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This study investigates the general macrophysical and microphysical properties of single-layer warm clouds over the Northern Hemisphere (NH) ocean and land areas using four standard CloudSat products during the period of 2008.The yearly averaged occurrence frequency of hydrometeor is 77.5% over the ocean and 65.8% over the land,to which the single-layer warm clouds contribute 20.9% and 9.5%,respectively.The maximum values of liquid water content (LWC) over the land are about 10-30% smaller and the occurring altitudes are nearly 0.5 km higher as compared to those over the ocean with the same liquid water path (LWP),which is likely related to the weak upward motions and large surface evaporation over the ocean.Moreover,the CFADs of radar reflectivity distinctly demonstrate the growth processes of cloud to drizzle to rain within warm clouds and how these processes vary regularly with increasing LWP.The CFAD distributions of radar reflectivity over the land always appear later and dBZ values always a little smaller than those over the ocean.This is due to the influence of continental aerosol in this region,confirming that the high aerosol concentrations may induce a suppression of drizzle and delay precipitation process in warm clouds.However,the particle sizes at the upper part of clouds over the land are larger than those over the ocean,inconsistent with our understanding of the aerosol effect.It may be attributed to the stronger vertical air motion over the land,which transports large particles to the upper part of clouds.We found that there exists a significant difference between ocean and land areas in the contoured frequency by optical depth diagrams (CFODDs) of radar reflectivity when LWP is 0.1-0.2 mm and optical depth exceeds 30.The faster growth of particles over the ocean might be caused by the evaporation-condensation mechanism,which can occur under a certain water vapor environment.However,few large droplets are presented in the early stage of continental warm clouds because of the aerosol effect,so the evaporation-condensation mechanism hardly occurs,1resulting in partially the drizzle formation will be a little late over the land.