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An Overview of the SGP Tandem Differential Mobility Analyzer

Collins, Don Texas A&M University
Spencer, Chance Texas A&M University

Category: Instruments

A differential mobility analyzer / tandem differential mobility analyzer (DMA / TDMA) system was integrated into the Aerosol Observing System (AOS) trailer at the SGP site in September, 2005. This instrument is used to continuously characterize the size-resolved concentration, hygroscopicity, and volatility of submicron particles. These data are used to infer aerosol composition and are used to predict humidity-dependent light scattering properties and critical supersaturation-dependent CCN concentration. Currently, aerosol size distributions and size-resolved hygroscopicity at 7 particle sizes are measured roughly 20 times per day. Once-daily measurements of the size-resolved hydration state of the aerosol are made to facilitate comparison of in situ and remote sensing measurements when the ambient RH is intermediate of the efflorescence and deliquescence points of typical aerosol types. All measured distributions are fitted using series of lognormals to assist users in examining changes in aerosol concentration and properties occurring over a range of timescales. An overview of the DMA / TDMA system and a summary of the dataset acquired to date will be presented.

This poster will be displayed at the ARM Science Team Meeting.