3.1
The Sander's Barotropic Tropical Cyclone Track Model (SANBAR)
Robert W. Burpee, Cooperative Institute for Marine and Atmospheric Sciences, RSMAS, University of Miami, Miami, FL
Sanders designed a barotropic tropical cyclone (TC) track model, that became known as SANBAR, that predicted the stream function derived from an objective analysis of wind observations averaged from 1000-100 hPa. The data input for the objective analysis consisted of winds observed by radiosondes, subjectively-estimated bogus winds representing the vertically averaged flow over the sparsely observed oceanic regions, and information about the TC strength and motion. The original operational model covered a limited area, had a grid size of 154 km, and represented the stream function near the TC by the storm’s steering flow and an idealized vortex.
SANBAR became operational at the National Hurricane Center (NHC) during the 1970 season and, with modifications, its track forecasts remained competitive with later TC track models at periods of 24-48 h until it was retired after the 1989 season. The modifications replaced the objective analysis so that newer types of wind observations (Omega dropwindsondes and satellite cloud-drift wind estimates) could be part of the initial data, increased the grid resolution, and improved the vortex parameterization.
Verifications document modest skill of SANBAR’s forecast tracks calculated relative to the track forecasts of the climatology and persistence model, CLIPER, that measures forecast skill. The verifications will be presented from 1972, the first year of the TC track verification program developed by NHC, to 1989.
Session 3, Forecasting (Room 617)
Monday, 12 January 2004, 1:30 PM-2:30 PM, Room 617
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