Generation of synthetic observations and their Impact on COAMPS-TC analysis and forecast

To supplement observations for tropical cyclone (TC) initialization, we generate synthetic observations around a TC based upon the TC location and wind structure parameters provided by operational forecast centers. In this study, we examine the impact of those synthetic observations on the TC analysis and the forecast produced by the COAMPS-TC. Specifically, we study the sensitivity of the TC analysis and forecast to the synthetic observations in the sense of (a) data usage, (b) generation method, (c) vertical depth, (d) horizontal coverage, and (e) horizontal distribution. We have selected cases ranging from a tropical storm to a category-4 tropical cyclone in order to study the sensitivity with respect to weak and strong cyclones. The NRL Atmospheric Variational Data Assimilation System (NAVDAS) is used in analyzing those observations with a 6-h update cycle, and the numerical experiments are conducted by the COAMPS-TC with triply nested grids of 45/15/5 km resolution. The detailed design as well as sensitivity study results will be presented in the conference.