Oceanic shallow cumuli observations from ship–borne X- and W-Band radars during RICO

Ship-based radar measurements obtained during the Rain in Cumulus over the Ocean (RICO-2005) experiment are used to study characteristics of oceanic shallow cumuli. With the Doppler capability, we can observe many high-resolution examples of small scale dynamical phenomena, whether they are occurring by themselves or caused by microphysics. The X-Band collected vertical profiles every 1.1 seconds (f=0.9 Hz) while the W-band did it every 0.6 seconds (f=1.5 Hz) with vertical resolution of 30 m for both radars. This rapid sampling rate gave us high resolution observation of the three moments recorded with both radars. X-Band Radar observations are compared directly with those from the W-Band. An initial analysis demonstrates the utility of the X-Band for clouds studies. Statistics and diurnal variability of the Marine Boundary Layer under the trade wind regimen will be presented. Combining data from the cloud radars and the ETL Ceilometer, a detailed analysis of the cloud fraction over the area and its relation to the diurnal precipitation cycle will be discussed.