2000年江淮梅雨的分析和中期预报着眼点

20 0 0年江淮梅雨期的环流特征 ,在其入梅时表现为 :西太平洋副热带高压 1 2 0°E脊线的季节性北移具有明显的两周振荡周期 ;南亚高压脊线北移至 2 5°N和印度季风的爆发——加尔各答稳定西风的结束均能很好地预示江淮梅雨的开始。在出梅时 :亚洲地区地转风急流轴入梅后持续北移到 47.5°N,5 0°N稳定的超长波脊先于西太平洋副高调整 ,梅雨期后期在菲律宾东部洋面生成的 3号台风的北上 ,均对出梅的环流调整起到了显著的作用。

Analysis and Medium-Range Forecast for Mei-yu Events over the Changjiang-Huaihe River Basin in 2000

The circulation features during the 2000 Jianghuai mei-yu period suggested that at the beginning of mei-yu event,the seasonal northward moving of the 120°E ridge of western Pacific subtropical high has a evident 2-week oscillation period;both the northward moving to 25°N of the ridge of South Asia high and the onset of Indian monsoon -the end of stable Calcutta westerly obviously foretell the beginning of Jianghuai mei-yu. At the end of mei yu period,the continuous northward moving to 47 5°N of the geostrophic wind jet axis of Asia region during the meiyu season,regulation of stable ultra-long wave ridge of 50°N superposing wave was earlier than that of western Pacific subtropical high and the northward moving of typhoon 0003 occurred in the eastern ocean surface of Philippine in the late period of mei yu season significantly contributed to the circulation regulation of the end of mei-yu.