HR: 15:10h
AN: H22E-06    [PDF]
TI: A Budget of Equatorial Kelvin Waves as Observed in AIRS Data
AU: * Leroy, S
EM: Stephen.S.Leroy@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., MS 169-237, Pasadena, CA 91109 United States
AU: Fetzer, E
EM: Eric.Fetzer@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., MS 169-237, Pasadena, CA 91109 United States
AU: Granger, S
EM: Stephanie.Granger@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., MS 169-237, Pasadena, CA 91109 United States
AB: AIRS is the first satellite instrument to offer coverage sufficient to map and characterize Kelvin waves in the stratosphere and troposphere. It generates temperature profiles with 1-K accuracy at 1-km vertical resolution in the troposphere above cloud tops and humidity profiles with 10% accuracy at 2-km vertical resolution below 300 hPa. Profiles at an individual site are obtained twice daily, at ~1:30 am and pm, with a horizontal resolution of ~50 km. The swath width is 1500 km. We will present an analysis of temperature and humidity fluctuations associated with tropical Kelvin waves by two different analyses. In the first, we bin temperature and humidity fields from the AIRS level 2 retrieved product into $15^\circ$ longitude bins and 2 days in time, Fourier transform in longitude and time, and, with information on phasing in the vertical dimension, identify modes according to the gravity wave dispersion relation. The large horizontal and temporal bins are necessary to overcome the sounding gaps at low latitude which result from AIRS being a nadir sounder. In the second, we fit temperature and humidity fluctuations to a wave model using Bayesian interpolation, thus overcoming the necessity of binning. With Bayesian interpolation it is possible to fit an atmospheric timeseries to a desired physical model---horizontally propagating waves in this case---while simultaneously distinguishing the waves from the noise of other atmospheric fluctuations. Our final results will be a characterization of the sources and sinks of Kelvin wave activity in the troposphere---to be accomplished by examining momentum flux---and a map of phasing between temperature and humidity fluctuations associated with Kelvin waves which should reveal something about the nature of wave-convection interactions. If AIRS satisfies its design requirements of 1-K temperature accuracy with 1-km vertical resolution, it should easily be able to resolve the temperature fluctuations associated with Kelvin waves.
DE: 3334 Middle atmosphere dynamics (0341, 0342)
DE: 3360 Remote sensing
DE: 3374 Tropical meteorology
DE: 3384 Waves and tides
SC: Hydrology [H]
MN: 2003 Fall Meeting