有关东亚夏季风北边缘的定义及其特征

Definition and features of the north edge of Asian summer monsoon

中文关键词:  可降水量，东亚夏季风，季风北边缘定义

英文关键词:Precipitable water, Asian summer monsoon, Definition of north edge

中文摘要:

      采用欧洲中心（ECMWF）44年再分析（ERA40）日总可降水量（TPW）资料，用标准化可降水量指数（NPWI）定义了夏季风北边缘，并进一步研究了亚洲夏季风北边缘的气候特征及其年际、年代际变化特征。结果表明，用标准化可降水量指数定义的夏季风北边缘在亚洲可以确定出印度夏季风系统和东亚夏季风系统；就夏季风北边缘的平均位置而言，其在100°E以西沿青藏高原南侧呈东—西走向，年际变化极小；在100°E以东呈东北—西南走向，从青藏高原东侧北上经西北地区东部、华北地区北部、东北地区西部延伸到东北亚地区，并存在明显的年际、年代际变化。

英文摘要:

      By using the daily total precipitable water amount (TPW) from the ECMWF reanalysis (ERA40) in 1958-2001, the north edge of the Asian sub-tropical summer monsoon was defined by a normalized precipitable water index (NPWI), and its climatology and interannual/interdecadal variability were examined. Results show that two monsoon systems (the Indian monsoon system and the East Asian monsoon system) can be identified in terms of the north edge of Asian summer monsoon defined by the NPWI. The mean north edge goes eastwards along the south side of the Tibetan Plateau in the area west of 100°E, and then turns northeastwards along the northeast side of the Tibetan Plateau via the east of Northwest China, the north of North China, the west of Northeast China to the northeast Asia. The north edge of the East Asian monsoon system has distinct interannual variability in the area east of 100°E, while that of the Indian monsoon does not show obvious interannual variation in the area west of 100°E.