| 摘要: |
| 为研究西太平洋海域在河南“7·20”极端降雨事件中的作用,利用海表面温度、海平面气压、位势高度和风场等再分析数据与降水观测数据,分析了2021年夏季河南极端降雨事件的水汽输送来源及其与西太平洋副热带高压多尺度变化特征的关系。数据显示,2021年夏季河南极端降雨期间,西太平洋副热带高压偏强偏北,河南地区以东至西北太平洋中低空出现显著的东风异常和西向水汽输运。结果表明,2021年夏季河南暴雨区中高空相对涡度、位势高度和垂直上升运动存在显著异常,从西北太平洋海域通过中低空异常东风输送的水汽是主要来源。经验模态分解结果显示,副热带高压强度指数的第二模态(intrinsic mode functions of west Pacific subtropical high,IMFWPSH)与河南地区降雨第二模态存在统计显著关系并在此次极端降雨事件中扮演重要角色。诊断分析发现,在IMFWPSH正位相期间,副热带西太平洋存在异常增强的上升运动并在中低空产生异常东风,河南地区上升气流异常增强,因此,IMFWPSH可为河南地区降雨提供重要条件。 |
| 关键词: 河南 极端降雨 西太平洋副热带高压 台风 |
| DOI：10.11693/hyhz20220500121 |
| 分类号: |
| 基金项目:中国科学院战略性先导科技专项项目,XDB42010403号;国家自然科学基金项目,42022040号;山东省自然科学基金资助项目,ZR2020JQ18号;中国科学院创新交叉团队项目,JCTD-2020-12号。 |
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| MOISTURE SOURCE OF EXTREME RAINFALL IN HENAN IN SUMMER 2021 AND THE POSSIBLE ROLE OF THE WESTERN PACIFIC SUBTROPICAL HIGH |
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SUN Qi-Ming1,2,3, HU Shi-Jian2,3,4, ZHAO Yi-Jun1
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1.Shandong University of Science and Technology, Qingdao 266590, China;2.CAS Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Qingdao 266071, China;3.University of Chinese Academy of Sciences, Beijing 100049, China;4.Pilot National Laboratory for Marine Science and Technology(Qingdao), Qingdao 266237, China
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| Abstract: |
| In order to study the role of the Western Pacific Ocean in the “7.20” extreme rainfall event in Henan Province, water vapor transportation, origination, and relationship with multiscale variation of the western Pacific subtropical high during extreme rainfall events in Henan Province, central China in summer 2021 were analyzed using reanalysis data of sea surface temperature, sea surface pressure, potential height, and wind field, and observational data of precipitation. Results show that during the extreme rainfall in Henan in summer 2021, the western Pacific subtropical high was relatively stronger and more northerly, and significant east wind anomalies and westward water vapor transport occurred in the middle and low altitude from the east of Henan to the northwest Pacific Ocean. Significant anomalies in relative vorticity, potential height, and vertical upward movement at upper level existed in the summer of 2021 in Henan rainstorm area, and the water vapor transported from the northwest Pacific Ocean via abnormal easterly winds at the middle and lower levels was the main water source. In addition, analysis with an Empirical Mode Decomposition method revealed a statistically significant relationship between the second mode of subtropical high intensity index (IMF2WPSH) and the second mode of rainfall in Henan Province, and the IMF2WPSH plays an important role in this extreme rainfall event. During the positive phase of the IMF2WPSH, there was an abnormally enhanced upward movement in the subtropical western Pacific and an abnormal east wind in the low-middle altitude, by which updraft was abnormally enhanced. The IMF2WPSH could be used to predict extreme rainfall event in Henan and the neighboring regions. |
| Key words: Henan extreme rainfall western Pacific subtropical high typhoon |
