Comparison of water cloud microphysics over mid-latitude land and ocean using CloudSat and MODIS observations

The microphysical properties and processes of water (liquid-phase) clouds in the mid-latitudes were studied using space-borne radar and radiometer data, with a focus on comparisons between continental (over China) and oceanic (over the northwest Pacific) clouds. The probability distribution functions (PDFs) of cloud parameters were examined and found to be both reasonable and consistent with previous observations. The PDFs of oceanic cloud parameters as a function of radar reflectivity were generally better defined than those of land cloud parameters. Precipitation characteristics were categorized into non-precipitating, drizzle, and precipitating, as well as the total-precipitating category, according to the maximum radar reflectivity within the cloud layer. The fractional occurrence of the precipitation categories was analyzed as a function of the liquid water path. The statistics showed general trends that were very similar for both land and oceanic clouds, such as a monotonically decreasing trend for the non-precipitating category, a convex shape for the drizzle category, and a monotonically increasing trend for the precipitating and total-precipitating categories with increasing liquid water path. The fractional occurrence of the precipitation categories was further investigated as a function of multiple cloud parameters to better understand land-ocean contrasts in cloud development stages. The vertical structure of clouds also revealed that oceanic clouds produced heavier precipitation in optically thicker regions, compared to land clouds with fewer cloud droplets. However, the differences between land and oceanic clouds were small when comparisons included only those clouds with a high density of droplets