Simulated impact of projected 21st century warming on Atlantic hurricane activity

Observational analyses have raised concern that warming of the oceans could lead to pronounced increases in hurricane frequency and in other storm metrics such as the Power Dissipation Index (PDI). To explore this possibility, we use a new regional dynamical downscaling model covering the Atlantic basin which reproduces the observed rise and much of the interannual variation in hurricane activity during 1980-2006, when the model is forced with observed sea-surface temperatures and large-scale atmospheric conditions for those years.

As a sensitivity experiment, the original forcing fields (1980-2006) are perturbed according to the August-October mean changes projected by an ensemble mean of the models utilized in the 4th Assessment of the IPCC4 (years 2080-2099, A1B emission scenario). Since the model does not produce category 4-5 storms in the control simulation, results from this model related to high intensity storms should be treated with caution. Uncertainty in the large-scale climate projections will translate into uncertainties in the downscaled tropical storm projections in ways that have not yet been quantified.

The latest simulation results using this approach will be presented at the meeting.