中国大陆降水时空格局演变新事实

基于1961年-2014年54年的降水格点数据,利用反距离权重法插值计算分析了中国大陆年降水时空分布,对年降水量进行分类,统计出54年的各个降水分区所占面积变化特征。引进降水重心概念,以年降水量为权重,计算出中国大陆54年的年降水重心并分析其移动特征。结果表明,各个降水分区面积变化与重心移动整体上为随机性序列,波动性明显。其中年降水量在400~600mm的面积占比最大,趋势性最明显,波动幅度最大;受东北和华北地区的降水变异特征显著的影响,年降水重心在东北-西南方向的离散度较大,具有指示局部气候异常的作用。降水重心的纬度与1 400mm的分类降水面积相关性最大,经度方向相关性不明显。在54年时间尺度和中国大陆空间尺度下,气候变化中的整体降水格局未发生重大改变。

Spatial and temporal patterns of precipitation over mainland China and new facts

Based on the 54-year yearly grid precipitation data of mainland China from 1961 to 2014, the inverse distance weighted interpolation method was used to analysis the spatial-temporal variation on precipitation. Annual precipitation was classified by different quantities and the 54-year area percentage variation of each type was calculated out. A concept of precipitation barycenter was introduced. This study took the amount of precipitation as weights to estimate the annual precipitation barycenter and its changing features. The results show that area percentage variation of each annual precipitation type and the coordinate changing of annual precipitation barycenter were in random sequence with clearly fluctuant features. The annual precipitation type of 400~600mm accounts for the largest area proportion. Also its trend and fluctuation range are the most significant one. By the significant effect of precipitation variability in Northeast and North China, the divergence of precipitation barycenter is larger in northeast-southwest direction. So it can indicate the regional climate abnormal variation. Annual precipitation barycenter changing of the 54 years is most related to >1400mm rainfall area at the latitudinal direction(Y-coordinate). In terms of the longitudinal direction(X-coordinate), there is on obvious correlation. So at this space (mainland China) and time (54years from 1961~2014) scale, the overall precipitation patterns did not change significantly.