Analysis for urban/rural albedo from MODIS over East China

Studies of albedo over urban/rural surface are important to better understand the land surface process in the ABL(atmospheric boundary layer). Urban landscape is the most heterogeneous surface that strongly influences the structure and development of the ABL. In this paper, the directional hemispherical reflectance (black-sky albedo, BSA), the bihemispherical reflectance (white-sky albedo, WSA) and the actual albedo (blue-sky albedo, A) are retrieved from the MODIS BRDF/albedo product (MOD43B1) for three broadbands (0.3- 0.7μm, 0.7-5.0μm, 0.3-5.0μm) in the Changjiang Delta of China. Particular attention is directed to examine the difference of surface albedos over urban and rural areas. The seasonal and spatial variations are investigated. Validation has also been done against field observation and showed that the albedo from MODIS is less than the observed. Albedo in visible broadband (0.3-0.7μm) over urban area is larger than that over rural area, but is less in near infrared broadband (0.7-5.0μm). For the total short broadbrand, it is difficult to reach qualitative conclusion because of urban complexity. The correlations of albedos and NDVI are strongly influenced by the spectral band and land cover. They are positive for the visible and the total broadbands, but negative for the near infrared in same season.

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