Comments on Symmetric and Asymmetric Structures of Hurricane Boundary Layer in Coupled Atmosphere-Wave-Ocean Models and Observations
NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF METEOROLOGY
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In a recent paper, Lee and Chen 2012, hereafter LC12 presented numerical simulations of symmetric and asymmetric hurricane boundary layer structures in a fully coupled atmosphere wave ocean model and used these simulations to compare aspects of the boundary layer structure against an analysis of observations. One of their main conclusions was that the azimuthally averaged inflow layer tends to misrepresent the overall inflow structure in tropical cyclones, especially the asymmetric structure p. 3593. Another main conclusion was that the complicated asymmetric three-dimensional boundary layer structures attributed by them to be due in part to the air sea and wind wave coupling make it difficult to parameterize the atmosphere wave ocean coupling effects without a fully coupled model p. 3593. After careful examination of their study, we have a number of questions regarding their methodology, their interpretations including their interpretations of previous literature, and their conclusions. Specifically, we inquire about aspects of the methodology for defining the dynamical boundary layer depth, the selection of the boundary layer scheme, and we question the conclusions inferred. In addition to the foregoing concerns, inaccuracies in their literature review are noted and inconsistencies between their conclusions and reported results are identified. For many decades, physical processes across the air sea interface and within the atmospheric boundary layer have been known to be essential for the development and maintenance of a tropical cyclone Ooyama 1969 Emanuel 1986, 1995 Smith et al. 2009 Smith and Montgomery 2010 Bryan and Rotunno 2009 Bryan 2012. However, the boundary layer is the least-observed part of a storm in particular, its turbulence structure. With the advent of the global positioning system GPS dropsonde Hock and Franklin 1999, the mean boundary layer structure has been progressively studied.
- Physical and Dynamic Oceanography