Surface reflectance ratios for several land classes in Japan between visible and infrared bands from satellite and sky measurement data

surface reflectance ratios for certain land classes in Japan between the visible and infrared bands were computed using the observed sky radiometer data and several data sets of Terra/MODIS in 2002 and 2003. They were found to be different from those in USA. The values of aerosol optical thickness tau(a) were retrieved from Terra/ASTER and Landsat-7/ETM+ data sets over Japan assuming new surface reflectance ratios. We found a good agreement between the retrieved and observed aerosol optical thickness values at our study site. This study suggested the necessity of further works on local and seasonal variations in surface reflectance ratios.