Utilization Of The Spectral Dimension To Reveal Distinct Processes Controlling The Albedo Of Earth

Knowledge of the total reflected solar radiation (RSR) by Earth is vital for quantification of the global energy budget. This RSR has typically been observed in its broadband form, but is actually comprised of a detailed spectrum. The spectrum fingerprints Earth system processes that can otherwise become masked, such as the compensating spectral contributions behind the observed symmetry in hemispheric albedo. Specific wavelengths within the spectrum of RSR have been used in passive retrievals for decades, but only relatively recently has progress been made by considering the whole spectrum simultaneously. These studies have, for example, examined the value of the spectrum for retrieving specific variables, or extracted patterns of variability within the spectrum itself. However, a crucial link is yet to be made between robust spectral signatures in the RSR spectrum, and the processes within the Earth system that control their structure.

To directly address this issue, solar reflectance spectra are simulated for an entire year using atmospheric and surface properties derived from a diverse combination of A-train satellite observations, spectral characteristics of the SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument, and a state-of-the-art fast radiative transfer code. We begin by presenting clusters of the simulated RSR spectra, and reveal how they are related to properties of clouds, aerosols, atmospheric gases and the surface. Next, we will show whether similar clusters exist in observed SCIAMACHY spectra, and examine how they vary in space and time. Finally, these results will be put into context by discussing their implications for improved understanding of global energy flows, and the extent to which they demonstrate a need for spectrally resolved observations of RSR in the future.