NAVAL RESEARCH LAB WASHINGTON DC WASHINGTON United States
We present an algorithm for retrieving aerosol layer height ALH and aerosol optical depth AOD for smoke over vegetated land and water surfaces from measurements of the Earth Polychromatic Imaging Camera EPIC onboard the Deep Space Climate Observatory DSCOVR. The algorithm uses Earth-reflected radiances in six EPIC bands in the visible and near-infrared and incorporates flexible spectral fitting that accounts for the specifics of land and water surface reflectivity. The fitting procedure first determines AOD using EPIC atmospheric window bands 443, 551, 680, and 780 nm, then uses oxygen O-2 A and B bands 688 and 764 nm to derive ALH, which represents an optical centroid altitude. ALH retrieval over vegetated surface primarily takes advantage of measurements in the O-2 B band. We applied the algorithm to EPIC observations of several biomass burning events over the United States and Canada in August 2017. We found that the algorithm can be used to obtain AOD and ALH multiple times daily over water and vegetated land surface. Validation is performed against aerosol extinction profiles detected by the Cloud-Aerosol Lidar with Orthogonal Polarization CALIOP and against AOD observed at nine Aerosol Robotic Network AERONET sites, showing, on average, an error of 0.58 km and a bias of -013 km in retrieved ALH and an error of 0.05 and a bias of 0.03 in retrieved AOD. Additionally, we show that the aerosol height information retrieved by the present algorithm can potentially benefit the retrieval of aerosol properties from EPICs ultraviolet UV bands.
Journal Article - Open Access
Atmospheric Measurement Techniques , 12, 6, 01 Jan 0001, 01 Jan 0001, [ 1 ] Univ Iowa, Ctr Global and Reg Environm Res, Dept Chem and Biochem Engn, Iowa City, IA 52241 USA[ 2 ] Univ Iowa, Informat Initiat, Iowa City, IA 52241 USA[ 3 ] Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA[ 4 ] Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA[ 5 ] NASA, Goddard Space Flight Ctr, Atmospher Chem and Dynam Lab, Greenbelt, MD 20770 USA[ 6 ] Naval Res Lab, Marine Meteorol Div, Monterey, CA 93943 USA[ 7 ] Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA