| 2008年梅雨异常大尺度环流成因分析 |
| |
| 引用本文： | 牛若芸,金荣花.2008年梅雨异常大尺度环流成因分析[J].高原气象,2009,28(6):1326-1334. |
| |
| 作者姓名： | 牛若芸 金荣花 |
| |
| 作者单位： | 中国气象局,国家气象中心,北京,100081 |
| |
| 基金项目： | 中国气象局气象新技术推广预报员专项，国家气象中心预报员团队梅雨干旱课题 |
| |
| 摘 要： | 利用NCEP再分析资料对2008年江淮梅雨异常特征及其大尺度环流成因进行了分析研究。结果表明： （1）2008年入（出）梅显著偏早、 梅雨期长度略偏短， 梅雨分布呈南涝北旱、 东多西少， 梅雨量偏少、 强度偏弱。（2）该年入梅显著偏早是东亚大气环流由冬季型向夏季型转换提前所致， 副热带高空西风急流北跳、 500 hPa西风带环流调整、 西太平洋副热带高压季节性北跳、 夏季风北涌至江淮流域的时间均早于常年。（3）该年出梅显著偏早的主导因素是冷空气活动。（4）南涝北旱梅雨型是受南亚高压东段脊线位置接近常年、 副热带高压脊线处于适宜梅雨发生纬度带的南段、 低空西南急流和水汽输送带北缘位置以及高空强辐散和中低空强辐合区位置偏南的影响。（5）东多西少梅雨型是冷空气路径偏西所致。（6）梅雨期夏季风北涌至江淮流域活动次数偏少是梅雨量偏少的重要因素。
|
| 关 键 词： | 江淮流域 梅雨异常 大尺度环流 |
Causes Analysis of Large Scale Circulation of Abnormal Characteristic in Meiyu Period of 2008 |
| |
| NIU Ruo-yun,JIN Rong-hua.Causes Analysis of Large Scale Circulation of Abnormal Characteristic in Meiyu Period of 2008[J].Plateau Meteorology,2009,28(6):1326-1334. |
| |
| Authors: | NIU Ruo-yun JIN Rong-hua |
| |
| Abstract: | Using the daily NCEP reanalysis dataset the abnormal characteristics and causes of large scale circulation in Meiyu period of 2008 are analyzed. The results show that (1) the abnormal characteristics of Meiyu in 2008 contain the beginning/ending date earlier,the duration shorter,the rainfall pattern waterlogged in south and droughty in north,and also excessive in East and few in West in the Yangtze-Huaihe Valley,the amount of Meiyu precipitation less and the density of Meiyu weaker. (2) The beginning of Meiyu period earlier significantly is induced by transition in advance of East Asian circulation from winter pattern to summer pattern,which is mainly presented as the date of northward jump of East Asian subtropical upper-level westerly jet,adjustment of the northern westerly belt circulation,seasonal northward jump of the west pacific ocean subtropical high and pushing northward to the Yangtze-Huaihe Valley of summer monsoon are all earlier than normal. (3) The dominant factor of the ending of Meiyu period earlier significantly is cold air activity. (4) The rainfall pattern waterlogged in south and droughty in north is caused by the eastern ridge position of South Asia high closing to that of normal year,the ridge position of subtropical high placed in the south section of suitable latitude zone of Meiyu occurring and duration,the northern site of low level southwest jet and the water vapor transport field further south,and also the position of upper level divergence with low-middle level convergence further south. (5) The rainfall pattern excessive in East and few in West is induced by the westerly cold air activities. (6) The number of times of pushing northward to the Yangtze-Huaihe Valley of summer monsoon are less than nomal,which is an important factor that cause the amount of Meiyu precipitation is less than normal. |
| |
| Keywords: | Yangtze-Huaihe Valley Meiyu abnormal Large scale circulation |
| 本文献已被 万方数据 等数据库收录！ |
| 点击此处可从《高原气象》浏览原始摘要信息 |
|
点击此处可从《高原气象》下载全文 |
|
