Analysis Of The Surface Albedo Distribution And Variation In Beijing Region With The MODIS Data

Using MODIS surface albedo (MOD43B3), vegetation indices (MOD13A2), and land cover (MOD12Q1) and products in the period of 2000-2005. the spatial and temporal distribution of surface albedo over Beijing region are investigated. Temporal variation surface albedo during 2000-2005 was calculated, and the relationship between the NDVI and surface albedo was checked. The results show that the surface albedo is lower in northwest mountainous area (0.11) than that in southeast plain (0.15). The albedo over Beijing urban area (0.12) is nearly equal in summer and autumn. The albedo over the Yongding River basin demonstrates high value (0.18) for its lower vegetation cover. According to the topography and vegetation cover around Beijing area, we also find that the NDVI is negatively related to the surface albedo, and the data show that the surface albedo is descending in most part of Beijing during the six years, but ascending in mountainous areas and the urban area.In addition, we also calculated the surface albedo and vegetation indices with 16 days cycle during 2000-2005. The results show that the surface albedo is distinctively high around Beijing area in winter during the year of 2000,2003 and 2005. The albedo over Yongdinghe River basin is obviously high, the highest value(0.56) presents to the year of 2001 in winter. The annual change of seasonal albedo over Beijing urban area is nearly equal to the mountainous area. The vegetation indices demonstrate that the seasonal change is obvious, and the vegetation cover over Beijing urban is very lower.Finally, we investigate the spectrum albedo of representative content over Beijing area. We found that the albedo value of different content take on a stated law. Along with the wave band from visible light to near infrared, the value of spectrum curve is ascending, the highest value is in 1.24μm spectrum, and it shows the downtrend later. The yearly average shows that the albedo in visible light is nearly consistent in cropland and urban. The albedo begins to ascend to thetiptop in 1.24um spectrum and then reduce gradually. According to the different spectrum albedo curve in the four seasons, we discover the spectrum curve is nearly identical in spring and autumn, the highest value is about 0.25, and in summer the wave is evident, especially in near infrared, the value express 0.3 in farmland. This is explaining that the chroma is high, and the active nature is great. But the curve is relatively even in winter, it is related to the vegetation cover and ground snow.