The Earth's albedo is a fundamental climate parameter for understanding the
radiation budget of the atmosphere. It has been traditionally measured from
space platforms, but also from the ground for sixteen years from Big Bear Solar
Observatory by 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 is 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 sixteen
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 albedo is in remarkable
agreement with that from the CERES instruments, although each method measures
different slices of the Earth's Bond albedo.Comment: Accepted for publication in Geophysical Research Letter
