Atmospheric science is a worthwhile undertaking that is enjoyable as well. The increasing importance of weather prediction during a period of global climate change needs not be emphasized here, but the challenges and rewards of the study are still of interest – even to scientists who do not study the atmosphere.
In example, a research team led by Dr. Kristi A. Gebhart of Air Resources Division, National Park Service, Fort Collins, CO, has completed studies on the back-trajectory-based source apportionment of airborne sulfur and nitrogen concentrations at Rocky Mountain National Park, Colorado. Her findings were published in Atmospheric Environment earlier this year (Volume 45, Issue 3, January 2011, Pages 621-633).
Dr. Gebhart says that “the Rocky Mountain Atmospheric Nitrogen and Sulfur Study (RoMANS), conducted during the spring and summer of 2006, was designed to assess the sources of nitrogen and sulfur species that contribute to wet and dry deposition and visibility impairment at Rocky Mountain National Park (RMNP), Colorado. Several source apportionment methods were utilized for RoMANS, including the Trajectory Mass Balance (TrMB) Model, a receptor-based method in which the hourly measured concentrations are the dependent variables and the residence times of back trajectories in several source regions are the independent variables. The regression coefficients are estimates of the mean emissions, dispersion, chemical transformation, and deposition between the source areas and the receptors. For RoMANS, a new ensemble technique was employed in which input parameters were varied to explore the range, variability, and model sensitivity of source attribution results and statistical measures of model fit over thousands of trials for each set of concentration measurements.
Surprisingly, she found that most of the depositions were from places other than Colorado: “results showed that carefully chosen source regions dramatically improved the ability of TrMB to reproduce temporal patterns in the measured concentrations, and source attribution results were also very sensitive to source region choices. Conversely, attributions were relatively insensitive to trajectory start height, trajectory length, minimum endpoints per source area, and maximum endpoint height, as long as the trajectories were long enough to reach contributing source areas and were not overly restricted in height or horizontal location. Source attribution results estimated that more than half the ammonia and 30–45% of sulfur dioxide and other nitrogen-containing species at the RoMANS core site were from sources within the state of Colorado. Approximately a quarter to a third of the sulfate was from within Colorado.”
This research shows not only the importance of the Federal government in regulating the air pollutants, but also the importance of a United Nations regulation of air pollutants.
Though one country, state or county – or even a single person – might not think they are able to affect anyone else by their emissions, or that the emissions would be so diffuse by the time they arrive at their neighbor’s lands, they are certainly wrong.
Like all science, atmospheric science teaches us just how much people depend on each other, and what an integral role we play in our environment.
If you have further questions about her research, you may either read her findings yourself, or contact her at gebhart-AT-cira.colostate-DOT-edu.