Details:

Journal Title:
Monthly Weather Review
Personal Author:
Chen, Y. J.; Zhang, F. Q.; Green, B. W.; Yu, X. P.;
Chen, Y. J.; Zhang, F. Q.; Green, B. W.; Yu, X. P.; Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research); ESRL (Earth System Research Laboratory); GSL (Global Systems Laboratory); CIRES (Cooperative Institute for Research in Environmental Sciences);
OAR (Oceanic and Atmospheric Research); ESRL (Earth System Research Laboratory); GSL (Global Systems Laboratory); CIRES (Cooperative Institute for Research in Environmental Sciences); Less -
Description:
Tropical cyclone (TC) intensity is strongly influenced by surface fluxes of momentum and moist enthalpy (typically parameterized in terms of "exchange coefficients" C-d and C-k, respectively). The behavior of C-d and C-k remains quite uncertain especially in high wind conditions over the ocean; moreover, moist enthalpy flux is extremely sensitive to sea surface temperature (SST). This study focuses on numerical simulations of Hurricane Katrina (2005) from an atmosphere-ocean coupled modeling system to examine the combined impacts of air-sea flux parameterizations and ocean cooling on TC evolution. Three momentum flux options-which make C-d increase, level off, or decrease at hurricane-force wind speeds-with five different C-k curves are tested. Maximum 10-m wind speed V-max is highly sensitive to C-d, with weaker sensitivities for minimum sea level pressure P-min and track. Atmosphere-only runs that held SST fixed yielded TCs with P-min substantially deeper than observations. Introducing ocean coupling weakens TC intensity with much more realistic P-min. The coupled run with the flux parameterization that decreases C-d at high wind speeds yields a simulated TC intensity most consistent with observations. This C-d parameterization produces TCs with the highest V-max. Increasing C-k generally increases surface heat fluxes and thus TC intensity. For coupled runs using the default C-k parameterization, the simulated SST fields are similar (regardless of C-d parameterization) and agree well with satellite observations. The mesoscale oceanic eddies, which are well resolved in the ocean model, contribute to the magnitude of TC-induced SST cooling and greatly influence TC intensity.
Source:
Monthly Weather Review, 146(1), 287-306.
DOI:
http://dx.doi.org/10.1175/mwr-d-17-0170.1
Document Type:
Journal Article;
Funding:
Grant no. NA17OAR4320101;
Rights Information:
Other
Compliance:
Submitted
Main Document Checksum:
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urn:sha256:c0e45c3f0051c3fbfa8fb7528d6d76be985412ee9e1cb856435d53b33ec368e4
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