Thursday, 2 August 2001
The Role of Upper Tropospheric Inertial Stability in Hurricane Intensification
More often then not, tropical cyclones fail to reach their maximum potential intensity (MPI). This observation can be attributed to an upper tropospheric state that is not conducive to hurricane growth. It takes work on the part of the hurricane to vent it's outflow far from the storm core. Should this work be minimized by the existence of an appropriate upper tropospheric state then acheiving the MPI would be more attainable. A state of inertial instability or weak inertial stability (such as on the
anticyclonic shear side of a jet) would provide significant relief in the hurricane's expenditure of energy. The purpose of this work is to study how such upper tropospheric conditions relate to hurricane intensification.
Using an axisymmetric model it is demonstrated that intensification occurs earlier in the storm's evolution when upper tropospheric inertial stability is reduced. The rate of intensification is unaffected. In addition, evolution of the two-dimensional tangential velocity and moist entropy fields reveal eyewall replacement cycles that occur at more frequent intervals during lengthy integrations. These eyewall replacement cycles increase the equilibrium eyewall radius which results in the eventual decay of the vortex.