There are two major mechanisms proposed to explain the response of climate system to solar forcing. One is the top-down stratospheric ozone mechanism [Haigh, 1996; Balachandran et al., 1999; Shindell et al., 1999] which emphasizes the variation in stratospheric ozone in response to solar ultraviolet (UV) variability. The other is the bottom-up air-sea coupling mechanism [Meehl et al., 2003; Van Loon et al., 2007] which suggests that the increased net solar radiation over cloud-free regions in the subtropics translates into greater evaporation and moisture convergence. This strengthens the trades and cooler SSTs in eastern equatorial Pacific. We will use two state-of-the-art fully coupled earth system models, COSMOS (Community system Earth models) and CCSM4 (Community Climate System Model), to investigate the influence of the 11-year solar activity on the global climate system. The sensitivity of including 11-year solar forcing is examined. The preliminary results indicate that the atmosphere temperature may indeed response according to the additional solar forcing for both models. Also, the bottom-up air-sea coupling mechanism can be reproduced in the COSMOS model. We will further examine and quantify the possibly amplification resulting from the small solar variation in the future work.
![](images/flag.png)
![](images/blue_ribbon.png)