US CLIVAR Hurricane Workshop

Summary:

In recent years, global climate models have become an increasingly important tool for simulating the effects of climate change on tropical storms and hurricanes. The increasing horizontal resolution of these models has enabled them to provide an improved representation of tropical cyclone formation rates and their regional variation. This is particularly important when these models are used to estimate the possible effects of climate change on tropical cyclone behavior.

Several research questions remain to be resolved in this work:

• Many models predict a decrease in global tropical cyclone numbers, particularly in the Southern Hemisphere. What is the fundamental reason for this change?
• Prediction of future tropical cyclone behavior in the Atlantic Ocean is of crucial importance, yet tropical cyclones in this basin have typically been less well simulated. Do the new generation of higher-resolution climate models simulate the Atlantic better? Do they simulate a similar tropical cyclone response to climate change, thus giving more confidence in our prediction?
• Many studies have shown that tropical cyclone behavior responds strongly to changes in sea surface temperature. What is the tropical cyclone response of climate models to an imposed, common increase in sea surface temperature? How sensitive is the simulation of tropical cyclone variability to differences in SST analysis?
• What is the relationship between local versus remote forcing and hurricane formation in the North Atlantic? How does tropical cyclone frequency respond to an increase in tropical mean sea surface temperature versus an increase in the Atlantic alone? What about the response of tropical cyclones to local and remote forcing in other regions of tropical cyclone formation, is it similar to or different from that in the Atlantic?
• How does the role of changes in atmospheric carbon dioxide differ from the role played by sea surface temperatures in changing tropical cyclone characteristics in a warmer world?
• How does air-sea interaction modify the climate response of tropical cyclones?

This workshop will review current progress in these issues, through presentations based on results of common climate model experiments already produced by group members. In addition, discussion will focus on novel syntheses of these results, as well as applicable analytical techniques, and how they might be applied to address some of the fundamental issues mentioned above.

Scientific Organizing Committee: