| 摘要: |
| 利用1979—2016年NCEP再分析资料，分析了南海季风爆发的年代际转折与东亚副热带夏季降水的关系。结果表明：南海夏季风爆发时间在1993/1994年出现年代际转变，1979—1993年爆发时间相对偏晚，夏季华南降水偏少，长江中下游至日本南部降水偏多；1994—2016年爆发时间偏早，夏季华南降水偏多，长江中下游到日本南部降水偏少。南海季风爆发时间年代际转折与夏季东亚副热带降水关系可能受到菲律宾越赤道气流强度的调控，季风爆发时间与菲律宾越赤道气流有显著正相关，且均在1993/1994年间存在年代际转变。在1994—2016（1979—1993）年南海夏季风爆发偏早（晚），菲律宾越赤道气流偏弱（强），澳大利亚北部有偏北（南）风异常，将暖池的热量往赤道输送，使得赤道对流增强（减弱），产生异常上升（下沉）运动汇入Hadley环流上升支，增强（减弱）的Hadley环流导致下沉主体偏北（南），促使副高脊线偏北（南），从西北太平洋（孟加拉湾）往华南地区（江淮到日本南部）输送水汽增强，所以华南（江淮到日本南部）夏季降水偏多。 |
| 关键词: 南海季风 年代际转折 夏季降水 副热带高压 |
| DOI：10.16032/j.issn.1004-4965.2019.075 |
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| THE RELATIONSHIP BETWEEN INTERDECADAL CHANGE OF SOUTH CHINA SEA MONSOON ONSET WITH SUBTROPICAL EAST ASIA SUMMER RAINFALL |
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ZHAO Xiao-fang1, WAHG Li-juan1, CHEN Hong2, WANG Zhi-qiang3
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1. Key Laboratory of Meteorological Disaster, Ministry Education/ Joint International Research Laboratory of Climate and Environment Change/ Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044, China;2. Hainan Meteorological Observatory, Haikou 570203;3. Shanghai Flight Department, China Eastern Airlines, Shanghai 201100
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| Abstract: |
| The relation between interdecadal-change of South China Sea monsoon (SCSSM) onset date with subtropical East Asia summer rainfall is investigated by NCEP reanalysis data during 1979—2016. Results indicate that the onset data of the SCSSM show a significant interdecadal change around 1993—1994. During 1979—1993, the SCSSM started late compared with previous years, corresponding to less rainfall in south China and more rainfall in the area from Yangtze River to southern Japan. In 1994—2016, the SCSSM started earlier, corresponding to opposite rainfall distribution in south China and the area from Yangtze River to southern Japan. The relation between the interdecadal change of SCSSM onset date with subtropical East Asia summer rainfall may be controlled by summer Philippine cross-equatorial flow (CEF). A significant positive correlation and an obvious interdecadal change around 1993—1994 are found between the SCSSM onset date and Philippine CEF. In 1994—2016(1979—1993), the early (late) onset of the SCSSM corresponded to a weak (strong) Philippine CEF. Therefore, a north wind anomaly in northern Australia can transport the heat of the warm pool to the equator, which can strengthen (weaken) the convection around the equator. An ascending movement can strengthen the Hadley circulation, corresponding to a more north (more south) descending movement; therefore, the subtropical high ridge is more north (more south). The water vapor increases from the northwestern Pacific Ocean (Bay of Bengal) to south China (Yangtze River to southern Japan). Therefore, south China summer rainfall (Yangtze River to southern Japan) also increases. |
| Key words: South China Sea Monsoon interdecadal change summer rainfall subtropical high |
