High-resolution numerical simulation of tropical cyclone intensity change with assimilation of satellite, radar, and in-situ data

The forecast of tropical cyclone (TC) intensity change is a challenging problem in tropical meteorology community. Commonly, the forecast of TC intensity change is limited by the initial conditions and physics parameterizations of numerical models.;High resolution numerical simulations are conducted with the advanced research version of the Weather Research and Forecasting (WRF) model. Satellite, radar, and in-situ observations, collected during the NASA Tropical Cloud Systems and Processes (TCSP) mission, are assimilated into the model. The assimilation of the NASA QuickSCAT ocean surface winds, NOAA GOES-11 atmospheric motion vector winds, and aircraft dropsonde data improves the simulations of two Tropical Storms, Cindy (2005) and Gert (2005).;With the improved initial condition through similar data assimilation procedure, simulations of Hurricane Emily's rapid intensification are performed with various microphysical and planetary boundary layer schemes in the WRF model. The intensity forecast of Emily is highly sensitive to the physical parameterizations due to significantly different structures in the eyewall. However, results also indicate that none of the experiments captures the observed rapid intensification. A diagnostic study is then conducted to investigate the errors in the model by comparing the simulations with the observational data. It is found that the thermal and dynamic structure of the storm in the initial condition has unrealistic features. In addition, the simulated eye is too large and the eyewall contracts too slowly.;The simulations of Hurricane Emily suggest that an accurate forecast of TC rapid intensification is closely related to the accuracy of the simulated storm-scale structure. The impact of high-resolution Doppler radar data on Hurricane Dennis' (2005) intensification is investigated. The radar reflectivity data show a relatively small impact on the short-term intensity and track forecast, although the data has a significant impact on the storm convective, precipitation, and thermal structure. The radar wind data, however, exhibit a significant positive impact on the short-term forecast of both the intensity and track.;This dissertation explores two questions: (1) How sensitive is the numerical simulation of TC rapid intensity change to the model physical parameterizations? (2) To what extent can data assimilation improve the intensity forecast?...