Concerning the interpretation of enhanced cloud shortwave absorption using monthly‐mean Earth Radiation Budget Experiment/Global Energy Balance Archive measurements

To study the signature of enhanced shortwave absorption in clouds, several recent studies have used monthly‐mean shortwave radiation measurements from the Earth Radiation Budget Experiment (ERBE) together with monthly‐mean surface insolation as obtained from the Global Energy Balance Archive (GEBA). In this paper we discuss probable causes of inconsistent results, among themselves, from these studies and with other studies that have reported enhanced shortwave cloud absorption relative to theoretical model calculations. Two factors are identified as potential contributing sources of inconsistencies. One is the inseparability of the seasonal variations of water vapor and clouds in the continental area of the northern hemisphere when using collocated monthly ERBE/GEBA data. The second is the impact of data collocation errors on the signature of cloud absorption. Both factors are quantitatively examined using observational data and radiative transfer models.