The Sanders Barotropic Tropical Cyclone Track Prediction Model (SANBAR)
Sanders designed a barotropic tropical cyclone (TC) track prediction model for the North Atlantic TC basin that became known as the Sanders barotropic (SANBAR) model. It predicted the streamfunction of the deeplayer mean winds (tropical circulation vertically averaged from 1000 to 100 hPa) that represents the vertically averaged tropical circulations. Originally, the wind input for the operational objective analysis (OA) consisted of winds measured by radiosondes and 44 bogus winds provided by analysts at the National Hurricane Center (NHC), which corresponded to the vertically averaged flow over sparsely observed tropical, subtropical, and midlatitude oceanic regions. The model covered a fixed regional area and had a grid size of ∼154 km. It estimated the initial storm motion solely on the basis of the large-scale flow from the OA, not taking into account the observed storm motion.
During 1970, the SANBAR model became the first dynamical TC track model to be run operationally at NHC. Track forecasts of SANBAR were verified from the 1971 TC season when track model verifications began at NHC until its retirement after the 1989 Atlantic TC season. The average annual SANBAR forecast track errors were verified relative to Climatology and Persistence (CLIPER), the standard no-skill track forecast. Comparison with CLIPER determines the skill of track forecast methods. Verifications are presented for two different versions of the SANBAR model system used operationally during 1973–84 and 1985–89. In homogeneous comparisons (i.e., includes only forecasts for the same initial times) for the former period, SANBAR’s track forecasts were slightly better than CLIPER at 24–48-h forecast intervals; however, from 1985 to 1989 the average SANBAR track forecast errors from 24–72 h were ∼10% more skillful than homogeneous CLIPER track forecasts.
KeywordsTropical Cyclone Track Forecast Tropical Meteorology Absolute Vorticity Tropical Circulation
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- DeMaria, M., and J. M. Gross, 2003: Evolution of tropical cyclone forecast models. Hurricanes: Coping with Disaster, Progress and Challenges since Galveston, 1900, Robert H. Simpson, Ed., Amer. Geophys. Union, 103–126.Google Scholar
- Gaertner, J. P., 1973: Investigation of forecast errors of the SANBAR hurricane track model. M.S. thesis, Dept. of Meteorology, Massachusetts Institute of Technology, 57 pp.Google Scholar
- Goldenberg, S. B., S. D. Aberson, and R. E. Kohler, 1985: Incorporation of Omega dropwindsonde data into SANBAR: An operational barotropic hurricane-track forecast model. Preprints, 16th Conf. on Hurricanes and Tropical Meteorology, Houston, TX, Amer. Meteor. Soc., 44–45.Google Scholar
- -,-, and-, 1987: An updated fine-grid version of the operational barotropic hurricane-track prediction model. Preprints, 17th Conf. on Hurricanes and Tropical Meteorology, Miami, FL, Amer. Meteor. Soc., 86–89.Google Scholar
- Horsfall, F. M., M. DeMaria, and J. M. Gross, 1997: Optimal use of large-scale boundary and initial fields for limited-area hurricane forecast models. Preprints, 22d Conf. on Hurricanes and Tropical Meteorology, Fort Collins, CO, Amer. Meteor. Soc., 571–572.Google Scholar
- Hovermale, J. B., and R. E. Livezey, 1977: Three-year performance characteristics of the NMC hurricane model. Preprints, 11th Tech. Conf. on Hurricanes and Tropical Meteorology, Miami Beach, FL, Amer. Meteor.Soc., 367–374.Google Scholar
- King, G. W., 1966: On the numerical prediction of hurricane trajectories with vertically averaged winds. M.S. thesis, Dept. of Meteorology, Massachusetts Institute of Technology, 51 pp.Google Scholar
- Marks, D. G., 1989: The beta and advection model for tropical cyclone track forecasting. Extended Abstracts, 18th Conf. on Hurricanes and Tropical Meteorology, San Diego, CA, Amer. Meteor. Soc., 38–39.Google Scholar
- Neumann, C. J., 1972: An alternate to the HURRAN tropical cyclone forecast system. NOAA Tech. Memo. SR-62/, 24 pp.Google Scholar
- -, 1981: Trends in forecasting the tracks of Atlantic tropical cyclones. Bull. Amer. Meteor. Soc., 62, 1473–1485.Google Scholar
- -, J. R. Hope, and B. I. Miller, 1972: A statistical method of combining synoptic and empirical tropical cyclone forecast sustems. NOAA Tech. Memo. NWS SR-63/, 32 pp.Google Scholar
- Pike, A. C., 1972: Improved barotropic hurricane track prediction by adjustment of the initial wind field. NOAA Tech. Memo. NWS SR-66, 16 pp.Google Scholar
- Velden, C. S., and S. B. Goldenberg, 1987: The inclusion of high density satellite wind information in a barotropic hurricane-track forecast model. Preprints, 17th Conf. on Hurricanes and Tropical Meteorology, Miami, FL, Amer. Meteor. Soc., 90–93.Google Scholar
- Williams, F. R., 1972: Application of the SANBAR hurricane track forecast model. M.S. thesis, Dept. of Meteorology, Massachusetts Institute of Technology, 39 pp.Google Scholar