中国地区MODIS反照率两种反演结果的比较

以2002-2004年中国地区Terra MODIS数据开展对照反演试验,获得大范围具有相同时空代表性的反照率全反演结果和当量反演结果,统计分析MODIS反照率两种反演结果的差异,结果表明:在MODIS 1-7波段及可见光、近红外和短波波段,黑空反照率、白空反照率的当量反演结果与全反演结果的绝对偏差均小于0.05,且黑空反照率两种反演结果的绝对偏差明显小于白空反照率两种反演结果的绝对偏差;MODIS反照率两种反演结果在红外波段的绝对偏差大于其在可见光波段的绝对偏差;夏季MODIS反照率两种反演结果的绝对偏差最大,秋季则最小.

Analysis of the differences between the two kinds of MODIS albedos over China

To examine the differences between the albedos separately derived with the full inversion (FI) and the magnitude inversion (MI) over large area, a couple of contrastive inversion experiments were conducted with the Terra MODIS data of years 2002-2004 over China to achieve two different kinds of MODIS albedos under the same temporal and spatial circumstances. The statistical analyses revealed that: The absolute biases between the FI and MI albedos, including the black-sky albedo (BSA) and the white sky-albedo (WSA), were all less than 0.05 for the MODIS bands 1-7 and the three broad bands, i.e. the visible (VIS), the near infrared (NIR) and the shortwave (SW), and the absolute biases for BSA were distinctly less than those for WSA; the differences between the FI and MI albedos derived at infrared bands were larger than those derived at visible bands; the differences between the FI and MI albedos in summer were the largest among four seasons, while those in autumn were the smallest.