2010 Annual Research Report

This past summer, Co-Investigator Pathare and numerous colleagues concluded the observational phase of an MFR-funded field campaign in Eldorado Valley, Nevada to study dust devils, which are particle-loaded vertical convective vortices commonly observed on Earth and especially Mars (where their associated dust-lifting may be responsible for the persistent dustiness of the Martian atmosphere). During the survey period, at least two and usually three observers were positioned at spotter stations located approximately 100 m apart, thereby allowing an area of A = 0.55 km² to be surveyed. Researchers observed 442 dust devils in Eldorado Valley this past summer, which in addition to the dust devils surveyed in 2009 brings their grand total to more than 1,000 dust devils.

Pathare and colleagues are now in the process of analyzing the bounty of dust devil data that we have collected, which we anticipate will result in several published manuscripts (possibly within a single special issue). Our first publication (Pathare et al., 2010) utilized the firld data collected in 2009 to address the power law hypothesis of dust devil diameters advanced by Lorentz (Icarus, 203, 683-684, 2009).  Although the close correspondence of the group's observed dust devil densities to the values predicted by Lorentz (2009) would seem to support the power law hypothesis, our qualitative estimates of dust devil diameter are more consistent with an exponential function than a power law formulation (Pathare et al., 2010). They will validate this preliminary assessment by quantitatively calculating dust devil diameters directly from simultaneous stereo photographs taken of dust devils (via a parallax measurement technique), resulting in the most comprehensive size-frequency distribution of terrestrial dust devils ever compiled.

Pathare is also actively engaged in five other active avenues of research: (1) Laboratory study of the effects of impurities on the flow of icy materials on Mars (PI: Bill Durham, MIT); (2) Modeling the recent dynamics of circumpolar Martian ice flow features (PI: Dale Winebrenner, UW); (3) Characterizing the quantitative stratigraphy of north polar basal layers (PI: Patrick Russell, Smithsonian); (4) Searching for buried, bulk water-ice deposits at non-polar latitudes on Mars (PI: William Feldman, PSI); and (5) Modeling the production and modification of small craters on Mars (PI: Jean-Pierre Williams, Ashima Research). 

Papers:

Pathare, A.V., M.R. Balme, S.M. Metzger, A. Spiga, M.C. Towner, N.O. Renno, and F. Saca (2010). Assessing the power law hypothesis for the size–frequency distribution of terrestrial and martian dust devils. Icarus (209), p. 851-853.

Abstracts:

Pathare, A., M. Balme, S. Metzger, A. Spiga, M. Towner, and F. Saca. Field Observations of the Size-Frequency Distribution of Terrestrial Dust Devils: Assessing the Power Law Hypothesis of Dust Devil Diameters. 41^st Lunar and Planetary Science Conference. Abstract #2325.

Balme, M.R., S.M. Metzger, A. Pathare, N. Renno, F. Saca, A. Spiga, and M. Towner. 
A New Field Study of Terrestrial Dust Devils with Application to Mars: Using a Stereo-Camera Survey and GIS to Calculate the Size-Frequency Distribution of Dust Devils in the Southwest USA. 41^st Lunar and Planetary Science Conference. Abstract #2349.

Durham, W.B., A.V. Pathare, and L.A. Stern. Laboratory Measurements of Grain-Size-Sensitive Creep of Particulate-Laden Ice at Planetary Temperatures. 41^stLunar and Planetary Science Conference. Abstract #2135.

Feldman, W.C., S. Maurice, and A. Pathare. Map of Upper Regolith Layer Hydrogen Content Measured Using the Mars Odyssey Neutron Spectrometer. American Geophysical Union Fall meeting 2010, Abstract #P53A-1495.

Koutnik, M.R., D.P. Winebrenner, E.D. Washington, A.V. Pathare, and S. Byrne. Equilibration Timescales for Ice Flow on Gemina Lingula Indicate Enhanced Flow at Low Temperatures. 41^st Lunar and Planetary Science Conference. Abstract #2272.

Metzger, S., M. Balme, A. Pathare, N. Renno, M. Towner, F. Saca, and A. Spiga. Dust Devil Sediment Loading, Wind Speeds and Pressure Excursions. 41^st Lunar and Planetary Science Conference. Abstract #2342.

Spiga, A., A. Pathare, M. Balme, N. Renno, F. Saca, D. Halleaux, and S. Metzger. In Situ Studies of Terrestrial Dust Devils and Ambient Meteorology: Field Measurements of Vorticity. 41^st Lunar and Planetary Science Conference. Abstract #1327.

Stillman, D., D.P. Winebrenner, R.E. Grimm, and A. Pathare. The Radar Effects of Perchlorate-Doped Ice in the Martian Polar Layered Deposits. American Geophysical Union Fall meeting 2010, Abstract #P34A-03.

Williams, J.-P., O. Aharanson, and A.V. Pathare. The Production of Small Primary Craters on Mars. 41^st Lunar and Planetary Science Conference. Abstract #2574.