AGS-PRF: Bridging the Gap--A Combined Observational and Modeling Approach to Develop a Unified Giant Sea Salt Aerosol Source Function

Sea salt aerosols are particles that are formed from blowing winds and breaking waves over the ocean surface. These particles can act as the building blocks for cloud droplets and eventually precipitation. Very large particles, known as giant sea salt aerosols (GSSA) have been historically difficult to observe because most instrumentation has been designed for smaller particles.

There remains considerable uncertainty regarding the production and vertical mixing of GSSA particles within the lowest part of the atmosphere above the ocean’s surface. This study will make measurements of GSSA using a specialized instrument and combine that with numerical modeling to address questions about how these particles move through the atmosphere.

This research is societally important because it will help to guide numerical model development for better representation of clouds and precipitation. This is a postdoctoral research fellowship award, so it also contributes to the development of the next generation of atmospheric scientists.

This award is for observational and modeling research that will address a critical gap in aerosol research relating to giant sea salt aerosol production and distribution. The research plan consists of a three-pronged approach. The researcher will use the mini-Giant Nuclei Impactor to make observations of GSSA during research cruises from Hawai’i.

These data will be analyzed to construct a distribution of GSSA from the turbulent wave layer through the mixed layer of the atmosphere. In parallel, the PI, with help from a mentor, will use Large Eddy Simulation (LES) modeling to identify environmental variables, such as wind and humidity, that have the greatest influence on the vertical transport of GSSA.

Finally, the results from the observations and modeling will be brought together to derive a new sea spray source function that can be used in numerical models.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.