Spatial and Temporal Distribution of Sea Salt Aerosol Mass Concentrations in the Marine Boundary Layer From the Arctic to the Antarctic

Global warming, increases in sea surface temperatures (SST), and reductions in sea ice may lead to changes in the distribution of global sea salt aerosol (SSA) concentrations, which may in turn affect the global climate. However, there are few global-scale observations of SSA over marine environments. Here, we report SSA mass concentrations observed along the cruise tracks of the Chinese Polar Research Expedition in summer 2008-2018. We found the following: (1) There are significant differences between SSA concentrations in sea areas at different latitudes, and that of the Arctic Ocean was significantly lower than other sea areas; (2) over the last 10 years, the SSA concentrations in the Bering Sea were significantly higher in 2016 than in 2012, and trends from the Arctic Ocean and Southern Ocean are similar, as both showed a minimum in 2014; (3) the sea-air temperature differences among the various marine regions studied may contribute to the different distribution of SSA concentrations; (4) sea ice fraction and SST are probably the main factors controlling the interannual changes in SSA concentrations in the Arctic Ocean and Bering Sea, respectively; and (5) The large sea-air temperature difference in the Southern Ocean may promote the emission of SSA. Therefore, the SST parameterization of GEOS Chem model in the low SST sea area (the Southern Ocean) may have an excessively large effect on suppressing SSA emission resulting in a significant underestimation of the GEOS-Chem model in the Southern Ocean (-62%).