Thunderstorm Nowcasting in an Oceanic Environment: A Feasibility Study

The U.S. Navy and the Lockheed Martin Corporation have developed a weather radar processor called the Tactical Environmental Processor (TEP) that computes radar moment data (reflectivity, radial velocity and spectrum width) from the four-face, agile beam SPY-1 radar. The SPY-1 radar is a shipborne radar whose primary mission is to track missiles. Adding the weather radar processor to the SPY-1 is an augmentation of its capabilities that will benefit Naval operations.

The TEP was deployed on a destroyer, the USS O'KANE (DDG77), for testing. The ship sailed from Bath, Maine to Pearl Harbor, Hawaii from August to December of 1999. During the transit, radar moment data were collected for a variety of weather conditions that include clear air return and precipitation returns. In addition to the radar data, meteorological data were collected from the deck of the ship and rawinsondes were released.

The NCAR Auto-Nowcaster (AN) provides short-term (0-60 minute), time- and space-specific nowcasts of thunderstorm intensity using fuzzy-logic techniques. The AN has been successfully deployed at multiple sites to produce automated nowcasts in operational environments. The AN uses a variety of input data that includes Doppler radars (like the WSR-88D), satellite imagery, numerical modeling output, surface and upper air data, among others. The AN has had considerable development and testing on continental convection.

A feasibility study is underway to evaluate the potential performance of the AN in oceanic environments, using the TEP radar data, satellite imagery, upper air and surface data as input. Results from this feasibility study will be presented.