Simulated tropical cyclones using the National Center for Atmospheric Research community climate model

The possibility of simulating tropical cyclones (TCs) using the National Center for Atmospheric Research community climate model (CCM2) is explored. Daily outputs from two long-term simulation runs using the standard T42 resolution CCM2 are examined to identify simulated tropical cyclones (STCs) using a search scheme that selects qualified STCs resembling observed TCs. The two simulation cases are a 20-year run driven by climatological sea surface temperatures (SSTs) and a 10-year run, corresponding to the decade from 1979 to 1988, with the same model configuration except for the use of observed SSTs. A composite technique is adopted to reveal the horizontal and vertical structures of well-developed STCs, and a comparison with those of observed TCs is presented. Then, the climatologies of STCs from the two simulation cases are discussed in terms of their genesis, movements, and seasonal and interannual variations through the comparisons with observed TC statistics. Despite obvious shortcomings of the standard CCM2, such as a coarse horizontal resolution, the structure and climatology of STCs identified in both climate runs are in reasonably good agreement with those of observed TCs. The annual STC frequency shows a better agreement with the observed SST run than the climatological SST run, while many other aspects of STCs in the two climate runs are comparable.