High-Frequency Orographically Forced Variability in a Single-Layer Model of the Martian Atmosphere
Abstract
A shallow water model with realistic topography and idealized zonal wind forcing is used to investigate orographically forced modes in the Martian atmosphere. Locally, the model reproduces well the climatology at the sites of Viking Lander I and II (VLl and VL2) as inferred from the Viking Lander fall and spring observations. Its variability at those sites is dominated by a 3-sol (Martian solar day) oscillation in the region of VLl and by a 6-sol oscillation in that of VL2. These oscillations are forced by the zonal asymmetries of the Martian mountain field. It is suggested that they contribute to the observed variability by reinforcing the baroclinic oscillations with nearby periods identified in observational studies. The spatial variability associated with the orographically forced oscillations is studied by means of extended empirical orthogonal function analysis. The 3-sol VL1 oscillation corresponds to a tropical, eastward-traveling, zonal-wavenumber one pattern. The 6-sol VL2 oscillation is characterized by two midlatitude, eastward-traveling, mixed zonal-wavenumber one and two and zonal-wavenumber three and four patterns, with respective periods near 6.1 and 5.5 sols. The corresponding phase speeds arc in agreement with the conclusions drawn from the VL2 observations.
Additional Information
Journal of the Atmospheric Sciences, submitted July 1993. The authors acknowledge conversations with D.J. Banfield, D.H. Boggs, J.O. Dickey, M. Ghil, and S.L. Marcus. They also thank Jim Pollack for providing the Martian GCM topography and three anonymous referees for their constructive criticisms and suggestions. The research described in this publication was carried out in part by the Jet Propulsion Laboratory (JPL), California Institute of Technology (CIT), under a contract with the National Aeronautics and Space Administration, and in part by the Climate Dynamics Center, University of California, Los Angeles. It was funded through the JPL/CIT Director's Discretionary Fund for 1992. The model development and simulations took place on JPL's and the NASA Ames Research Center's CRAY Y-MP computers.Attached Files
Submitted - KEPjpltr93-1596.pdf
Files
| Name | Size | Download all |
|---|---|---|
|
md5:139d3ecd5b299943bcab95e092a9ffcb
|
8.0 MB | Preview Download |
Additional details
- Eprint ID
- 29659
- Resolver ID
- CaltechAUTHORS:20120309-091232415
- NASA
- JPL/CIT Director's Discretionary Fund for 1992
- Created
-
2012-03-14Created from EPrint's datestamp field
- Updated
-
2019-10-03Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences
- Other Numbering System Name
- JPL Technical Reports
- Other Numbering System Identifier
- 93-1596