A new instrument for determining the coarse-mode sea salt aerosol size distribution

After sample collection, the same optical microscope methodology utilized by the GNI was used to analyze the wetted salt particles that impacted onto the slides. In this proof-of-concept study, multiple miniGNIs were attached serially to a kite string, allowing for sampling at multiple altitudes simultaneously. The robustness of the results from this new instrument and methodology for sampling at ambient RH (~75%) the SSA particle size distribution with r(d) > 3.3 mu m are compared with a similar study.

We find that the SSA particle number concentration decreases weakly with altitude and shows no correlation to instantaneous U-10 wind speed along the windward coastline of OModified Letter Turned Commaahu in the Hawaiian Islands.Significance StatementThe goal of our work is to determine the size distribution of large (dry salt radius > 3.3 mu m) sea salt aerosol (SSA) particles in the atmosphere. Understanding the number concentration and size distribution of SSA particles is important because they play a role in many atmospheric processes, affecting visibility, atmospheric chemistry, cloud properties, precipitation formation, etc.

We designed, built, and tested a new low-cost instrument for sampling large SSA particles. In this paper we compare our results to a similar prior study to give insight into the observations made with the new instrument. We flew the instrument on a kite for sampling, but future work could explore using the instrument on other platforms, such as a drone or unmanned aircraft system (UAS).