Air–Sea Enthalpy and Momentum Exchange at Major Hurricane Wind Speeds Observed during CBLAST
Name
Bell-2012-Air-Sea Enthalpy and Momentum Exchange at Major Hurricane.pdf
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5.77 MB
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Adobe PDF
Checksum (MD5)
556f3aa83977cf26144674c2c97843d5
Author(s)
Bell, Michael M.
Montgomery, Michael T.
Emanuel, Kerry Andrew
Date Issued
November 2012
Journal
Journal of the Atmospheric Sciences
Publisher
American Meteorological Society
Citation
Bell, Michael M., Michael T. Montgomery, and Kerry A. Emanuel. "Air–Sea Enthalpy and Momentum Exchange at Major Hurricane Wind Speeds Observed During CBLAST." Journal of the Atmospheric Sciences 69, no. 11 (November 2012): 3197-3222. Copyright 2012 American Meteorological Society.
Version
Final published version
Abstract
Quantifying air–sea exchanges of enthalpy and momentum is important for understanding and skillfully predicting tropical cyclone intensity, but the magnitude of the corresponding wind speed–dependent bulk exchange coefficients is largely unknown at major hurricane wind speeds greater than 50 m s[superscript −1]. Since direct turbulent flux measurements in these conditions are extremely difficult, the momentum and enthalpy fluxes were deduced via absolute angular momentum and total energy budgets. An error analysis of the methodology was performed to quantify and mitigate potentially significant uncertainties resulting from unresolved budget terms and observational errors. An analysis of six missions from the 2003 Coupled Boundary Layers Air–Sea Transfer (CBLAST) field program in major hurricanes Fabian and Isabel was conducted using a new variational technique. The analysis indicates a near-surface mean drag coefficient CD of 2.4 × 10[superscript −3] with a 46% standard deviation and a mean enthalpy coefficient CK of 1.0 × 10[superscript −3] with a 40% standard deviation for wind speeds between 52 and 72 m s[superscript −1]. These are the first known estimates of CK and the ratio of enthalpy to drag coefficient CK/CD in major hurricanes. The results suggest that there is no significant change in the magnitude of the bulk exchange coefficients estimated at minimal hurricane wind speeds, and that the ratio CK/CD does not significantly increase for wind speeds greater than 50 m s[superscript −1].
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1175/jas-d-11-0276.1
