Estimation of Dissipative Heating Using Low-Level In Situ Aircraft Observations in the Hurricane Boundary Layer

Abstract

Data collected in the low-level atmospheric boundary layer in five hurricanes by NOAA research aircraft are analyzed to measure turbulence with scales small enough to retrieve the rate of dissipation. A total of 49 flux runs suitable for analysis are identified in the atmospheric boundary layer within 200 m above the sea surface. Momentum fluxes are directly determined using the eddy correlation method, and drag coefficients are also calculated. The dissipative heating is estimated using two different methods: 1) integrating the rate of dissipation in the surface layer and 2) multiplying the drag coefficient by the cube of surface wind speed. While the latter method has been widely used in theoretical models as well as several numerical models simulating hurricanes, these analyses show that using this method would significantly overestimate the magnitude of dissipative heating. Although the dataset used in this study is limited by the surface wind speed range <30 m s?1, this work highlights that it is crucial to understand the physical processes related to dissipative heating in the hurricane boundary layer for implementing it into hurricane models.