基于再分析资料的西南区域近50 a空中水资源的气候特征

利用1961—2012 年NCEP/ NCAR 的再分析月平均资料，分析了中国西南区域(四川、重庆、云南、贵州、广西大部分地区、西藏东部)水汽总量和水汽输送的气候特征。结果表明：西南区域水汽总量近50 a 来呈整体减少趋势；水汽含量在850—700 hPa 之间最为丰富；西南区域东湿西干，重庆、贵州、广西、四川东部水汽总量相对丰富；影响西南区域全年水汽量的有四个输送通道，春季水汽主要来源于孟加拉湾和偏西气流，夏季主要受到孟加拉湾和印度洋季风影响，秋季水汽主要来源于西太平洋，冬季则主要来源于偏西风和西太平洋；西南区域全年主要为水汽汇合区（除云南大部分地区以外），常年有两个水汽辐合中心，一个在西藏与四川交接处（青藏高原东南侧），一个在贵州及其附近地区；而云南上空主要为水汽辐散，仅夏季部分地区为水汽汇合区。

Climatological characteristics of water vapor over southwest Chinaduring the recent 50 years based on the reanalysis data

Based on the monthly reanalysis data from 1961 to 2012 provided by the European center, the characteristics of water vapor andits transport over southwest China are analyzed. The analysis results indicate that the water vapor content of southwest China had been decreasedin the 50 years. The water vapor between 850 -700 hPa is more abundant than other layers. There is more water vapor content in eastof southwest China and less in west. The water vapor is mainly from four channels: In spring, the water vapor comes from the Bay of Bengleand westerly. In summer, the water vapor comes from the Bay of Bengle and Indian Ocean. In autumn, the water vapor comes from the westPacific Ocean. In winter, the water vapor comes from westerly and the west Pacific Ocean. Most part of southwest China is water vapor convergence.There are two water vapor convergence centers, One locates in the border of Tibet and Sichuan, and the other in Guizhou and surroundingareas. Most part of Yunnan is water vapor divergence, except in summer.