Sensitivities of hurricane intensity to planetary boundary layer schemes in a full physics three dimensional nonhydrostatic mesoscale model

In what has become a very influential paper Emanuel (1986) developed a model for a mature hurricane that later became the basis for his potential intensity (E-PI) theory. E-PI theory predicts an upper bound for hurricane intensity (as measured by maximum average tangential wind at the boundary layer top) for a given tropical environment. However, simulations of hurricane intensity still show no skill as compared to current empirical statistical models. In this work we examine the simulated hurricane structure as simulated in a full-physics but highly idealized three dimensional model to test the accuracy of E-PI in a three dimensional context.

In the first part of this work, we focus on the sensitivities of the simulated vortex intensity to the planetary boundary layer scheme. An equivalent Ck and Cd calculated form a complicated PBL scheme, such as the Blackadar PBL scheme, is employed in a simple modified bulk aerodynamic PBL scheme. It is shown that the simulated hurricane intensity and structure strongly resembles that predicted with the Blackadar PBL scheme. Based on this work it is suggested that the simplest bulk-aerodynamic PBL scheme with equivalent Ck and Cd curves consistent with the more complicated schemes can be used to obtain a more complete understanding of the hurricane intensity problem.