AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Long-term Interannual Variability of Aerosol Sources Impacting Mauna Loa Observatory, Hawaii
LAUREN POTTER, Sonia Kreidenweis, Molly Morman, Barry Huebert, Steven Howell, John Zhuang, Nicole Hyslop, Warren White, Colorado State University
Abstract Number: 430 Working Group: Remote and Regional Atmospheric Aerosols
Abstract Located in the remote Pacific Ocean at an elevation of nearly 4 kilometers above sea level, Mauna Loa Observatory (MLO) is an ideal and unique measurement site for ground-based, free tropospheric observations. This study will make use of two long-term Mauna Loa Observatory aerosol datasets to identify contributions of long distance influence from both natural (biogenic and volcanic) and anthropogenic aerosol sources. The first dataset is obtained from a collection of daily filter samples collected from 1989-2009 during nighttime downslope (free-tropospheric) transport conditions obtained by the University of Hawaii at Manoa and analyzed for total aerosol-phase concentrations of NO$_3$^-, SO$_4$^(2-), MSA, Cl$^-, oxalate, Na$^+, NH$_4$^+, K$^+, Mg$^(2+), and Ca$^(2+). The second dataset consists of recently analyzed PM$_(2.5) filter samples obtained at the Interagency Monitoring of Protected Visual Environments (IMPROVE) Network Mauna Loa Observatory location (MALO). The IMPROVE sampler was run during overnight hours only for continuous three and four day time periods and covers the time period from 1988-2010. Filters were weighed to determine total PM$_(2.5) mass and analyzed for the following elements: Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, and Pb. We identified seasonal and interannual variability in aerosol concentrations from both datasets at Mauna Loa Observatory and further investigated these patterns using HYSPLIT and EPA PMF model analyses to identify relevant aerosol sources. The data reflect changes in large scale circulation patterns that impact transport efficiency to this receptor site, in addition to changes in source emission strength. In this work we focus on the impacts of circulation changes on the variability and trends in the observations.