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黄思洁, 李秀珍, 温之平. 中国东部夏季风北界年际变化的东西差异及其影响因子[J]. 大气科学, 2019, 43(5): 1068-1080. DOI: 10.3878/j.issn.1006-9895.1812.18173
引用本文: 黄思洁, 李秀珍, 温之平. 中国东部夏季风北界年际变化的东西差异及其影响因子[J]. 大气科学, 2019, 43(5): 1068-1080. DOI: 10.3878/j.issn.1006-9895.1812.18173
HUANG Sijie, LI Xiuzhen, WEN Zhiping. Interannual Variation of Northern Edge of Summer Monsoon in Eastern China: Zonal Discrepancies and Impact Factors[J]. Chinese Journal of Atmospheric Sciences, 2019, 43(5): 1068-1080. DOI: 10.3878/j.issn.1006-9895.1812.18173
Citation: HUANG Sijie, LI Xiuzhen, WEN Zhiping. Interannual Variation of Northern Edge of Summer Monsoon in Eastern China: Zonal Discrepancies and Impact Factors[J]. Chinese Journal of Atmospheric Sciences, 2019, 43(5): 1068-1080. DOI: 10.3878/j.issn.1006-9895.1812.18173

中国东部夏季风北界年际变化的东西差异及其影响因子

Interannual Variation of Northern Edge of Summer Monsoon in Eastern China: Zonal Discrepancies and Impact Factors

  • 摘要: 采用1958~2016年JRA-55(Japanese 55-year Reanalysis)月平均再分析资料,利用夏季平均的可降水量定义了东亚夏季风北界,通过谐波分解、回归分析、合成分析、波活动通量等分析方法,研究了东亚夏季风北界位置的年际变化特征和东西差异。根据各经度上夏季风活动北界位置年际变化的一致性可划分为华北区域(107.5°~115°E)和东北区域(122.5°~130°E)两个区域,两个区域夏季风北界位置的年际变化具有明显差别。两个区域的夏季风北界位置的异常偏北都与东侧的异常反气旋式水汽环流密切相关,与华北区域北界位置密切联系的异常反气旋式水汽环流位于黄海附近,与东北区域北界位置相关的异常反气旋式水汽环流则位于日本海北部。两个区域分别位于反气旋式环流西侧,受偏南风水汽输送影响,区域水汽输送以及辐合增强。影响华北区域的反气旋式异常与中高纬度波列的传播有关;影响东北区域夏季风北界位置偏南年与偏北年的反气旋式环流的可能成因存在非对称性,偏南年对应西北太平洋低纬度正异常高度场以及中纬度负异常高度场,可能受东亚—太平洋遥相关波列的影响;偏北年则对应着东北亚的正异常高度场,可能与局地增温有关。

     

    Abstract: Based on monthly reanalysis data from the JRA-55 (Japanese 55-year Reanalysis) during the period 1958-2016, the northern edge of the East Asian Summer Monsoon (EASM) is defined by the Precipitable Water (PW) in summer. In this study, the authors used harmonic decomposition, regression analysis, composite analysis, wave activity flux analysis, and other analytical methods to study the interannual variation of the displacement of the northern edge of the EASM. The results show a dramatic west-to-east discrepancy with independent variations over North China (107.5°-115°E) and Northeast China (122.5°-130°E), which are related to an anticyclonic moisture circulation anomaly to the east. The discrepancy related to the location of northern edge in North China lies over the Yellow Sea, and that of Northeast China lies over the northern Sea of Japan. As a result, these two regions experience enhanced transport of southerly moisture and moisture convergence. The abnormal anticyclonic circulation influencing North China is related to the propagation of wave trains in the upper-troposphere mid-high latitudes from the east of Europe. The abnormal anticyclonic circulation affecting Northeast China is due to the asymmetry between the southward-displaced and northward-displaced monsoon edge conditions. The former might be related to the northward propagation of abnormal signals from low latitudes via the East Asia-Pacific teleconnection, whereas the latter might be related to the positive geopotential height anomaly caused by local warming over northeastern Asia.

     

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