双月刊

ISSN 1006-9895

CN 11-1768/O4

东亚副热带西风急流位置变化及其对中国东部夏季降水异常分布的影响
作者:
作者单位:

作者简介:

通讯作者:

基金项目:

国家自然科学基金资助项目40675041,国家重点基础研究发展规划项目2006CB400506


Location Variation of the East Asia Subtropical Westerly Jet and Its Effect on the Summer Precipitation Anomaly over Eastern China
Author:
Affiliation:

Fund Project:

  • 摘要
  • |
  • 图/表
  • |
  • 访问统计
  • |
  • 参考文献
  • |
  • 相似文献
  • |
  • 引证文献
  • |
  • 资源附件
    摘要:

    利用1951~2004年美国国家环境预报中心 (NCAR/NCEP) 再分析候平均资料和同期中国740站日降水资料, 分析了东亚副热带西风急流轴位置的变化趋势及其对中国东部夏季降水分布的影响, 结果表明: (1) 夏季7~8月东亚副热带西风急流位置和形态在1975~1980年间出现转折, 1980年后西风急流中心逐渐向西移动的同时伴随有西风急流向南偏移。 (2) 在1980年以后华北地区降水量减少和降水强度减弱, 雨季开始时间推迟、 雨季变短, 而长江中下游地区入梅提前、 梅雨期变长, 降水量增加, 从而形成南涝北旱的降水分布形势。 (3) 1957~1964年华北典型多雨时期, 西风急流呈纬向分布, 在华北地区有高低空急流耦合, 强辐合上升区正好位于华北, 并有充足的水汽条件供应, 使得华北降水偏多。而1980~1987年和1997~2002年华北地区为典型少雨时期, 1980~1987年西风急流中心位置偏南和1997~2002年急流位置显著偏西, 在华北地区均无高低空急流耦合的环流形势, 水汽辐合区位于长江流域, 强辐合上升区位置在30°N以南区域, 有利于江南地区降水增加而华北地区少雨, 这表明西风急流位置变化导致环流调整对中国东部降水分布有显著影响。因而, 在讨论东亚副热带西风急流位置与中国东部地区降水异常的关系时, 不仅要考虑西风急流南北位置变化, 还需要综合分析西风急流的东西位置和形态的变化。

    Abstract:

    The location change of the East Asia subtropical Westerly Jet (EAWJ) axis and its impacts on the spatial distribution of summer precipitation anomaly in eastern China are investigated by using the NCEP/NCAR reanalysis mean pentad data and observed daily rainfall data from 1951 to 2004. The main results are as follows: (1) The location change of the EAWJ is greatly abrupt in summer (July and August) during 1975-1980, since then the westerly jet core shifted southward and westward remarkably.(2) Both rainfall amount and rainfall intensity in North China have been decreasing in summer since 1980. At the same time, the length of the rain season shortens, because the beginning date of the rainy season is late and the ending date early, respectively. In contrast, the plum rains start date is early and the end date late. The rainfall increases more than before in the middle-lower reaches of the Yangtze River, so the precipitation distribution with flood in the south and drought in the north of China forms.(3) There is more precipitation in North China during 1957-1964, corresponding to the EAWJ longitudinal distribution. There is coupling between the upper-level jet and the low-level jet in North China. Meanwhile, the strong convergence and the sufficient water vapor supply appear in this region, which are related to the more precipitation occurrence. There are two periods of the less precipitation in North China, which are 1980-1987 and 1997-2002, respectively. The EAWJ core is abnormally southward and westward remarkably without coupling of the 200-hPa jet and 850-hPa jet during the periods of 1980-1987 and 1997-2002, respectively. Meanwhile, the stronger convergence and sufficient water vapor supply appear in the Yangtze River, which are related to more precipitation in the south and less precipitation in the north of China. This suggests that the change in the westerly jet location and intensity is associated with the precipitation distribution in eastern China. Therefore, not only the latitudinal location, but also the longitudinal location and intensity of the westerly jet center are important for the relationship between the EAWJ and the abnormal rainfall in eastern China.

    参考文献
    相似文献
    引证文献
引用本文

杜银,张耀存,谢志清.东亚副热带西风急流位置变化及其对中国东部夏季降水异常分布的影响.大气科学,2009,33(3):581~592 DU Yin, ZHANG Yaocun, XIE Zhiqing. Location Variation of the East Asia Subtropical Westerly Jet and Its Effect on the Summer Precipitation Anomaly over Eastern China. Chinese Journal of Atmospheric Sciences (in Chinese),2009,33(3):581~592

复制
分享
文章指标
  • 点击次数:
  • 下载次数:
  • HTML阅读次数:
  • 引用次数:
历史
  • 收稿日期:
  • 最后修改日期:
  • 录用日期:
  • 在线发布日期: 2011-12-06
  • 出版日期: