Map of methane concentrations in Autumn (first martian year observed) over layed on true color map of Mars. Credit: NASA/Universita del Salento

The presence and origin of methane on Mars is a source of debate within the science community. Observations over the last decade suggest that methane clouds form briefly over Mars during the summer months. This has left many scientists scratching their heads, since it doesn't fit into models of the Martian atmosphere. To better understand how this trace gas would behave in the the martian atmosphere, models are being created and evaluated that utilize ground-based and atmospheric observations to eventually uncover the truth about the nature of methane in the Martian atmosphere.

From recent observations, it has been suggested that there is evidence for the periodic (seasonal) release of methane occur from discrete surface locations on Mars, although the exact location and mechanism of release is still unknown. Utilizing the Mars Weather Research and Forecasting (WRF) General Circulation Model (GCM)-based on an Earth climate model--an analysis was performed to address the behavior of gases in the Martian atmosphere. The specific goal of this study was to characterize the source of the strongly debated possibility of the existence of methane.

Method

Numerical model simulations with the Mars WRF GCM were applied to the ground-based observations by Mumma et al., (2009). The MarsWRF simulates the natural behavior of trace gas plumes in the Martian atmosphere to reveal the development of the plume over time. These results provide constraints on the timing and location of the release of a methane plume and are interpreted to show the release of methane from localized surface sources with spatial and temporal variability. The observations could be reproduced best if the release occurred just before the time of observation-no more than 1-2 sols earlier-and if this release were nearly instantaneous rather than a slow, steady emission. Furthermore, it required a source region spanning a broad latitudinal range rather than a point emission.

Mars Methane Release: Northern Summer

Implications:

Recent observations suggest that there is strong evidence for the periodic release of methane on Mars occurring from discrete surface locations, although the exact location and mechanism of release is still unknown. Numerical model simulations with the Mars Weather Research and Forecasting (MarsWRF) general circulation model (GCM) have been applied to the ground-based observations of atmospheric methane by Mumma et al., (2009). MarsWRF simulations reproduce the natural behavior of trace gas plumes in the Martian atmosphere, and reveal the development of the plume over time. These results provide constraints on the timing and location of release of the methane plume.

Significance to Solar System Exploration:

The results of this analysis suggests that it is potentially possible to isolate plume source locations to within tens of kilometers, which is within the roving capabilities of future Mars rovers. The numerical approach provides a means to restricting the timing, duration and size of methane release events, and can be used for other trace gas plumes on Mars as well as elsewhere in the solar system. Future missions to Mars will hopefully shed light on the atmospheric behavior of gases in the Martian atmosphere, and ultimately, have the capability to make concrete observations of methane and its source.

Last Updated: 3 April 2012