HR: 17:36h
AN: A44A-09    [Abstracts]
TI: Propagation of Kelvin Waves in the Troposphere as Seen in AIRS Data
AU: * Leroy, S S
EM: leroy@huarp.harvard.edu
AF: Harvard University, Anderson Group, 12 Oxford St., Cambridge, MA 02138 United States
AU: Fetzer, E J
EM: Eric.J.Fetzer@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109 United States
AU: Granger, S L
EM: Stephanie.L.Granger@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109 United States
AB: While Kelvin waves are known to propagate upward in the tropical stratosphere from satellite data and in situ measurements reveal signs of upward propagation in the stratosphere, no observations linking Kelvin wave activity and the distribution of tropospheric water vapor have been made. Retrievals of tropospheric temperature, water vapor, and outgoing longwave radiation from AIRS data offer a rich new opportunity to probe the interaction of clouds, convection, water vapor and dynamics associated with tropical waves. We focus on Kelvin waves. We have extracted all successful retrievals of temperature and water vapor using AIRS infrared data between 2S and 2N latitude for the month of January, 2003. Because the data is irregularly sampled in longitude and time, we use Bayesian interpolation with zonal propagation as the basis functions to find what Kelvin waves are present. We have found a class of Kelvin waves which originate in the troposphere and propagate into the stratosphere. These waves are defined by monotonically decreasing phase of temperature anomalies starting within the troposphere. An animation of the temperature anomalies reveals nearly barotropic structure between 300 hPa and 500 hPa with specific humidity anomalies strong correlated with temperature anomalies. Below this layer is evidence of a checkerboard pattern in the longitude-height temperature anomaly field, an indication of the presence of both upward and downward propagation as might be induced by reflection at the Earth's surface. That specific humidity and temperature are in phase in the 300- to 500-hPa layer poses problems for theories of Kelvin wave generation. If diabatic effects were responsible for wave generation, then the phasing between convection/humidity and temperature would have convective anomalies leading temperature anomalies by 90. Furthermore, kinematic effects could not be responsible for wave generation because its efficiency approaches zero at increasingly large horizontal scales. We will speculate on other potential Kelvin wave generation mechanisms which may be at work.
DE: 3360 Remote sensing
DE: 3374 Tropical meteorology
DE: 3384 Waves and tides
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting