Linear Theory Calculations for the Sea Breeze in a Background Wind: The Equatorial Case Academic Article uri icon


  • The equatorial coastal circulation is modeled in terms of the linear wave response to a diurnally oscillating heat source gradient in a background wind. A diurnal scaling shows that the solution depends on two parameters: a nondimensional coastal width L and a nondimensional wind speed U. The solutions are interpreted by comparing to the U = 0 theory of Rotunno. For U ≠ 0 the Fourier integral solution consists of three distinct wave branches. Two of these branches correspond to the prior no-wind solution of Rotunno, except with Doppler shifting and associated wave dispersion. The third branch exists only for U ≠ 0 and is shown to be broadly similar to flow past a steady heat source or a topographic obstacle. The relative importance of this third branch is determined largely by the parameter combination U/L. For sufficiently large U/L the third branch becomes the dominant part of the solution. The spatial structures of the three branches are described in terms of group velocity arguments combined with a desingularized quadrature method. © 2009 American Meteorological Society.

author list (cited authors)

  • Qian, T., Epifanio, C. C., & Zhang, F.

citation count

  • 26

publication date

  • June 2009