Organic aerosol value-added product: method development and year-long results from SGP
Authors
Qi Zhang — University of California, Davis
Caroline Parworth — University of California at Davis
Shan Zhou — University of California Davis
Jerome D Fast — Pacific Northwest National Laboratory
—
Chitra Sivaraman — Pacific Northwest National Laboratory
Fan Mei — Pacific Northwest National Laboratory
Alison Tilp — Brookhaven National Laboratory
Category
Aerosol Properties
Description
Organic aerosol (OA) makes up a large portion of aerosols in the atmosphere. A better understanding of the chemical composition of OA is needed to quantify the effects that aerosols have on radiation and clouds. OA is composed of thousands of species, making its chemical and physical properties difficult to characterize. However, recent studies indicate that the application of multivariate factor analysis on ambient OA data acquired with aerosol mass spectrometers (AMS) can lead to the identification of distinct OA factors representative of different sources and evolution processes. The OA factors thus determined can be particularly useful for closure studies on aerosol optical and cloud condensation properties. Three aerosol chemical speciation monitors (ACSM) were recently added to two long-term measurement sites (Tropical Western Pacific and Southern Great Plains) and a mobile facility supported by the ARM Climate Research Facility. The ACSM is a smaller version of an AMS designed to provide long-term, continuous measurements of aerosols with low maintenance. In this presentation, we will report the development of methods that take measurements of total OA and mass spectral information from the ACSM and derive OA factors using Positive Matrix Factorization (PMF). We will describe how the OA factors are derived, the quality assurance (QA) procedures, and comparisons of side-by-side measurements from AMS and ACSM instruments deployed during the Aerosol Life Cycle Intensive Operational Period at Brookhaven National Laboratory. The code generated in this analysis will be run within the ARM Data Management Facility, and the new data product, called Organic Aerosol Composition (OACOMP), will be added to the ARM Data Archive. The results from over a year-long period of ACSM measurements from the SGP site will be presented, along with an analysis that explains the seasonal and multi-day variations in inorganic and organic aerosol components.
