North American regional climate simulations: Dynamical downscaling experiments to predict hurricane activity under global warming

The relationship between tropical cyclone activity and global warming is one of the most intensely debated issues. There is an emerging consensus from various modeling studies that TC frequency will decrease with global warming, but there is low confidence in these projections, as stated by IPCC-AR4 Summary for Policy Makers.

This paper presents the results from dynamical downscaling simulations using NCAR's Nested Regional Climate Model (NRCM), whereby the Advanced Research WRF Model (ARW) is one-way coupled with the Community Climate System Model (CCSM). Three 11-year periods (1995-2005, 2020-2030, and 2045-2055) were simulated with the NRCM over the domain covering North America to Europe and Northern Africa with 36km grid-spacing resolution. Here projection A2 (IPCC-AR4) is used as the future CO2 increase scenario. Simulated TCs are explicitly detected and tracked using an objective tracking algorithm. The presentation will focus on the simulated changes in TC frequency, intensity, tracks, and duration with the A2 global warming scenario.