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First direct measurements of enthalpy flux in the hurricane boundary layer: The CBLAST results
Author(s) -
Zhang Jun A.,
Black Peter G.,
French Jeffrey R.,
Drennan William M.
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl034374
Subject(s) - boundary layer , enthalpy , stagnation enthalpy , turbulence , flux (metallurgy) , wind speed , environmental science , sensible heat , atmospheric sciences , heat flux , meteorology , physics , thermodynamics , heat transfer , materials science , metallurgy
Hurricanes extract energy from the warm ocean through enthalpy fluxes. As part of the Coupled Boundary Layer Air‐Sea Transfer (CBLAST) experiment, flights were conducted to measure turbulent fluxes in the high‐wind boundary layer of hurricanes. Here we present the first field observations of sensible heat and enthalpy flux for 10m wind speeds to 30 ms −1 . The analyses indicate no statistically significant dependence of these bulk exchange coefficients on wind speed. As a measure of hurricane development potential, we compute the mean ratio of the exchange coefficient for enthalpy to that for momentum and find it to be significantly below the lowest threshold estimated by previous investigators. This suggests that the enthalpy flux required for hurricane development may come from sources other than turbulent fluxes, such as lateral fluxes from the vortex warm core, or sea spray. Alternatively, it demands a re‐evaluation of the theoretical models used to derive the threshold.