A theory for the spinup of tropical depressions



Recent advances in our understanding of the physics of precipitation over tropical oceans is married with vorticity dynamics to produce a simple theory for the development or non-development of tropical depressions. This early phase of tropical cyclogenesis is perhaps the least understood part of the whole process. The theory predicts a finite amplitude threshold for intensification, with weaker disturbances decaying. Furthermore, only disturbances with radii larger than a critical value develop. Rough estimates of this critical radius place it near 1600 km, though better estimates of various parameters could change this value significantly. Copyright © 2007 Royal Meteorological Society