Hyperspectral Atmospheric Correction using L2gen

Amir Ibrahim1, Bryan A Franz1, Ziauddin Ahmad2, Richard J Healy3 and Bo-Cai Gao4, (1)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (2)Science and Data Systems, Inc., Siver Spring, MD, United States, (3)NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA, Science Applications International Corporation, 10260 Campus Point Drive, San Diego, California, 92121, USA, (4)Naval Research Lab DC, Washington, DC, United States
A feasible hyperspectral Atmospheric Correction (AC) algorithm is necessary to satisfy ocean color science threshold requirements for the Pre-Aerosol, Clouds, and ocean Ecosystem (PACE) mission. An AC algorithm must compensate for gaseous absorption, molecular scattering, and aerosol extinction in the Top of Atmosphere (ToA) radiance measurements, and detect and avoid clouds. L2gen is the multi-sensor Level-1 to Level-2 processing module developed and maintained by NASA's Ocean Biology Processing Group (OBPG) that performs AC and is capable of retrieving ocean color products for multi-spectral sensors. In this work, we present an updated version of l2gen that is capable of performing AC for hyperspectral sensors. The upgrade is based on combining the classical approach of l2gen multi-spectral capabilities to correct for the atmospheric path radiance, with a faster version of the ATmospheric REMoval code (ATREM) to compensate for 7 absorbing gases in the atmosphere, including water vapor. The l2gen-hyperspectral version was tested using the Hyperspectral Imager for Coastal Ocean (HICO) scenes collected at the Marine Optical BuoY (MOBY) site, and other AERosol Robotic NETwork - Ocean Color (AERONET-OC) coastal sites. The new processing capabilities of l2gen is a major step in support of the PACE mission.