Forecasting Tropical Cyclone Recurvature Using an Empirical Orthogonal Function Representation of the Synoptic Forcing.
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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Empirical Orthogonal Function EOF representation of the synoptic forcing is combined with past meridional and zonal displacements persistence to forecast tropical cyclone recurvature at 36, 54 and 72 h. Recurvature is defined following Leftwich 1978, 1982 Recurvature is a net displacement northward of 315 luring the forecast period or the attaining of northeastward motion during the 12 hours prior to the end of the forecast period. The combination of persistence and EOF coefficients consistently out-performed the individual methods for forecasting recurvature in both the dependent and independent data samples. Evaluation stores were the Brier p-score, the Heidke skill score and percent correctly forecast. Seven forecast aids used by Joint Typhoon Warning Center JTWC Guam, were tested for ability to forecast tropical cyclone recurvature at 24, 48 and 72 h. Using the skill scores described above for the 1979-81 typhoon seasons, performance indicates large annual variations of skill between the models. Author
- Statistics and Probability