Heat Uptake and Transport in the Southern Ocean at High-Resolution and its Projected Changes under Increased Greenhouse Gas Emissions

Hosts: Rebecca Beadling and Graeme MacGilchrist

Between 1971 to 2018, the ocean has taken up >90% of the excess heat trapped on the planet from global warming. Despite occupying only ~25% of the global ocean area, the global ocean south of 30°S, known as the Southern Ocean (SO), accounts for the overwhelming majority of the oceanic heat uptake over the last century. By absorbing this excess heat, the SO is limiting the amount of heat humans “feel” as the climate warms. The ability of the SO to absorb excess heat is intimately tied to its unique and complex ocean circulation, where water from the world’s ocean basins converge and the strongest winds on the planet pull water from the abyss to the ocean surface.

There is a large disagreement among coarse resolution (≥ 1° ocean horizontal grid spacing) model simulations on the amount of and spatial distribution of heat uptake within the SO. Much of this disagreement stems from the varying ability of coarse resolution models to represent key ocean processes that influence oceanic heat uptake and redistribution in the SO. This disagreement amongst models in their patterns of SO heat uptake contributes to uncertainty in model projections for the 21st century. Constraining the amount of heat gain in the SO is important for improving projections of global and regional surface air temperatures, sea level rise, and ocean carbon storage.

The intern will work directly with project mentors to quantify patterns of ocean heat uptake, storage, and transport by ocean circulation in the SO in historical (1850 to 2014) and 21st century (2014 to 2100) projections performed in a hierarchy of coupled climate models recently developed at GFDL, with ocean horizontal grid spacings ranging from 0.50° to 0.125°. The project is highly adaptable and will be guided by the intern’s specific interests, skills, and motivation. Some targeted questions may include: How is heat entering the ocean surface from the atmosphere? In which vertical layers and ocean basins is heat stored? How does ocean circulation redistribute within the ocean? How do these change as the climate warms? How does this impact global and regional sea level?

The intern will use existing python modules to analyze GFDL model output and produce figures and statistics to address questions surrounding SO heat uptake and storage in climate simulations. Potential candidates should have an interest in oceanography, climate change, physics, and/or math. Experience in computer programming will be advantageous.