A Study of Aerosol Effects on Stratocumulus Clouds Using CloudSat and MODIS Data

Microphysical properties of stratocumulus clouds are investigated using data from CloudSat cloud profiling radar for the subtropical East Pacific region.CloudSat retrieval indicates that droplet number concentration remains approximately constant in the vertical direction.The effects of aerosol particles on cloud microphysical properties and liquid water path are studied using data from the cloud profiling radar onboard CloudSat and data from MODIS.It is found that,for constant liquid water path,increasing aerosols can lead to decreased droplet effective radius.However,the aerosol effect on cloud droplet radii is not significant as seen in previous studies.It is difficult to find the effect of aerosols on cloud liquid water path because the liquid water path itself has high variability in the stratocumulus clouds.In addition,it is found that liquid water path derived from CloudSat is higher than that from MODIS,and that the variability of liquid water path in stratocumulus clouds is greater than that of aerosol optical depth in the ambient.