The paper ‘Surface heat fluxes drive a two‐phase response in Southern Ocean mode water stratification’ was published in the Journal of Geophysical Research: Oceans earlier this year.  This was led by Ciara Pimm (previously a PhD student at U. Liverpool, now based at WHOI) and included Andrew Meijers as a key BIOPOLE contributor.  This work contributes to WP3 as it covers the physical processes central to the Southern Ocean subduction of heat, carbon and other tracers and their subsequent export into the global ocean.   

The paper’s plain language summary reads:  

‘The Southern Ocean, surrounding the Antarctic continent, plays an important role in the uptake and transport of heat and carbon. Subantarctic mode waters, which are characterized by their low stratification, play an important role in this uptake of heat and carbon, and therefore the factors impacting their properties need to be properly understood. To understand how surface forcing affects Subantarctic mode waters, sensitivity studies are conducted in an ocean state estimate, which consider the relative importance of surface heat flux, freshwater flux, and wind stresses on the stratification of mode waters. Surface heat flux has the largest impact on mode water formation both on seasonal and longer interannual timescales. Initially, surface heat loss leads to a decrease in stratification in the mode waters. However, there is a delayed response where the surface temperature response is effectively damped by the atmosphere and there is an opposing-signed salinity response advected into the region, leading to a subsequent increase in stratification in the mode waters.’

The full paper may be (open) accessed here.   

A follow up study that looks in more dynamical detail at the processes responsible for this two phase response is presently under review.