利用NCEP/NCAR再分析资料及云南124个观测站降水资料， 采用多种统计方法分析了低纬高原地区水汽输送水平变化和垂直变化的气候特征。结果表明： （1）影响云南的水汽输送源地和路径存在明显的季节差异， 冬半年主要受西风带水汽输送的影响， 夏半年主要受热带海洋水汽输送的影响。（2）各边界整层水汽收支季节差异显著， 冬半年水汽主要从西边界输入， 夏半年主要从南边界输入， 北边界一年四季均为水汽输出， 东边界水汽收支月际波动最大， 且会发生水汽收支性质转变。（3）各边界水汽收支随高度增加而减小， 各季节西边界和南边界从低层至高层基本为水汽输入； 东边界和北边界水汽收支存在显著的垂直差异和季节差异特征。秋季和冬季水汽输入层较春季和夏季深厚。年际尺度上冬季和春季水汽收支变化相对比较简单， 东边界和北边界均为水汽输出， 而西边界和南边界为水汽输入； 夏季和秋季的水汽收支变化比较复杂， 各边界水汽收支的年际差异非常显著。云南夏季降水异常与净水汽收支有明显的正相关关系， 来自南半球在80°E -90°E附近转向北的越赤道气流和索马里越赤道气流带来的水汽输送对云南的夏季旱涝有十分重要的影响。

Using the monthly reanalysis data of NCEP/NCAR and the monthly precipitation of 124 meteorological stations in Yunnan， based on the various statistical methods， the horizontal variation and the vertical variation of water vapor transportation over the low-latitude highlands are studied.The results are shown as following： （1） the resources and the paths of the vapor transportation influencing the low-latitude highlands exist obvious seasonal differences.In the wintertime， the source of water vapor transportation over the low-latitude highlands is from westerly wind belt transportation， but from the tropical ocean water vapor transportation in the summertime.（2） The seasonal differences of the water vapor budget at different levels are significant.In the wintertime， the water vapor inflow mainly from the western boundary but from the southern boundary in the summertime， and the water vapor outflow from the northern boundary in all seasons.The monthly fluctuation of the water vapor budget on the eastern boundary is the largest and the property of water vapor budget sometimes is converted.（3） The water vapor budget decreases with the increasing of the height at the different boundaries in different seasons.The water vapor transportation flows in Yunnan at the western and southern boundary in all seasons.It exits obvious vertical and seasonal differences for the water vapor budget at the eastern and northern boundary.For the water vapor importation layer at the eastern boundary， it is deeper in autumn and winter than that in spring and summer.At the interannual scale， the variation of water vapor budget in winter and spring is relatively simple but complex in autumn and summer.The water vapor outflows at the eastern and northern boundary but inflows at the western and southern boundary in winter and spring.The interannual variation of water vapor budget is very complex in summer and autumn and the interannual difference of water vapor budget at each boundary is significant.There is a significant positive correlation between Yunnan summer precipitation and the net water vapor budget.The water vapor transportation brought by transequatorial airflows from the southern hemisphere turning north near 80°E-90°E and Somali cross-equatorial airflow has significant impact on summer drought and flood in Yunnan.