On the observed morphology of gravity-wave and equatorial-wave variance in the stratosphere

摘要: Abstract A first systematic attempt is made to explain the variance of horizontal velocities u′ 2 + v′ and relative temperature fluctuations T ′ produced by gravity waves equatorial in 20–60 km height range atmosphere. Single-wave spectral theories wave field are applied derive simplified quantities which parameterize both dissipative nondissipative effects controlling variances. The major simplification omission variations source strengths background winds, can modify success or otherwise resulting simulations gives some measure importance retained terms compared neglected terms. simplifications produce independent individual parameters, making them valid over entire field, neglect winds enables their computation from temperatures alone. This approach accurately models phase depth observed annual variation at high latitudes, its attenuation on moving equatorward. simulated cycle arises principally seasonal density stratification atmosphere below 60 km, although dependence Brunt-Vaisala frequency N accounts for deeper variation. decrease above 40 also consistent with upper heights. An Gaussian distribution about equator large vertical wavelengths agrees equatorial-wave theory. Several prominent features not simulated, so probably due processes omitted during initial semiannual quasi-biennial variances perceived role driving similar oscillations these regions. nonsimulated peak upper-stratospheric July–Sep-tember sites United States coincides weakening westward flow. It argued that this will reduce wavenumbers, increase order conserve flux action. hypothesis confinement July–September, higher latitude. However, it cannot a feature Wales (52'N), nor absence data Japanese rocket station. Appreciable differences annual-mean among around North America indicate geographical intensities. accurate modelling suggests dominant geographically variable but temporally constant, topographic forcing supporting previous lower-atmosphere studies States.