Earth's albedo variations 1998–2014 as measured from ground‐based earthshine observations

The Earth's albedois a fundamental climate parameter for understanding the radiation budget of the atmosphere. It has been traditionally measured not only from space platforms but also from the ground for 16 years from Big Bear Solar Observatoryby observing the Moon. The photometric ratio of the dark (earthshine) to the bright ( moonshine) sides of the Moon is used to determine nightly anomalies in the terrestrial albedo, with the aim of quantifying sustained monthly, annual, and/or decadal changes. We find two modest decadal scale cycles in the albedo, but with no significant net change over the 16 years of accumulated data. Within the evolution of the two cycles, we find periods of sustained annual increases, followed by comparable sustained decreases in albedo. The evolution of the earthshine albedois in remarkable agreement with that from the Cloudsand the Earth's Radiant Energy Systeminstruments, although each method measures different slices of the Earth's Bond albedo.