1900-2009年中国均一化逐月降水数据集研制

收集、整理全国1900-2009年110年逐月站点历史降水量资料,采取标准正态检验(SNHT)方法,对台站序列进行了均一性检验,并对部分明显不连续的站点序列进行了均一化调整和订正.在此基础上,分别对近百年降水距平序列和1971-2000年气候标准值进行了网格化,形成了逐月网格化气候数据集(5°×5°,2°×2°),并采用经验正交展开(EOF)技术方案进行了统计插补实验,形成了完整的5°×5°经纬度网格点数据集.基于不同分辨率网格数据集,建立了110年中国降水变化序列,计算了110年中年及季节降水量变化趋势.结果表明,中国近110年来年降水量变化略呈下降趋势,但没有达到统计显著性水平,各个季节的情况略有差别.统计插补后对1900年以后几年的降水量略有下降,使得近百年线性趋势略上升.

Development of Homogenized Monthly Precipitation Dataset in China during 1900-2009

Based on the collection and processing of the China’s national-wide monthly station observational precipitation data during 1900-2009,the data series for each station has been tested for their homogeneity with Standard Normalized Homogeneity Test(SNHT) method and the inhomogeneous part of the series are adjusted.Then the 1971-2000 climatology normals and precipitation anomalies during 1900-2009 have been transformed into the grid boxes at resolutions of 5o×5o and 2o×2o,respectively,and two gridded form datasets are constructed by combining the normals and anomalies.After that,the missing values for the 5o×5o grid dataset are interpolated by Empirical Orthogonal Function(EOF) techniques.With the datasets at different resolutions,the precipitation change series during 1900-2009 over Chinese Mainland were built,and the annual and seasonal precipitation changing trends for recent 110 years were analyzed.The result indicated that the annual precipitation showed a slightly dryer trend during the 110 years,but with no statistical confidence.To be pointed out,the interpolation of the missing values makes the precipitation amounts in the early 1900s decrease,so the trend for the 110 years increased.