Atmospheric Correction of Hyperspectral GCAS Airborne Measurements Over the North Atlantic Ocean and Louisiana Shelf

The Geostationary Coastal and Air Pollution Events Airborne Simulator (GCAS) instrument has been used as a precursor for a hyperspectral instrument on the future geostationary satellite, yet its ability to “measure” ocean reflectance needs to be evaluated. Here, we demonstrate its capacity through v...

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Bibliographic Details
Published in:IEEE Transactions on Geoscience and Remote Sensing
Main Authors: Zhang, Minwei, Hu, Chuanmin, Kowalewski, Matthew G., Janz, Scott J.
Format: Article in Journal/Newspaper
Language:unknown
Published: Digital Commons @ University of South Florida 2018
Subjects:
Atmospheric measurements
Sea measurements
Atmospheric modeling
Calibration
Pollution measurement
Oceans
MODIS
Life Sciences
North Atlantic
Online Access:https://digitalcommons.usf.edu/msc_facpub/1996
https://doi.org/10.1109/TGRS.2017.2744323
Description
Summary:The Geostationary Coastal and Air Pollution Events Airborne Simulator (GCAS) instrument has been used as a precursor for a hyperspectral instrument on the future geostationary satellite, yet its ability to “measure” ocean reflectance needs to be evaluated. Here, we demonstrate its capacity through vicarious calibration and atmospheric correction of data collected during flight campaigns over the Louisiana shelf in September 2013 and over the North Atlantic Ocean in November 2015. GCAS-measured at-sensor radiance was first vicariously calibrated using concurrent measurements by the Moderate Resolution Imaging Spectrometer (MODIS) and radiative transfer simulations with the MODerate resolution atmospheric TRANsmission (MODTRAN). Then, atmospheric correction has been implemented using MODTRAN-developed lookup tables and the traditional Gordon and Wang “black pixel” approach but with nonzero water-leaving radiance in the near-infrared accounted for through iteration. The atmospheric correction algorithm was applied to the vicariously calibrated GCAS imagery, with resulting R rs compared with concurrent MODIS R rs and in situ R rs . The comparison shows a mean relative difference of about 25% (N = 11) between GCAS and in situ R rs in the blue-green bands for clear to moderately turbid waters.

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