Validation of the Aatsr Land Surface Temperature Product over Inland Waters and Vegetated Surfaces

The Land Surface Temperature (LST) product of AATSR was validated with in situ measurements at two thermally homogeneous sites: Lake Tahoe, CA/NV, USA and a large rice field close to Valencia, Spain. The AATSR LST product is based on the split-window technique using the nadir view of the 11 and 12 μm channels. The algorithm coefficients are provided for 13 different land cover classes plus one lake class (denoted by an index i) and weighted by the vegetation cover fraction (f). In the operational implementation of the algorithm, i and f are assigned from a global classification and monthly fractional vegetation cover maps at spatial resolution of 0.5o×0.5o. Since this area is much larger than the size of the validation sites, they are misclassified in the operational LST product so the AATSR LST algorithm was applied to the brightness temperatures extracted from the L1b data for the two test sites using the appropriate coefficients for each case. The comparison of the ground measured LSTs with the AATSR derived LSTs showed an excellent agreement for both sites, with nearly zero average biases, and standard deviations ≤0.5 oC.