Analyses and Modeling of Typhoon Imbudo in 2003

Imbudo is a super-typhoon over the northwestern Pacific in July 2003. It caused serious damages when it made landfall in the southern part of China. This paper documents typhoon Imbudo observationally and numerically during its landing stage in China. All available observations and modeling results by the current model RAMS (Regional Atmospheric Modeling System) are used to investigate Imbudo's motion, intensity, convection, structure and precipitation. Imbudo moved west-northwestward until 18 UTC 23 July 2003 and then went on northwestward. FNL (final) analysis data showed that the motion of Imbudo was dominated by changes of the subtropical high. At its mature stage, the central pressure dropped to 910 hPa and the maximum wind speed was as high as 67 ms-1, which is the intensity of a super-typhoon. QSCAT surface wind field exhibited asymmetric characteristics. NOAA-16 and 17 satellite imagery also showed convective asymmetry before it made landfall in the southern part of China. Almost all kinds of observational data such as TRMM and QSCAT data were used to identify the asymmetric characteristic of the Imbudo. In order to get more insights into the typhoon dynamics and the precipitation field, a 4 km x 4 km horizontal resolution modeling using RAMS-v4.4 was performed. It is shown that the RAMS modeling captured the main features of this super-typhoon. However, there still remained some problems to be solved for the improvement of modeling typhoon precipitation accuracy.