基于TRMM数据的西南地区年降水时空特征研究

Spatial-temporal Characteristics of Annual Precipitation in Southwest China Based on TRMM 3B43 V7 Data

【目的】深入了解中国西南地区(川、渝、黔、滇)降水资源变化的时空分布规律。【方法】利用1998—2014年TRMM3B43V7数据,采用非参数Mann-Kendall趋势检验、Sen-Median趋势分析、变异系数和Hurst指数对西南地区降水进行了分析。【结果】1)西南地区TRMM 3B43V7月降水数据和年降水数据与地面121个实测站点数据间具有较高的相关性,TRMM 3B43V7数据在西南复杂地貌区域具有较高精度;2)1998—2014年西南地区的降水呈下降趋势,其中研究区内云南省下降最明显;3)西南地区年均降水从西北往东南方向呈现出"低-高-低-高"的特征,研究区年均降水量主要集中在500~1 500mm之间,占整个区域的96.3%;4)近17a西南降水量呈下降和增加趋势的面积分别占整个西南地区的70.08%和21.97%,稳定区域只有7.95%;5)降水的变异系数在0.048~0.229之间,西南地区年降水的波动变化较小;6)西南地区96.12%的区域呈现出正向持续性,68.15%区域降水将持续减少,只有20.77%的区域降水将增加。【结论】TRMM 3B43V7降水数据在西南地区适应性较好,可以为西南地区水资源研究、极端天气灾害预警及水土流失等生态问题提供科学依据。

[Purposes]To study the temporal and spatial distribution of precipitation in Southwest China（SWC）（Sichuan,Chongqing,Guizhou and Yunnan）.[Methods]The methods of non-parametric Mann-Kendall test,Sen-Median trend analysis,coefficient of variation,and Hurst index were calculated to analyze the precipitation resource based on the Tropical Rainfall Measuring Mission（TRMM）3B43precipitation data from 1998—2014.[Findings]The main results show that：1）TRMM 3B43V7 precipitation data in SWC region had a high precision and correlation（R）,the correlation between monthly precipitation and measured data at121 meteorological stations was 0.93,the correlation between annual precipitation and measured data was 0.87.2）Annual precipitation in SWC had a decrease trend in recent 17 years,especially Yunnan Province.3）In terms of spatial-temporal variation,annual precipitation rendered out a＂low-high-low-high＂features from northwest to southeast direction in SWC region;average annual rainfall was concentrated between 500～1 500 mm,accounting for 96.3% of the entire region,so water resource was rich in SWC region.4）Annual rainfall decrease area in SWC was larger than increased area,account for 70.08% and 21.97%,while stable area was 7.95%.5）The coefficient of variation of precipitation was between 0.048～0.229,the fluctuation of annual precipitation was smaller in SWC.6）About 96.12% areas in SWC had a very self-similarity and long-range dependence,68.15% of the entire study area＇s precipitation was predicted to decline in future,only 20.77% of the regional＇s precipitation would follow a continuous increasing trend.[Conclusions]The TRMM 3B43V7 precipitation data had good adaptability in SWC,which could provide scientific basis for ecological problems such as water resources research,early warning of extreme weather disasters and soil and water loss in SWC.