Date of Award
Master of Science in Applied Physics - (M.S.)
Federated Physics Department
Philip R. Goode
Carsten J. Denker
The Earthshine group has been making sustained observations of the Earthshine from Big Bear Solar Observatory in California since late 1998. There have also been intermittent observations from 1994-5. High and low resolution Earthshine spectral observations have also been under taken at Palomar Observatory since 1999. The group has re-invigorated and modernized a nearly forgotten way of measuring the Earth's albedo, and hence its energy balance, previously studied by Danjon (and his followers) for about twenty-five years early in the last century, using their observations of the Earthshine from France. This is an overview paper covering observations, reductions, simulations, and analysis, of the Earth's reflectance from photometric and spectral observations of the moon. The Earthshine group developed a modern method of measuring, instantaneously, the large scale reflectance of the Earth. From California an observer sees the moon reflecting sunlight from the third of the Earth to the west in the evening (before midnight) which is during the moon's rising phase and from the third of the Earth to the east in the morning (after midnight) which is during the moon's declining phase. The group has precisely measured the scattering from the moon, as a function of lunar phase, which enables the measurement, in a typical night's observations, the Earth's reflectance to an accuracy of 2.0% (equivalent to measuring the Earth's emission temperature to ~0.8 K). The group identified the lunar phase function as the major source of discrepancy between Danjon's estimates of the albedo and more recent measurements. The albedo variation is due to the interplay of cloud cover and the different landscapes.
Hickey, Jeffrey Patrick, "Earthshine : Photometry, modeling, and spectral observations" (2006). Theses. 443.