Earth Observations from DSCOVR EPIC Instrument
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Author/Creator ORCID
Date
2018-09-01
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Citation of Original Publication
Marshak, Alexander, Jay Herman, Szabo Adam, Blank Karin, Simon Carn, Alexander Cede, Igor Geogdzhayev, Dong Huang, Liang-Kang Huang, Yuri Knyazikhin, Matthew Kowalewski, Nickolay Krotkov, Alexei Lyapustin, Richard McPeters, Kerry G. Meyer, Omar Torres, and Yuekui Yang. "Earth Observations from DSCOVR EPIC Instrument", Bulletin of the American Meteorological Society 99, 9 (2018): 1829-1850, accessed Jan 11, 2023, https://doi.org/10.1175/BAMS-D-17-0223.1
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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
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Abstract
The National Oceanic and Atmospheric Administration (NOAA) Deep Space Climate Observatory (DSCOVR) spacecraft was launched on 11 February 2015 and in June 2015 achieved its orbit at the first Lagrange point (L1), 1.5 million km from Earth toward the sun. There are two National Aeronautics and Space Administration (NASA) Earth-observing instruments on board: the Earth Polychromatic Imaging Camera (EPIC) and the National Institute of Standards and Technology Advanced Radiometer (NISTAR). The purpose of this paper is to describe various capabilities of the DSCOVR EPIC instrument. EPIC views the entire sunlit Earth from sunrise to sunset at the backscattering direction (scattering angles between 168.5° and 175.5°) with 10 narrowband filters: 317, 325, 340, 388, 443, 552, 680, 688, 764, and 779 nm. We discuss a number of preprocessing steps necessary for EPIC calibration including the geolocation algorithm and the radiometric calibration for each wavelength channel in terms of EPIC counts per second for conversion to reflectance units. The principal EPIC products are total ozone (O₃) amount, scene reflectivity, erythemal irradiance, ultraviolet (UV) aerosol properties, sulfur dioxide (SO₂) for volcanic eruptions, surface spectral reflectance, vegetation properties, and cloud products including cloud height. Finally, we describe the observation of horizontally oriented ice crystals in clouds and the unexpected use of the O₂ B-band absorption for vegetation properties.