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IPCC Models and Hurricanes - Visualizations of Increased Shear

These animations and still images illustrate the factors likely to influence Atlantic hurricanes under CO2 induced global warming. On the one hand, the oceans are projected to warm, increasing the thermodynamic potential of hurricanes. On the other hand, vertical wind shear is projected to increase, the effect of which should be in the opposite sense to that of the warming oceans. What is the effect of both factors together?

Even though the effect of each factor in isolation is well established, the net effect of warming oceans and increased shear on Atlantic hurricane intensity and frequency is yet to be understood.

It is also important to note that the model-projected increase in vertical wind shear is limited to the East Pacific and Tropical Atlantic, with other regions showing a decrease in wind shear (see IPCC models and hurricanes website or Vecchi and Soden (2007) for discussion).

(scroll down for still images)

Medium Resolution Flash" Download Animation (640x480): QuickTime (14 MB) | WMV (12 MB) | H.264 (7 MB)

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Summary Table

The following is a suggested table to summarize the results over the various basins. Each cell shows the general effect of the model-projected changes in each parameter on tropical activity.

Ocean Basins	Effect of Ocean Warming	Effect of Wind Shear Change	Effect of Relative Humidity Change	Net Effect
Atlantic and East Pacific				???
West Pacific and Indian Ocean

Still Images

Model Projections of Tropical Storm Genesis Change: An index of genesis potential combines the projected changes for various tropical storm-relevant paramters. There is a pronounced increase in the West/Central Pacific and Indian Oceans, but the changes in the Atlantic and East Pacific are mixed; see discussion here
Model Projections of Tropical Wind Shear Change in Northern Hemisphere Summer/Fall: Vertical wind shear is an important influence to tropical storm development and genesis, with higher shear associated with reduced activity and intensity. There is a pronounced shear increase projected for the Atlantic and East Pacific, while for the West/Central Pacific shear is projected to decrease; see discussion here
Still image, three panels horizontal High Resolution (7MB)
Still image, three panels vertical High Resolution (7MB)