My scientific interests on Mars include aeolian geomorphology, recent (and current) climate changes, and the mobility of wind-blown sand and dust. Mars has very distinct seasonal patterns of winds and atmospheric water, dust, and CO₂ content. I would like to better understand how these cycles interact with each other to produce the current martian climate, and how aeolian features on the surface record ancient climatic conditions. Here are brief descriptions of my current projects on which I have recently reported (with other projects in the works):
 
 
1. I am a member of the recently created Mars Dunes Consortium. From this website you can learn news about Mars dunes, find published papers and conference abstracts relating to aeolian processes, and learn more about dunes in general. We are currently planning a Mars Dunes Workshop for fall 2007.
 
2. I've been working with Paul Geissler of the USGS and Bob Haberle of NASA Ames to study how albedo changes on the martian surface impact recent climate change, weather patterns, wind stresses, and other observed atmospheric patterns over the last few decades. Recently we published a Nature Letter in which the Ames global circulation model (GCM) shows a net increase in near surface atmospheric temperatures and wind stresses from the Viking era (1970s) to the early Mars Global Surveyor era (1990s). The changes occurred because there was a net global albedo decrease of ~0.02 (between latitudes 65° S - 65° N) caused by redistribution of relatively bright dust. Apparently the many global dust storms on Mars during the 1970s scattered a great deal of bright dust over much of the planet, and so the albedo maps derived from Viking data reflect this general brightening. Since then, there have been few large dust storms (none I know of during the mid-1980s through the beginning of the Mars Global Surveyor mission in the mid-1990s), and so winds and dust devils slowly swept up the dusty mess left behind by the stormy 1970s, depositing the bright dust in calmer areas and exposing more of the underlying dark surface to the sun's rays.
 
Our Nature article had some press coverage, and some who heard the news would like to attribute our modeled warming (of 0.65° C or 1.2° F) over the 20 year period to changes in solar output, but our work doesn't involve any such changes. The warming we have modeled is caused by changes on the surface of Mars, rather than by any changes in the Sun. Furthermore, the climate forcing process we have identified is caused by the redistribution of bright dust over a darker surface, a process which does not occur on Earth (at least not to such a magnitude that it influences the global climate system). Earth does undergo albedo changes that impact the climate, but the controlling processes are quite different -- such as changes in cloud cover, sea ice, and vegetation. Thus the warming we have modeled is caused by a process that is unique to Mars, and nothing in our work can be used to make inferences about climate change on Earth. I hope this clears up any confusion to the layperson.
 
3. I am continuing to study how changes in surface albedo impact short-term climate change on Mars (we also call this "interannual variations", which can be caused both by changes in overall climate and simple changes in weather patterns from year to year -- it's hard to tease out which is which, especially since the two likely interact with one another). In the summer of 2007 I presented some recent work with colleagues Tony Colaprete and Mike Smith at the Mars 7th International Conference. There's still much to do to undestand how albedo changes caused by the 2001 global dust storm impacted water vapor in the year following the storm, but we're working on it. Our modelling suggests that surface brightness does indeed impact air temperatures (as measured by TES and reported by Mike Smith), which in turn impact where and when clouds form and how much water vapor is in the air. It also seems that the flow of air (we call this "dynamics") around the planet is affected by the change in air temperatures (caused by changes in surface brightness, remember all of these things are connected). All of these coupled processes make understanding one simple change quite difficult, but this also makes the study much more interesting. Science always suprises me, and so I find I'm never bored with my work.