Earth Planets Space, Vol. 61 (No. 4), pp. 447-453, 2009
Jeffrey M. Forbes1, Xiaoli Zhang1, Scott E. Palo1, James Russell2, Christopher J. Mertens3, and Martin Mlynczak3
1Department of Aerospace Engineering Sciences, UCB 429, University of Colorado, Boulder, CO 80309-0429
2Center for Atmospheric Sciences, Hampton University, Hampton, VA 23668
3NASA Langley Research Center, Hampton, VA 23681-0001
(Received September 28, 2007; Revised March 18, 2008; Accepted March 25, 2008; Online published May 14, 2009)
Temperature measurements from the SABER instrument on the TIMED spacecraft are used to elucidate the properties of Kelvin waves and other equatorial oscillations over the altitude range 20-120 km during 2002-2006. The dominant Kelvin waves transition from long periods (5-10 days) and short wavelengths (9-13 km) in the stratosphere, to shorter periods (2-3 days) and longer wavelengths (35-45 km) in the 80-120 km height region. Ultra-Fast Kelvin Waves (UFKW) with periods of 2.5-4.5 days intermittently exist at amplitudes of order 3-10 K between 80-120 km during all months of the year, with variability at periods typically in the 20-60 day range. An Intra-seasonal oscillation (ISO) of zonal mean temperatures also exists with periods 20-60 days that may be driven by Eliassen-Palm Flux Divergences (EPFD) due, at least in part, to UFKW and migrating diurnal tides.
Key words: SABER (Sounding the Atmosphere using Broadband Emissioni Radiometry), TIMED (Thermosphere Ionosphere Mesosphere Energetics Dynamics), Ultra-Fast Kelvin Waves (UFKW), Intra-seasonal oscillation (ISO), Eliassen-Palm Flux Divergences (EPFD).