Vertical exchange of momentum and energy in the subcloud layer of Australian Hurricane Kerry (1979)

Abstract

Vertical turbulent energy and momentum transfers gathered by aircraft below cloud base in a hurricane east of Australia are examined. Spectrum analysis shows that the humidity instrumentation was unsuitable for this purpose; only fluxes of sensible heat and of momentum could be computed. Maximum energy of the spectra is in the range of 600–1000 m wavelength. Both fluxes are directed downward, but their magnitude is only about 10% of air-sea exchanges.

Therefore the heat transfer from above does not reduce the requirement of “large” sensible heat flux from the surface. The small shearing stress was unexpected; a new model for the vertical wind structure observed in the central portion of hurricanes is proposed.