doi:  10.3878/j.issn.1006-9895.1808.18164
东亚夏季环流多齿轮耦合特征及其对中国夏季降水异常的影响分析

Coupling Wheels in the East Asian Summer Monsoon Circulations and Their Impacts on Precipitation Anomalies in China
摘要点击 136  全文点击 117  投稿时间:2018-05-17  
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基金:  气象预报业务关键技术发展专项YBGJXM 2017国家自然科学基金项目41221064、41475057、41772173,高原与盆地暴雨旱涝灾害四川省重点实验室科技发展基金项目省重点实验室2018-青年-06,气象预报业务关键技术发展专项YBGJXM(2017)05-06
中文关键词:  多齿轮耦合  东亚夏季风  夏季降水异常  稳定性检验
英文关键词:  Coupling wheels  East Asian summer monsoon  Summer rainfall anomalies  Stability test
           
作者中文名作者英文名单位
庞轶舒PANG Yishu四川省气候中心,成都 610072;中国气象局成都高原气象研究所/高原与盆地暴雨旱涝灾害四川省重点实验室,成都 610072
祝从文ZHU Congwen中国气象科学研究院,北京 100081
马振峰MA Zhenfeng四川省气候中心,成都 610072;中国气象局成都高原气象研究所/高原与盆地暴雨旱涝灾害四川省重点实验室,成都 610072
秦宁生and QIN Ningsheng四川省气候中心,成都 610072;中国气象局成都高原气象研究所/高原与盆地暴雨旱涝灾害四川省重点实验室,成都 610072
引用:庞轶舒,祝从文,马振峰,秦宁生.2019.东亚夏季环流多齿轮耦合特征及其对中国夏季降水异常的影响分析[J].大气科学,43(4):875-894,doi:10.3878/j.issn.1006-9895.1808.18164.
Citation:PANG Yishu,ZHU Congwen,MA Zhenfeng,and QIN Ningsheng.2019.Coupling Wheels in the East Asian Summer Monsoon Circulations and Their Impacts on Precipitation Anomalies in China[J].Chinese Journal of Atmospheric Sciences (in Chinese),43(4):875-894,doi:10.3878/j.issn.1006-9895.1808.18164.
中文摘要:
      东亚夏季风成员的相互作用,构成了东亚夏季风高、低层环流的“多齿轮耦合”形态。本文利用多变量主成分分析(MV-EOF)等方法诊断分析了东亚夏季风多齿轮耦合的变化特征、耦合机制、时间稳定性、空间稳定特征及其对中国夏季降水的影响机制,并在此基础上构建了典型多齿轮耦合形态影响夏季降水的概念模型。结果表明,多齿轮耦合受到垂直温、压场的强迫和青藏高原大地形的影响,主要表现在年际变化上(周期为2~6年)。其前两个模态稳定地反映了东亚夏季风成员典型联动作用。在第一模态中,北方气旋、南亚高压和西太平洋副热带高压为主要耦合系统。其中北方气旋为正压结构,在高层通过南侧偏西气流与南亚高压耦合,南亚高压则通过中纬东部地区下沉辐散气流与西太平洋副热带高压联动。当该耦合模态增强时,有利于中国夏季降水呈自北向南“+-+-”分布。第二模态主要反映中高纬气旋、东亚副热带西风气流、南亚高压、西北太平洋反气旋系统和西太平洋副热带高压耦合特征。其中,中高纬气旋和西北太平洋反气旋为正压系统,两者通过其间的东南气流联动。气旋系统在高层通过南侧西风与东亚副热带西风急流和南亚高压联动。反气旋在中低层通过南侧的偏东气流影响副热带高压强度和面积。当该耦合模态增强时,中国黄河以北及河套地区降水偏多,黄河以南降水偏少。
Abstract:
      The interaction of East Asian summer monsoon (EASM) members constitutes the “the coupling wheels” pattern for the circulations over the upper and lower layers of EASM. In this paper, the variation, mechanisms, temporal and spatial stability of the coupling wheels as well as their impacts on abnormal precipitation over China in the East Asian summer monsoon (EASM) region are diagnosed and analyzed using Multi-Variable Empirical Orthogonal Function (MV-EOF). On the basis of the above work, conceptual models are constructed for typical coupling wheels in the EASM and their impacts on summer rainfall. Our results show the coupling wheels are manifested in interannual variation (with the period of about 2-6 years) and forced by vertical temperature and pressure fields as well as the large terrain of the Tibet Plateau. The first two modes of the coupling wheels are stable and reflect typical linkages between the EASM members. In the first mode, the Northern Cyclone (NC), the South Asian high (SAH) and the western Pacific subtropical high (WPSH) are the major coupling components. As a barotropic system, the NC couples with the SAH through westerly winds on its southern side, while the SAH interacts with the WPSH by divergent descending air flow in the eastern part of middle-latitude area. When this mode enhances, summer rainfall distribution in China shows a pattern of “+-+-” from north to south. The second mode mainly reflects the coupling characteristics of the mid- and high-latitude cyclones, the East Asian subtropical westerly jet (EASWJ), the SAH, the Northwest Pacific anticyclone (NPA) and the WPSH. As barotropic systems, the mid- and high-latitude cyclones and NPA are linked by southeasterly winds. In addition, the cyclones are coupled with the SAH and the EASWJ through westerly winds on the southern side of the cyclones in upper layers. While the intensity and area of the WPSH are affected by easterly winds on the southern side of the NAP in lower layers. Enhancement of this coupling mode is favorable for more precipitation over areas to the north of the Yellow River and the HETAO region, but less rainfall would occur to the south of the Yellow River.
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