为了更加全面地了解青藏高原MODIS地表反照率的反演质量,利用2003-2013年MODIS地表反照率数据MCD43B2统计分析了该产品在青藏高原的反演效率和反演质量。结果表明:(1)各周期的平均反演效率均超过80%,冬、夏季节的反演效率较低,春、秋季节则较高,最高可达90%以上;(2)所有反演结果中,高质量全反演结果的比例最高,且在春、秋季节较高,最高约为80%,而冬、夏季节较低,最低时略高于50%;(3)"无雪"状态反演结果的平均比例介于70%~95%,且以高质量全反演结果为主,而"积雪"状态反演结果的平均比例约为10%,且以当量反演结果为主。这些结果表明该产品可以为青藏高原绝大部分区域提供时空分布连续的高精度地表反照率,但冬、夏季节的反演效率和反演结果的精度,以及"积雪"状态下反演结果的精度,都还有待提高。
For a comprehensive understanding of the retrieval quality of MODIS land surface albedo(LSA)product in the Qinghai-Xizang Plateau,it is statistically analyzed with MCD43B2,the retrieval quality data accompanied with the MODIS LSA,in this paper,and results are as following:(1)the mean retrieval effectiveness(MRE)in each retrieval period is above 80%. The MREs are low in winter and summer,while MREs are high to more than 90% in spring and autumn.(2)Among all LSAs,those with the best quality of full inversions(BQFI)have the highest percentage. The percentages of LSAs with the BQFI in spring and autumn are high and the highest one is nearly up to 80%. Meanwhile,the percentages of LSAs with the BQFI in winter and summer are low and the lowest one is a little more than 50%.(3)The mean percentage for snow-free LSAs is between70% and 95%,and the snow- free LSAs are mainly those with the BQFI. However,the mean percentage for snow LSAs is about 10%,and the snow LSAs are mainly derived with the magnitude inversion. All above indicate that MODIS LSA product could provide spatio-temporal continuousness,high-accuracy LSA for most area of the Qinghai-Xizang Plateau,but the MREs and the accuracy in winter and summer,as well as the accuracy of the snow LSAs should be further improved in the future.