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.
弄清地层水的地球化学特征及其成因，有利于明确天然气的运移路径，阐述天然气的运移和聚集规律，进一步预测天然气聚集的有利区域。以三湖凹陷台南-泗北地区第四系地层水为研究对象，采用阴离子分析、阳离子分析、氢同位素分析、氧同位素分析等方法，阐明了该地区地层水的化学特征和成因。研究结果如下(1）研究区地层水溶解性总固体（TDS）含量较高，主要为 CaCl2 的 IV 型和 V 型；（2）r(Na+)/r(Cl-)较低、脱硫系数较低、r(Ca2+)/r(Mg2+)较高、碱交换指数较高，说明七格泉地层处于停滞区，有利于生物气的积累和保存。(3）由于白化和水岩反应，地层水富含 Ca2+，贫 Na+，贫 Mg2+。(4) 研究区的地层水来源于昆仑山冰川融水，冰川融水转化为地下水后沿山体斜坡带渗入地层。在地下水的渗透和汇聚过程中，地层中的许多盐类物质被溶解，导致 TDS 逐渐增加。然后，TDS 较高的地层水迁移到洼地北部的反斜面，最后被困在地层中。
{"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":"55 1","pages":""},"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}
Pub Date : 2024-03-15DOI: 10.1186/s40562-024-00331-z
Fangxiu Meng, Kang Xie, Peng Liu, Huazhou Chen, Yao Wang, Haiyun Shi
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.
东北是中国的主要粮食生产基地。极端降水（EP）事件会严重影响农业生产和社会经济，但人们对东北地区极端降水事件的了解还很有限。本研究利用非平稳广义极值（GEV）模型，研究了 1959-2017 年间东北地区极端降水事件的趋势和潜在风险，尤其是初夏和盛夏（极端降水事件高发期）。然后，分别分析了初夏和盛夏东北地区EP与大尺度环流的关系。结果表明，东北地区初夏 EP 主要呈正趋势，而盛夏 EP 则呈负趋势。同时，所有回归期的 EP 在初夏都呈现明显的上升趋势，这与更频繁的 EP 事件相对应。然而，在盛夏，2 年回归期 EP 随位置参数的变化而减小，20 年、50 年和 100 年回归期 EP 随尺度参数的变化而略有增大。重现期为 2 年的 EP 多发生在辽宁省，而重现期为 100 年的 EP 则多发生在吉林省和黑龙江省。此外，初夏 EP 的增加主要受东北冷涡的影响，仲夏冷空气对 EP 的影响更强，这也清楚地解释了仲夏 EP 增加不明显的原因。总之，本研究的成果将有利于东北地区的防灾减灾工作。
{"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":"48 1","pages":""},"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}
Pub Date : 2024-03-07DOI: 10.1186/s40562-024-00321-1
G. K. Pavur, H. Kim, B. Fang, V. Lakshmi
Accurate and timely inland waterbody extent and location data are foundational information to support a variety of hydrological applications and water resources management. Recently, the Cyclone Global Navigation Satellite System (CYGNSS) has emerged as a promising tool for delineating inland water due to distinct surface reflectivity characteristics over dry versus wet land which are observable by CYGNSS’s eight microsatellites with passive bistatic radars that acquire reflected L-band signals from the Global Positioning System (GPS) (i.e., signals of opportunity). This study conducts a baseline 1-km comparison of water masks for the contiguous United States between latitudes of 24°N-37°N for 2019 using three Earth observation systems: CYGNSS (i.e., our baseline water mask data), the Moderate Resolution Imaging Spectroradiometer (MODIS) (i.e., land water mask data), and the Landsat Global Surface Water product (i.e., Pekel data). Spatial performance of the 1-km comparison water mask was assessed using confusion matrix statistics and optical high-resolution commercial satellite imagery. When a mosaic of binary thresholds for 8 sub-basins for CYGNSS data were employed, confusion matrix statistics were improved such as up to a 34% increase in F1-score. Further, a performance metric of ratio of inland water to catchment area showed that inland water area estimates from CYGNSS, MODIS, and Landsat were within 2.3% of each other regardless of the sub-basin observed. Overall, this study provides valuable insight into the spatial similarities and discrepancies of inland water masks derived from optical (visible) versus radar (Global Navigation Satellite System Reflectometry, GNSS-R) based satellite Earth observations.
{"title":"Spatial comparison of inland water observations from CYGNSS, MODIS, Landsat, and commercial satellite imagery","authors":"G. K. Pavur, H. Kim, B. Fang, V. Lakshmi","doi":"10.1186/s40562-024-00321-1","DOIUrl":"https://doi.org/10.1186/s40562-024-00321-1","url":null,"abstract":"Accurate and timely inland waterbody extent and location data are foundational information to support a variety of hydrological applications and water resources management. Recently, the Cyclone Global Navigation Satellite System (CYGNSS) has emerged as a promising tool for delineating inland water due to distinct surface reflectivity characteristics over dry versus wet land which are observable by CYGNSS’s eight microsatellites with passive bistatic radars that acquire reflected L-band signals from the Global Positioning System (GPS) (i.e., signals of opportunity). This study conducts a baseline 1-km comparison of water masks for the contiguous United States between latitudes of 24°N-37°N for 2019 using three Earth observation systems: CYGNSS (i.e., our baseline water mask data), the Moderate Resolution Imaging Spectroradiometer (MODIS) (i.e., land water mask data), and the Landsat Global Surface Water product (i.e., Pekel data). Spatial performance of the 1-km comparison water mask was assessed using confusion matrix statistics and optical high-resolution commercial satellite imagery. When a mosaic of binary thresholds for 8 sub-basins for CYGNSS data were employed, confusion matrix statistics were improved such as up to a 34% increase in F1-score. Further, a performance metric of ratio of inland water to catchment area showed that inland water area estimates from CYGNSS, MODIS, and Landsat were within 2.3% of each other regardless of the sub-basin observed. Overall, this study provides valuable insight into the spatial similarities and discrepancies of inland water masks derived from optical (visible) versus radar (Global Navigation Satellite System Reflectometry, GNSS-R) based satellite Earth observations.","PeriodicalId":48596,"journal":{"name":"Geoscience Letters","volume":"299 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140055123","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}
Pub Date : 2024-03-05DOI: 10.1186/s40562-024-00325-x
Yanan Liu, Qiong Wu, Yizhi Zhang, Lujun Jiang
The rainy season in South China is divided into two phases, the pre- and postrainy seasons, according to the seasonal progression of the East Asian summer monsoon. The precipitation prediction skills for the two rainy seasons are investigated using subseasonal-to-seasonal (S2S) hindcast data from the European Centre for Medium-Range Weather Forecasts (ECMWF) for 2001–2019. The precipitation prediction skills and biases differ between the two rainy seasons, although some similar characteristics exist regarding circulation patterns and their influence on precipitation. During the two rainy seasons, the prediction ability of circulation at 850 hPa in key areas is relatively high, and the influence of circulation on precipitation is well captured; additionally, the relationship between circulation in key areas at 500 hPa and precipitation is less accurately constrained. Moreover, the precipitation prediction skill in the prerainy season is higher than that in the postrainy season. The main bias is that the 200 hPa westerly winds provide favorable divergence conditions for prerainy season precipitation (preprecipitation), while the postrainy season precipitation (postprecipitation) displays almost no correlation with the circulation in the reanalysis product; however, the simulated circulation at 200 hPa is closely connected to the precipitation in both rainy seasons; therefore, the lower prediction skill in the postrainy season is likely associated with overestimation of the complex physical mechanism of the upper-level circulation in the model.
{"title":"Evaluating precipitation prediction skill for the pre- and postrainy seasons in South China in ECMWF subseasonal forecasts","authors":"Yanan Liu, Qiong Wu, Yizhi Zhang, Lujun Jiang","doi":"10.1186/s40562-024-00325-x","DOIUrl":"https://doi.org/10.1186/s40562-024-00325-x","url":null,"abstract":"The rainy season in South China is divided into two phases, the pre- and postrainy seasons, according to the seasonal progression of the East Asian summer monsoon. The precipitation prediction skills for the two rainy seasons are investigated using subseasonal-to-seasonal (S2S) hindcast data from the European Centre for Medium-Range Weather Forecasts (ECMWF) for 2001–2019. The precipitation prediction skills and biases differ between the two rainy seasons, although some similar characteristics exist regarding circulation patterns and their influence on precipitation. During the two rainy seasons, the prediction ability of circulation at 850 hPa in key areas is relatively high, and the influence of circulation on precipitation is well captured; additionally, the relationship between circulation in key areas at 500 hPa and precipitation is less accurately constrained. Moreover, the precipitation prediction skill in the prerainy season is higher than that in the postrainy season. The main bias is that the 200 hPa westerly winds provide favorable divergence conditions for prerainy season precipitation (preprecipitation), while the postrainy season precipitation (postprecipitation) displays almost no correlation with the circulation in the reanalysis product; however, the simulated circulation at 200 hPa is closely connected to the precipitation in both rainy seasons; therefore, the lower prediction skill in the postrainy season is likely associated with overestimation of the complex physical mechanism of the upper-level circulation in the model.","PeriodicalId":48596,"journal":{"name":"Geoscience Letters","volume":"27 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140036379","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}
In this research, we explore the application of artificial neural networks, specifically the vector-quantized temporal associative memory (VQTAM) and VQTAM coupled with locally linear embedding (VQTAM-LLE) techniques, for simulating 2-D magnetotelluric forward modeling. The study introduces the concepts of VQTAM and VQTAM-LLE in the context of simulating 2-D magnetotelluric responses, outlining their underlying principles. We rigorously evaluate the accuracy and efficiency of both VQTAM variants through extensive numerical experiments conducted on diverse benchmark resistivity and real-terrain models. The results demonstrate the remarkable capability of VQTAM and VQTAM-LLE in accurately and efficiently predicting apparent resistivity and impedance phases, surpassing the performance of traditional numerical methods. This study underscores the potential of VQTAM and VQTAM-LLE as valuable computational alternatives for simulating magnetotelluric responses, offering a viable choice alongside conventional methods.
{"title":"Simulating 2-D magnetotelluric responses using vector-quantized temporal associative memory artificial neural network-based approaches","authors":"Phongphan Mukwachi, Banchar Arnonkijpanich, Weerachai Sarakorn","doi":"10.1186/s40562-024-00328-8","DOIUrl":"https://doi.org/10.1186/s40562-024-00328-8","url":null,"abstract":"In this research, we explore the application of artificial neural networks, specifically the vector-quantized temporal associative memory (VQTAM) and VQTAM coupled with locally linear embedding (VQTAM-LLE) techniques, for simulating 2-D magnetotelluric forward modeling. The study introduces the concepts of VQTAM and VQTAM-LLE in the context of simulating 2-D magnetotelluric responses, outlining their underlying principles. We rigorously evaluate the accuracy and efficiency of both VQTAM variants through extensive numerical experiments conducted on diverse benchmark resistivity and real-terrain models. The results demonstrate the remarkable capability of VQTAM and VQTAM-LLE in accurately and efficiently predicting apparent resistivity and impedance phases, surpassing the performance of traditional numerical methods. This study underscores the potential of VQTAM and VQTAM-LLE as valuable computational alternatives for simulating magnetotelluric responses, offering a viable choice alongside conventional methods.","PeriodicalId":48596,"journal":{"name":"Geoscience Letters","volume":"3 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140018310","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}
Pub Date : 2024-02-27DOI: 10.1186/s40562-024-00322-0
Kim-Anh Nguyen, Yuei-An Liou
Stringent measures, such as lockdowns, were implemented to curb the virus's spread, leading to reduced pollution levels and environmental improvements at various geographic scales, from cities to regions and nations. Such positive effects have been found and reported for regional scales, but not for a global scale till nowadays. This study aims to fill the gap by uncovering the modifications of global spatiotemporal eco-environmental vulnerability patterns between pre-pandemic (2016) and amid-pandemic (2020) periods. By analyzing various factors influencing the eco-environmental health or geo-health, such as human activities, climate change, and ecological dynamics, we seek to understand the intricate relationships and dynamics within these influential factors. We examined six categories of environmental vulnerability, which encompassed socioeconomics, land resources, natural hazards, hydrometeorology, and topography, using a five-dimensional stressor framework. Our analysis revealed a significant decrease in vulnerability levels across all categories, except for the very low level increased by 78.5% globally. These findings emphasize the detrimental impact of human activities on the global environment. They underscore the urgency of implementing spatial management strategies that prioritize sustainable geo-health development and foster a more resilient Earth.
{"title":"Rethinking our world: a perspective on a cleaner globe emerging from reduced anthropogenic activities","authors":"Kim-Anh Nguyen, Yuei-An Liou","doi":"10.1186/s40562-024-00322-0","DOIUrl":"https://doi.org/10.1186/s40562-024-00322-0","url":null,"abstract":"Stringent measures, such as lockdowns, were implemented to curb the virus's spread, leading to reduced pollution levels and environmental improvements at various geographic scales, from cities to regions and nations. Such positive effects have been found and reported for regional scales, but not for a global scale till nowadays. This study aims to fill the gap by uncovering the modifications of global spatiotemporal eco-environmental vulnerability patterns between pre-pandemic (2016) and amid-pandemic (2020) periods. By analyzing various factors influencing the eco-environmental health or geo-health, such as human activities, climate change, and ecological dynamics, we seek to understand the intricate relationships and dynamics within these influential factors. We examined six categories of environmental vulnerability, which encompassed socioeconomics, land resources, natural hazards, hydrometeorology, and topography, using a five-dimensional stressor framework. Our analysis revealed a significant decrease in vulnerability levels across all categories, except for the very low level increased by 78.5% globally. These findings emphasize the detrimental impact of human activities on the global environment. They underscore the urgency of implementing spatial management strategies that prioritize sustainable geo-health development and foster a more resilient Earth.","PeriodicalId":48596,"journal":{"name":"Geoscience Letters","volume":"17 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140001787","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}
Pub Date : 2024-02-26DOI: 10.1186/s40562-024-00326-w
Yonghan Choi, Joo-Hong Kim, Sang-Yoon Jun, Taejin Choi, Xiangdong Zhang
To compensate for the lack of conventional observations over the Arctic Ocean, ship-borne radiosonde observations have been regularly carried out during summer Arctic expeditions and the observed data have been broadcast via the global telecommunication system since 2017. With these data obtained over the data-sparse Arctic Ocean, observing system experiments were carried out using a polar-optimized version of the Weather Research and Forecasting (WRF) model and the WRF Data Assimilation (WRFDA) system to investigate their effects on analyses and forecasts over the Arctic. The results of verification against reanalysis data reveal: (1) DA effects on analyses and forecasts; (2) the reason for the year-to-year variability of DA effects; and (3) the possible role of upper-level potential vorticity in delayed DA effects. The overall assimilation effects of the extra data on the analyses and forecasts over the Arctic are positive. Initially, the DA effects are the most apparent in the temperature variables in the middle/lower troposphere, which spread to the wind variables in the upper troposphere. The effects decrease with time but reappear after approximately 120 h, even in the 240-h forecasts. The effects on forecasts vary depending on the proximity of the radiosonde observation locations to the high synoptic variability. The upper-level potential vorticity is known to play an important role in the development of Arctic cyclones, and it is suggested as a possible explanation for the delayed DA effects after about 120 h.
为弥补北冰洋常规观测数据的不足，在夏季北极考察期间定期开展了船载无线电探空仪观测，并自2017年起通过全球电信系统播发观测数据。利用在数据稀缺的北冰洋上空获得的这些数据，使用极地优化版天气研究与预报（WRF）模式和WRF数据同化（WRFDA）系统开展了观测系统实验，以研究它们对北冰洋上空分析和预报的影响。根据再分析数据进行验证的结果揭示了：(1)DA 对分析和预报的影响；(2)DA 影响年际变化的原因；(3)高层位势涡度在延迟 DA 影响中可能发挥的作用。额外数据对北极地区分析和预报的总体同化效果是积极的。最初，DA效应在对流层中/低层的温度变量中最为明显，然后扩散到对流层高层的风变量。这种效应随着时间的推移而减弱，但在大约 120 小时后再次出现，甚至在 240 小时的预报中也是如此。对预报的影响因无线电探空仪观测点是否靠近高同步变率而异。众所周知，高层位涡在北极气旋的发展过程中起着重要作用，这也是在大约 120 小时后出现延迟 DA 效应的可能原因。
{"title":"Multi-year assessment of the impact of ship-borne radiosonde observations on polar WRF forecasts in the Arctic","authors":"Yonghan Choi, Joo-Hong Kim, Sang-Yoon Jun, Taejin Choi, Xiangdong Zhang","doi":"10.1186/s40562-024-00326-w","DOIUrl":"https://doi.org/10.1186/s40562-024-00326-w","url":null,"abstract":"To compensate for the lack of conventional observations over the Arctic Ocean, ship-borne radiosonde observations have been regularly carried out during summer Arctic expeditions and the observed data have been broadcast via the global telecommunication system since 2017. With these data obtained over the data-sparse Arctic Ocean, observing system experiments were carried out using a polar-optimized version of the Weather Research and Forecasting (WRF) model and the WRF Data Assimilation (WRFDA) system to investigate their effects on analyses and forecasts over the Arctic. The results of verification against reanalysis data reveal: (1) DA effects on analyses and forecasts; (2) the reason for the year-to-year variability of DA effects; and (3) the possible role of upper-level potential vorticity in delayed DA effects. The overall assimilation effects of the extra data on the analyses and forecasts over the Arctic are positive. Initially, the DA effects are the most apparent in the temperature variables in the middle/lower troposphere, which spread to the wind variables in the upper troposphere. The effects decrease with time but reappear after approximately 120 h, even in the 240-h forecasts. The effects on forecasts vary depending on the proximity of the radiosonde observation locations to the high synoptic variability. The upper-level potential vorticity is known to play an important role in the development of Arctic cyclones, and it is suggested as a possible explanation for the delayed DA effects after about 120 h.","PeriodicalId":48596,"journal":{"name":"Geoscience Letters","volume":"86 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139969334","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}
Pub Date : 2024-02-25DOI: 10.1186/s40562-024-00327-9
Zhaoxiang Chu, Yiming Wang, Yukun Ji, Xiaozhao Li
The findings of the major strategic consulting project of Chinese Academy of Engineering ‘Research on the strategy of coal mine safety and abandoned mine resources development and utilization in China’ suggest that almost 13,000 discarded collieries in China will provide abundant surface lands and massive underground heritages to not only develop but also store renewable energy within the Earth’s Critical Zone, thus helping attain its net-zero energy goal.
{"title":"China: legacy collieries versus renewable energy","authors":"Zhaoxiang Chu, Yiming Wang, Yukun Ji, Xiaozhao Li","doi":"10.1186/s40562-024-00327-9","DOIUrl":"https://doi.org/10.1186/s40562-024-00327-9","url":null,"abstract":"The findings of the major strategic consulting project of Chinese Academy of Engineering ‘Research on the strategy of coal mine safety and abandoned mine resources development and utilization in China’ suggest that almost 13,000 discarded collieries in China will provide abundant surface lands and massive underground heritages to not only develop but also store renewable energy within the Earth’s Critical Zone, thus helping attain its net-zero energy goal.","PeriodicalId":48596,"journal":{"name":"Geoscience Letters","volume":"90 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139969684","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}
Pub Date : 2024-02-25DOI: 10.1186/s40562-024-00324-y
Suqin Zhang, Xia Qu, Gang Huang
Victoria mode (VM), the second dominant mode of North Pacific sea surface temperature variability, has been identified as one of the important factors influencing the Indian summer monsoon (ISM) onset. The positive phase of the May VM delays the ISM onset by both tropical and extratropical pathways. Here, we found a significant interdecadal enhancement of their relationship since the early 1990s, which is mainly attributed to the structure changes and increased variance of the VM. In recent decades, the VM has shown more significant warm SST anomalies in the tropical central Pacific, which drive the large-scale divergent circulation more effectively. This enhanced divergent circulation leads to low-level divergence and reduced rainfall in the tropical Asian summer monsoon region. The reduced rainfall excites equatorial Rossby wave response and anomalous easterly winds in the northern Indian Ocean, delaying the ISM onset. Besides, the increased variance of the VM after 1992/1993 stimulates a stronger extratropical Rossby wave train. This stationary Rossby wave train induces a stronger cooling to the northwest of India, which weakens the land-sea thermal contrast and leads to the delayed ISM onset. This finding should be taken into account to improve short-term predictions of the monsoon onset.
维多利亚模式（VM）是北太平洋海面温度变化的第二主导模式，已被确定为影响印度夏季季风（ISM）开始的重要因素之一。五月 VM 的正相位通过热带和外热带路径延迟了 ISM 的开始。在这里，我们发现自 20 世纪 90 年代初以来，它们之间的关系出现了显著的年代际增强，这主要归因于 VM 的结构变化和方差增大。近几十年来，VM 在热带中太平洋表现出更显著的暖 SST 异常，更有效地驱动了大尺度发散环流。这种增强的发散环流导致热带亚洲夏季季风区的低层发散和降雨量减少。降雨量的减少激发了印度洋北部的赤道罗斯比波响应和异常东风，推迟了国际海洋气象机制的发生。此外，1992/1993 年后增加的 VM 变异激发了更强的外热带罗斯比波列。这个静止的罗斯比波列引起印度西北部更强的降温，从而削弱了陆海热对比，导致国际海洋气象机制推迟出现。应考虑这一发现，以改进对季风开始的短期预测。
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Pub Date : 2024-01-30DOI: 10.1186/s40562-024-00319-9
Fei Xin, Yichen Shen, Chuhan Lu
Under the proposal of “seamless forecasting”, it has become a key problem for meteorologists to improve the skills of subseasonal forecasts. Since the launch of the subseasonal-to-seasonal (S2S) plan by WMO, the precision of model predictions has been further developed. However, when we are focusing on the practical applications of models in the South China (SC) in recent years, we found that large disagreements appear between forecast members. Some of the members predicted well in this area, while others are not satisfactory. To improve the accuracy of subseasonal forecast in the SC, new methods making full use of different forecast models must be proposed. In this passage, we introduced a weighted ensemble forecasting method based on online learning (OL) to overcome this difficulty. As the state-of-the-art forecast models in the world, three models from China Meteorological Administration, European Centre for Medium-Range Weather Forecasts and National Centers for Environmental Prediction provided by the S2S prediction dataset are used as ensemble members, and an ensemble weight is trained through the aforementioned OL model for the predictions of temperature and precipitation in subseasonal timescale in the SC. The results show that the forecast results produced under the OL method are better than the original model predictions. Compared with the three model ensemble results, the weighted ensemble model has a good ability in depicting the temperature and precipitation in the SC. Furthermore, we also compared this strategy against the climatology predictions and found out that the weighted ensemble model is superior in 10–30 days. Thus, the weighted ensemble method trained thorough OL may shed light on improving the skill of subseasonal forecasts.
在 "无缝预报 "的建议下，如何提高副季节预报的技能已成为气象学家面临的关键问题。自世界气象组织（WMO）推出 "从副季到季"（S2S）计划以来，模式预报的精度得到了进一步提高。然而，当我们关注近年来模式在华南地区的实际应用时，我们发现预报成员之间出现了较大的分歧。有些成员在这一地区的预报效果很好，而有些则不尽如人意。为了提高华南副季节预报的精度，必须提出充分利用不同预报模式的新方法。本文介绍了一种基于在线学习（OL）的加权集合预报方法，以克服这一困难。以S2S预报数据集提供的中国气象局、欧洲中期天气预报中心和美国国家环境预报中心的三个预报模式作为世界上最先进的预报模式，通过上述OL模式训练出一个集合权重，用于预报南极洲副季节尺度的气温和降水。结果表明，OL 方法产生的预报结果优于原始模式的预报结果。与三种模式的集合结果相比，加权集合模式对南极洲气温和降水的描述能力更强。此外，我们还将这一策略与气候学预测结果进行了比较，发现加权集合模式在 10-30 天内的预测结果更优。因此，经过 OL 训练的加权集合方法可能有助于提高副季节预报的技能。
{"title":"Application of a weighted ensemble forecasting method based on online learning in subseasonal forecast in the South China","authors":"Fei Xin, Yichen Shen, Chuhan Lu","doi":"10.1186/s40562-024-00319-9","DOIUrl":"https://doi.org/10.1186/s40562-024-00319-9","url":null,"abstract":"Under the proposal of “seamless forecasting”, it has become a key problem for meteorologists to improve the skills of subseasonal forecasts. Since the launch of the subseasonal-to-seasonal (S2S) plan by WMO, the precision of model predictions has been further developed. However, when we are focusing on the practical applications of models in the South China (SC) in recent years, we found that large disagreements appear between forecast members. Some of the members predicted well in this area, while others are not satisfactory. To improve the accuracy of subseasonal forecast in the SC, new methods making full use of different forecast models must be proposed. In this passage, we introduced a weighted ensemble forecasting method based on online learning (OL) to overcome this difficulty. As the state-of-the-art forecast models in the world, three models from China Meteorological Administration, European Centre for Medium-Range Weather Forecasts and National Centers for Environmental Prediction provided by the S2S prediction dataset are used as ensemble members, and an ensemble weight is trained through the aforementioned OL model for the predictions of temperature and precipitation in subseasonal timescale in the SC. The results show that the forecast results produced under the OL method are better than the original model predictions. Compared with the three model ensemble results, the weighted ensemble model has a good ability in depicting the temperature and precipitation in the SC. Furthermore, we also compared this strategy against the climatology predictions and found out that the weighted ensemble model is superior in 10–30 days. Thus, the weighted ensemble method trained thorough OL may shed light on improving the skill of subseasonal forecasts.","PeriodicalId":48596,"journal":{"name":"Geoscience Letters","volume":"81 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139586048","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}
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