Abstract: Based on the parameterization of downward shortwave radiation, upward shortwave radiation, downward longwave radiation and upward longwave radiation above the surface, a scheme is proposed to estimate instantaneous net radiation over arid and semiarid areas for clear sky days using only remote sensing observations. The scheme attempts to eliminate the need for ground meteorology data as the estimates of land surface radiation balance, by using various land and atmospheric data products available from moderate resolution imaging spectroradiometer(MODIS). The preliminary results, using 89 cases over the degraded grassland and 85 cases over the farmland during July to October in 2003, July to November in 2004 and June to October in 2005, show good agreement with ground-based observations, with the root mean square error of 47. 5 and 49. 2 W/m² respectively, which have better accuracies than the other similar studies.

Key words: MODIS, farmland, degraded grassland, arid and semiarid, net radiation

摘要： 通过对地表处向下短波辐射、向上短波辐射、向下长波辐射和 向上长波辐射通量的4个能量收支分量的参数化, 利用多个MODIS 陆地和大气产品, 给出一个不需要地面观测气象数据, 仅用卫星遥感数据来计算晴空条件下干旱与半干旱地表上的净辐射通量计算方案。方案计算了2003 年7?10 月、2004 年 7?11 月及 2005 年 6?10月期间退化草地 89 个晴空数据和农田85个晴空数据, 与地面观测数据对比表明方案能有效计算净辐射通量, 均方根误差达到 47. 5 和49. 2 W/m², 优于国内外同类研究的精度。

关键词: MODIS, 农田, 退化草地, 干旱与半干旱, 净辐射