青藏高原地区MODIS反照率的精度分析

摘要

应用2002-2004年青藏高原CAMP／Tibet试验期间4个地面站点的反照率观测结果定量分析Te丌aMODISlkm分辨率短波SW波段（0．3—5．0μm）反照率全反演结果和当量反演结果的精度。对于全反演结果，黑空反照率、白空反照率与地面观测结果的均方根差分别为0．0187和0．0168；对于当量反演结果，黑空反照率、白空反照率与地面观测结果的均方根差分别为0．0766和0．0761。综合全反演结果和当量反演结果，则黑空反照率、白空反照率与地面观测结果的均方根差分别为0．0679和0．0675。当地面观测结果与MODIS反照率当量反演结果均为“无雪”状态时，黑空反照率、白空反照率与地面观测结果的均方根差分别为0．0352和0．0364；当地面观测结果为“积雪”状态，MODIS反照率当量反演结果为“无雪”状态时，黑空反照率、白空反照率与地面观测结果的均方根差分别高达0．1556和0．1541。%Using ground-observed albedos from four stations over the Tibetan Plateau from 2002 to 2004 in the CAMP/Tibet experiments, the accuracies of Terra MODIS ( MODerateesolution Imaging Spectroradiometer) shortwave bands(0. 3-5.0 μ m) albedos in 1 km resolution derived with the full inversion and the magnitude inversion are individually quantitatively assessed. When MODIS albedos are derived with the full inversion,the root-mean-square errors(RMSEs) between the ground-observed albedos and the black-sky albedos(BSA) ,and the white-sky albedos(WSA) are 0. 018 7 and 0. 016 8 ,respectively; when MODIS albedos are derived with the magnitude inversion, they are 0. 076 6 and 0. 076 1, respectively. And, when MODIS albedos derived with the full inversion and the magnitude inversion are all included, the RMSEs are 0. 067 9 and 0. 067 5, respectively. When the ground-observed albedos and MODIS albedos derived with the magnitude inversion are both from the no-snow condition, RMSEs between the ground-observed albedos and BSA, and WSA derived with the magnitude inversion are 0. 035 2 and 0. 036 4, respectively. However, when the ground-observed albedos are fromthe snowy condition, while MODIS albedos derived with the magnitude inversion are from the no-snow condition,RMSEs between the ground-observed albedos and BSA, and WSA derived with the magnitude inversion are 0. 155 6 and 0. 154 1.