Comparison of MODIS surface reflectance with mast-based spectrometer observations using CORINE20001and cover database

In this work we compared the MODIS surface reflectance observations with the spectrometer measurements made from the 30 m high mast set up at Sodankyla. Combining MODIS data from wider area around the mast location with the information of land cover types found in high resolution (25 m*25 m) CORINE2000 database we were able to retrieve the reflectance of coniferous forests, which is the land cover type around the tower. As a result we found a good co-variation between the reflectance values of MODIS and the mast-based spectrometer although there was a consistent low bias in MODIS values. The effect of aerosol content in the atmosphere on the biases between two instruments was studied and a significant correlation was found between the biases and the AOD values.