07121-DW1801

Performers
National Center for Atmospheric Research (NCAR), Boulder, CO 80305
Georgia Institute of Technology (GA Tech), Atlanta, GA 30332

Abstract
Project Overview:
The study will conduct an assessment of potential impacts of global warming on North Atlantic hurricane activity with a focus on the Gulf of Mexico. The large-scale component will be provided by existing global climate simulations from the NCAR CCSM3 archive of simulations undertaken for the IPCC. This is one of the best global climate models and by using the IPCC archive we are assured of a simulation set that has been thoroughly and critically examined by the scientific community and has well understood characteristics. These global simulations are of too course a resolution for assessing hurricane activity, so we plan to nest the NCAR Advanced Research Weather Research and Forecasting (ARW) model in its Nested Regional Climate Model (NRCM) mode into the CCSM3 and conduct a set of high resolution downscaling simulations for current and future climate. This work will be conducted in collaboration with an ongoing NCAR downscaling program for high-impact weather, thus substantially increasing the available resources and enabling efficiencies through combination of the efforts. The hurricane results will be used to advise RPSEA on how much the hurricane intensity and frequency is likely to change in the Gulf of Mexico over approximately the next 50 years. All data will also be archived and made available for further studies on hurricane responses to climate variability and change.

Project Impacts:
Since the disastrous 2004 and 2005 hurricane seasons, there has been a considerable amount of debate on whether we are currently seeing impacts of global warming and on what the likely future changes will be. The debate has at times been acrimonious and the lack of hard evidence has left open opportunities for misinterpretation and justification of pre-existing beliefs. In addition to the immediate findings that will be relayed as a direct result of this study, NCAR will, with RPSEA's approval, archive all simulations in a form that will be readily accessible to other researchers, thus enabling a wider group to investigate this important issue. We also envisage using the these initial simulations as a basis for future simulations at higher resolution and with improved physics as computing systems and our overall knowledge improves.

Principal Investigator Greg Holland