Towards An Improved Long-term Data Record From The Advanced Very-high Resolution Radiometer: Evaluation, Atmospheric Correction, And Intercalibration

Abstract

Long-term data records from satellite observations are crucial for the study of land surface properties and their long-term dynamics. The AVHRR long term data record (LTDR) is an ongoing effort to generate a consistent climate record of daily atmospherically corrected observations with global coverage that is suitable for long term studies of the Earth surface. In this dissertation, I identified three areas for the improvement of the LTDR: (1) The comprehensive evaluation of the LTDR performance and characterization if its uncertainties. (2) The retrieval of water vapor information from AVHRR data for a more accurate atmospheric correction. (3) The recalibration of the record to address inconsistency issues. The first study consisted on a global long-term evaluation of the LTDR with matched observations from the Landat-5 Thematic Mapper instrument. Results from this evaluation showed that the record performance was close to the proposed specification. The second study proposed a method for the retrieval of water vapor from AVHRR data, which provides a crucial input for the atmospheric correction process. Evaluation of the retrieved values with reference datasets showed excellent results, with a water vapor error lower than 0.45g/cm2. Finally, the last chapter proposed a novel method for the selection of stable areas suitable for satellite intercalibration and for the derivation of recalibration coefficients. The evaluation of the original and recalibrated record showed that for most cases the recalibrated record performed better.