DOPPLER-SPREAD PARAMETERIZATION OF GRAVITY-WAVE MOMENTUM DEPOSITION IN THE MIDDLE ATMOSPHERE .1. BASIC FORMULATION

This paper presents a parameterization of gravity-wave momentum and en ergy deposition in the middle atmosphere, given a wave spectrum incide nt from below and arbitrary temperature and wind profiles through whic h it progresses upward. An associated turbulence diffusivity is also o btained. The work constitutes an extension and application of the auth or's previous analysis of gravity-wave saturation in the middle atmosp here. In that analysis the dissipation of waves, and so too the moment um and energy deposited by them, is controlled largely by a Doppler sp reading caused by the fluctuating winds that are induced by the waves themselves, acting via the Eulerian advective nonlinearity. The presen t work adds the effects of Doppler shifting caused by the background w inds of the region and parameterizes the whole. Implementation of the parameterization requires the adoption of some specific incident spect rum in vertical wavenumber m. The question of suitable spectra and the ir implementation is discussed in Part 2 of this paper, where too some modifications associated with quasi monochromatic spectra are introdu ced. Modelers who wish to go straight to the operational relations as exemplified by these spectra will find them in Part 2. Copyright (C) 1 996 Elsevier Science Ltd.