Abstract for School and Workshop on Polar Climates: Theoretical, Observational and Modelling Advances

[willaguiar]

Hello everyone, Im submitting an abstract on our results for the School and Workshop on Polar Climates: Theoretical, Observational and Modelling Advances. Please let me know your thoughts on it. Deadline for submission is April 1st. Download abstract here

[adele-morrison]

Suggested revised abstract:

Ocean surface vertical resolution controls Dense Shelf Water formation around Antarctica

The formation of deep and bottom waters in polar regions is a major control on oceanic carbon and heat uptake and is the main process that ventilates the deep and abyssal ocean. Nevertheless, ocean models often fail to accurately represent the formation of the two main dense waters that fill the deep and abyssal oceans, Antarctic Bottom Water and North Atlantic Deep Water (NADW). This study probes a model that has a good representation of dense water formation over the Antarctic continental shelf to investigate how sensitive the dense water formation is to the model configuration. In particular, we test how the thickness of the ocean top vertical layer alters the production of NADW and Antarctic Dense Shelf Water (DSW), a precursor of Antarctic Bottom Water. Several sensitivity studies are run with the ACCESS-OM2-01 and the MOM6 Pan-Antarctic ocean-sea ice models, with varying top cell thickness. We find that increasing the thickness of the top vertical layer decreases the rate of DSW production over the Antarctic continental shelf in both ACCESS-OM2 and MOM6, with a 60% decrease when the upper layer is increased from 1m to 5m thick. This result is insensitive to the choice of boundary layer mixing scheme, and occurs with both the K-profile parameterisation (KPP) and energetics based planetary boundary layer (ePBL) parameterisations. Ocean only, single column experiments show that the decrease in dense water formation is caused by a more buoyant surface layer in simulations with thicker surface cells. In contrast, the production of the densest NADW waters in the Labrador Sea increases as the top ocean cell thickens. We hypothesise that the differing responses between the Antarctic and North Atlantic dense water formation to vertical resolution is due to convection in the North Atlantic being driven primarily by heat fluxes, while convection at the Antarctic margins is primarily salt-driven.

[AndyHoggANU]

I found the last few sentences confusing. Can I suggest:

Ocean only, single column experiments show that the decrease in dense water formation is caused by a less dense surface layer in simulations with thicker surface cells.

In contrast to the Antarctic region, in the North Atlantic Ocean the production of the densest NADW waters in the Labrador Sea increases as the top ocean cell thickens.