Effects of Sea Surface Temperature

Abstract

SST affects surface rainfall and associated cloud microphysical processes mainly through the change in surface evaporation flux (e.g., Lau et al. 1993, 1994; Wu and Moncrieff 1999; Cui and Li 2006). Lau et al. (1993) studied rainfall responses to SST in the presence of same large-scale forcing in the deep convective regime and found 22% increase of convective precipitation and 13% increase of surface evaporation rate when imposed SST increases from 28°C to 30°C. Costa et al. (2001) studied sensitivity of precipitation to SST with cloud-resolving model simulations that are imposed with the forcing derived from TOGA COARE data, and revealed 6.4% increase of precipitation with 2°C increase of SST, which is associated with 17.8% increase of convective precipitation and 19.0% decrease of stratiform precipitation. Wu and Moncrieff (1999) from their SST sensitivity simulations found 3.3% increase of time mean precipitation when time mean SST increases from 27.4°C to 29.4°C and 5.8% increase of precipitation when the SST increases from 29.4°C to 31.4°C. Cui and Li (2006) analyzed the quasi-equilibrium simulation data (Gao et al. 2007) from the model that is imposed with zero large-scale vertical velocity and found that the increase of SST from 29°C to 31°C causes 19% increase of surface rain rate. In this chapter, sensitivity of time-mean surface rainfall and diurnal variation of rainfall to SST is discussed through the analysis of equilibrium model simulation data based on Zhou and Li (2009, 2011).