The sensitivity of Southern Ocean aerosols and cloud microphysics to sea spray and sulfate aerosol production in the HadGEM3-GA7.1 chemistry-climate model

Atmospheric Chemistry and Physics (2019)

Here we evaluate the representation of Southern Ocean aerosols in the HadGEM3-GA7.1 chemistry-climate model. Compared with aerosol optical depth (AOD) observations the model simulates too-high AOD during winter and too-low AOD during summer.

By switching off dimethylsulfide (DMS) emission in the model, we show that sea spray aerosol is the dominant contributor to AOD during winter. By examining MODIS AOD as a function of wind speed from the ERA-Interim reanalysis and comparing it with the model, we show that the sea spray aerosol source function in HadGEM3-GA7.1 overestimates the wind speed dependency.

Our results highlight the importance of atmospheric chemistry for simulating aerosols and clouds accurately.