Geoscience Letters最新文献_第3页

A fresh look at the intensity and impulsive strength of geomagnetic storms 重新审视地磁暴的强度和脉冲强度

IF 4 3区地球科学

Geoscience Letters Pub Date : 2024-04-29 DOI: 10.1186/s40562-024-00337-7

V. Manu, N. Balan, Y. Ebihara, Qing-He Zhang, Zan-Yang Xing

{"title":"A fresh look at the intensity and impulsive strength of geomagnetic storms","authors":"V. Manu, N. Balan, Y. Ebihara, Qing-He Zhang, Zan-Yang Xing","doi":"10.1186/s40562-024-00337-7","DOIUrl":"https://doi.org/10.1186/s40562-024-00337-7","url":null,"abstract":"We notice that the important early decreasing part of the main phase (MP) from the positive main phase onset (MPO) to 0-level of Dst and SymH indices is missed in the treatment of the main phase (MP) of geomagnetic storms. We correct this inconsistency in 848 storms having positive MPO (out of 1164 storms) in SymH during 1981–2019 by raising the 0-level of SymH to the MPO-level. The correction considers the full range of the main phase, increases the corrected (revised) storm intensity (SymHMin*) and impulsive strength (IpsSymH*) by up to − 149 nT and − 134 nT, respectively, and seems important for all aspects of global space weather. For example, the corrected SymHMin* changes the conventional storm identification and classification and corrected IpsSymH* clearly identifies all 3 severe space weather (SvSW) events from over 1100 normal space weather (NSW) events with a separation of 52 nT; it also identifies all 8 minor-system-damage space weather (MSW) events from the NSW events. Large fluctuations occur in the global geomagnetic field during space weather events. The fluctuations at low latitudes are referred as geomagnetic storms. The Dst and SymH indices have been used for studying the storms and other aspects of global space weather. However, we notice that the Dst and SymH values during the main phase and recovery phase of the storms having positive main phase onset (MPO > 0 nT) are significantly less than their actual values. We correct this inconsistency in 848 such storms (out of 1164 storms) in SymH during 1981-2019 by raising the 0-level of SymH to the MPO-level. The corrected/revised storm intensity (SymHMin*) and impulsive strength (IpsSymH*) increase by up to − 149 and − 134 nT. The correction seems important for studying all aspects global space weather. For example, the correction identifies the storms corresponding to severe space weather causing power outage and/or telecommunication failure from those corresponding to normal space weather. ","PeriodicalId":48596,"journal":{"name":"Geoscience Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140834641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Unraveling the role played by a buried mud diapir: alternative model for 2016 Mw 6.4 MeiNong earthquake in southwestern Taiwan 揭示埋藏的泥质断裂带所扮演的角色：台湾西南部 2016 年 6.4 级美浓地震的替代模型

IF 4 3区地球科学

Geoscience Letters Pub Date : 2024-04-25 DOI: 10.1186/s40562-024-00335-9

Geng-Pei Lin, Wu-Lung Chang, Chi-Yu Chiu

引用次数: 0

Features and mechanisms of sea surface salinity intraseasonal variability in the Northern Bay of Bengal 孟加拉湾北部海面盐度季节内变化的特征和机制

IF 4 3区地球科学

Geoscience Letters Pub Date : 2024-04-18 DOI: 10.1186/s40562-024-00334-w

Rong Cui, Xuhua Cheng, Wei Duan, Long Jiang, Yifei Zhou

{"title":"Features and mechanisms of sea surface salinity intraseasonal variability in the Northern Bay of Bengal","authors":"Rong Cui, Xuhua Cheng, Wei Duan, Long Jiang, Yifei Zhou","doi":"10.1186/s40562-024-00334-w","DOIUrl":"https://doi.org/10.1186/s40562-024-00334-w","url":null,"abstract":"In response to abundant freshwater input from rainfall and river discharge, the northern Bay of Bengal (BoB) is featured by low sea surface salinity (SSS) and strong intraseasonal variability (ISV). This study investigates the characteristic and dynamic mechanisms of SSS ISV in the northern BoB based on satellite observations and the output of Simple Ocean Data Assimilation (SODA). The strong SSS ISV is mainly concentrated near the mouth of the Ganges–Brahmaputra River and along the east coast of India, where the horizontal salinity gradient varies greatly. SSS ISV in the northern BoB is notably in phase with freshwater transport, which peaks from July to November. The contribution of riverine freshwater is significant both geographically and temporally. The SSS budget analysis indicates that the horizontal advection plays a dominant role in SSS ISV. Once currents cross the salinity field, large horizontal advection anomalies become important and favor SSS ISV. Altered SSS patterns can impact water density, potentially influencing the strength and direction of currents. This, in turn, may have cascading effects on local and regional climate patterns.","PeriodicalId":48596,"journal":{"name":"Geoscience Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140625794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Streamlining hyperparameter optimization for radiation emulator training with automated Sherpa 利用自动谢尔巴系统简化辐射模拟器训练的超参数优化

IF 4 3区地球科学

Geoscience Letters Pub Date : 2024-04-13 DOI: 10.1186/s40562-024-00336-8

Soonyoung Roh, Park Sa Kim, Hwan-Jin Song

引用次数: 0

Severe weather disasters to epidemics in China during low and high solar activities from 1 to 1911 Common Era 公元 1 至 1911 年太阳活动频繁和频繁期间中国从恶劣天气灾害到流行病的情况

IF 4 3区地球科学

Geoscience Letters Pub Date : 2024-03-30 DOI: 10.1186/s40562-024-00333-x

Jann-Yenq Liu, Yuh-Ing Chen, Po-Han Lee

引用次数: 0

Deformation characteristics and instability mechanism of large-scale anti-dip rock slides 大尺度反倾岩体滑坡的变形特征和失稳机理

IF 4 3区地球科学

Geoscience Letters Pub Date : 2024-03-29 DOI: 10.1186/s40562-024-00329-7

Xuebing Wang, Nan Zhang, Zhihua Zhang, Luqi Wang, Shu Yu, Peng Zhao, Guoqiang Yan

引用次数: 0

Determination of Euler pole parameters for Sundaland plate based on updated GNSS observations in Sumatra, Indonesia 根据印度尼西亚苏门答腊岛的最新全球导航卫星系统观测结果确定巽他板块的欧拉极参数

IF 4 3区地球科学

Geoscience Letters Pub Date : 2024-03-25 DOI: 10.1186/s40562-024-00330-0

Satrio Muhammad Alif, Kuo-En Ching, Takeshi Sagiya, Widya Nabila Wahyuni

{"title":"Determination of Euler pole parameters for Sundaland plate based on updated GNSS observations in Sumatra, Indonesia","authors":"Satrio Muhammad Alif, Kuo-En Ching, Takeshi Sagiya, Widya Nabila Wahyuni","doi":"10.1186/s40562-024-00330-0","DOIUrl":"https://doi.org/10.1186/s40562-024-00330-0","url":null,"abstract":"To provide a precise Euler pole parameter of Sundaland plate for earthquake potential evaluation in Sumatra, Indonesia after the 2004 M9.2 Aceh earthquake, we adopted 37 new Global Navigation Satellite System (GNSS) observations in Sumatra and 30 transformed published velocities in Indochina and Malaysia under the International Terrestrial Reference Frame 2014 (ITRF2014). The 37 GNSS data were processed using the software Bernese v.5.2. The GNSS velocities were calculated by the coordinate time series analysis with the least squares method. The grid search algorithm was used in Euler pole parameter estimation, which was validated using the bootstrap resampling. The optimized Euler pole parameters are the latitude of 45.63 ± 0.45°, the longitude of − 88.71 ± 0.38° and the angular velocity of 0.337 ± 0.002°/Myr in counterclockwise direction. Besides, the distinguishable and systematic pattern in space is shown in the residual velocities, which may imply the possibility of minor postseismic deformation, Tibetan crustal flows, or the hypothesis that the Sundaland Plate is composed of several microplates.","PeriodicalId":48596,"journal":{"name":"Geoscience Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140298757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evaluation of residential building damage for the July 2021 flood in Westport, New Zealand 新西兰西港 2021 年 7 月洪灾住宅建筑损毁评估

IF 4 3区地球科学

Geoscience Letters Pub Date : 2024-03-22 DOI: 10.1186/s40562-024-00323-z

Ryan Paulik, Alec Wild, Conrad Zorn, Liam Wotherspoon, Shaun Williams

{"title":"Evaluation of residential building damage for the July 2021 flood in Westport, New Zealand","authors":"Ryan Paulik, Alec Wild, Conrad Zorn, Liam Wotherspoon, Shaun Williams","doi":"10.1186/s40562-024-00323-z","DOIUrl":"https://doi.org/10.1186/s40562-024-00323-z","url":null,"abstract":"Reliable flood damage models are informed by detailed damage assessments. Damage models are critical in flood risk assessments, representing an elements vulnerability to damage. This study evaluated residential building damage for the July 2021 flood in Westport, New Zealand. We report on flood hazard, exposure and damage features observed for 247 residential buildings. Damage samples were applied to evaluate univariable and multivariable model performance using different variable sample sizes and regression-based supervised learning algorithms. Feature analysis for damage prediction showed high importance of water depth variables and low importance for commonly observed building variables such as structural frame and storeys. Overfitting occurred for most models evaluated when more than 150 samples were used. This resulted from limited damage heterogeneity observed, and variables of low importance affecting model learning. The Random Forest algorithm, which considered multiple important variables (water depth above floor level, area and floor height) improved predictive precision by 17% relative to other models when over 150 damage samples were considered. Our findings suggest the evaluated model performance could be improved by incorporating heterogeneous damage samples from similar flood contexts, in turn increasing capacity for reliable spatial transfer.","PeriodicalId":48596,"journal":{"name":"Geoscience Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140197584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Geochemical characteristics and origin of the formation water of the Saline Lake Basin: a case study of the Quaternary Qigequan Formation in the Sanhu Depression, Qaidam Basin 盐湖盆地地层水的地球化学特征及成因：柴达木盆地三湖凹陷第四纪垣曲地层个案研究

IF 4 3区地球科学

Geoscience Letters Pub Date : 2024-03-19 DOI: 10.1186/s40562-024-00332-y

Xiaoxue Liu, Zhenxue Jiang, Xianglu Tang, Jun Zhu, Fenying Zhang, Yuchao Wang, Mingshuai Xu

{"title":"Geochemical characteristics and origin of the formation water of the Saline Lake Basin: a case study of the Quaternary Qigequan Formation in the Sanhu Depression, Qaidam Basin","authors":"Xiaoxue Liu, Zhenxue Jiang, Xianglu Tang, Jun Zhu, Fenying Zhang, Yuchao Wang, Mingshuai Xu","doi":"10.1186/s40562-024-00332-y","DOIUrl":"https://doi.org/10.1186/s40562-024-00332-y","url":null,"abstract":"Clarifying the geochemical characteristics of formation water and its origin is conducive to clarifying the gas migration path, elaborating the law of gas migration and accumulation, and further predicting the favourable area of gas accumulation. Taking Quaternary formation water from the Tainan-Sebei area of the Sanhu Depression as the research object, the chemical characteristics and origin of the region are clarified using anion analysis, cation analysis, hydrogen isotope analysis, oxygen isotope analysis and so on. The results are as follows. (1) The formation water in the study area has a high total dissolved solids (TDS) content and is mainly type IV and V of CaCl2. (2) Low r(Na+)/r(Cl−), low desulfurization coefficient, high r(Ca2+)/r(Mg2+) and high indices of base exchange indicate that the Qigequan Formation is in a stagnant zone, which is beneficial for the accumulation and preservation of biogenic gas. (3) Due to albitization and water–rock reactions, the formation water is rich in Ca2+, poor in Na+ and poor in Mg2+. (4) The formation water in the study area originates from the glacial meltwater of the Kunlun Mountains, which converts into groundwater and seeps into the formation along the piedmont slope zone. In the process of groundwater infiltration and convergence, many salt substances in the formation are dissolved, resulting in a gradual increase in TDS. Then, the formation water with a high TDS migrates to the anticline in the northern part of the depression and is finally trapped in the formation.","PeriodicalId":48596,"journal":{"name":"Geoscience Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140166029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Extreme precipitation trends in Northeast China based on a non-stationary generalized extreme value model 基于非平稳广义极值模型的中国东北地区极端降水趋势

IF 4 3区地球科学

Geoscience Letters Pub Date : 2024-03-15 DOI: 10.1186/s40562-024-00331-z

Fangxiu Meng, Kang Xie, Peng Liu, Huazhou Chen, Yao Wang, Haiyun Shi

{"title":"Extreme precipitation trends in Northeast China based on a non-stationary generalized extreme value model","authors":"Fangxiu Meng, Kang Xie, Peng Liu, Huazhou Chen, Yao Wang, Haiyun Shi","doi":"10.1186/s40562-024-00331-z","DOIUrl":"https://doi.org/10.1186/s40562-024-00331-z","url":null,"abstract":"Northeast China is the main food production base of China. Extreme precipitation (EP) events can seriously impact agricultural production and socioeconomics, but the understanding of EP in Northeast China is still limited. In this study, using the non-stationary generalized extreme value (GEV) model, we investigate the trend and potential risk of EP in Northeast China during 1959–2017, especially in early and mid-summer (periods of high frequency of EP). Then, the relationships between EP and large-scale circulation over Northeast China in early and mid-summer are analyzed separately. The EP in Northeast China mainly presents positive trends in early summer but negative trends in mid-summer. Meanwhile, the EP with all the return periods presents apparently increasing trends in early summer, corresponding to more frequent EP events. Nevertheless, in mid-summer, the EP with 2-year return period decreases with location parameter, and the EP with 20-year, 50-year, and 100-year return periods slightly increases with scale parameter. The EP with 2-year return period occurs frequently in Liaoning Province, while the EP with 100-year return period is more likely to occur in Jilin Province and Heilongjiang Province. Moreover, the increase of the EP in early summer is mainly influenced by the northeast cold vortex; the effect of cold air on the EP is stronger in mid-summer, giving a clear explanation why the EP in mid-summer does not increase significantly. Overall, the outcomes of this study would be beneficial for the disaster prevention and mitigation in Northeast China.","PeriodicalId":48596,"journal":{"name":"Geoscience Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140153249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0