USAP-DC

The Southern Ocean is a conduit for exchange between the atmosphere and deep ocean, where heat and carbon are stored for thousands of years, via the ocean''s overturning circulation. However, there remains incomplete understanding how the shape of the seafloor can impact the overturning circulation and the carbon transported by it. Recent theoretical work has suggested that there will be upwelling hotspots downstream of undersea ridges, evidenced by localized carbon outgassing hotspots in models and mapped-data products. However, there has been no direct evidence of localized outgassing near bathymetric features so far. This project will use novel analyses that combine ocean dynamics with corresponding biological and chemical oceanographic observations to more completely account for outgassing and better constrain the global carbon budget, of which the Southern Ocean plays a large role. In addition, a better understanding of the three-dimensional nature of the Southern Ocean''s overturning circulation will help improve predictions of ocean transport, which affects large-scale weather patterns, the yield of fisheries and the melting of the polar ice caps. This work provides broader impacts in two categories, supporting junior scientists through workforce development and promoting research infrastructure by developing new open numerical code that can be used by many research groups. This project proposes to investigate the patterns of carbon outgassing in the Southern Ocean and its connection to the three-dimensional meridional overturning pathways using the Biogeochemical Southern Ocean State Estimate (B-SOSE), a model that assimilates most available observations with the model physics in a self-consistent and conserving manner. The project will first construct an Eulerian isopycnal carbon budget to investigate local carbon outgassing. Then they will use a complementary Lagrangian analysis of the thickness-weighted velocities mapping the three-dimensional pathways of the overturning circulation, critical for interpreting the carbon budget. Finally, the project compare B-SOSE model output and wave glider and autonomous float data at the Southwest Indian Ridge using a suite of ‘virtual’ deployments to understand why outgassing hotspots have not yet been seen in float data. This award reflects NSF''s statutory mission and has been deemed worthy of support through evaluation using the Foundation''s intellectual merit and broader impacts review criteria.

Person	Role
Youngs, Madeleine	Investigator and contact

Antarctic Ocean and Atmospheric Sciences

Award # 2441799

USAP-2441799_1

None in the Database