Floats deployed by the SOCCOM program are being used to estimate pCO2 throughout the year in the Southern Ocean. The first estimates of air-sea CO2 fluxes from these observations were published in Gray et al. (2018). We have combined these float estimates with the traditional ship-based measurements to produce new estimates of the Southern Ocean CO2 flux. This work, published in Bushinsky et al. (2019) affirmed the importance of the wintertime outgassing highlighted in the Gray et al. study.
We also investigated whether the difference between prior flux estimates and those that included float observations could be explained by the difference in where and when the floats sample relative to the shipboard data. We did this through a model subsampling approach, finding that much of the difference between CO2 flux estimates with and without float data can be explained by the increased coverage that floats provide. Additionally, we found that this change in the contemporary Southern Ocean CO2 flux had to be balanced by land or ocean fluxes in the Southern Hemisphere and that float observations every ten days were sufficient to resolve the annual CO2 flux at a given location.
I am continuing this work through an analysis of how well climate models represent this key air-sea flux in the Southern Ocean, investigations of interannual variability, and more.