Research Letter

Terrestrial glint seen from deep space: Oriented ice crystals detected from the Lagrangian point

Alexander Marshak

Corresponding Author

E-mail address: alexander.marshak@nasa.gov

NASA Goddard Space Flight Center, , Greenbelt, Maryland, USA

Correspondence to: A. Marshak

E-mail address: alexander.marshak@nasa.gov

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Tamás Várnai

NASA Goddard Space Flight Center, , Greenbelt, Maryland, USA

Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, , Baltimore, Maryland, USA

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Alexander Kostinski

Department of Physics, Michigan Technological University, , Houghton, Michigan, USA

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First published: 15 May 2017
Cited by: 3

Abstract

The Deep Space Climate Observatory (DSCOVR) spacecraft resides at the first Lagrangian point about one million miles from Earth. A polychromatic imaging camera onboard delivers nearly hourly observations of the entire sunlit face of the Earth. Many images contain unexpected bright flashes of light over both ocean and land. We construct a yearlong time series of flash latitudes, scattering angles, and oxygen absorption to demonstrate conclusively that the flashes over land are specular reflections off tiny ice platelets floating in the air nearly horizontally. Such deep space detection of tropospheric ice can be used to constrain the likelihood of oriented crystals and their contribution to Earth albedo. These glint observations also support proposals for detecting starlight glints off faint companions in our search for habitable exoplanets.

Plain Language Summary

The Deep Space Climate Observatory (DSCOVR) spacecraft resides at the first Lagrangian point about one million miles from Earth. An imaging camera onboard delivers nearly hourly observations of the entire sunlit face of the Earth. Many images contain unexpected bright flashes of light over both ocean and land. We construct a yearlong time series of flash latitudes, scattering angles, and oxygen absorption to demonstrate conclusively that the flashes over land are specular reflections off tiny ice platelets floating in the air nearly horizontally. Such deep space detection of tropospheric ice can be used to constrain the likelihood of oriented crystals and their contribution to Earth albedo. These glint observations also support proposals for detecting starlight glints off faint companions in our search for habitable exoplanets.

Number of times cited: 3

  • , Calibration of the DSCOVR EPIC visible and NIR channels using MODIS Terra and Aqua data and EPIC lunar observations, Atmospheric Measurement Techniques, 10.5194/amt-11-359-2018, 11, 1, (359-368), (2018).
  • , Synoptic ozone, cloud reflectivity, and erythemal irradiance from sunrise to sunset for the whole earth as viewed by the DSCOVR spacecraft from the earth–sun Lagrange 1 orbit, Atmospheric Measurement Techniques, 10.5194/amt-11-177-2018, 11, 1, (177-194), (2018).
  • , EPIC Spectral Observations of Variability in Earth’s Global Reflectance, Remote Sensing, 10.3390/rs10020254, 10, 2, (254), (2018).