A surface based method for analyzing feedback contributions

A climate feedback analysis method based on the surface energy budget is proposed. This method, known as the surface feedback-response analysis method (SFRAM), follows a relatively new climate feedback framework that differs from the classical feedback framework with a top of the atmosphere (TOA) perspective. The SFRAM allows for a quantification of the (partial) surface temperature contributions of the external forcing alone and radiative and non-radiative feedbacks to the total surface temperature change pattern. The partial surface temperature changes are addable and their sum is equal to the total surface temperature change. The decomposition of feedbacks is based on thermodynamic and dynamical processes that directly affect the energy flux convergence at the surface. This includes not only radiative feedbacks that directly affect the TOA radiative fluxes (e.g. water vapor feedback), but also non-radiative feedbacks such as those due to changes in evaporation, convection, and sensible and latent heat fluxes among others. Furthermore, the SFRAM separates the ‘direct' contributions, changes in energy flux convergence at the surface directly due to the external forcing alone and individual feedbacks, from the ‘indirect' contributions, changes in energy flux convergence at the surface due to changes in atmospheric temperature; the latter being equivalent to the lapse rate feedback. The lapse rate feedback is said to be the ‘indirect' contributions because the atmospheric temperature changes are caused by changes in energy flux convergence in the atmosphere due to the external forcing alone and feedbacks. Interestingly, the lapse rate feedback is found to be positive when the climate system is forced by a CO2 increase from the surface perspective, which is opposite that found by the classical TOA perspective.