农田蒸散量模型构建及蒸散状况分析

笔者以辽宁省为例，利用1981~2002年间18个代表站点常规气象资料与土壤湿度观测资料，建立了不同供水条件下农田蒸散量的模拟模型，计算了自然条件下的农田蒸散量的变化。结果表明，辽宁省农田蒸散量年内呈单峰形变化，峰值出现在玉米抽雄开花期。农田蒸散量区域分布中间高四周低，趋势与自然降水分布不一致。农田蒸散量年际间呈波动性变化，多水年农田蒸散量明显高于正常年，90年代辽宁中部、辽东、辽南、辽北地区农田蒸散量呈逐年上升趋势，辽西地区农田蒸散量呈逐年下降趋势。

Analysis of Field evapotranspiration status in liaoning Province

The paper is a case study in liaoning,On the base of the routine weather data and the constant observational data of soil moisture for 18 representative stations during 1981~2002, the field actual evapotranspiration dynamic model of five regions in the Liaoning province was established under different supply water. By using the function relationship, the actual evapotranspiration was calculated in natural condition in lianning .The Results showed that the annual change of the actual evapotranspiration was in single-peak type,the peak value occurred during booting flower stage of corn.The regional distribution of the actual evapotranspiration was higher midst than all around,the trend of regional distribution of evapotranspiration didn’t conform to that of natural precipitation.The field actual evapotranspiration wave during 1981~2002, It is the higher the field actual evapotranspiration of the more precipitation year than that of the natural precipitation year, the actual evapotranspiration is appearing the increasing tendency in the central, eastern,southern and northern region of Liaoning province in 1990s,but the actual evapotranspiration is appearing the descending tendency in the western region of Liaoning province in 1990s.