Research : thermohaline circulation (THC)
Hysteresis in the Atlantic THC
We are exploring the potential for a rapid collapse in the THC by exploring the response to freshwater input in the North Atlantic. Specifically, we are mapping the hysteresis structure of the FAMOUS AOGCM's response to freshwater hosing.
Relevant papers:
• Hawkins et al., 2011, 'Bistability of the Atlantic overturning circulation in a GCM and links to ocean freshwater transport', Geophys. Res. Lett., 38, L10605
Optimal perturbations in the Atlantic
As part of the RAPID and THOR projects we are estimating the perturbations to the ocean state which result in the most rapid change in the THC and related aspects of climate. These regions are also optimal for additional observations to improve climate predictions.
Relevant papers:
• Hawkins & Sutton, 2011, 'Estimating climatically relevant singular vectors for decadal predictions of the Atlantic Ocean', Journal of Climate, 24, p109
• Hawkins & Sutton, 2009, 'Decadal predictability of the Atlantic Ocean in a coupled GCM: forecast skill and optimal perturbations using Linear Inverse Modelling', Journal of Climate, 22, p3960
Risk assessment of rapid climate change
The RAPID-RAPIT project is assessing the risk (both probability and impacts) of a rapid change in the Atlantic THC, primarily using a multi-thousand member ensemble of integrations of the HadCM3 GCM on climateprediction.net. The risk of smaller, internally generated, rapid changes in the MOC will also be assessed using a variety of GCMs.
Relevant papers:
• Hawkins & Sutton, 2008, 'Potential predictability of rapid changes in the Atlantic meridional overturning circulation', GRL, 35, L11603
