HR: 0830h
AN: SA51A-0499    [PDF]
TI: Planetary Scale Inertio Gravity Waves in the Mesosphere
AU: Porter, H S
EM: HaydenPorter@furman.edu
AF: Furman University, 1100 Pointset Rd., Greenville, SC 29613 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: Mengel, J G
EM: jmengel@pop900.gsfc.nasa.gov
AF: Science Systems and Applications, 10210 Greenbelt Rd., Lanham, MD 20706 United States
AU: Talaat, E R
EM: Elsayed.Talaat@jhuapl.edu
AF: Applied Physics Laboratory, 1100 Johns Hopkins Rd., Laurel, MD 20723 United States
AB: In the polar region of the upper mesosphere, horizontal wind oscillations have been observed with periods around 10 hours. Waves with such periodicity are generated in our Numerical Spectral Model (NSM), and they are identified as planetary scale inertio gravity waves (IGW). In addition to stationary waves for zonal wavenumber m = 0, eastward and westward propagating waves for m = 1 to 4 appear above 70 km, which grow in magnitude up to about 100 km and have periods between 9 and 11 hours. The m = 1 westward propagating IGWs have the largest amplitudes, which can reach at the poles 30 m/s. The IGWs are intermittent but reveal systematic seasonal variations, with the largest amplitudes occurring generally in winter and spring. The IGWs propagate upward with a vertical wavelength of about 25 km. Without the migrating tidal excitation sources, the IGWs are different but still appear with comparable amplitudes. Like the planetary waves (PW) in the model, the IGWs are apparently produced by instabilities that arise in the mean zonal circulation. When the solar heating for m = 0 is turned off, the IGWs, and PWs, essentially disappear.
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