Investigation of the energy budget and physical mechanisms associated with long-term climate changes in IPCC AR4 models

According to the IPCC 4th report, global average surface temperatures will be 2.8˚C higher in the late 21st century than in the late 20th century (A1B scenario). In this study, we used the cyclostationary EOF (CSEOF) technique to analyze various variables of the IPCC AR4 model data in an attempt to understand the energy budget and physical, dynamical, and thermodynamical changes in future climates. The climate change signal over the tropical domain (0°-360°E × 30°S-30°N) exhibits significant tropospheric warming and stratospheric cooling and increased specific humidity in the mid-to-lower atmosphere. The resulting changes in total cloud cover and atmospheric temperature alter the energy budget in the tropics, which, in turn, results in physical, dynamical and thermodynamical changes throughout the atmospheric column. We will show a detailed energy budget analysis in the tropics based on many IPCC AR4 models in association with the climate change signal. Physical, dynamical and thermodynamical mechanisms of the climate change will also be addressed.