The effects of clouds, sea surface temperature, and its diurnal variation on precipitation efficiency are investigated us ing grid-scale data from nine equilibrium sensitivity cloud-resolving model experiments driven ...The effects of clouds, sea surface temperature, and its diurnal variation on precipitation efficiency are investigated us ing grid-scale data from nine equilibrium sensitivity cloud-resolving model experiments driven without large-scale vertical velocity. The precipitation efficiencies are respectively defined in surface rainfall, cloud, and rain microphysical budgets. We mathematically and physically demonstrate the relationship between these precipitation efficiencies. The 2 ℃ increases in spatiotemporal invariant sea surface temperature （SST） from 27 ℃ to 29 ℃ and from 29 ℃ to 31 ℃, and the inclusion of diurnal SST difference 1 ℃ and the 1℃ increase in diurnal SST difference generate opposite changes in the precipitation efficiency by changing ice cloud-radiation interactions. The radiative and microphysical processes of ice clouds have opposite effects on the precipitation efficiency because of the rainfall increase associated with the reduction in the saturation mixing ratio caused by the exclusion of radiative effects and the decrease in rainfall related to the reduction in net condensation caused by the exclusion of deposition processes. The radiative effects of water clouds on the precipitation efficiency are statistically insensitive to the radiative effects of ice clouds.展开更多
基金supported by the National Basic Research Program of China (Grant Nos. 2013CB430103 and 2011CB403405)the National Natural Science Foundation of China (Grant Nos. 41075039 and 41175065)the Priority Academic Program Development of Jiangsu Higher Education Institutions, China (Grant No. PAPD2011)
文摘The effects of clouds, sea surface temperature, and its diurnal variation on precipitation efficiency are investigated us ing grid-scale data from nine equilibrium sensitivity cloud-resolving model experiments driven without large-scale vertical velocity. The precipitation efficiencies are respectively defined in surface rainfall, cloud, and rain microphysical budgets. We mathematically and physically demonstrate the relationship between these precipitation efficiencies. The 2 ℃ increases in spatiotemporal invariant sea surface temperature （SST） from 27 ℃ to 29 ℃ and from 29 ℃ to 31 ℃, and the inclusion of diurnal SST difference 1 ℃ and the 1℃ increase in diurnal SST difference generate opposite changes in the precipitation efficiency by changing ice cloud-radiation interactions. The radiative and microphysical processes of ice clouds have opposite effects on the precipitation efficiency because of the rainfall increase associated with the reduction in the saturation mixing ratio caused by the exclusion of radiative effects and the decrease in rainfall related to the reduction in net condensation caused by the exclusion of deposition processes. The radiative effects of water clouds on the precipitation efficiency are statistically insensitive to the radiative effects of ice clouds.
