Abstract:Operational positioning and forecast errors of tropical cyclones (TC) over the western North Pacific in 2009 are evaluated according to “Regulations on Typhoon Operation and Service”. The evaluations are performed on the positioning of six methods, the track forecasts from twelve integrated, three objective and six numerical weather prediction (NWP) methods, and the intensity forecasts from four methods. The results show that the TC positioning is better than that in 2008, with an average error in all methods 17.1 km and each less than 21 km. The average errors of domestic integrated track forecast in 24 h, 48 h, and 72 h are 115.8 km, 217.5 km and 357.1 km, respectively, which are worse than those in 2008. The objective forecasts are better than the integrated forecasts with the average errors 113.0 km in 24 h and 211.4 km in 48 h. The comparison of the track forecast errors from four official integrated methods shows that National Meteorological Center (NMC) has good performance in TC track forecast in China Seas. The intensity forecasts still rely mainly on statistical methods with the average errors of 4.90 m·s-1 in 24 h and 7.43 m·s-1 in 48 h. Comparing to the average performance in recent 10 years, the intensity forecast has not made obvious improvement.