3.3
Could hurricanes develop from random convection in a warmer world?

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Thursday, 2 February 2006: 4:30 PM
Could hurricanes develop from random convection in a warmer world?
A302 (Georgia World Congress Center)
David S. Nolan, Univ. of Miami/RSMAS, Miami, FL; and K. A. Emanuel and E. D. Rappin

In our present day climate, hurricanes are believed to occur only through a "finite amplitude instability," which is to say that a precursor disturbance (such as an easterly wave) of sufficient strength is required for tropical cyclogenesis. The likelihood of tropical cyclogenesis is also known to increase as the local sea surface temperature (SST) increases, as shown by some modeling studies and statistical analyses of genesis locations. Using the WRF model, we will explore the sensitivity to SST of the threshold disturbance strength for cyclogenesis in idealized, three-dimensional, cloud-resolving simulations of convection in equilibrium over warm oceans. Preliminary results have shown that if SSTs are high enough, cyclones can form spontaneously. The boundary between these subcritical and supercritical regimes will be explored.