On the variability of projected tropical cyclone genesis in GCM ensembles

The development of projections for changes in the genesis of tropical cyclones (TCs) for a changed climate is explored in this article using outputs from the Coupled Model Intercomparison Project: Phase 3 (CMIP3) models. In this study, we explore how the projected change in the genesis frequency of TCs strongly depends upon the selection of models used in the ensemble. Results from 16 CMIP3 models are analysed and validated against the National Center for Environmental Prediction (NCEP) and European Centre for Medium Range Weather forecast re-analysis at 40 km (ERA40) reanalysis and an ensemble mean of TC genesis diagnostics is calculated using the CMIP3 models. The response of these models to a future climate using the IPCC A2 scenario is also studied in the context of selecting models to calculate an ensemble mean.