A conceptual model of ocean heat uptake under climate change

Add to your list(s) Download to your calendar using vCal

• Prof. David Marshall, University of Oxford
• Wednesday 25 March 2015, 14:00-15:00
• British Antarctic Survey, Room 307.

If you have a question about this talk, please contact Dr Alexander Brearley.

If external to BAS, please email the organiser in advance to gain access to the building

A conceptual model of ocean heat uptake is developed. The roles of Southern Ocean Ekman and eddy transports, North Atlantic Deep Water (NADW) formation, and diapycnal mixing in controlling ocean stratification and transient heat uptake are investigated under climate change scenarios, including imposed surface warming, increased Southern Ocean wind forcing, with or without eddy compensation, and weakened meridional overturning circulation (MOC) induced by reduced NADW formation. With realistic profiles of diapycnal mixing, ocean heat uptake is dominated by Southern Ocean Ekman transport and its long-term adjustment controlled by the Southern Ocean eddy transport. The time scale of adjustment setting the rate of ocean heat uptake increases with depth. For scenarios with increased Southern Ocean wind forcing or weakened MOC , deepened stratification results in enhanced ocean heat uptake. In each of these experiments, the role of diapycnal mixing in setting ocean stratification and heat uptake is secondary. Conversely, in experiments with enhanced diapycnal mixing as employed in ‘‘upwelling diffusion’’ slab models, the contributions of diapycnal mixing and Southern Ocean Ekman transport to the net heat uptake are comparable, but the stratification extends unrealistically to the sea floor. The simple model is applied to interpret the output of an Earth system model, the Second Generation Canadian Earth System Model, in which the atmospheric CO2 concentration is increased by 1% per year until quadrupling. It is found that Southern Ocean Ekman transport is essential to reproduce the magnitude and vertical profile of ocean heat uptake.

This talk is part of the British Antarctic Survey - Polar Oceans seminar series series.

This talk is included in these lists:

• All Talks (aka the CURE list)
• Annual Food Agenda
• Biology
• British Antarctic Survey
• British Antarctic Survey, Room 307
• Cambridge Environment
• Climate Science Seminars within Cambridge
• Featured lists
• Life Sciences
• Life Sciences
• ME Seminar
• Queens' College Politics Society
• School of Physical Sciences
• Talks related to atmosphere and ocean dynamics and climate science
• Talks related to sustainability and the environment
• history
• my_list
• ob366-ai4er
• other talks

Note that ex-directory lists are not shown.