HR: 14:40h
AN: A12D-05    [PDF]
TI: Gravity Waves in ER-2 Observations During CRYSTAL-FACE: Propagation Characteristics and Potential Role in Cirrus Cloud Formation
AU: * Alexander, M J
EM: alexand@cora.nwra.com
AF: Colorado Research Associates Division of NorthWest Research Associates, 3380 Mitchell Lane, Boulder, CO 80301 United States
AU: Sherwood, S
EM: Steven.Sherwood@yale.edu
AF: Yale University, P. O. Box 208109, New Haven, CT 06520 United States
AU: Mahoney, M J
EM: Michael.J.Mahoney@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive MS 246-101, Pasadena, CA 91109 United States
AU: Bui, P
EM: pbui@mail.arc.nasa.gov
AF: NASA Ames Research Center, Mail Stop 245-4, Moffett Field, CA 94035 United States
AB: Gravity waves are known to affect cloud formation via the temperature perturbations they cause, and these effects can be significant in conditions that are otherwise marginal for cloud formation. Cirrus clouds near the tropopause can form in the cold phases of gravity waves. The ER-2 aircraft observations during the CRYSTAL-FACE campaign provide a unique set for gravity wave analysis. For the first time, data from both the Microwave Temperature Profiler (MTP) and Meteorological Measurement System (MMS) were obtained together from the ER-2 platform, with flight paths near convection. Analyses of MTP and MMS data can be combined to provide the full set of gravity wave parameters needed to model their origin, propagation, and eventual fate. This wave analysis requires long, constant-level flight paths. First a wavelet analysis in horizontal wavenumber is performed along the flight path direction for measurements of temperature and horizontal wind. From this, the strongest wave modes are identified, and the vertical wavenumber estimated from the MTP data for these modes. Linear wave theory is then employed to compute the propagation directions and intrinsic frequencies for these strongest wave modes. The results of this analysis thus provide the full three-dimensional propagation characteristics for the dominant gravity wave modes in the data. We subsequently use these results to examine their role in cirrus cloud formation at lower altitudes, and compare the results to in situ measurements made from the WB-57F aircraft platform.
DE: 0320 Cloud physics and chemistry
DE: 3384 Waves and tides
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting