Positive Radiative-Dynamic Feedback in Martian Dust Storms

Details Positive Radiative-Dynamic Feedback in Martian Dust Storms Positive Radiative-Dynamic Feedback in Martian Dust Storms

Dec 2010

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010agufm.p51e..03r&link_type=abstract

American Geophysical Union, Fall Meeting 2010, abstract #P51E-03

Physics

[0300] Atmospheric Composition And Structure, [3329] Atmospheric Processes / Mesoscale Meteorology, [5405] Planetary Sciences: Solid Surface Planets / Atmospheres, [6225] Planetary Sciences: Solar System Objects / Mars

Scientific paper

This work follows from the work of Rafkin [2010] that identified a positive radiative-dynamic feedback mechanism for the growth and maintenance of Mars dust storms under idealized conditions. In this study, the feedback mechanism is explored under more realistic settings including complex background atmospheric structures, topography, thermal tidal forcing, and a variety of mesoscale circulations. As expected, the more complex situation tends to mute the evidence and the impact of the proposed feedback process. Nonetheless, telltale signatures of the feedback mechanism are present and are consistent with the findings from the idealized scenario. Mesoscale simulations at the proposed MSL landing site of Mawrth Valles serve as the foundation for feedback studies with the Mars Regional Atmospheric Modeling System. A background dust field is specified based on MGS-TES retrievals and a dynamically active perturbation dust field is superimposed. The perturbation field arises from dust lifting (both resolved and subgrid scale) and it is subject to transport, diffusion, and sedimentation; the perturbation field is allowed to evolve over time consistent with the dynamics. The dust is tracked via a bin model with 8 discrete mass bins. To test for radiative-dynamic feedback, the radiative activity of the perturbation dust can be toggled on or off. If lifted dust behaves as a passive tracer then the simulations with radiatively active perturbation dust should evolve similarly to those with radiatively inactive dust. In idealized cases, a large difference was noted between these two scenarios indicating that lifted dust was modifying the local circulation. In the realistic scenarios presented here, simulations with radiatively active dust produce a noticeable local drop in atmospheric pressure and an increase in wind speeds, particularly in dust lifting regions where atmospheric dust concentrations are maximized. Analysis of wind residuals show a tendency for rotational and convergent flow, although the total wind tends to be dominated by the strong mesoscale forcing associated with topography. Results are therefore consistent with the hypothesis that a positive-radiative dynamic feedback process contributes to local and regional dust storm growth and maintenance on Mars. Locations where dust is most easily lifted or where surface dust fluxes are large are found to be most susceptible to the process. Implications of these findings in the context of the global dust cycle are discussed.

Affiliated with

Also associated with

No associations

Rating

Positive Radiative-Dynamic Feedback in Martian Dust Storms does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Positive Radiative-Dynamic Feedback in Martian Dust Storms, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Positive Radiative-Dynamic Feedback in Martian Dust Storms will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1498542