The dependence of precipitation efficiency on rainfall type in a cloud-resolving model

摘要

The rain microphysical precipitation efficiency (RMPE), the cloud microphysical precipitation efficiency (CMPE), and the large-scale precipitation efficiency (LSPE)are analyzed using 21 day two-dimensional cloud-resolving model simulation data for the period of 18 December 1992 to 9 January 1993 in the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) for eight rainfall types separated by a partitioning scheme based on the surface rainfall budget. RMPE estimated from grid-scale data is considered to be the reference precipitation efficiency. Mean versus gridded estimates of RMPE and CMPE show that they are not very sensitive to spatial scales for all rainfall types. The root-mean-square (RMS) differences between LSPE and RMPE are larger than the standard deviations of RMPE for five rainfall types, and the time-mean LSPE estimates are lower than those of RMPE for six rainfall types, indicating that LSPE is not a good estimate for RMPE. Although the RMS differences between CMPE and RMPE are smaller or marginally smaller than the standard deviations of RMPE for all rainfall types, CMPE estimates are lower than those of RMPE for four rainfall types.