92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Tuesday, 24 January 2012: 11:30 AM
On the Vertical Extent of the Impact of Orographically Generated Gravity Waves
Room 252/253 (New Orleans Convention Center )
In-Sun Song, Next Generation Model Development Center, Seoul, South Korea; and S. Y. Kim, J. Kim, T. J. Oh, and H. S. Lee

Orographically generated gravity waves have profound impacts in the magnitude of the subtropical jet and the separation between the tropospheric subtropical jet and the stratospheric polar night jet. Yet, in some models, the impact of the orographic gravity wave parameterization has been confined below the stratopause to avoid side effects of orographic gravity wave parameterization and better wind and temperature climatology in the mesosphere. However, it has not been reported that there are well-justified reasons for limiting the vertical propagation of the orographic gravity waves. This study examines the vertical extent of the impact of orographic gravity waves by comparing offline results obtained from a ray-tracing model with those from columnar parameterization for various background flow states. We employ the conventional columnar orographic gravity wave parameterization scheme for the specification of the orographic gravity wave sources and the computation of wave breaking in both the columnar and ray-tracing computations. We use ray-tracing equations with spherical curvature terms, Runge-Kutta 4th order scheme with adaptive step control, and C1 interpolation in the computation of the ray-tracing model. Both the columnar parameterization and ray-tracing model assume hydrostatic gravity waves and therefore cannot consider the effects of the vertical reflection. Wave amplitude is only controlled by the wave breaking condition. Amplitude variation due to the change in the horizontal cross sections of ray tubes is ignored in the ray-tracing computation. Detailed results will be presented during conference.

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