HR: 0830h
AN: SA51A-0496    [PDF]
TI: Role of Small Scale Gravity Waves in Generating Nonmigrating Tides in the Mesosphere
AU: Mengel, J G
EM: jmengel@pop900.gsfc.nasa.gov
AF: Science Systems and Applications, 10210 Greenbelt Rd., Lanaham, MD 20706 United States
AU: * Mayr, H G
EM: hmayr@pop900.gsfc.nasa.gov
AF: Goddard Space Flight Center, 8800 Greenbelt Rd., Greenbelt, MD 20771 United States
AU: Talaat, E R
EM: Elsayed.Talaat@juuapl.edu
AF: Applied Physics Laboratory, 1100 John Hopkins Rd., Laurel, MD 20723 United States
AU: Porter, H S
EM: HaydenPorter@furman.edu
AF: Furtman University, 3300 Pointset Rd., Greenville, SC 29613 United States
AB: We demonstrated with the Numerical Spectral Model (NSM) that nonlinear interactions between planetary waves (PW) and migrating tides could generate in the upper mesosphere nonmigrating tides having amplitudes comparable to those observed. The NSM incorporates Hines' Doppler Spread Parameterization for small scale gravity waves (GW), which affect in numerous ways the dynamics of the mesosphere. The latitudinal (seasonal) reversals in the zonal circulation and temperature variations above 70 km, largely caused by GWs (Lindzen, 1981), contribute to the instabilities that generate the PWs as well as filter them. The PWs in turn are amplified by the momentum deposition of upward propagating GWs, as are the migrating tides. The GWs thus affect the migrating tides and PWs, the building blocks of non-migrating tides. We present here the results of two computer experiments, which indicate that the GWs also contribute significantly to the process of nonlinear coupling between PWs and tides. In one, we turn off the GW source to show the effect on the nonmigrating tides. In the second case, we demonstrate the effect on the stationary non-migrating diurnal tide by selectively suppressing the GW momentum source for zonal wavenumber m = 0.
DE: 3332 Mesospheric dynamics
DE: 3334 Middle atmosphere dynamics (0341, 0342)
DE: 3337 Numerical modeling and data assimilation
DE: 3367 Theoretical modeling
DE: 3384 Waves and tides
SC: SPA - Aeronomy [SA]
MN: 2003 Fall Meeting