50 a来我国东北及邻近地区年降水量的年代际异常变化

利用中国东北地区195个和蒙古国6个气象台站的年降水量资料, 利用EOF、 REOF和分段线性拟合等方法, 分析了50 a来东北及其邻近地区年降水量的年代际异常变化. 结果表明: 1)50 a来的降水变化, 东北演变过程为多-少-多; 华北的演变过程为多-少. 自1980年代起, 东北地区由干变湿, 而华北地区则由湿变干. 2)降水主要呈3种分布形式: 全区一致型; 南北反向型; 南北部一致与中部相反分布型. 3)降水量总体呈下降趋势, 但近30 a来东北北部有增湿趋势, 而南部的干旱化一直在加剧. 4)大部分地区的降水量在1970年代中期和1980年代初期经历了一次突变, 但是变化的方向、范围及时间各地不尽一致.

Interdecadal Variations of Annual Precipitation in Northeast China and Its Neighborhood during Past 50 Years

The climatic inter-decadal variations in Northeast China are analyzed and studied by using the observational data from 195 stations in Northeast China and 6 stations in Mongolia with EOF and REOF analyses and the means of separated time interval linear fitting.It is found that:(1) In the recent 50 years the annual precipitation performed the course of more-less-more in Northeast China and more-less in North China,showing that Northeast China has been changing from dry to humid while Northern China has been changing from humid to dry since the 1980s.(2) There are three precipitation patterns in the studied region: the consistent pattern in all of the sub-regions,the opposite pattern in the north and the south and the pattern with consistency in the north and south but opposite in the middle.(3) The precipitation is gradually decreasing,resulting in a worse drought of the south,but it is slightly increasing in the northeast part in the last 30 years.(4) The precipitation in most sub-regions experienced an abrupt change in the middle of the 1970s and early in the 1980s,but the changing direction,scope and time were different.