Introducing Potential Radiative Forcing (PRF) for quantifying the Earth radiation budget

In order to investigate the contributions of atmospheric factors to variability in surface shortwave irradiance (S) under both cloud-free and cloudy sky conditions, we defined the sensitivity ofS to differential increases from given values of cloud, aerosol, and water vapor as potential radiative forcing (PRF). The expected change in S due to one factor would be the product of the PRF and the change in that factor. We formulated the PRF from a simple equation and described the geographical features of the PRF over China in January and July. We noted some shortcomings, but confirmed the usefulness of the PRF for determining the relative contributions. In particular, we suggested that accurate knowledge of aerosol absorption properties was critical for quantitative radiation budget estimates.