Thursday, 6 June 2002
Radiative Properties of Oceanic Boundary Layer Clouds: Sensitivity to Cloud Scale Resolution
Millimeter radars have become very useful and reliable sources of information on cloud variability. Currently, much of this information has been obtained from 35 GHz cloud radars at 90-m vertical and 10-sec temporal resolution. It is possible to obtain finer cloud scale variability (30-m vertical and 2-sec temporal resolution) using a 94 GHz cloud radar. In this study, we evaluate the effect of cloud scale resolution on solar radiative transfer. Using cloud radar data from marine stratus (California, 1999) and fair-weather cumulus (Miami, 2000), we obtain two sets of cloud optical properties. The first set has a resolution that corresponds to a 35 GHz radar. The second set has higher resolution that corresponds to a 94 GHz radar. These two sets are used as input for the solar radiative calculations, which are performed using Monte Carlo method. Detailed analyses of the radiative calculations will be presented in order to determine whether the additional resolution has a significant impact on the radiative transfer.