age. In addition, the ApaFT and ZrnHe ages for the granite are ca. 6Ma inferring a rapid cooling age which is consistent with regional ZrnFT dates. Those data imply the timing of mountain building of Mindoro orogen is ca. 6-7Ma which is similar to the Taiwan orogen.Considering both orogens have similar timing of mountain building, we suggest that while the Philippine Sea changes the motion to NW trending at ca. 7-8Ma and Eurasia continental margin subducts to the Philippine Sea plate and Philippine Mobile belt, respectively, that results in both orogens deforming simultaneously.
ENSO Feedback Mechanism on PM2.5 Concentration in Indonesia
Authors: Nahas Alberth , Sopaheluwakan Ardhasena , Putri Ayuna Santika , Kinanti Nanda Putri , Taryono Taryono , Setiawan Budi
Published: February 2023

The presence of a short-lived climate pollutant, PM2.5, can influence the condition of air quality in specific regions. In the atmosphere, the PM2.5 concentration pattern might be affected by climate phenomena, such as El Niño Southern Oscillation (ENSO). In this study, we examined the ENSO (El Niño and La Niña) feedback on PM2.5 concentration in Indonesia by using an hourly reanalysis dataset from CAMS global emission inventories during the period 2004 - 2021. We analyzed the spatial anomaly of PM2.5 concentrations by calculating the difference between each El Niño/La Niña in three stages; Moderate, Strong, and Very Strong episodes with the Normal condition. Results show that PM2.5 conditions in Indonesia during ENSO revealed different responses in each region. ENSO had positive feedback to most of the western and central parts of Indonesia, especially the islands of Sumatra and Kalimantan. This positive feedback on PM2.5 generally occurred in forest fire prone areas. Those areas were sensitive to El Niño episodes which caused the prolonged droughts associated with suppressed rainfall to enhance the risk of forest fires occurring, resulting in elevated PM2.5 concentrations emitted from burned materials. Meanwhile, several areas in central Java, western Java, and Nusa Tenggara showed a weak negative effect. Other areas in eastern Indonesia generally showed no feedback or ENSO events did  not have a significant effect on PM2.5 concentrations. 
The use of open-source, affordable hardware in soil gas research
Authors: Levintal Elad
Published: February 2023

The development of new affordable sensors and hardware, and the ability to log high-resolution data for long periods of time can enhance the ability to capture soil gas process-related heterogeneity. The use of novel open-source sensors, defined as hardware whose design is made publicly available, lowers the cost dramatically compared to commercial solutions and allows implementing higher spatiotemporal resolution sensor grids that are imperative for modeling and mechanistic understandings. Here, I will present the basic concepts, advantages, and challenges of using open-source, low-cost, do-it-yourself hardware for soil gas monitoring (mainly O2, CO2, CH4, and N2O), including examples in which this type of sensors was utilized to solve soil-related research questions. For example, the development of a low-cost wireless underground sensor network for O2/CO2 monitoring under waterlogged conditions using the relatively new low-power long-range (LoRa) communication protocol. Another example is a portable, low-cost incubation chamber for quantifying soil microbial activity using in-situ sensors for measuring O2, CO2, CH4, and air temperature at high temporal resolution (<1 min). In all the presented studies, only readily buyable hardware is used, and complete technical guides on design, assembly and installation are provided. By doing so, the adoption and cost barriers can be reduced, allowing easier reproducibility and opening the technology for new applications in soil gas monitoring studies.