1998~2010年全球中低纬度降水时空特征分析

基于1998~2010年热带降雨测量(Tropical Rainfall Measuring Mission,TRMM)卫星3B43资料在像元尺度进行Mann-Kendall非参数检验,计算Hurst指数,绘制降水"月历"与演化态势图谱。分析全球中低纬度降水时空特征,结果表明:全球中低纬度降水主要集中在夏季和冬初且各月降水的年际波动比较明显;全球中低纬度降水呈现由低纬向中纬递减的趋势,海洋降水明显多于陆地,海陆梯度特征显著;月尺度降水大部分地区为增加(或减少)但统计不显著的趋势,同时绝大部分地区具有显著的长程自相似性;12月份降水变化态势的空间差异明显强于其它月份,而3月份则最不明显;季节尺度98%以上的地区降水具有显著的长程自相似性,季节演化态势表现出极强的空间差异性。

On spatial-temporal dynamics of precipitation in global mid-low latitudes from 1998 to 2010

Based on the TRMM(Tropical Rainfall Measuring Mission) 3B43 precipitation data,the Mann-Kendall test was performed and the Hurst index was calculated at the pixel scale to analyze the spatial-temporal dynamics of precipitation in global mid-low latitudes from 1998 to 2010.Furthermore,the "Monthly Calendar" and the seasonal evolvement map were drawn.It shows that,summers and early winters are the rainy period in a year.Significant fluctuations of monthly precipitation in the past 13 years can be observed.Over all,the precipitation shows a decreasing trend from the low latitude to the high latitude.Precipitation in the ocean is more than that on the land and therefore very significant sea-land gradient characteristics can be found.On monthly scale,the changing trends of precipitation in most areas are ’increasing but not significant’ or ’decreasing but not significant’,however,there’re very strong self-similarity and long-range dependence for the 12 monthly time sequences of precipitation data.December shows the most prominent spatial differences of precipitation variation while March is the least significant one.On seasonal scale,more than 98% areas have very strong self-similarity and long-range dependence for the 4 seasonal time sequences of precipitation data;the spatial differences of precipitation variation are very significant in the seasonal evolvement map.The results and conclusions in this study are aimed at providing a useful reference on the research of global water cycle,global climate change and so on.