Dynamical modeling of a planetary wave mechanism for a Martian polar warming |
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| Institution: | 1. Department of Physics, Jahangirnagar University, Savar, Dhaka-1342, Bangladesh;2. Fakultät für Physik und Astronomie, Ruhr-Universittät Bochum, D-44780 Bochum, Germany;1. Faculty of Engineering and Natural Sciences, International University of Sarajevo, Hrasnička cesta 15, Ilidža, 71210 Sarajevo, Bosnia and Herzegovina;2. Centre for Theoretical Physics, The British University in Egypt (BUE), El-Shorouk City, Cairo, Egypt;3. Department of Physics, Faculty of Science, Port Said University, Port Said 42521, Egypt;1. Insititute for Automation and Control Processes, Far Eastern Branch, Russian Academy of Sciences, Vladivostok 690041, Russia;2. Institute for Complex Analysis of Regional Problem, Far Eastern Branch, Russian Academy of Sciences, Birobidzhan 679016, Russia;1. Centre for Research in Earth and Space Science (CRESS), York University, Canada;2. Dept. of Geological Sciences, Indiana University, United States;3. USRA/Ames Research Center, United States;4. Ames Research Center, United States;5. Jet Propulsion Laboratory, United States;6. Malin Space Science Systems, United States;7. Salish Kootenai College, United States;8. Southwest Research Institute, United States;9. Texas A&M University, United States;10. Cornell University, United States;11. Jet Propulsion Laboratory/Caltech, United States |
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| Abstract: | A dynamical mechanism for the Martian (atmospheric) polar warming observed by the Viking IRTM during the 1977 winter solstice dust storm (and a similar one possibly observed by Mariner 9 in 1971) is proposed, and investigated using a simplified nonlinear model. The model is of a type previously used to successfully simulate the essential aspects of terrestrial sudden stratospheric warmings. The dynamical mechanism is, in part, very similar fundamentally to that responsible for these warmings, involving planetary-scale waves. A number of numerical experiments have been conducted to assess the basic viability of such a mechanism for the martian polar warming and to examine its sensitivity to several factors. These experiments demonstrate that a planetary wave mechanism can produce a polar warming with the magnitude and suddenness of that observed. A planetary wave mechanism must primarily involve wavenumber 1, as wavenumber 2 is too strongly vertically trapped to produce a warming like that observed. The necessary wave forcing in the present model can be topographic (mechanical) or thermal (and nonstationary), and is relatively large but certainly plausible. The strong radiative damping in the Mars atmosphere acts to substantially inhibit a warming, through its effects on both the zonal flow and the wave. Dissipation plays a greater role relative to transience in a model Martian warming of the type studied here than in a sudden stratospheric warming. Increasing radiative damping during a warming due to higher temperatures and greater dust loading may play a role in yielding a relatively rapid cooling phase for the Mars warming event. The residual mean meridional circulation during a model warming entails strong poleward and downward flow into high northern latitudes, throughout a very deep region. This probably indicates similar transport of atmospheric dust, as well as water. Such transports are of considerable potential significance for both the dust and water cycles on Mars. |
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