Assessing Global and Local Radiative Feedbacks Based on AGCM Simulations for 1980–2014/2017

Abstract

We examine radiative feedbacks based on short-term climate variability by analyzing atmospheric general circulation model (AGCM) simulations, including Atmospheric Model Intercomparison Project within CMIP phase 6 (AMIP6) with known effective radiative forcing (ERF) for 1980–2014 and one with zero ERF for 1980–2017. We first verify the Kernel-Gregory feedback calculation by showing that both clear-sky radiative fluxes and all-sky radiative feedbacks from the kernel method agree with model simulations. We find that global-mean net feedback for 1980–2017/2014 is −2 W m−2 K−1, about twice the feedback estimated for long-term warming (4 × CO2) experiments. This difference is mainly caused by a near-zero global-mean net cloud feedback for 1980–2017/2014. We show that the lapse rate feedback for 1980–2017/2014 is the largest contributor to the amplified temperature change over the three poles (Arctic, Antarctic, and Tibetan Plateau), followed by surface albedo feedback and Planck feedback deviation from its global mean. Except for a higher surface albedo feedback in Antarctic, other feedbacks are similar between Arctic and Antarctic.