PROJECT TITLE :

Atmospheric Correction of AISA Measurements Over the Florida Keys Optically Shallow Waters: Challenges in Radiometric Calibration and Aerosol Selection

ABSTRACT:

An Airborne Imaging Spectrometer for Applications (AISA) hyperspectral imager was deployed on a manned aircraft flown at 1305-m altitude to collect information over optically shallow waters within the Florida Keys with the ultimate goal of mapping water quality and benthic habitats. As a initial step, we have a tendency to developed a practical atmospheric correction (AC) approach to derive surface remote-sensing reflectance (Rrs) from AISA measurements using radiative transfer simulations and constraints obtained from field spectral Rrs measurements. Unlike previously published technique, the AC approach removes the surface Fresnel reflection and accounts for aircraft altitude and nonzero near-infrared (NIR) reflectance through iteration over the pre-established lookup tables (LUTs) based on MODTRAN calculations. Simulations and comparison with concurrent in situ Rrs measurements show the feasibility of the approach in deriving surface Rrs with acceptable uncertainties. The possibility of errors within the radiometric calibration of AISA is demonstrated, though a definitive assessment cannot be created thanks to lack of enough concurrent in situ measurements. The necessity for noise reduction and the problem in finishing up a vicarious calibration are also discussed to help advance the planning of future AISA missions.