Seasonal and Interannual Variations in Aerosol Characteristics at the ARM Southern Great Plains Site

Multiple years of aerosol data have been collected from routine observations at the ARM Southern Great Plains (SGP) site, along with specialized data from a number of intensive studies. More recently, the suite of routine measurements has included PM1 composition measured with an aerosol chemical speciation monitor (ACSM) and hygroscopicity via a tandem differential mobility analyzer. These two measurements complement the collocated measurements of cloud condensation nuclei (CCN), and can be used to develop detailed CCN spectra that extrapolate to lower and higher supersaturations. We present some initial results from a new effort to produce CCN spectra by merging these observations. In addition to providing guidance for modeling efforts, the merged spectra provide insights into seasonal and interannual variations in aerosol types and sources impacting SGP.