夏季云贵高原地区降水特征及云水资源的匹配

基于云贵高原地区1961—2010年高分辨率(0.5°×0.5°)逐日降水格点资料,分析了云贵高原及东、西两个区域的夏季降水变化特征。并结合欧洲中期天气预报中心(ECMWF)提供的1979—2010年ERA-Interim再分析资料,计算了其夏季水汽输送通量和净水汽收支。结果表明:(1)云贵高原夏季平均降水分布不均匀,存在区域差异:云贵高原西部的中部为降水量低值区,其向南、向西逐渐增加;东部由其东南部向西北部递减的分布形式。(2)将云贵高原分成两个区域,东、西部区域的降水都呈增加的趋势,降水量较高的区域降水增长速度较快。(3)大气中的水汽从云贵高原南边界和西边边界进入,从北边界和东边界流出,全区以净水汽输出为主,输出值与降水的变化都呈增长趋势。其中东部水汽为净输入;西部为净输出,向各区域的水汽输送量逐渐增加与各区降水量呈增长趋势变化同样相一致。(4)影响西部夏季降水的水汽主要源于孟加拉湾北部、南海北部和横断山到四川盆地地区,而东部水汽主要来自南海北部和四川盆地西部。

Spatio Temporal Characteristics of Precipitation and Water Vapor Resource over the Yunnan Guizhou Plateau in Summer

Based on high resolution (0.5°×0.5°) daily precipitation data from 1961 to 2010, the spatio temporal characteristics of summer rainfall over the eastern, western and whole Yunnan Guizhou Plateau (hereafter YGP) were investigated. Besides, using the European Centre for Medium Range Weather Forecasts (ECMWF) Interim Reanalysis data (ERA Interim hereafter) from 1979 to 2010, we examined the average water vapor flux over the YGP in summer. The results show that the distribution of climatological annual precipitation in YGP is uneven. A dry center is located in the middle of the western YGP and it increases gradually southward and westward. Meanwhile, precipitation over the eastern YGP decreases from southeast to northwest. The YGP is divided into eastern YGP (EYGP) and western YGP (WYGP). The precipitation over the two parts increases with higher increase rate of rainfall. In terms of water vapor transport, it mainly transports from southern and western boundaries to northern and eastern boundaries of the YGP. The whole YGP acts as a water vapor source annually. The net water vapor is positive in EYGP but negative in WYGP. The precipitation, however, increases over both regions. The water vapor over the WYGP is mainly from the northern part of the Bay of Bengal, the northern South China Sea and the area from the Hengduan Mountains to Sichuan Basin. As for the EYGP, the moisture is mainly from the northern South China Sea and western Sichuan Basin.