雅鲁藏布江流域地-气系统的水平衡

利用NCEP/NCAR1980-1989年10年逐日00UTC、12UTC再分析资料及青藏高原降水、径流资料,研究了青藏高原雅鲁藏布江流域的水平衡特征,估算了雅鲁藏布江流域的蒸发、土壤和地下水含量。结果表明:雅鲁藏布江流域夏季是水汽辐合区,降水大于蒸发;秋末到次年春季是水汽通量辐散区,蒸发大于降水。降水主要集中在6～9月。径流的年际变化趋势同降水相近,径流主要是由降水补给的,径流峰值滞后降水峰值一个月。雅鲁藏布江流域土壤及地下含水量从1～6月逐渐减少,7月以后开始增加,10月是土壤及地下水最丰富的时段。20世纪80年代中期和后期降水、蒸发、径流等呈增长趋势,这同ENSO事件有关。

Water Balance in Land-Atmospheric System over the Yalu Tsangpo River Basin

The characteristics of water balance over Yalu Tsangpo River basin in Tibet are researched by using NCEP/NCAR twice daily (0000 and 1200UTC) reanalysis data,monthly runoff and precipitation for the period of 1980-1989,and the evaporation,soil and surface water storage are also estimated.The main results are as follows:(1) the Yalu Tsangpo River basin acts as a r}isture sink from May through October,where precipitation exceeds evaporation,and as a moisture source during NovemberApril,where evaporation exceeds precipitation;(2) in Yalu Tsangpo River basin,precipitation mainly occurs during summer,and runoff,whose peak value lags that of precipitation one month,cheifly supplied by precipitation;(3) the soil and subsurface water storage decreases from January to June,but increases after July and reaches its maximum in October;and (4) over Yalu Tsangpo River basin there are raising trends in precipitation,evaporation,and runoff in late 1980s,which are related to ENSO events.