西部部分地区农田实际蒸散量分布特征

Distribution Characters of Actual Evaportranspiration onCrop Fields in Western China

利用我国西部五省16个农业气象站9年的土壤湿度资料,采用土壤水分平衡法估算了农田实际蒸散量,结合干燥度的计算,分析了时间和空间上的分布特点。结果表明:各地农田实际蒸散量与降水量的变化基本一致:从东南向西北随着干燥度的上升(降水量的减少),农田实际蒸散量逐步增加,其超过降水量的部分逐步增大,说明西部地区农田实际蒸散量的大小与灌溉及降水量密切相关。

Based on soil moisture data for 9 years at 16 agro-meteorological stations in the five Provinces of Western China, the actual evapotranspiration on the crop fields was estimated by using soil water balance equation and examined by calculating the dry index. The temporal and spatial distributions of evapotranspiration on the crop fields were discussed. The results showed that the changes of actual evapotranspiration on the crop fields accorded with the changes of precipitation. The actual evapotranspiration on the crop fields increased gradually as the dry indices increased from southeast to northwest. The greater the increment of the actual evapotranspiration on the crop fields had, the larger the required water amount for the actual evapotranspiration on the crop fields depended on the irrigation. As conclusion, the actual evapotranspiration on the crop fields in the Western China is closely related to precipitation and irrigation.