| 我国西南地区干湿季降水的主模态分析 |
| |
| 引用本文： | 张武龙,张井勇,范广洲.我国西南地区干湿季降水的主模态分析[J].大气科学,2014,38(3):590-602. |
| |
| 作者姓名： | 张武龙 张井勇 范广洲 |
| |
| 作者单位： | 1.中国科学院大气物理研究所季风系统研究中心, 北京100190;成都信息工程学院大气科学学院, 成都610225 |
| |
| 基金项目： | 国家自然科学基金面上项目41275089，国家重点基础研究发展计划2009CB421405、2012CB955604，中国科学院“百人计划”项目 |
| |
| 摘 要： | 利用我国西南地区26个台站降水资料，通过经验正交函数（EOF）分解的方法，分析了1980～2009年该地区干季（10～4月）和湿季（5～9月）降水的主模态。我国西南地区干季降水的时空变化存在两种主模态，它们分别可以解释总方差的22.4%和15.6%。第1主模态为全区一致型，具有准两年周期振荡的年际变化特征；第2主模态为东南—西北反向型，从20世纪90年代中期至21世纪初呈现2～3年的变化周期。我国西南地区湿季降水的时空变化存在三种主模态，它们分别可以解释总方差的17.1%，13.8%和11.1%。第1主模态为全区一致型，20世纪90年代初期具有较强的2～4年周期；第2主模态为经向偶极子型分布，并具有显著的4年周期；第3主模态为纬向偶极子型分布，具有2～4年的年际变化信号。进一步利用NCEP/NCAR再分析资料以及美国国家海洋和大气管理局（NOAA）的海表面温度（SST）资料，通过合成分析和回归分析的方法探讨了与干湿季降水各主模态对应的大尺度大气环流和海温状况。我国西南地区干季降水第1主模态与北极涛动（AO）有明显的正相关关系，对应的大气环流和海温状况表现为高纬北冰洋与中纬度地区上空高度场的反向异常分布，北大西洋和北太平洋海温低纬与中高纬的偶极子型异常分布；第2主模态与中高纬欧亚大陆上空高度场经向偶极子型异常分布有关，中纬度北太平洋的海温异常与该模态具有紧密的联系。我国西南地区湿季降水第1主模态与北大西洋涛动（NAO）显著负相关，对应的大气环流和海温状况表现为北大西洋上，高纬度与中纬度地区上空高度场的偶极子型异常分布，海温从低纬到中高纬的三极子型异常分布；第2主模态受欧亚大陆上空高度场经向三极子型异常分布影响，并与北太平洋海温异常的一致型分布有关；第3主模态可能与El Ni?o Modoki有关，同时受到南亚高压的影响，赤道太平洋海温的纬向三极子型异常分布对该模态具有一定的潜在预报意义。
|
| 关 键 词： | 干湿季降水 主模态 经验正交函数分解大尺度大气环流 海温 |
| 收稿时间： | 2013/4/19 0:00:00 |
| 修稿时间： | 9/3/2013 12:00:00 AM |
Dominant Modes of Dry-and Wet-Season Precipitation in Southwestern China |
| |
| ZHANG Wulong,ZHANG Jingyong and FAN Guangzhou.Dominant Modes of Dry-and Wet-Season Precipitation in Southwestern China[J].Chinese Journal of Atmospheric Sciences,2014,38(3):590-602. |
| |
| Authors: | ZHANG Wulong ZHANG Jingyong and FAN Guangzhou |
| |
| Institution: | 1.Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100190;Department of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu 6102252.Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100190;3.Department of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu 610225 |
| |
| Abstract: | This study investigates the dominant modes of interannual variability of precipitation in dry (October-April) and wet (May-September) seasons over southwestern China through empirical orthogonal function (EOF) analysis of monthly precipitation reported by 26 meteorological stations during 1980-2009. The dominant modes are shown to be specific in each season. In the dry season, the first leading mode is generally distributed uniformly throughout the region with quasi-biennial oscillation, and the second leading mode is characterized by an obvious two-three year period of southeast and northwest opposite distribution from the mid-1990s until recently. In the wet season, the first leading mode shows the same distribution with an obvious two-four year period in the early 1990s, and the second leading mode shows spatial distribution of a meridional dipole pattern during a significant four-year period. The third leading mode is of a zonal dipole distribution and exhibits changes in two-four-year periods. We further examine the relationships of dominant modes of dry-and wet-season precipitation with large-scale atmospheric circulation and sea surface temperature (SST). In the dry season, the first leading mode is closely related to Arctic Oscillation (AO). For this mode, high-and mid-latitude opposite distribution in the 500-hPa height field is detected in addition to a meridional dipole-like structure in the North Atlantic and North Pacific SST fields. The second leading mode is related to a meridional dipole-like structure in the 500-hPa height field over Eurasian Continent and SST anomalies over the mid-latitude North Pacific. In the wet season, the first leading mode is significantly and negatively correlated with North Atlantic Oscillation (NAO). This mode is related to a dipole pattern between high and middle latitudes in the 500-hPa height field and a meridional tripole-like structure in the North Atlantic SST field. The second leading mode is associated with a meridional tripole pattern in the 500-hPa height field over the Eurasian Continent and a nearly coincident distribution of North Pacific SST anomalies. The third leading mode is related to the El Ni?o Modoki and South Asia high. The zonal tripole-like structure in the equatorial Pacific SST field may act as a potential predictor of the third mode. |
| |
| Keywords: | Dry-and wet-season precipitation Dominant modes EOF analysis Large-scale atmospheric circulation Sea surface temperature |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《大气科学》浏览原始摘要信息 |
| 点击此处可从《大气科学》下载免费的PDF全文 |
