Update to “Reconciliation of coarse mode sea‐salt aerosol particle size measurements and parameterizations at a subtropical ocean receptor site” regarding the use of aerodynamic particle sizers in marine environments

Abstract

In the January 2006 issue of Journal of Geophysical Research, Reid et al. presented their findings regarding the sometimes large biases found in the measurement of the size and inferred mass concentration of coarse mode sea‐salt particles. This was done on the R/P Floating Instrument Platform (FLIP) off of the coast of Oahu, Hawaii, where long fetches of the clean marine environment could be studied. As part of this analysis, data from optical particle counters and TSI aerodynamic particle sizers (APS) (model 3320) were compared to filter mass and chemistry. It was found that a ground‐based APS 3320 gave superior performance on measurement of sea‐salt properties relative to other size spectrometers when previously published correction factors were used. However, a calibration study of APS instruments by Volckens and Peters (2005) was published while Reid et al. (2006) was in press. Volckens and Peters (2005) found significant differences in counting efficiency between wet and dry particles that included evidence for particle impaction inside the APS's acceleration nozzle. This finding does not impact Reid et al.'s (2006) key results or conclusions. However, it does bear relevance to specific comments made regarding what was suggested as appropriate use of APS‐type instruments. It also has bearing on some unexplained anomalous behavior in the Center for Interdisciplinary Remotely‐Piloted Aircraft Studies (CIRPAS) wing‐mounted APS unit. In this short note we briefly review the APS performance bibliography, provide correction factors for size estimates presented in Reid et al. (2006), and discuss how the most current findings impact the study of coarse mode sea salt.