SO-CHIC WorkPackage 3

Deep ocean ventilation pathways

Objectives

This WP aims to describe and understand the dynamics of dense water formation, transformation and import/export in the Weddell Sea, and their role in providing a ventilation pathway between the atmosphere and the abyssal ocean in the wider Southern Hemisphere. This will be approached through a coherent combination of synthesising existing observations, modelling at 1o globally and 1/12o regionally, and a limited number of new observations at key points. This work will address the following goals:

1. Produce decadal time series of observed dense water formation and along-slope transport within and from the Weddell Gyre, and combine these to identify the impact of upstream formation changes on deep interior pathways and ultimate export volumes and properties.
2. Identify the relative role of Ice Shelf Waters (ISW) and High Salinity Shelf Waters (HSSW) formation sites in setting the volume and properties of Weddell Sea dense water.
3. Track the pathways of export of Weddell Sea bottom water through the global ocean and identify the sites, timescales and processes driving consumption of this water.
4. Produce and test a framework for Weddell Gyre dynamics capable of explaining the structure and variability identified from a synthesis of Weddell Sea observations and linking such variability to changes in sea ice production and air-sea fluxes.

Tasks

• Task 3.0: Scientific Coordination [Lead: A.J.S. Meijers (UKRI-BAS); participant: S. Østerhus (UNIRES)]
• Task 3.1: Observe shelf processes and export [Lead S. Østerhus (UNIRES); participants T. Kanzow (AWI), A. Meijers (UKRI-BAS), P. Abrahamsen (UKRI-BAS), G. Madec (SU)]
• Task 3.2: Slope processes and dynamics [Lead T. Kanzow (AWI); participants A. Meijers (UKRIBAS), C. de Lavergne (SU), S. Østerhus (UNIRES)]
• Task 3.3: Bottom water export and consumption [Lead C. de Lavergne (SU); participants A. Meijers (UKRI-BAS), T. Kanzow (AWI), S. Østerhus (UNIRES)]
• Task 3.4: Synthesis and gyre scale dynamics [Lead A. Meijers (UKRI-BAS); participants: T. Kanzow (AWI), S. Østerhus (UNIRES), J-B. Sallée (SU), C. de Lavergne (SU)]

Partners

WP leaders: S. Østerhus (UNIRES), A.J.S. Meijers (UKRI-BAS)

Other participants: C. de Lavergne (SU), G. Madec (SU), T. Kanzow (AWI), M. Meredith (UKRIBAS), P. Abrahamsen (UKRI-BAS), J.B. Sallée (SU)

External collaborator: B. Huber (Uni. Columbia, USA), A. Gordon (Uni. Columbia, USA)