North Atlantic atmospheric and oceanic circulation

UK weather and climate are strongly shaped by the atmospheric circulation over the North Atlantic.

The position of the North Atlantic jet stream – the band of strong westerly winds crossing the North Atlantic at around 10 km altitude – dominates the weather we experience over timescales of days to decades. In turn, the atmospheric circulation is influenced by the sea surface below.

The evolution of the North Atlantic circulation in the coming decades will be influenced by a combination of natural internal variability and the response to climate change. CANARI will evaluate projected changes in the large-scale North Atlantic atmospheric and oceanic circulation with a particular focus on the roles of internal variability and the climate change response.

It will also investigate the interactions between changes in the large-scale atmospheric circulation and high-impact weather events over the UK. Weather systems (extratropical cyclones and anticyclones) are intrinsically linked with the large-scale atmospheric circulation through a range of dynamical processes. 

Low resolution climate models poorly represent some of these processes, resulting in model biases and lower confidence in projections. 

Higher resolution models simulate a wider range of the relevant space and time scales and can exhibit reduced biases. They can provide opportunities to advance our understanding of the interactions between the large-scale circulation and individual weather systems, especially extremes, and to assess how these relationships may change in future.

CANARI will also investigate the recent development of skillful seasonal-to-decadal forecasting capabilities by leading forecast centres. Our work will link learning on the roles of internal variability and the forced response to climate change to near term projections, with a focus on the extent to which the North Atlantic large-scale circulation and extreme weather events are predictable on seasonal-to-decadal timescales.