bluuebunny/crossref_metadata_2025 huggingface dataset:
Runoff characterisation by SEC measurements in spring water
Authors: Bozau Elke , Licha Tobias
Published: February 2023

Extreme weather periods in the Harz Mountains with heavy rain events (e.g., July 2017) and long dry periods (September 2016, May – November 2018, September 2020) trigger extreme changes in surface runoff. However, such events do not lead to unknown, unpredictable chemical changes of the spring water in the Upper Harz Mountains (Bozau et al., 2013 and 2021). In order to obtain more information on the chemical evolution and to predict drying out events, spring waters of several catchment areas of the Harz Mountains were monitored. Every spring has a typical runoff pattern combined with specific chemical variations. The order of drying out during long droughts depends on the catchment size of the individual spring and did not change in the observation period.Since February 2020, the specific electrical conductivity (SEC) of the spring "Innerstesprung" near Clausthal has been systematically measured at least once a week. This spring has its source in fractured Paleozoic greywacke, flows at the surface for about 30 m in a little artificial channel and then passes into the reservoir lake "Entensumpf". The measured SEC data are compared with daily precipitation rates. Drying out and first flush events show specific SEC trends. Furthermore, frozen snow covers are reflected by the SEC data. The SEC values of the spring water range between 55 and 100 µS/cm. Minimum values are typical for long rainy periods and snow melt in February. Only in 2017 (with about 300 mm precipitation during one week of July) 57 µS/cm were found in summer time. The maximum values of SEC are measured immediately before the drying out of the spring. Furthermore, a special effect of SEC enrichment after the first flush event has been observed. An impact of the enhanced deforestation which started in 2020 was not seen during the monitoring period. The spring runoff, precipitation and evaporation rates during the drying out events can be used for the calculation of the catchment areas. Furthermore, water-rock interactions along the flow path of spring water were investigated by batch tests.References:Bozau, E., Stärk, H.-J., Strauch, G., 2013. Hydrogeochemical characteristics of spring water in the Harz Mountains, Germany. Geochemistry, 73, 283-292.Bozau, E, Bauer, G., Licha, T., Lojen, S., 2021. Hydrochemical response of spring and mine waters in the Upper Harz Mountains (Germany) after dry periods and heavy rain events. ZDGG, 172(1), 73-82.
Deep-Seated Gravitational Slope Deformation and Slow-Moving Landslides Revealed by Multi-Period LiDAR and UAS Data in the Slate Belt of the Backbone Range, Central Taiwan
Authors: Hsieh Yu-Chung , Tung Ying-Hung , Chen Mien-Ming , Lin Hsi-Hung , Chi Chung-Chi
Published: February 2023

In the mountain area, Deep seated gravitational slope deformation (DSGSD) was a phenomenon that causes rock mass deformation under long-term gravity. In the Slate Belt of the Backbone Range, Taiwan where mainly slate distributed, it is more susceptible to develop DSGSD. After Typhoon Morakot (2009), the high-resolution airborne LiDAR topographic data of the entire island of Taiwan completed by 2016, which will be regularly updated every five years. This high-resolution airborne lidar topographic data could be applied to visual interpretation with the potential landslide area, multi-period data with activity of slope deformation. In this study, we used existing high-resolution LiDAR topographic data and the latest computerized 3D environments to conduct and explore preliminary geological information at the regional scale and potential large-scale landslide distribution with detailed topographical characteristics. The area of slow-moving landslides could be found by comparing multi- period LiDAR topographic data and UAV images. Through field investigations and UAV application in Lusan area of central Taiwan, the features caused by regional tectonic effects or DSGSD could be clarified and discussed activity and possible mechanism of rock mass failure caused by these DSGSD. The results help to understand the deformation mechanism of the slate area in the Central Range of Taiwan. In the future, we could further explore the possible causes of why DSGSD transform into catastrophic landslides.
How AuScope 3D Geomodels Portal integrates relatively metadata poor geological models into its metadata infrastructure
Authors: Fazio Vincent
Published: February 2023

The AuScope 3D Geomodels Portal is a website designed to display a variety of geological models and associated datasets and information from all over the Australian continent. The models are imported from publicly available sources, namely Australian government geological surveys and research organisations. Often the models come in the form of downloadable file packages designed to be viewed in specialised geological software applications. They usually contain enough information to view the model’s structural geometry, datasets and a minimal amount of geological textual information. Seldom do they contain substantial metadata, often they were created before the term ‘FAIR’ was coined or the importance of metadata had dawned upon many of us. This creates challenges for data providers and aggregators trying to maintain a certain standard of FAIR compliance across all their offerings. How to improve the standard of FAIR compliance of metadata extracted from these models? How to integrate these models into existing metadata infrastructure? For the Geomodels portal, these concerns are alleviated within the automated model transformation software. This software transforms the source file packages into a format suitable for display in a modern WebGL compliant browser. Owing to the nature of the model source files only a very modest amount of metadata can be extracted. Hence other sources of metadata must be introduced. For example, often the dataset provider will publish a downloadable PDF report file or a description on a web page associated with the model. Automated textual analysis is used to extract more information from these sources. At the end of the transformation process, an ISO-compliant metadata record is created for importing into a geonetwork catalogue. The geonetwork catalogue record can be used for integration with other applications. For example, AuScope’s flagship portal, the AuScope Portal displays information, download links and a geospatial footprint of models on a map. The metadata can also be displayed in the Geomodels Portal.
Tracing 36Cl in river water of Eastern Australia
Authors: Cendón Dioni I. , Wilcken Klaus , Harris Stephen J. , Hankin Stuart I. , Peterson Mark A. , Kelly Bryce F.J.
Published: February 2023

Chlorine-36, generally expressed as a ratio against stable chlorine (36Cl/Cl x1015), has a half-life of 301 kyr, thus it is a useful tracer for estimating residence time of old groundwater between 50 kyr - 1 Myr. An underutilised use of 36Cl/Cl is as a sensitive tracer of catchment scale processes such as: identifying sources of salinity, weathering, delineating groundwater-surface water interactions, quantifying irrigation infiltration, and identifying anthropogenic inputs.We highlight the utility of 36Cl/Cl for gleaning insights into regional natural and anthropogenic processes in the Nogoa, Namoi and Murrumbidgee river catchments of eastern Australia. All catchments are within important agricultural regions and are regulated by one or more large reservoirs in their headwaters. The Nogoa River (Lat 23°S) flows east and forms part of the Fitzroy River that meets the Coral Sea near the town of Rockhampton. The Namoi (Lat 30°S) and Murrumbidgee (Lat 35°S) rivers form part of the Murray-Darling Basin and flow westwards (inland) before joining the Darling and Murray Rivers respectively to flow south towards the Southern Ocean. River water was sampled bi-monthly in several stations from the upper to middle reaches of each river during two years between 2017-2020. Sampling took place during drought conditions; 2019 being the driest in ~120 years of instrumental records in many areas. Climatic conditions favoured sampling of baseflow with flows mostly relying on reservoir releases in some cases (Namoi River) until total reservoir and river dryness.At the ground surface 36Cl can be produced via two main pathways. Typically, the dominant source of 36Cl in surface water is atmospheric, which was produced in the troposphere and stratosphere via interaction of cosmic-ray protons and secondary neutrons with Ar. However, secondary cosmic-ray neutrons can produce 36Cl when they collide with rocks and minerals. These reactions are modulated by the composition of the geological materials and their elevation. The Nogoa and Namoi Rivers have similar basic geological materials in their headwaters at relatively lower altitudes, while the Murrumbidgee has abundant mafic and felsic igneous rocks in the headwaters at higher altitudes.In general, the Namoi River showed the higher 36Cl/Cl ratios (~650-300) followed by the Murrumbidgee River (~500-200) and the lowest readings were recorded in the Nogoa River (~200-100). These results do not follow simple latitudinal or elevation trends. In this presentation we discuss plausible geological and anthropogenic processes that may account for the observations.
From political pledges to the quantitative mapping of climate mitigation plans: comparison of two European cities
Authors: Albarus Ivonne , Fleischmann Giorgia , Aigner Patrick , Ciais Philippe , Denier van der Gon Hugo , Droge Rianne , Lian Jinghui , Narvaez Rincon Miguel Andrey , Utard Hervé , Lauvaux Thomas
Published: February 2023

Urban agglomerations play a crucial role in reaching global climate objectives. Many cities have committed to reducing their greenhouse gas emissions, but current emission trends remain unverifiable. The quantification of mitigation policies is often incomplete or unavailable, raising serious concerns about how and if climate mitigation targets will be achieved. To support the effective traceability of urban emissions trajectories, atmospheric monitoring of greenhouse gases (GHG) has been deployed over several metropolitan areas. This approach offers an independent and transparent solution to measuring urban emissions. However, careful design of the monitoring network is crucial to be able to monitor the most important sectors as well as to adjust to rapidly changing urban landscapes.We present here a joint study of Paris and Munich emissions trajectories to demonstrate how climate action plans, carbon emission inventories, and urban development plans can be combined to construct high-resolution projected emissions maps and to help design optimal atmospheric monitoring networks. We show that these two European cities will encounter widely different GHG emission trajectories in space and time, reflecting different emission reduction strategies and different constraints due to administrative boundaries. The projected CO2 emissions for the milestone years 2030 and 2050 are based on the 2019 spatially distributed 1km x 1km TNO inventory. Future emissions scenarios are based on the analysis of their respective Climate Action Plan. Individual mitigation measures are quantified, sectorized and the resulting saving potentials are applied to the 2019 TNO inventory, used as baseline. The projected CO2 emissions rely on future actions, hence uncertain, but we demonstrate how emission reductions vary significantly at the sub-city level. We show here how climate actions, population growth, and urbanization plans produce mixed spatial patterns across both cities. We conclude that quantified individual cities’ climate actions are essential for strengthening climate policies and their effectiveness at the city scale. Harmonization and compatibility of climate plans from various cities are necessary to make intercity comparisons of climate targets possible. In terms of atmospheric monitoring, our results demonstrate the need for additional measurement stations located inside the densest areas of the two cities but also in the cities’ outskirts to track local positive and negative emission trends over the coming decades. 
Identification of bedrock depth and blind fault by HVSR analysis along two profiles in Pohang, South Korea considering optimal weather environment and seismometer burial depth
Authors: Kang Su Young , Kim Kwang-Hee , Kim Doyoung , Kim Byungmin , Liu Lanbo , Lee Youngcheol
Published: February 2023

Many deep faults do not reach the earth’s surface and thus are not recognized. Such faults are rarely mapped by standard surface geological mapping. This seriously hinders seismic risk mitigation efforts. In this study, we applied the horizontal-to-vertical spectral ratio (HVSR) method to identify blind faults invisible at the surface. Despite its simplicity and low-cost implementation, we noticed that HVSR results were unstable using data collected by exposed seismometers or under higher wind speeds. Therefore, three-component seismic sensors for ambient noise observations were buried at different depths to examine the effects of ground coupling, wind speeds, and precipitations. Results from a series of field tests under diverse conditions guided us to establish data selection criteria. The first required condition is that seismic sensors should be buried (>0.3 meters) to secure ground coupling and to avoid any direct exposure to wind or precipitations. The other is that data should be collected at low wind speeds (< 3 m/s). The requirements were applied to ambient noise data along two profiles traversing unnamed and inferred faults in Pohang, Korea. We initially estimated the resonance frequencies for each site, which varied from 0.41 to 2.52 Hz. They were then converted to bedrock depths using an empirical relationship between the resonance frequency and depth to bedrock observed at boreholes in the area. The estimated depths to bedrock along profiles ranged from 8.0 to -472.0 meters. The resulting depth profiles show significant lateral variations in the bedrock depth, including the one near the Gokgang fault at which the thickness to the major impedance contrasts decreased from 196 to 20 meters. Sudden variations were also observed at unexpected locations along the profile. We examined the details, especially for sites of apparent changes in bedrock depth, and compared their characteristics with other geophysical studies, including Vs30, MASW, Bouguer gravity anomaly, and adjacent stations correlation. Their results are all well correlated to each other and indicate rapid changes in bedrock depth. We attribute the rapid changes to vertical displacements by ancient faulting activity.
Investigating Characteristics of Drought-Flood Abrupt Alternation Events in South Korea for Comprehensive Disaster Management
Authors: Son Ho-Jun , Byun Sung Ho , Yoon Hyeon-Cheol , Lee Joo-Heon , Kim Tae-Woong
Published: February 2023

Recently, due to the climate change, the frequency of extreme hydrological disasters such as drought and flood is increasing worldwide. Especially, sudden change in precipitation cause drought and flood often occur alternately in a short period of time, which is defined as a drought-flood abrupt alternation event. In this study, daily Standardized Precipitation Index (SPI) for the entire basin of South Korea is used to analysis the characteristics of the short-term abrupt alternation events of drought and flood, focusing on the short-term perspective rather than the monthly SPI. When the SPI value is less than –1.5 for 10 consecutive days, a drought event begins, whereas when the SPI value is more than 0.5 for 7 consecutive days, a drought event ends. On the contrary, when the SPI value is more than 1.5 for 10 consecutive days, a flood event begins, whereas when the SPI value is less than –0.5 for 7 consecutive days, a flood event ends. When the time interval between the end of drought event and the start of flood event is less than five days, a drought-flood abrupt alternation event is identified. The severity of drought-flood abrupt alternation event is defined similarly to the severity of drought using the SPI. We classified the severity into two types: SW(severity of whole period) and ST(severity of transition period). We used the additional statistical risk grade analysis. Nackdong River basin (southeastern region of Korea) has most severe grade of the SW rather than the other basins and the ST is lower than other basins. On the contrary, Yeongsan River basin (southwestern region of Korea) has most severe grade of ST rather than the other basins and the SW is lower than other basins. In conclusion, using daily SPI can determine the risk-prone areas through evaluating the frequency and severity of drought-flood abrupt alternation events. Due to climate change, increasing variability of precipitation, and frequent flood abrupt alternation events in the future, our results will cornerstone to predict the vulnerable and risk-prone region or preventing disasters.Acknowledgement: This research was supported by a grant(2022-MOIS63-001) of Cooperative Research Method and Safety Management Technology in National Disaster funded by Ministry of Interior and Safety(MOIS, Korea).
Transformation products of oxytetracycline by heterogeneous photo-Fenton-like process
Authors: Park Jeong-Ann
Published: February 2023

Oxytetracycline (OTC) is frequently detected antibiotic in surface water because it is widely used for both humans and animals; however, it is difficult to be completely removed by conventional wastewater treatment due to its recalcitrant nature. By using photo-Fenton-like process, OTC could be degraded or transformed, while only a few studies were conducted to detect its transformation products (TPs). In this study, a UHPLC (Ultra-high-performance liquid chromatography) system coupled with a Triple TOF 5600+ mass spectrometer (AB SCIEX Co., Redwood City, CA, USA) was used to identify the TPs of OTC during the heterogeneous photo-Fenton process. The heterogeneous photo-Fenton-like process was performed with MIL-100(Fe) and 50 mg/L of H2O2 under visible light, then 12 kinds of TPs were observed. The peak area of OTC (m/z 461) decreased immediately as the reaction wend, and 8 kinds of TPs were observed only after 1 min-reaction. OTC transformed initially and mainly by decarbonylation of C1 (m/z 433), hydroxylation of the aromatic ring (m/z 477a) and C11a (m/z 477b), and demethylation at low N-C bonds (m/z 447). m/z 477a and 475 were predominantly observed because the aromatic ring is one of the most favorable target site to be oxidized by ·OH. Additionally, keto/enol at C11a-C12 is another favorable oxidation site forming m/z 477b; further hydroxylation generated m/z 493, and additional secondary alcohol oxidation led to the formation of m/z 491. A methyl group at C4 abstraction (m/z 447) was degraded further into m/z 429 by dehydration of C6-C5a, abstraction of hydrogen at C5 turned into m/z 459, and m/z 441 was formed by dehydration at C6.
Analysis of natural disaster vulnerability by region through the use of big data of emergency disaster message history
Authors: Oh Seung-Hee , Kang Hyunjoo , Ju Sang-Lim
Published: February 2023

Between 2020 and 2022, when South Korea experienced Covid-19, it suffered from multiple natural disasters, including typhoons, forest fires, and earthquakes, as well as infectious diseases. Recently, not only in Korea but also worldwide due to climate change, the number and scale of natural disasters are increasing every year, and the damage caused by them is becoming more and more serious. We analyzed big data on disasters in South Korea to identify trends in disasters caused by climate change. So, between 2012 and 2022, we downloaded over 100,000 open data on emergency disaster alert messages (by mobile network Cell Broadcasting Service) provided by the central government and local governments to the general public through Public data portal (https://www.data.go.kr/) open API(Application Programming Interface). And we visualized the collected raw big data based on GIS after refinement, classification((Natural and social disasters, disaster type, disaster level, CBS msg type, emergency disaster message sending agency, etc.), and subdivision by city (we call it Si, Gun, Gu) unit area. Then, it was displayed based on GIS according to the type of disaster. We performed visualization work to derive the results of climate change trends in South Korea by disaster type and by region(Si, Gun, Gu).Through this, it was possible to identify the types of disasters that are becoming more severe in South Korea according to climate change. Also, based on these results, we were able to identify which disasters each region would be vulnerable to. In addition, based on these results, we were able to identify which disasters are particularly vulnerable according to the characteristics of each region and which disasters it is best to strengthen preparation for in the future.The results of analyzing the past history big data of our emergency disaster messages can be usefully used to present preventive and prepared plans for future disasters by central and local governments.This research was supported by a grant (20008820) of Disaster-Safety Inter-Miniterial Cooperation Program funded by Ministry of Interior and Safety (MOIS, Korea)
Life Cycle Cost Analysis of Seismic Reinforcement Plans
Authors: Lin Szu-Yun , Wang Chia-Hung
Published: February 2023

Owing to the aging of built environment, many cities are facing the increasing of disasters impact and risk. Reinforcing the existing buildings is one common strategy. This study aims to provide a reference for the reinforcement plan of private buildings through life cycle cost and benefit analysis from the perspective of the society as a whole. First, the seismic reinforcement strategies in different countries are reviewed for identifying suitable target buildings. The total annual earthquake loss related to the characteristics of building is assessed through the capacity spectrum method, fragility curves, and probabilistic seismic hazard analysis. The construction cost and reinforcement cost are estimated by historical data, and then the equivalent uniform annual cost method is used to analyze the life cycle cost of a certain reinforcement strategy. The privately owned buildings in Taipei City, Taiwan were analyzed to demonstrate the proposed method. The priority of reinforcement was determined by different vulnerability and risk measures of each building, and four different reinforcement strategies were compared in the case study. The results show that the proposed method can provide an objective reference for arranging the reinforcement order and economic-effectively reducing the impact of earthquakes on the whole community.
Monthly vegetation drought forecasting using copula functions, numerical weather prediction and artificial intelligence models
Authors: Won Jeongeun , Seo Jiyu , Lee Chaelim , Kim Sangdan
Published: February 2023

Drought inhibits vegetation growth, triggers wildfires, reduces agricultural production and has a significant impact on the health of terrestrial ecosystems. Continuously monitoring and forecasting the effects of drought on vegetation health can provide effective information for ecosystem management. The purpose of this study is to forecast the effect of meteorological drought on vegetation, that is, the ecological drought of vegetation. Because vegetation drought is a complex phenomenon, it should be approached based on the probabilistic relationship between meteorological drought and vegetation. Accordingly, a probabilistic approach was constructed to model the bivariate joint probability distribution between meteorological drought and vegetation using the copula function. In order to predict ecological drought based on the joint probability distribution, predictive information on meteorological drought and vegetation health is required. To this end, a meteorological drought was predicted using numerical weather prediction, and a short-term vegetation prediction model considering the meteorological drought prediction results was developed. The vegetation prediction model combining Convolutional Long Short-Term Memory and Random Forest was able to improve the prediction performance of vegetation by considering spatial and temporal patterns. The vegetation drought was forecast by linking the prediction information of vegetation and meteorological drought with the joint probability distribution. The approach of this study will be able to provide useful information to respond to the drought risk in terms of ecology. AcknowledgementThis work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2022R1A2B5B01001750).
Changes in Air Dose Rates due to Soil Water Content in Forests in Fukushima Prefecture, Japan
Authors: Nakanishi Miyu , Onda Yuichi , Kato Hiroaki , Takahashi Junko , Iida Hikaru , Takada Momo
Published: February 2023

Radionuclides released and deposited by the 2011 Fukushima Daiichi Nuclear Power Plant accident caused an increase in air dose rates in forests in Fukushima Prefecture. It has been reported that air dose rates increase during rainfall, but we found that air dose rates decreased during rainfall in forests in Fukushima. This is said to be due to the shielding effect of soil moisture. This study aimed to develop a method for estimating changes in air dose rates due to rainfall even in the absence of soil moisture data. Therefore, we used the preceding rainfall (Rw), an indicator that also takes into account past rainfall; we calculated Rw in Namie-Town, Futaba-gun, Fukushima Prefecture from May to July 2020, and estimated air dose rates. In this area, air dose rates decreased with increasing soil moisture. Furthermore, air dose rates could be estimated by combining Rw with a half-life of 2 hours and 7 days, and by considering hysteresis in the absorption and drainage processes. The coefficient of determination (R2) exceeded 0.70 for the estimation of soil water content at this time. Furthermore, good agreement was also observed in the estimation of air dose rates from Rw (R2 > 0.65). The same method was used to estimate air dose rates at the Kawauchi site from May to July 2019. Due to the high water repellency of the Kawauchi site, the increase in soil water content was very small and the change in air dose rate was almost negligible when soil water content was less than 15% and rainfall was less than 10 mm. This study enabled the estimation of soil water content and air dose rate from rainfall and captured the effect of rainfall on the decreasing trend of air dose rate. Therefore, in the future, This study can be used as an indicator to determine whether temporary changes in air dose rates are caused by influences other than rainfall. This study also contributes to the improvement of methods for estimating external dose rates for humans and terrestrial animals and plants in forests.
The physics and dynamics of selected dust storms in the EMM primary mission
Authors: Gebhardt Claus , Guha Bijay K. , Young Roland M. B. , Wolff Michael J. , Edwards Christopher S.
Published: February 2023

Mars dust storms are an interdisciplinary field of research. They impact the entry-descent-landing operations of spacecraft, the energy production by the solar panels of Mars rovers and landers, and others. As can be foreseen, dust storms are also critical for the future human exploration of Mars. Dust storm research is directly aligned with the Emirates Mars Mission (EMM) science objective on the lower atmosphere, and with the science objective of correlating the lower and upper atmosphere [1,2]. First results of EMM dust storm research were reported in [3].EMM has a high-altitude orbit and provides data products for studies of the Mars atmosphere and surface with a near-hemispheric view. Moreover, EMM can provide information on dust storm activity every few hours or less. EMM observed multiple dust storms during the primary mission, including a large regional dust storm in Sep. and Oct. 2022.The focus of this presentation are unique dust storm observations by the EMM camera EXI [4]. We study a subset of dust storms, which is of particular interest to our research. The formation and growth of dust storms is followed at a (sub-)hourly time scale. This includes results on the dust storm morphology, wind direction, wind speed, surface dust lifting, etc.. Based on that, the implications for the physics and dynamics of dust storms are considered.[1] Amiri, H.E.S., Brain, D., Sharaf, O. et al. The Emirates Mars Mission. Space Sci Rev 218, 4 (2022). https://doi.org/10.1007/s11214-021-00868-x[2] Almatroushi, H., AlMazmi, H., AlMheiri, N. et al. Emirates Mars Mission Characterization of Mars Atmosphere Dynamics and Processes. Space Sci Rev 217, 89 (2021). https://doi.org/10.1007/s11214-021-00851-6[3] Gebhardt, C., Guha, B. K., Young, R. M. B., & Wolff, M. J. (2022). A frontal dust storm in the northern hemisphere at solar longitude 97—An unusual observation by the Emirates Mars mission. Geophysical Research Letters, 49, e2022GL099528. https://doi.org/10.1029/2022GL099528[4] Jones, A.R., Wolff, M., Alshamsi, M. et al. The Emirates Exploration Imager (EXI) Instrument on the Emirates Mars Mission (EMM) Hope Mission. Space Sci Rev 217, 81 (2021). https://doi.org/10.1007/s11214-021-00852-5
Spatiotemporal characteristics of soil Moisture and land – atmosphere coupling over the Tibetan Plateau derived from three gridded datasets
Authors: Zan Beilei , Wang Huiming , Wei Jiangfeng , Song Yuanyuan , Mao Qianqian
Published: February 2023

Soil moisture is a crucial component of the water cycle and plays an important role in regional weather and climate. However, owing to the lack of In Situ observations, an accurate understanding of the spatiotemporal variations of soil moisture (SM) on the Tibetan Plateau (TP) is still lacking. In this study, we used three gridded SM products to characterize the spatiotemporal features of SM on the TP during the warm season (May to August). We analyzed the fifth-generation European Centre for Medium-Range Weather Forecasts atmospheric reanalysis (ERA5), Global Land Data Assimilation System (GLDAS), and Soil Moisture Active Passive (SMAP) datasets and used station observation data and triple collocation to quantify product accuracy and consistency. Results of the evaluation based on observation data show that both ERA5 and GLDAS overestimate SM, while the accuracy of SMAP is high. In terms of capturing the temporal variations of SM measured at stations, the performance of ERA5 and that of SMAP are superior to that of GLDAS. According to the evaluation based on triple collocation, SMAP exhibits the smallest random error over the TP and the highest temporal correlation with the unknown true SM in eastern TP. For SMAP, SM variability is the largest in the southern TP. For ERA5 and GLDAS, variability in the western TP is substantially larger than that for SMAP. Low-frequency (30–90 days) variations are the largest contributor to TP SM intraseasonal variability. Relative to SMAP, the contribution of high-frequency variations is low in ERA5 and GLDAS. Land-atmosphere coupling is stronger (weaker) in the western (southeastern) TP, which is relatively dry (wet). Our evaluation of SM product performance over the TP may facilitate the use of these products for disaster monitoring and climate and hydrological studies.
Impacts of Precipitation Forcing on Hydrological Simulation over Monsoon Asia
Authors: lee seulchan , jeong jaehwan , Mohammad Harmay Nurul Syahira , choi minha
Published: February 2023

Globally important hydroclimatic variations take place over monsoon Asia. However, sound understanding of hydrological processes is still challenging due to the unevenly distributed observation stations. This rising issue has been partially solved through land surface model (LSM) simulations, which is known as one of the most effective ways to predict hydrological states and fluxes in ungauged regions. Recent advances in remote sensing techniques produced several multi-source-based precipitation data, which serves as a major input forcing for modeling the land surface processes. In this context, this study aims to validate the precipitation estimates from Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA2), Global Data Assimilation System (GDAS), Integrated Multi-satellite Retrievals for GPM (IMERG), and Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS), and also evaluate the LSM-simulated soil moisture (SM) and evapotranspiration (ET) through NASA Land Information System (LIS). Precipitation products are validated with ground measurements-based Asian Precipitation - Highly-Resolved Observational Data Integration Towards Evaluation (APHRODITE) gridded data. Spatiotemporal errors in SM and ET outputs originating from precipitation uncertainty are quantified at locations with dense ground precipitation observations. Overall, the outcomes could possibly reveal additional error sources such as land use land cover (LULC) surface dataset or model parameterizations, which is crucial for more sophisticated LSM simulations.
Analysis of Mass Extinction Efficiency variation according to relative humidity using lidar and visibility data in Seoul
Authors: Joo sohee , Sim Juhyeon , Kim Jawon , Lee Yuseon , Noh Youngmin
Published: February 2023

The mass extinction efficiency(MEE), which indicates the degree of aerosol extinction(scatter and absorption) per unit PM mass concentration, is an important factor in converting optical concentration into mass concentration. Because its value varies depending on the particles' size and composition, which are particles' characteristics. In this study, the extinction coefficients of coarse and fine particles were calculated using the LiDAR data of Seoul observed by NIES(Japan's National Institute of Environmental Studies) and the visibility data of Seoul observed by the Korea Meteorological Administration. In the case of lidar data, two wavelengths (532nm, 1064nm) measured by lidar were used to calculate extinction coefficients, and the wavelength of 532 nm (532P and 532S) were used to classify extinction coefficients into coarse particles(PM10-2.5) and fine particles(PM2.5). In the case of visibility data, the PM10 and PM2.5 extinction coefficients were calculated using the equation of Koschmieder (1924) and Cheng et al. (2017). The PM10, PM10-2.5, and PM2.5 respective MEE were calculated using Seoul data of PM10 and PM2.5 at the same time provided by the Korea Environment Corporation. The relative humidity data provided by the Korea Meteorological Administration were divided into seven sections less than 40%, 40~49%, 50~59%, 60~69%, 70~79%, 80~89%, and 90~100%. According to relative humidity, this study examined the change of the calculated MEE. This study analyzes the effect of relative humidity on the Hygroscopic Growth of PM10, PM10-2.5, and PM2.5. 
Six years of spatiotemporal variations of large wood at the meander scale
Authors: Galia Tomáš , Škarpich Václav , Horáček Matěj
Published: February 2023

Meander bends are perceived as sites with high large wood (LW) retention potential by trapping transported LW at their concave banks or on point bars. We employed five field inventories between 2016 and 2022 (2016, 2019, 2020, 2021 and 2022) in 13 subsequent meander bends of the Odra (Oder) R., Czechia, to assess spatiotemporal variations of LW in the period characterised by ordinary flow events including a flood of 5-year recurrence interval (10/2020, 308 m3/s). We found an increasing trend in LW volume (121.1 m3 in 2016 and 138.1 m3 in 2022, respectively) in a 3.65 km long study reach. We observed a high disproportion in the longitudinal LW distribution during individual surveys along the study reach. Furthermore, four upstream meander bends had stable LW volumes during the study period, whereas the bends located in the middle and downstream part of the study reach indicated large fluctuations of LW loads without any regular trend. These fluctuations are likely related to (i) chronic recruitment of LW from outer meander banks, (ii) burial of LW during floodplain accretion, and (iii) LW mobility during high flows. Independent variables representing the characteristics of the riparian trees (tree basal area and the length of the riparian forest at the bend) were detected as significant predictors of the LW volume at the meander scale. Future research will focus on the complex links among the migration rates of individual meanders, the characteristics of riparian stands, and the dynamics of LW in the channel and floodplain.       
Comparison of optimization methods for the maximum likelihood ensemble filter
Authors: Enomoto Takeshi , Nakashita Saori
Published: February 2023

The Newton method, which requires the Hessian matrix, is prohibitively expensive in adjoint-based variational data assimilation (VAR). It may be rather attractive for ensemble-based VAR because the ensemble size is usually several orders of magnitude smaller than that of the state size. In the present paper the Newton method is compared against the conjugate-gradient (CG) method, which is one of the most popular choices in adjoint-based VAR. To make comparisons, the maximum likelihood ensemble filter (MLEF) is used as a framework for data assimilation experiments. The Hessian preconditioning is used with CG as formulated in the original MLEF. Alternatively we propose to use the Hessian in the Newton method. In the exact Newton (EN) method, the Newton equation is solved exactly, i.e. the step size is fixed to unity avoiding a line search. In the 1000-member wind-speed assimilation test, CG is stagnated early in iteration and terminated due to a line search error while EN converges quadratically. This behaviour is consistent with the workings of the EN and CG in the minimization of the Rosenbrock function. In the repetitive cycled experiments using the Korteweg-de Vries-Burgers (KdVB) model with a quadratic observation operator, EN performs competitively in accuracy to CG with significantly enhanced stability. These idealized experiments indicate the benefit of adopting EN for the optimization in MLEF.
A comparative study of UAV-based 3D point cloud analyses on landslide volume estimation for progressive rockslide
Authors: Chang Kuei-Ying , Huang Wei-Kai , Lin Cheng-Han , Lin Ming-Lang
Published: February 2023

Rock slope instability, such as rockslides and rock falls, are common issues along mountain highways. These natural phenomena not only control the slope morphology but also pose substantial risk to the safety of road users. When highway authority responds to those disasters, the first task is to estimate the landslide volume and potential sliding volume for planning emergency measures. Recent advances in UAV-based 3D point cloud analyses have improved our ability to investigate landslides efficiency with unprecedented time resolution. However, different techniques involve several limitations that should be considered when approaching landslide volume estimation for progressive rockslides. This study demonstrates how the effects of multitemporal point cloud dataset alignment may hinder the analysis of landslide development in high steep highway slope. A specific progressive rockslide occurred in Northern Cross-Island Highway of Taiwan is discussed. The landslide initiated on 14 September 2022 after Typhoon Muifa leave Taiwan. The first disaster caused the road to be blocked at the mileage of 49.8K for two days and developed continually for the next one month. We obtained pre- and post-disaster UAV-based point cloud data for three major disasters during the period. The DEMs of Difference (DoD) and Iterative Closest Point (ICP) approaches were used to minimize the positioning error and estimate the landslide volume for each event. In addition, the feasibility of another common approach multiscale model-to-model cloud comparison (M3C2) was also discussed. The study provides authorities and practitioners with qualitative comparison regarding the application of UAV-based 3D point cloud analyses on landslide volume estimation for progressive rockslides. The results also benefit scientists in developing scenario modeling based on numerical simulation.
Frequency of winter temperature extremes over Eurasia dominated by variabilities over the Atlantic Ocean
Authors: Wang Huan
Published: February 2023

 Widespread observed and projected increases in warm extremes, along with decreases in cold extremes, have been confirmed as being consistent with global and regional warming. However, based on observational datasets and state-of-the-art CMIP6 model simulations, we disclose that the decadal variation in the frequency of the surface air temperature (SAT) extremes over mid- to high latitudes over Eurasia (MHEA) in winter is primarily dominated by the thermodynamical effect of the surface heat fluxes release over the midlatitude North Atlantic induced by Atlantic multidecadal oscillation (AMO), which even masks the dynamical large-scale Rossby wave propagation. Besides, the stronger Atlantic meridional overturning circulation (AMOC) gives rise to both warm and cold extremes through increasing the variance of winter SAT over MHEA due to thermodynamical heat release and enhanced dynamical Rossby wave propagation.
Exploring different explainable artificial intelligence algorithms applied to a LSTM for streamflow modelling
Authors: Ley Alexander , Bormann Helge , Casper Markus
Published: February 2023

Machine Learning and Deep Learning have been proving their potential for streamflow modelling in various studies. In particular, long short-term memory (LSTM) models showed exceptionally good results. However, machine learning models often are considered “black boxes” with limited interpretability. Explainable artificial intelligence (XAI) comprise methods that analyze the internal processes of the machine learning network and allow to have a glance in the “black box”. Most proposed XAI techniques are designed for the analysis of images, and there is currently only limited work on time series data available.In our study, we applied various XAI algorithms including gradient-based methods (Saliency, InputXGradient, Integrated Gradient, GradientSHAP) but also perturbation-based methods (Feature Ablation, Feature Permutation) to compare their applicability for reasonable interpretation in the hydrological context. To our knowledge, only Integrated Gradient has been applied to a LSTM in hydrology so far. Gradient-based methods analyze the gradient of the output with respect to the input feature. Whereas perturbation-based methods gain information by altering or masking specific input features. The different methods were applied to a LSTM trained for the low-land Ems catchment in Germany, which has a major baseflow share of total streamflow.We analyzed the results regarding their “timestep of influence”, which describes the amount of past days having importance for the prediction of streamflow at a particular day. All of the algorithms applied result in a comparable annual pattern, characterized by relatively small timesteps of influence in spring (wet season) and increasing timesteps of influence in summer and autumn (dry season). However, the range of the absolute days of attribution varies between the methods. In conclusion, all methods produces reasonable results and appear to be suitable for interpretation purposes.Furthermore, we compare the results to ERA-5 reanalysis data and gained evidence that the LSTM recognizes soil water storage as the main driver for streamflow generation in the catchment: we found an inverse seasonality of soil moisture and timestep of influence.
Develop an ocean-atmosphere-wave regional coupled model Windwave version 1.0 for predicting wind and wave conditions of the Northwest Pacific Ocean
Authors: Fu Shu , Huang Wenyu , Lv Runqing , Yang Zifan , Qiu Tianpei , Sun Danyi , Luo Jingjia , Huang Xiaomeng , Fu Haohuan , Luo Yong , Wang Bin
Published: February 2023

A new ocean-atmosphere-wave regional coupled model named Windwave version 1.0 for simulating and predicting winds and waves has been developed for the Northwest Pacific Ocean. In particular, the global-to-regional nesting technique is adopted for the ocean component to alleviate the bias due to the inconsistency in the lateral boundary. This paper is devoted to describing the coupling details of Windwave and the initialization scheme and assessing its basic performance, especially in predicting surface winds and significant wave heights (SWH) on the weather timescale. The control experiment set contains 31 experiments for August 2020, with seven typhoons passing through the Northwest Pacific. Each experiment starts at 0:00 am UTC of each day and runs for three days. Experiment results show that the new coupled model performs well in predicting surface winds, SWH, surface air temperature, and sea surface temperature on the weather timescale. In particular, the Root Mean Square Errors (RMSEs) of surface winds at 10 m height over the Northwest Pacific of the control experiment are 1.82 m s-1, 2.22 m s-1, and 2.59 m s-1, respectively, at lead times of 24 h, 48 h, and 72 h. Meanwhile, the RMSEs of SWH at lead times of 24 h, 48 h, and 72 h are 0.39 m, 0.43 m, and 0.51 m. In addition, we have explored the impacts of the different sea surface aerodynamic roughness parameterization schemes on predicting surface winds and SWH. In total, five different sea surface aerodynamic roughness parameterization schemes are adopted, corresponding to one control set and four sensitivity sets of experiments. Under normal conditions, the sea surface aerodynamic roughness parameterization scheme considering the effects of wind-wave direction tends to perform better for winds and waves, while that depending on wave age and SWH tends to perform worse. Under extreme wind and wave conditions, the schemes considering the effects of wind-wave direction and that considering wave age and peak wave length have better performance. These findings can provide new insights for developing a more advanced sea surface aerodynamic roughness parameterization scheme.
Simultaneous observations of whistler mode waves by the DEMETER spacecraft and the Kannuslehto station
Authors: Drastichova Kristyna , Němec František , Manninen Jyrki , Parrot Michel
Published: February 2023

We use conjugate observations of magnetospheric whistler mode electromagnetic waves at frequencies up to 16 kHz to determine their typical spatial scales and propagation to the ground. For this purpose, we use data obtained by the DEMETER spacecraft at an altitude of about 700 km and by the ground-based Kannuslehto station in Finland. The overlap between the two data sets corresponds to more than 500 DEMETER half-orbits between November 2006 and March 2008. Two different approaches are used. First, specific wave events observed simultaneously by both the spacecraft and the ground station are analyzed in detail. Second, the correlations of the power spectral densities of measured signals are calculated as a function of the frequency and geomagnetic longitude/L-shell separation. These are used to determine typical longitudinal/L-shell correlation lengths and to discuss wave propagation to the ground.