Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published May 1, 2001 | Published
Journal Article Open

Earthshine observations of the Earth's reflectance


Regular photometric observations of the moon's "ashen light" (earthshine) from the Big Bear Solar Observatory (BBSO) since December 1998 have quantified the earth's optical reflectance. We find large (∼5%) daily variations in the reflectance due to large-scale weather changes on the other side of the globe. Separately, we find comparable hourly variations during the course of many nights as the earth's rotation changes that portion of the earth in view. Our data imply an average terrestrial albedo of 0.297±0.005, which agrees with that from simulations based upon both changing snow and ice cover and satellite-derived cloud cover (0.296±0.002). However, we find seasonal variations roughly twice those of the simulation, with the earth being brightest in the spring. Our results suggest that long-term earthshine observations are a useful monitor of the earth's albedo. Comparison with more limited earthshine observations during 1994–1995 show a marginally higher albedo then.

Additional Information

Copyright 2001 by the American Geophysical Union. (Received November 2, 2000; revised March 8, 2001; accepted March 14, 2001.) Paper number 2000GL012580. We wish to thank those involved in earlier earthshine work at BBSO, especially J. Bruls, G. Eychaner, M. Haggerty, J. Maron and H. Zirin. This research was supported in part by grants from NASA (NAG5-7454) and the Western Regional Center of the National Institute for Global Environmental Change.

Attached Files

Published - grl14388.pdf


Files (574.8 kB)
Name Size Download all
574.8 kB Preview Download

Additional details

August 19, 2023
October 18, 2023