Statistical Analysis of Ensemble Forecasts of Tropical Cyclone Tracks over the Northwest Pacific Ocean.

摘要

The skill of three ensemble prediction systems (EPS) is evaluated to focus on tropical cyclone (TC) track forecasting over the North Pacific. Probability ellipses are defined to represent ensemble spread and encompass 68% of the ensemble members. The ellipses are centered on the ensemble mean forecast position. Forecast reliability is defined as whether the verifying position is within the ellipse 68% of the time. A statistical analysis of uncertainty in TC track forecasts examines the attributes of reliability and resolution of each EPS. The European Center for Medium- Range Forecasts (ECMWF) EPS had the highest degree of reliability and resolution. The sizes and shapes of the EPS ellipses varied with TC track characteristics. This suggests that EPS-based probability ellipses may provide value in identifying uncertainty with respect to likely TC track forecast errors.