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N.J. Woolf (Steward Observatory), W.A. Traub (Harvard-Smithsonian Center for Astrophysics), P. Smith (Steward Observatory), K.W. Jucks (Harvard-Smithsonian Center for Astrophysics)
We report the visible reflection spectrum of the integrated Earth, illuminated as it would be seen as an extrasolar planet. The reflectivity spectrum was derived from observation of lunar earthshine in the range 4800 to 9200 A at a spectral resolution of about 600. We observe absorption features of ozone, molecular oxygen and water. We see enhanced reflectivity at short wavelengths owing to Rayleigh scattering, with apparently negligible contributions from aerosol and ocean water scattering. We also see enhanced reflectivity at long wavelengths starting at about 7300 A, corresponding to the well-known red reflectivity edge of vegetation due to its chlorophyll content, however this signal is only suggestive, not conclusive, due to the lack of agreement with our simple model at wavelengths beyond 7900 A.