Abstract:

By using meteorological data of Dingxi region and EOS／MODIS data，some basic surface parameters and the net radiation of earth’ssurface in the dry-farming region in Northwest China are derived，moreover，the seasonal variety of the net radiation ofearth’s surface is analyzed.The results show that the derived value is close to the observed value，the relative error is less than 16%，which means the derived value may reflect the factin stance；the seasonal variety of the net radiation is least in winter and most in summer and spring，and there is a symmetrical feature of its distribution in different seasons，its frequency distribution range is also
wide in this dry-farming region

Key words: EOS／MODIS, the dry-farming region inNorthwest China

摘要：

应用定西地区的气象资料和4次EOS-MODIS卫星资料，对典型的西北半干旱雨养农业区的基本地表特征参数进行反演，并在此基础上对地表净辐射量进行估算，进而分析了它的季节变化。结果表面，应用卫星数据估算的净辐射结果与实际观测值基本接近，相对误差在16%以内，基本反映了当地的实际情况；雨养农业区净辐射的季节变化表现为冬季最小，其次是秋季，夏春两季最大，并且四季相差比较大；净辐射四季变化也呈现出不均匀的分布特性，频率分布范围较宽。

关键词: 净辐射, EOS-MODIS, 西北雨养农业区