{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,16]],"date-time":"2025-10-16T13:57:51Z","timestamp":1760623071583,"version":"build-2065373602"},"reference-count":18,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2018,2,7]],"date-time":"2018-02-07T00:00:00Z","timestamp":1517961600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>NASA\u2019s Earth Polychromatic Imaging Camera (EPIC) onboard NOAA\u2019s Deep Space Climate Observatory (DSCOVR) satellite observes the entire sunlit Earth every 65 to 110 min from the Sun\u2013Earth Lagrangian L1 point. This paper presents initial EPIC shortwave spectral observations of the sunlit Earth reflectance and analyses of its diurnal and seasonal variations. The results show that the reflectance depends mostly on (1) the ratio between land and ocean areas exposed to the Sun and (2) cloud spatial and temporal distributions over the sunlit side of Earth. In particular, the paper shows that (a) diurnal variations of the Earth\u2019s reflectance are determined mostly by periodic changes in the land\u2013ocean fraction of its the sunlit side; (b) the daily reflectance displays clear seasonal variations that are significant even without including the contributions from snow and ice in the polar regions (which can enhance daily mean reflectances by up to 2 to 6% in winter and up to 1 to 4% in summer); (c) the seasonal variations of the sunlit Earth reflectance are mostly determined by the latitudinal distribution of oceanic clouds.<\/jats:p>","DOI":"10.3390\/rs10020254","type":"journal-article","created":{"date-parts":[[2018,2,7]],"date-time":"2018-02-07T12:20:29Z","timestamp":1518006029000},"page":"254","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["EPIC Spectral Observations of Variability in Earth\u2019s Global Reflectance"],"prefix":"10.3390","volume":"10","author":[{"given":"Weidong","family":"Yang","sequence":"first","affiliation":[{"name":"Goddard Earth Sciences Technology and Research, Universities Space Research Association, Columbia, MD 21046, USA"},{"name":"NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA"}]},{"given":"Alexander","family":"Marshak","sequence":"additional","affiliation":[{"name":"NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7419-2522","authenticated-orcid":false,"given":"Tam\u00e1s","family":"V\u00e1rnai","sequence":"additional","affiliation":[{"name":"NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA"},{"name":"Joint Center for Earth System Technology, University of Maryland at Baltimore County, Baltimore, MD 21250, USA"}]},{"given":"Yuri","family":"Knyazikhin","sequence":"additional","affiliation":[{"name":"Department of Earth and Environment, Boston University, Boston, MA 02215, USA"}]}],"member":"1968","published-online":{"date-parts":[[2018,2,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1016\/j.jqsrt.2012.09.017","article-title":"A Method of Retrieving Cloud Top Height and Cloud Geometrical Thickness with Oxygen A and B bands for the Deep Space Climate Observatory (DSCOVR) Mission: Radiative Transfer Simulations","volume":"122","author":"Yang","year":"2013","journal-title":"J. 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