GOSAT TANSO-CAI L1B and L1B+ Products

摘要

GOSAT (IBUKI) has TANSO-CAI instrument for observing the optical properties of aerosols and clouds. CAI has 4 bands (380nm, 674nm, 870nm, 1600nm), band 1 to 3 have 500m spatial resolution at nadir direction and 1000km observation width, and band 4 has 1500m spatial resolution and 750km observation width. Geometric information (latitude and longitude of all pixels) is calculated by ortho correction method using altitude data. Radiance data are converted using prelaunch calibration constants. In CAI Level 1 B+ product, radiance data are projected to map using polar stereographic projection for higher than 60 degree latitude, and using Mercator projection for lower than 60 degree latitude. Band 2 and 3 has variations of radiance offset which is proportional to the average of the all pixels' incident radiance. Radiance offset variation is corrected using the radiance value of the corner pixels which are not exposed to light but varies with incident radiance.