{"title":"东亚夏季大气河流是外热带和季风水汽羽流的连续体","authors":"Chanil Park, Seok-Woo Son","doi":"10.1175/jcli-d-23-0731.1","DOIUrl":null,"url":null,"abstract":"Abstract East Asian atmospheric rivers (ARs) exhibit the most pronounced activity in summer with significant impacts on monsoon rainfall. However, their detailed characteristics from a synoptic perspective are yet to be revealed. In this study, we unravel the inherently complex nature of East Asian summer ARs by applying a multiscale index that quantifies the relative importance of high- (HF) and low-frequency (LF) moisture transports in AR development. It is found that both HF and LF processes contribute to shaping the summertime ARs in East Asia, contrasting to the wintertime ARs dominated by HF processes. Stratification of ARs with the multiscale index reveals that HF-dominant ARs are driven by baroclinically-deepening extratropical cyclones, analogous to the widely-accepted definition of canonical ARs. In contrast, LF-dominant ARs result from enhanced monsoon southwesterly between a quasi-stationary cyclone and anticyclone with the latter being the anomalous expansion of the western North Pacific subtropical high, reminiscent of the classical monsoon rainband. While HF-dominant ARs are transient, LF-dominant ARs are quasi-stationary with a higher potential for prolonged local impacts. The intermediate ARs, constituting a majority of East Asian summer ARs, exhibit synoptic conditions that combine HF- and LF-dominant ARs. Therefore, East Asian summer ARs cannot be explained by a single mechanism but should be considered as a continuum of extratropical cyclone-induced and fluctuating monsoon flow-induced moisture plumes. This finding would serve as a base for the advanced understanding of hydrological impacts, variability, and projected change of East Asian ARs.","PeriodicalId":15472,"journal":{"name":"Journal of Climate","volume":"26 1","pages":""},"PeriodicalIF":4.8000,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Atmospheric rivers in East Asia summer as the continuum of extratropical and monsoonal moisture plumes\",\"authors\":\"Chanil Park, Seok-Woo Son\",\"doi\":\"10.1175/jcli-d-23-0731.1\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Abstract East Asian atmospheric rivers (ARs) exhibit the most pronounced activity in summer with significant impacts on monsoon rainfall. However, their detailed characteristics from a synoptic perspective are yet to be revealed. In this study, we unravel the inherently complex nature of East Asian summer ARs by applying a multiscale index that quantifies the relative importance of high- (HF) and low-frequency (LF) moisture transports in AR development. It is found that both HF and LF processes contribute to shaping the summertime ARs in East Asia, contrasting to the wintertime ARs dominated by HF processes. Stratification of ARs with the multiscale index reveals that HF-dominant ARs are driven by baroclinically-deepening extratropical cyclones, analogous to the widely-accepted definition of canonical ARs. In contrast, LF-dominant ARs result from enhanced monsoon southwesterly between a quasi-stationary cyclone and anticyclone with the latter being the anomalous expansion of the western North Pacific subtropical high, reminiscent of the classical monsoon rainband. While HF-dominant ARs are transient, LF-dominant ARs are quasi-stationary with a higher potential for prolonged local impacts. The intermediate ARs, constituting a majority of East Asian summer ARs, exhibit synoptic conditions that combine HF- and LF-dominant ARs. Therefore, East Asian summer ARs cannot be explained by a single mechanism but should be considered as a continuum of extratropical cyclone-induced and fluctuating monsoon flow-induced moisture plumes. This finding would serve as a base for the advanced understanding of hydrological impacts, variability, and projected change of East Asian ARs.\",\"PeriodicalId\":15472,\"journal\":{\"name\":\"Journal of Climate\",\"volume\":\"26 1\",\"pages\":\"\"},\"PeriodicalIF\":4.8000,\"publicationDate\":\"2024-06-28\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Climate\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.1175/jcli-d-23-0731.1\",\"RegionNum\":2,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"METEOROLOGY & ATMOSPHERIC SCIENCES\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Climate","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1175/jcli-d-23-0731.1","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"METEOROLOGY & ATMOSPHERIC SCIENCES","Score":null,"Total":0}
引用次数: 0
摘要
摘要 东亚大气河流(ARs)在夏季表现出最明显的活动,对季风降雨有重大影响。然而,从同步角度来看,它们的详细特征尚待揭示。在本研究中,我们采用了一种多尺度指数,量化了高频(HF)和低频(LF)水汽输送在 AR 发展过程中的相对重要性,从而揭示了东亚夏季 AR 的内在复杂性。研究发现,高频和低频过程都有助于形成东亚夏季的大气环流,这与高频过程主导的冬季大气环流形成鲜明对比。用多尺度指数对ARs进行分层显示,高频主导的ARs是由气压加深的外热带气旋驱动的,这与广泛接受的典型ARs定义相似。与此相反,LF 主导的自回归现象是由准静止气旋和反气旋之间增强的季风西南气流造成的,后者是北太平洋西部副热带高压的异常扩张,让人联想到经典的季风雨带。以高频为主的反气旋是短暂的,而以低频为主的反气旋则是准静止的,更有可能对局部地区造成长期影响。构成东亚夏季季候风大部分的中间型季候风表现出结合高频和低频主导型季候风的同步条件。因此,东亚夏季气旋不能用单一机制来解释,而应将其视为外热带气旋诱发和季风气流诱发水汽羽流波动的连续体。这一发现将为进一步了解东亚夏季气旋的水文影响、变异性和预测变化提供基础。
Atmospheric rivers in East Asia summer as the continuum of extratropical and monsoonal moisture plumes
Abstract East Asian atmospheric rivers (ARs) exhibit the most pronounced activity in summer with significant impacts on monsoon rainfall. However, their detailed characteristics from a synoptic perspective are yet to be revealed. In this study, we unravel the inherently complex nature of East Asian summer ARs by applying a multiscale index that quantifies the relative importance of high- (HF) and low-frequency (LF) moisture transports in AR development. It is found that both HF and LF processes contribute to shaping the summertime ARs in East Asia, contrasting to the wintertime ARs dominated by HF processes. Stratification of ARs with the multiscale index reveals that HF-dominant ARs are driven by baroclinically-deepening extratropical cyclones, analogous to the widely-accepted definition of canonical ARs. In contrast, LF-dominant ARs result from enhanced monsoon southwesterly between a quasi-stationary cyclone and anticyclone with the latter being the anomalous expansion of the western North Pacific subtropical high, reminiscent of the classical monsoon rainband. While HF-dominant ARs are transient, LF-dominant ARs are quasi-stationary with a higher potential for prolonged local impacts. The intermediate ARs, constituting a majority of East Asian summer ARs, exhibit synoptic conditions that combine HF- and LF-dominant ARs. Therefore, East Asian summer ARs cannot be explained by a single mechanism but should be considered as a continuum of extratropical cyclone-induced and fluctuating monsoon flow-induced moisture plumes. This finding would serve as a base for the advanced understanding of hydrological impacts, variability, and projected change of East Asian ARs.
期刊介绍:
The Journal of Climate (JCLI) (ISSN: 0894-8755; eISSN: 1520-0442) publishes research that advances basic understanding of the dynamics and physics of the climate system on large spatial scales, including variability of the atmosphere, oceans, land surface, and cryosphere; past, present, and projected future changes in the climate system; and climate simulation and prediction.