Abstract
The paper investigates the processes that drive the spatiotemporal evolution of baroclinic transient waves in the Martian atmosphere by a simulation experiment with the Geophysical Fluid Dynamics Laboratory (GFDL) Mars general circulation model (GCM). The main diagnostic tool of the study is the (local) eddy kinetic energy equation. Results are shown for a prewinter season of the Northern Hemisphere, in which a deep baroclinic wave of zonal wavenumber 2 circles the planet at an eastward phase speed of about 70° Sol-1 (Sol is a Martian day). The regular structure of the wave gives the impression that the classical models of baroclinic instability, which describe the underlying process by a temporally unstable global wave (e.g., Eady model and Charney model), may have a direct relevance for the description of the Martian baroclinic waves. The results of the diagnostic calculations show, however, that while the Martian waves remain zonally global features at all times, there are large spatiotemporal changes in their amplitude. The most intense episodes of baroclinic energy conversion, which take place in the two great plain regions (Acidalia Planitia and Utopia Planitia), are strongly localized in both space and time. In addition, similar to the situation for terrestrial baroclinic waves, geopotential flux convergence plays an important role in the dynamics of the downstream-propagating unstable waves. © 2013 American Meteorological Society.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 3415-3447 |
| Number of pages | 33 |
| Journal | Journal of the Atmospheric Sciences |
| Volume | 70 |
| Issue number | 11 |
| DOIs | |
| State | Published - Nov 2013 |
| Externally published | Yes |
Bibliographical note
KAUST Repository Item: Exported on 2020-10-01Acknowledged KAUST grant number(s): KUS-C1-016-04
Acknowledgements: This work was supported by Grant NNX09AT57G from the Mars Fundamental Research Program of NASA and in part by Award KUS-C1-016-04 made by King Abdullah University of Science and Technology (KAUST). The contribution by R. J. W. was made possible by funding from the NASA Planetary Atmospheres Program and the Mars Data Assimilation Program. The many helpful comments by Jeffrey Barnes and anonymous reviewers on earlier manuscript versions of the paper helped us significantly improve the design of the numerical experiments and the analysis of the results.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.