伊犁河流域水汽含量时空变化及其和降水量的关系

Spatial-temporal Variation of Water Vapor and Its Relationship with the Precipitation in the Ili River Basin

利用1976—2006年伊宁探空站的实测资料计算了逐月水汽含量,结合地面水汽压建立适合于伊犁河流域的W-e模型,结合DEM重建了1961—2009年伊犁河流域的月均水汽含量,利用EOF和交叉谱方法分析水汽含量和降水量的时空分布特征,并分析夏季干湿年、典型强降水过程中水汽输送特征。结果表明:大气水汽含量在空间分布上表现为西部多于东部、平原多于山地、迎风坡大于背风坡,下游平原及上游河谷地带是高值区,水汽含量在13～15mm,这与地形和绿洲城镇的分布有关;在850hPa至700hPa的高度上存在一个最大水汽含量带,对应海拔约2 000m。水汽含量年代际变化呈上升趋势,夏季增加明显(0.48mm/10a)。降水量和水汽含量标准化场EOF分解表明两者的时空分布极为相似,存在气候振动的一致性和河谷南北相反的分布型式。雨季水汽含量源地以热带海洋为主,同时也受北冰洋为源地的西北向水汽输送的影响。

We calculated monthly water vapor content using measurement data in 1976-2009 from Yining radiosonde station,and established W-e model suitable for the Ili River basin with ground vapor pressure,calculated the water vapor content in the Ili River basin in 1961-2009 combining with the DEM data,analyzed the temporal and spatial distribution characteristics of water vapor and precipitation with EOF and cross spectrum method,and researched water vapor transport characteristics during typical strong precipitation process in summer in dry and wet years.In the Ili River basin,the water vapor content at the west is more than at the east,the plain is more than the mountain,the windward slope is more than leeward slope,and downstream plain and upstream valley areas are high value areas with water vapor content of 13-15 mm.It is related to the terrain and distribution of the oasis towns.At 850 hPa and 700 hPa height,there is a maximum water vapor area,corresponding to an altitude around 2 000 m.Water vapor increased at inter-decadal scale and increased obviously in summer（0.48 mm/10a）.Precipitation and water vapor EOF decomposition standardization fields show that their temporal and spatial distributions are extremely similar,and there are distribution types of climate vibration consistency and north-south opposite distribution type for the river valley.The fountainheads of water vapor give priority to Tropical Marine in rainy season,and water vapor content also is influenced by water vapor transmission from the Arctic Ocean.