As human civilization pours more greenhouse gases into the atmosphere thereby causing and exacerbating climate change, the ocean serves as a temporarily and partial buffer as it absorbs large quantities of the emitted greenhouse gases (e.g., CO2), removing them from the atmosphere. Around Antarctica one of the densest water masses in the ocean is formed due several processes including intense cooling by the atmosphere. This water mass captures large quantities of atmospheric CO2, which subsequently sink to great depths and flow northward within the newly formed dense water mass, as part of the so called meridional overturning circulation (MOC) of the ocean. The MOC stretches across the entire globe, and further influences or underscores many aspects of climate (additionally to the CO2 capture), including heat transport. Thus it is of great importance to improve the understanding of MOC pathways and dynamics, in order to better understand the state and evolution of the climate system as a whole. Yet the MOC in the southern ocean remains only partially understood, and vastly under-sampled. The latter state is due to the great difficulties and price of taking measurements in the stormy, frigid, and remote southern ocean. That is even more so for the deep components of the MOC described above, i.e., it is exceedingly difficult logistically to take continuous measurements of circulation at depths of several kilometers underwater in this setting. However, continuous observation of the surface of the ocean (e.g., current velocity, temperature, etc) is now routinely and continuously conducted using satellite remote sensing. The present project proposes to use and extend knowledge of the relation between shallow and deep ocean circulation dynamics, in order to indirectly measure the deep circulation in the southern ocean through satellite remote sensing. The achievement of this goal would then allow inspection and continuous monitoring of the deep MOC in the southern ocean. That will in turn improve our understanding of the climate system, as well as inform as to the rate of changes within the ocean, and of potential changes in its climate change buffering capabilities. To achieve these goals, theoretical relations between the deep and shallow circulation in the southern ocean will be inspected in various scenarios within realistic numerical models of the southern ocean to validate and inform further development of these theoretical relations. These relations will then be applied to contemporary and past decades remote sensing data in the southern ocean to evaluate the deep circulation, its properties, and its evolution over time.

Additional material on this project can be found in the following link: https://dept.atmos.ucla.edu/stewart/remotely-sensing-overturning-circulation-variability-southern-ocean

Project researchers:

Postdoctoral researcher: Aviv Solodoch, UCLA, AOS department, asolodoch@atmos.ucla.edu

PI: Professor Andrew Stewart, UCLA, AOS department

Co-PI: Professor Andy McC. Hogg, Australian National University (ANU), Research School of Earth Sciences