Using Deep Space Climate Observatory Measurements to Study the Earth as an Exoplanet

Jiang, Jonathan H.; Zhai, Albert J.; Herman, J. R.; Zhai, Chengxing; Hu, Renyu; Su, Hui; Natraj, Vijay; Li, Jiazheng; Xu, Feng; Yung, Yuk L.

doi:10.3847/1538-3881/aac6e2

Cited by 51 publications

(76 citation statements)

References 52 publications

(56 reference statements)

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“…Similar contribution values are also observed using <R> 1 (which shows about the same percentage increase in UV and about 1% more increase for longer wavelengths during winter and summer). This conclusion is very consistent with Jiang et al [12], who found that Antarctica reflects more sunlight than the Arctic during their respective summers. In addition, excluding polar regions does not change the daily averages during the equinoxes (22 September and 22 March), when polar regions occupy only very small fractions of the EPIC field of view.…”

Section: Effects Of Polar Regionssupporting

confidence: 92%

“…In addition, since the EPIC measures the reflectance from Earth in the nearly backward direction (no shadows are observed), these observations can provide additional information for studying the radiative properties of vegetation surfaces [5]. Furthermore, these observations and analysis provide useful information for studying Earth-like exoplanets [8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

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EPIC Spectral Observations of Variability in Earth’s Global Reflectance

et al. 2018

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NASA's Earth Polychromatic Imaging Camera (EPIC) onboard NOAA's Deep Space Climate Observatory (DSCOVR) satellite observes the entire sunlit Earth every 65 to 110 min from the Sun-Earth 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's reflectance are determined mostly by periodic changes in the land-ocean 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.

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Section: Effects Of Polar Regionssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

EPIC Spectral Observations of Variability in Earth’s Global Reflectance

et al. 2018

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“…In this paper, we reanalyze the two-year DSCOVR/EPIC observations presented by Jiang et al (2018) to study the Earth as a proxy exoplanet. We integrate over the disk of the Earth to reduce each image to a single point source, in order to simulate the light curve of a distant exoplanet.…”

Section: Introductionmentioning

confidence: 99%

Earth as an Exoplanet: A Two-dimensional Alien Map

Fan

et al. 2019

ApJL

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Resolving spatially-varying exoplanet features from single-point light curves is essential for determining whether Earth-like worlds harbor geological features and/or climate systems that influence habitability. To evaluate the feasibility and requirements of this spatial feature resolving problem, we present an analysis of multi-wavelength single-point light curves of Earth, where it plays the role of a proxy exoplanet. Here, ~10,000 DSCOVR/EPIC frames collected over a two-year period were integrated over the Earth's disk to yield a spectrallydependent point source and analyzed using singular value decomposition. We found that, between the two dominant principal components (PCs), the second PC contains surface-related features of the planet, while the first PC mainly includes cloud information. We present the first two-dimensional (2D) surface map of Earth reconstructed from light curve observations without any assumptions of its spectral properties. This study serves as a baseline for reconstructing the surface features of Earth-like exoplanets in the future.

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“…If horizontally oriented ice crystals broadly exist in clouds, the disk‐integrated phase curves of the exoplanet could be prominently altered. Jiang et al () shows that cloud changes can cause significant variation of single‐pixel, disk‐integrated light from potential exoplanet observations. Since the size of terrestrial glints is very small compared to the size of the Earth and since we only have single‐pixel, disk‐integrated exoplanet observations at present, it is currently not possible to determine the existence of glint signals from current observations.…”

Section: Summary and Discussionmentioning

confidence: 99%

Study of Terrestrial Glints Based on DSCOVR Observations

Fan

Kopparla

et al. 2019

Earth and Space Science

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Small flashes of reflected light—called glints—are found in images taken by spacecraft observing the Earth, and occur due to specularly reflected solar radiation. These glints have been found over both ocean and land. Using Deep Space Climate Observatory observations, we show that glints over land are due to specular reflection off horizontally oriented ice platelets floating in the air, while glints over ocean have contributions from reflection off either platelets floating above the ocean or a relatively smooth ocean surface. We use a radiative transfer model to simulate different kinds of glints and to explore their properties. This technique of comparing observations of terrestrial glints with model simulations may provide new information relevant to atmospheric dynamics and the search for habitable exoplanets.

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Using Deep Space Climate Observatory Measurements to Study the Earth as an Exoplanet

Cited by 51 publications

References 52 publications

EPIC Spectral Observations of Variability in Earth’s Global Reflectance

EPIC Spectral Observations of Variability in Earth’s Global Reflectance

Earth as an Exoplanet: A Two-dimensional Alien Map

Study of Terrestrial Glints Based on DSCOVR Observations

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