Sept 5, 2012: Recent dust science articles
As we approach a new season, perhaps some recent dust science articles would be of interest!
First, Science recently published work by a team at NASA's Goddard Space Flight Center and at Univ of Maryland that presents new remote sensing data showing that mineral/soil dust(not industrial particulates) 'advecting' as aerosols from Asia (largely China) to North America is arriving in such significant quantities that, they say, those Asian aerosols may match the total dust emissions emitted from all North American source areas. See a summary at: http://earthobservatory.nasa.gov/IOTD/view.php?id=78742&src=eoa-iotd and see the Scienceabstract at: http://www.sciencemag.org/content/337/6094/566.abstract
How much these Asian aerosols contribute to the dust-on-snow reductions in snow albedo that we're observing in the Colorado snowpack is not addressed in this research. However, prior research has shown that most of our dust-on-snow particles are too large to have made the trans-Pacific journey. Until new research shows otherwise, it's still reasonable to attribute the primary effects on snow albedo to our own Colorado Plateau source area dust. (See the Neff and Lawrence articles listed on the CSAS Publications website). Nonetheless, this is an interesting article with interesting imagery of aerosol plumes traversing the northern hemisphere across the Pacific to North America, showing large-scale atmospheric circulations. And, it offers some perspective on what a serious problem dust is in China ...
Closer to home, a pair of recent papers published in the July 26, 2012 issue (Vol 48) of Water Resources Research by Tom Painter, his students, and their team further explore the findings of the initial Painter et al dust-on-snow publication in . Tom is first author on the Part I article summarizing six years worth of dust-on-snow observations at Senator Beck Basin, from spring 2005 to spring 2010. See the abstract for Tom's "Part I" article at http://www.agu.org/pubs/crossref/2012/2012WR011985.shtml
The second article, Part II of the pair, is first-authored by PhD student McKenzie Skiles. She investigates "interannual variability in radiative forcing and snowmelt rates". Her snowmelt energy budget modeling results, 'removing' the dust from the dust-contaminated snowpacks actually observed at Senator Beck Basin from 2005 to 2010, show substantial advances in the date of 'snow all gone' (SAG) in those seasons, as compared to SAG in a modeled dust-free snowpack, as well as accelerated timing and rates of snowmelt outflow (at the base of the snowpack). She also explores the comparative impacts of increases in mean air temperatures on those processes, finding that direct absorption of radiation by dust is already exceeding the spring snowmelt energy budget impacts that 2 and 4 degree C increases in air temperatures (added to the actual measured temperatures at Senator Beck Basin) would have produced. See the abstract for McKenzie's article, a "Featured Article" in this issue of Water Resources Research, at http://www.agu.org/pubs/crossref/2012/2012WR011986.shtml
Chris Landry, Executive Director
Center for Snow and Avalanche Studies
PO Box 190, Silverton, CO 81433 USA