23 research outputs found
Cloud products from the Earth Polychromatic Imaging Camera (EPIC): algorithms and initial evaluation
This paper presents the physical basis of the Earth Polychromatic Imaging
Camera (EPIC) cloud product algorithms and an initial evaluation of their
performance. Since June 2015, EPIC has been providing observations of the
sunlit side of the Earth with its 10 spectral channels ranging from the UV to
the near-infrared. A suite of algorithms has been developed to generate the
standard EPIC Level 2 cloud products that include cloud mask, cloud effective
pressure/height, and cloud optical thickness. The EPIC cloud mask adopts the
threshold method and utilizes multichannel observations and ratios as tests.
Cloud effective pressure/height is derived with observations from the
O2 A-band (780 and 764 nm) and B-band (680 and 688 nm) pairs. The
EPIC cloud optical thickness retrieval adopts a single-channel approach in
which the 780 and 680 nm channels are used for retrievals over ocean and
over land, respectively. Comparison with co-located cloud retrievals from
geosynchronous earth orbit (GEO) and low earth orbit (LEO) satellites shows
that the EPIC cloud product algorithms are performing well and are consistent
with theoretical expectations. These products are publicly available at the
Atmospheric Science Data Center at the NASA Langley Research Center for
climate studies and for generating other geophysical products that require
cloud properties as input.</p