Preliminary Study of Sensitive Areas for Several Tropical Cyclone Track Prediction Cases in 2007

Abstract

Conditional nonlinear optimal perturbation (CNOP) obtained by the ensemble-based calculation method is employed to find possible sensitive areas for improving 48-h or more than 48-h tropical cyclone (TC) track predictions in several cases affecting China in 2007. These sensitive areas are examined by observing system simulation experiments (OSSEs). Results show that these sensitive areas improve TC track predictions for 48 h or more to different extents. Further analysis is performed to determine the distribution characteristics of sensitive areas in these cases. Results show that areas south of Luzon and over surrounding oceans are significant for 48-h or more than 48-h TC track predictions, especially 60-h to 72-h track predictions. Areas over oceans north or east to Taiwan Island seem to be secondary sensitive for 48-h or more than 48-h TC track predictions