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The University of Miami's 94-GHz Doppler Cloud Radar (W-band) and 9.4 GHz Doppler Cloud Radar (X-band) were deployed on the research vessel Seward Johnson during the Rain in Cumulus over the Ocean Experiment (December 28, 2004 - January 24, 2005) to characterize the dynamics of trade-wind boundary layer cumulus clouds around the islands of Antigua and Barbuda in the eastern Caribbean. Data collection during the RICO experiment was also taken by a NOAA K-band scanning radar onboard the Seward Johnson; radar on three aircraft: the BAE-146, the University of Wyoming's King Air, and the NCAR C-130; a land-based scanning S-POLKa radar system (S-band and K-band) on Barbuda; and operations on the island of Antigua. For general information about RICO 2005, go to the RICO Website.
Shallow, maritime, cumulus convection is one of the most prevalent cloud types on the planet. Trade wind cumuli typically extend to no greater than 4 km altitude, the height of the tropical trade wind inversion, and are dominated by warm rain processes. Poor representation of cloud processes in climate and weather modeling simulations is a major source of uncertainty. The Global Climate Models and the Large Eddy Simulation (LES) assume trade wind cumuli are non-precipitating even though radar observations clearly show they often precipitate. The objective of the 2005 RICO experiment was to characterize the trade wind cumulus clouds in particular reference to precipitation. This is the first attempt to provide radar derived cloud climatology of shallow clouds over the Caribbean Sea. Antigua and Barbuda appear to have suitable exposure to the easterly trades, a necessary condition to study shallow cumuli. The aim is to study the climatology of the fractional cloudiness over the area of study and analyze the dynamics of the Marine Boundary Layer. The map (Fig. 1) shows the cruise track of the R/V Seward Johnson in the Caribbean Sea during the RICO 2005 experiment. The ship departed Fort Pierce, Florida, on December 28, 2004, and finished the cruise on January 24, 2005, in Antigua.
Figure 1. The ship departed Fort Pierce, Florida, on December 28, 2004, and finished the cruise in Antigua on January 24, 2005.
Figure 2. The Research Vessel Seaward Johnson in port in Antigua during the RICO 2005 experiment.