Cloud Statistics during JASMINE from 35 GHz Cloud Radar

Between May 4 and May 31, 1999, the NOAA/Environmental Technology Laboratory (ETL) operated a vertically pointing mm-wave cloud radar (MMCR) from the deck of the NOAA R/V Ron Brown. The ship was the major observing platform for the Joint Air-Sea Monsoon Interaction Experiment (JASMINE). The MMCR is particularly useful in detecting weakly precipitating clouds, and is also highly sensitive to non-precipitating ice and water clouds. JASMINE could be divided into two observing regimes, based on the amount of received precipitation. During the low precipitating period of JASMINE the radar detected mostly cirrus clouds between 9.0 and 14.0 km AGL. During the period of heavy precipitation cloud tops ranged from 14.0 km to at least 17.0 km and higher (due to attenuation during rainfall events the radar signal often attenuated at about 17.0 km). The precipitation had a strong diurnal component and primarily occurred in the night-time hours between 2300 and 0800 local time. In this paper, we will use the radar data to examine the bulk cloud statistics, including information on cloud base heights, cloud top heights, cloud thickness, and the occurrence of cloud as function of altitude for both the precipitating and non-precipitating periods.