Analysis And Improvement Of MODIS Albedo Retrieval Quality Over The Tibetan Plateau

Albedo is an important surface parameter that affects the balance of radiation budget of the earth-atmosphere system. The Tibetan Plateau (TP) has a significant impact on the severe weather of our country and Asia, even though the global climate change. MCD43, the MODIS global surface albedo product, so far is the only satellite remote sensing retrieval services product, which can provide high spatial and temporal resolution of surface albedo near real-time over TP. Comprehensive understanding of the spatial and temporal distribution of MODIS albedo retrieval quality over TP is helpful to further understanding the retrieval accuracy of MCD43.With more superior potential applications than MODIS, the high-resolution earth observation instrument carried on China’s new generation of polar-orbiting meteorological satellite FY-3, MERSI, basically has the same spectral channel settings as MODIS. Enhancing the continuity of spatial and temporal distribution and shortening the inversion period of albedo inversion products by the improvement of inversion method with combined multi-angle observations from MERSI and MODIS, to promote the joint inversion research of observations from meteorological satellite, which is very important for scientific research and application.The main work of this paper includes:(1) The status of MODIS albedo retrieval quality on TP. In this paper, the temporal and spatial distribution of retrieval quality on TP form 2003 to 2013 is statistical analyzed with MCD43B2, the MODIS albedo retrieval quality product. The results show that:almost with no annual difference, the average retrieval efficiency is 91% on TP; Differences of the efficiency in different inversion period is relatively large, the efficiency in winter and summer is lower than other seasons due to snow and rainfall; the average proportion of high-quality inversions is 65%, and reduced to 16% within snow statue; the spatial distribution of albedo is uneven, and there is a very distinct geographical distribution on TP.(2) Spectral fusion of MERSI and MODIS inversions. Anisotropic correction is firstly done with MODIS inversions in this paper to eliminate the effects of different viewing angles of different sensors, in which way, the MODIS data with the same viewing angles of MERSI can be obtained; then, based on the statistical fit, the spectral fusion is achieved by the acquired spectral conversion equations of MERSI and MODIS under different surface types, to eliminate the influence of spectral response function on both observations.(3) The improvement of albedo inversion method by combining MERIS and MODIS observations. The spectral fusion with MERSI and MODIS observations is firstly conducted of different spectral conversion equations under different surface types, and then, albedo is inversed with reflectance observed by MODIS. In this paper,3 group comparison inversion experiments are set up. The results show that: more clear sky observations can be got in a short period with combined inversion. Not only the continuity of the spatial distribution of the inversions can be improved, but also the inversion period can be shorten.