[Previous] | [Session 15] | [Next]
T. H. McConnochie, B. J. Conrath, D. Banfield, P. J. Gierasch (Cornell U.), M. D. Smith (NASA/GSFC)
We have used Mars Global Surveyor Thermal Emission Spectrometer (MGS TES) data to generate a time series of maps that illustrate the properties of the polar vortices on Mars. This represents the first detailed study of the structure and evolution of the Martian circumpolar jets. These jets are an important component of the general circulation, and control the critical wintertime transports of water, dust, and momentum into the polar regions. The polar vortices on Mars are analogous to the stratospheric polar vortices on Earth.
We have mapped column-integrated aerosol abundances and vertically resolved temperatures below the 0.1 mb pressure level. Data from each orbit is smoothed and sampled at 1 degree intervals in latitude. The smoothed data is then interpolated onto a uniform longitude-time grid. We calculate the wind field implied by the temperature data using the "balance winds" methodology suggested by Randel (1987, J. Atmos. Sci, 44). From the wind field, we generate maps of potential vorticity for use as a dynamical tracer.
In addition to resolving numerous transient weather events along the vortex boundary, our maps provide graphical illustration of the stationary and traveling planetary waves that were reported by Banfield et al. (2002, Icarus, in press; 2003, in prep.). The largest transient displacements in the polar vortex boundary have amplitudes approaching 10 degrees in latitude. However, the vortex boundary remains intact at all times; no sudden warming events comparable to those which occur occasionally in the terrestrial arctic stratosphere have been observed.
Funding for this research was provided by NASA through the Mars Data Analysis Program.
If the author provided an email address or URL for general inquiries,
it is as follows:
Bulletin of the American Astronomical Society, 34, #3< br> © 2002. The American Astronomical Soceity.