AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Determination of Seasonal and Height Resolved Number Concentration Patterns in a Pollution Impacted Rural Continental Location
ROBERT BULLARD, Charles Stanier, Patrick Sheridan, John Ogren, University of Iowa
Abstract Number: 536 Working Group: Remote and Regional Atmospheric Aerosols
Abstract Aerosols play an important role in Earth’s radiation balance and their climate forcing effects represent the largest uncertainties in the Intergovernmental Panel on Climate Change’s 2007 fourth assessment report. The nucleation, with subsequent growth of nuclei into liquid or solid phase particles is the main source of ultrafine aerosol particles in the atmosphere. While data on nucleation is limited to specialized field campaigns which are limited both temporally and spatially, data on atmospheric particle number concentration is much more widespread. Our current goal is to use five years (2006 – 2010) of highly time resolved particle number concentration data (NOAA Global Monitoring Division of the Earth System Research Laboratory) in conjunction with vertical flight concentration data (NOAA Airborne Aerosol Observatory) near Bondville, IL to better understand season, diurnal, and vertical variation in aerosol number concentration. Preliminary analysis shows peaks in condensation nuclei greater than 10 nm during the spring months (May, April) and during the fall months (September, October). The diurnal pattern of aerosol number has a midday peak which is enhanced during the months of highest number concentration. Particle number peaks coincide with months and times of day of low aerosol mass and surface area. Average vertical profiles show a nearly monotonic decrease with altitude in all months, and vary in magnitude similar to the ground-based measurements. Individual vertical profiles show evidence of plumes of enhanced number concentration, and periods when the entire boundary layer is enhanced by high particle number concentration. These results, while not directly indicating nucleation, will assist field researchers and modelers by providing the seasonal intensity patterns of particle number increases on the ground and aloft.