Influence of Temperature on the Beta Drift of Tropical Cyclones

The ß-drift is an important component of tropical cyclone (TC) motion that arises from the interaction between the TC relative vorticity and the Earth's vorticity. It is not known how theß-drift varies with air and sea surface temperature. Here we use a full-physics atmospheric model to simulate the sensitivity of TCsß-drift to temperature when no mean background flow is included. We perform a series of idealized experiments where sea surface and atmospheric temperature are both changed andfind that the intensity increases linearly with increasing temperature as expected, but the size undergoes a quadratic increase with temperature. Theß-drift is also very sensitive to changes in temperature because of this size effect. The TCs move faster and more poleward and westward as temperature increases. There is a linear relationship between the ß-drift speed and size (when the gale force wind radius is at least 250 km) or mean relative angular momentum. This relationship is robust for different initial wind profiles or maximum intensities. This study hints that in a warmer environment TC climatology may be shifted westwards and polewards independent of the basin.