Shortwave reflected energy from NISTAR and the Earth Polychromatic Imaging Camera onboard the DSCOVR spacecraft
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Author/Creator ORCID
Date
2023-08-09
Type of Work
Department
Program
Citation of Original Publication
Weaver, Clark Jay, Jay Herman, Alexander Marshak, Steven R. Lorentz, Yinan Yu, Allan W. Smith, and Adam Szabo. “Shortwave Reflected Energy from NISTAR and the Earth Polychromatic Imaging Camera Onboard the DSCOVR Spacecraft.” EGUsphere, August 9, 2023, 1–18. https://doi.org/10.5194/egusphere-2023-638.
Rights
This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
Public Domain Mark 1.0
Public Domain Mark 1.0
Subjects
Abstract
We describe a new method for estimating the total reflected shortwave energy from the Earth Polychromatic Imaging Camera (EPIC) and compare it with direct measurements from the NIST Advanced Radiometer (NISTAR) instrument (Electrical substitution radiometer) - both are onboard the Lagrange-1 orbiting Deep Space Climate Observatory (DSCOVR). The 6 narrow-band wavelength channels (340 to 780 nm) available from EPIC provide a framework for estimating the integrated spectral energy for each EPIC pixel. The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and the SCIAMACHY instrument provide spectral information away from the EPIC wavelengths, particularly for wavelengths longer than 780 nm. The total area-weighted reflected shortwave energy from an entire EPIC image is compared with co-temporal Band B Shortwave reflected energy observed by NISTAR. Our analysis from March to December 2017 shows the two are highly correlated with differences ranging from -10 to 10 Watts m⁻². The offset bias over the entire period is less than 0.2 Watts m⁻². We also compare our EPIC energy maps with the Clouds and the Earth's Radiant Energy System (CERES) Single Scanner Footprint (SSF) Shortwave (SW) reflected energy observed within 3 hours of an EPIC image. Our EPIC-AVIRIS SW estimate is 5-20 % higher near the EPIC image center and 5-20 % lower near the image edges compared with the CERES SSF.