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Title: A simple method for simulating wind profiles in the boundary layer of tropical cyclones

A method to simulate characteristics of wind speed in the boundary layer of tropical cyclones in an idealized manner is developed and evaluated. The method can be used in a single-column modelling set-up with a planetary boundary-layer parametrization, or within large-eddy simulations (LES). The key step is to include terms in the horizontal velocity equations representing advection and centrifugal acceleration in tropical cyclones that occurs on scales larger than the domain size. Compared to other recently developed methods, which require two input parameters (a reference wind speed, and radius from the centre of a tropical cyclone) this new method also requires a third input parameter: the radial gradient of reference wind speed. With the new method, simulated wind profiles are similar to composite profiles from dropsonde observations; in contrast, a classic Ekman-type method tends to overpredict inflow-layer depth and magnitude, and two recently developed methods for tropical cyclone environments tend to overpredict near-surface wind speed. When used in LES, the new technique produces vertical profiles of total turbulent stress and estimated eddy viscosity that are similar to values determined from low-level aircraft flights in tropical cyclones. Lastly, temporal spectra from LES produce an inertial subrange for frequencies ≳0.1 Hz, butmore » only when the horizontal grid spacing ≲20 m.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. National Center for Atmospheric Research, Boulder, CO (United States)
  2. Univ. of Colorado, Boulder, CO (United States)
  3. Univ. of Colorado, Boulder, CO (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
  4. Univ. of Miami, Miami, FL (United States)
Publication Date:
Report Number(s):
NREL/JA-5000-67445
Journal ID: ISSN 0006-8314
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Boundary-Layer Meteorology
Additional Journal Information:
Journal Volume: 162; Journal Issue: 3; Journal ID: ISSN 0006-8314
Publisher:
Springer
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE; National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
17 WIND ENERGY; boundary-layer dynamics; large-eddy simulation; single-column modelling; tropical cyclone
OSTI Identifier:
1344169