Potential sea salt aerosol sources from frost flowers in the pan-Arctic region

• Published in: Journal of Geophysical Research: Atmospheres
• Main Authors: Xu, Li, Russell, Lynn M., Burrows, Susannah M.
• Language: unknown
• Published: 2022
• Subjects: 54 ENVIRONMENTAL SCIENCES; Arctic; Barrow; Sea ice; Alaska
• Online Access: http://www.osti.gov/servlets/purl/1340876; https://www.osti.gov/biblio/1340876; https://doi.org/10.1002/2015JD024713

In order to better represent observed wintertime aerosol concentrations at Barrow, Alaska, we implemented an observationally-based parameterization for estimating sea salt production from frost flowers in the Community Earth System Model (CESM). In this work, we evaluate the potential influence of this sea salt source on the pan-Arctic (60ºN-90ºN) climate. Results show that frost flower salt emissions substantially increase the modeled surface sea salt aerosol concentration in the winter months when new sea ice and frost flowers are present. The parameterization reproduces both the magnitude and seasonal variation of the observed submicron sea salt aerosol concentration at surface in Barrow during winter much better than the standard CESM simulation without a frost-flower salt particle source. Adding these frost flower salt particle emissions increases aerosol optical depth by 10% and results in a small cooling at surface. Here, the increase in salt particle mass concentrations of a factor of 8 provides nearly two times the cloud condensation nuclei concentration, as well as 10% increases in cloud droplet number and 40% increases in liquid water content near coastal regions adjacent to continents. These cloud changes reduce longwave cloud forcing by 3% and cause a small surface warming, increasing the downward longwave flux at the surface by 2 W m -2 in the pan-Arctic under the present-day climate.