The climatological model of the gravity wave ensemble at the middle atmosphere heights

Modeling the impact of the gravity wave source strength on the thermal structure of the middle atmosphere

“…In contrast to the climatological GW model (Belyaev and Alpatov, 2004), the source strength depends on latitude y.…”

“…The numerical scheme reported by Belyaev and Alpatov (2004) simulates the characteristics of GW ensemble propagating in stationary and horizontally uniform background atmospheric flow in the altitude range from 16 to 120 km. At the lower boundary the GW ensemble consists of 10 Â 12 Â 7 ¼ 840 wave modes, each characterized by three invariant parameters: (i) horizontal phase velocity C ( ¼ 1.5, 2.0, 3.0, 5.0, 7.5, 11.5, 17.0, 26.0, 40.0, 60.0 m/s); (ii) azimuth angle of propagation j measured from the eastward direction counter clockwise (the isotropic distribution of azimuth directions has step Dj ¼ 301); (iii) the frequency o 0 measured in stationary frame of reference, which has seven values 3 Â 10 À6 , 6Â 10 À6 , 1Â 10 À5 , 3 Â 10 À5 , 6 Â 10 À5 , 1 Â 10 À4 , 3 Â 10 À4 rad/s.…”

“…In our study, we parameterize a manifold of tropospheric GW sources by some hypothetical very simple spectrum S 0 (o 0 , C, y) of the vertical wave action flux prescribed at the lower boundary (E100 mb) of the model. This spectrum is used early in our climatological model of the GW ensemble (Belyaev and Alpatov, 2004). It is an invariant spectral characteristic of the subset of linear wave modes with respect to the background wind and temperature profiles.…”

“…9 in Belyaev and Alpatov, 2004). Since our lower model boundary as at 100 mb, a self consistent description of the GW field can be attained only for launch levels at and above this altitude.…”

“…Thus the wave impact on heat budget and dynamical structure has been reduced to a forcing, heating, as well as diffusion which is induced by GW breaking. We use synthetic GW parameterization which is based on, and represents an extension of, the climatological GW model developed in our previous study (Belyaev and Alpatov, 2004), as well as incorporates some elements of the parameterizations, proposed in the above cited papers. The essential difference of the present parameterization from those mentioned above concerns the simulation of meridional diffusivity basing on an idea that the irreversible mixing on isentropic surfaces may be caused by GW breaking.…”