A new approach for simultaneously retrieving cloud albedo and cloud fraction from surface-based diffuse and total solar radiation measurements

This study expands on our previous work (Xie and Liu, Environ. Res. Lett., 2013) that simultaneously retrieves cloud albedo and cloud fraction from surface-based direct and total solar radiative flux measurements. This new approach utilizes the equations for diffuse, instead of direct, and total radiative fluxes to close the system of equations. Compared to the previous study, cloud absorption is simultaneously retrieved with cloud albedo and cloud fraction based on a two-stream approximation. The new approach is validated by comparing to the solutions calculated by applying the Rapid Radiative Transfer Model (RRTM) to a variety of combinations of given values of cloud albedo and cloud fraction. The approach is also compared to the solution from direct and total radiative fluxes by employing surface radiation measurements at the ARM SGP site.