Simulation Of Seasonal Tropical Cyclone Activity Over The Western North Pacific By Using The WRF Model

Camargo point out that statistical and dynamical seasonal tropical cyclone activity forecasts are proposed to be made available on a public Website for forecaster and other users at the WMO. Forecasts for different regions, using differing methodologies, have been developed up to present. Tracks and intensity of tropical cyclone are always different and importance for forecasting over the western North Pacific.By using the WRF (weather research and forecasting) model, the paper continuously simulated the seasonal tropical cyclone activity over western North Pacific from1July to30September2004,2006and2010. The relevant data what we used are FNL reanalysis data from the National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP/NCAR). The FNL data were utilized to estimate the large-scale environmental parameter and as the initial background fields for the meso-scale model simulation. The best track data from JMA were used as the objective tropical cyclone tracks data. And to make use of the850hPa relative vorticity, the sea level pressure, temperature in different levels, and so on, detect and track the model tropical storms. This method is advanced by Camargo in2002. We used the whole numbers, tracks and intensity of tropical cyclone to analysis the model outcome in different years. On the other hand, we utilize GP index,500hPa geopotential height,200hPa to850hPa vertical wind shear and so on, to analysis the simulative result.Results show that:1) the simulated total number of Typhoons is close to that from Best-track data set. The simulated landfall TC number has anomaly with real Typhoon number and it is the same for separate monthly landfall number. The simulated intensity of Typhoons is weaker than that from Best-track data set;2) Following the diagnostic analysis, the model shows better ability in reproducing Typhoon in different years. With comparison between the monthly average element fields by model data and by FNL data, we can see tropical cyclone have similar character in generate and move. But the ability tends to be weaker as the model time increases. This suggests that the model can be used to simulate the feature of seasonal tropical cyclone activity but the time limit needs further exploration.