Diagnosis of multi-decadal evolution characteristics of middle atmosphere temperature changes

We apply the recently developed middle atmosphere climate feedback-response analysis method (MCFRAM) to diagnosing multi-decadal evolution of the temperature changes associated with chemistry-dynamics interactions in the middle atmosphere. By using the output fields from the Whole Atmosphere Community Climate Model (WACCM), we isolate the individual contributions of radiative, dynamical and chemical processes to the long-term temperature changes in the region between 20 km and 100 km. The MCFRAM technique is applied to two sets of multi-decadal runs of WACCM corresponding mainly to the second half of the 20th century and to the entire 21st century. By using the principle component analysis technique to extract and analyze the empirical orthogonal functions of the temperature changes, we find the significant differences in spatial patterns of the temperature changes between the two periods. More importantly, it is found that the differences are mostly contributed from the partial temperature changes associated with the radiative processes whereas the spatial patterns of the partial temperature changes associated with the dynamics and chemical heating remain nearly identical between the two periods.