【摘要】 基于DEM与G IS空间分析功能研究了石羊河流域主要农作物春小麦需水量ETc的时空分异规律。根据8个气象站近50年气象资料,应用1998年FAO推荐的Penm an-M on te ith公式计算参考作物蒸发蒸腾量ET0,由收集到的春小麦需水量试验资料获得多年平均作物系数Kc。近50年来流域上游的古浪、天祝春小麦全生育期ETc呈微弱的增加趋势,中游的凉州区表现出极显著的减少趋势,其他站减少趋势不显著。确立了ETc与海拔高度、纬度、坡向的多元回归关系,借助A rcv iew 3.3、A rcG IS9.0与V isua l B as ic6.0软件实现了春小麦ETc的空间尺度转换,并分析了石羊河流域25%、50%、75%三个不同水文年春小麦ETc的空间变异情况。石羊河流域春小麦ETc由山区向绿洲平原递增,多年平均值为270~591 mm。估计值与计算值相差在11.1%以内。更多还原

【Abstract】 DEM-based and GIS-assisted methods were employed to estimate the temporal and spatial variation of spring wheat evapotranspiration（ET_c） in Shiyang River Basin.Based on the data collected from eight meteorological stations in the Basin in recent 50 years,the reference crop evapotranspiration（ET₀） was calculated with the Penman-Monteith equation recommended by FAO in 1998.Crop coefficient（K_c） was calculated from selected experimental data for spring wheat evapotranspiration.In recent 50 years,ET_c values were gently increased in Gulang and Tianzhu in the upper reaches,while in Liangzhou in the middle reaches,the decreasing trend was greatly significant,and in other regions,the decreasing trend was not so significant.The multiple regression equation between ET_c and altitude,latitude,and aspect of slope was established.Spatial distribution of spring wheat ET_c in the Basin was obtained with Arcview3.3,ArcGIS9.0 and Visual Basic 6.0,and its spatial variations in different hydrological years of 25%,50% and 75% were analyzed.The results show that,spatial variation of ET_c was significant （from 270 mm to 591 mm） with the trend increasing from mountainous area to oasis plain in the Basin.The relative error between the calculated and estimated values of ET_c was within 11.1%.更多还原