Abstract

The 5~7-day ensemble forecasts for Tropical Cyclones (TC) of western North Pacific are provided using an ensemble predication system based on WRF model. The system contains 80 members with initial conditions from the WRF/EnKF ensemble perturbed members (link to “Dataset: WRF/EnKF ensemble analyses for western North Pacific”).

For years 2016-2018, the model domains covered triple meshes with a grid spacing of 18-km (grid size 660 x 520) for the outermost domain and grid spacings of 6-km (grid size 180 x180) and 2-km (grid size 360 x360) for two vortex-following domains. There are 57 vertical levels with model top at 10 hPa. The implementation of WRF has the following components: the WRF 6-class microphysics scheme, the Yonsei University (YSU) planetary boundary layer (PBL) scheme, the Noah land surface model, the Rapid Radiative Transfer Model for global models long-wave and shortwave scheme are used. The Tiedtke cumulus scheme is only used for the 18-km domain. The forecast time length is up to 5 days.

Since year 2019, the model domains has been changed to two meshes with a grid spacing of 12-km (grid size 720 x 560) for the outermost domain and a grid spacing of 2.4-km (grid size 400 x 400) for the vortex-following domain. The forecast time length is extended to 7 days. Unlike previous versions, the Multi-scale Kain-Fritsch (MSKF) cumulus scheme is adopted in both domains.

The ensemble forecasts and verification of track and intensity for some TCs are listed below.

NEPARTAK (2016)        

Initial time: 2016-07-03_12(UTC)

Track and Intensity Ensemble Forecasts

NAMTHEUN (2016)       

Initial time: 2016-08-31_12(UTC)

Track and Intensity Ensemble Forecasts

MERANTI (2016)

Initial time: 2016-09-10_00(UTC)

Track and Intensity Ensemble Forecasts

CHABA (2016)

Initial time: 2016-09-28_06(UTC)

Track and Intensity Ensemble Forecasts

SONGDA (2016)

Initial time: 2016-10-08_12(UTC)

Track and Intensity Ensemble Forecasts

SARIKA (2016)

Initial time: 2016-10-12_12(UTC)

Track and Intensity Ensemble Forecasts

HAIMA (2016)

Initial time: 2016-10-14_18(UTC)

Track and Intensity Ensemble Forecasts

IN-FA (2021)

Initial time: 2021-07-18_00(UTC)

Track and Intensity Ensemble Forecasts

MUIFA (2022) 

Initial time: 2021-09-09_00(UTC)

Track and Intensity Ensemble Forecasts

Verification: Mean Error and Spread

NANMADOL (2022)

Initial time: 2021-09-13_00(UTC)

Track and Intensity Ensemble Forecasts

Verification: Mean Error and Spread