Two-Dimensional Retrieval of Typhoon Tracks from an Ensemble of Multimodel Outputs

Abstract

n this study a method of retrieving optimum information of typhoon tracks in a multimodel ensemble of forecasts is explored. By treating the latitudes and longitudes of typhoon centers as components of two-dimensional track vectors and using the full ensemble mean as a first guess, it is shown that such a two-dimensional approach for the typhoon track forecast can be formulated as a multivariate optimization problem. Experiments with five nonhydrostatic primitive equation models during the 2004?08 typhoon seasons in the western North Pacific basin show some noticeable improvements in the forecasts of typhoon tracks in terms of the forecast errors and track smoothness with this multivariate approach. The advantages of the multivariate optimization approach are its portability and simplicity, which could make it easily adaptable to any operational typhoon forecast center that synthesizes typhoon track forecast products from different sources.