HR: 09:45h
AN: PP21E-08    [Abstracts]
TI: Atlantic Ocean Forcing of Multidecadal Variations in North American and European Summer Climate
AU: * Sutton, R T
EM: R.Sutton@reading.ac.uk
AF: Centre for Global Atmospheric Modelling, Department of Meteorology, University of Reading, PO Box 243, Earley Gate, Reading, RG6 6BB United Kingdom
AU: Hodson, D L
EM: dan@met.rdg.ac.uk
AF: Centre for Global Atmospheric Modelling, Department of Meteorology, University of Reading, PO Box 243, Earley Gate, Reading, RG6 6BB United Kingdom
AB: Instrumental records show that during the nineteenth and twentieth centuries there were marked variations on multidecadal timescales in the summertime climate of both North America and western Europe. In the continental US there were significant variations in rainfall and drought frequency, and it has been suggested that changes in the Atlantic Ocean, associated with a pattern of variation known as the Atlantic Multidecadal Oscillation (AMO), were responsible. If confirmed, such a link would be important for climate predictions because the AMO is thought to be driven at least in part by the ocean's Thermohaline Circulation, and may be predictable. However, thus far the evidence for an Atlantic link has been mainly circumstantial, being derived from observations and showing correlation rather than causality. Clarifying whether AMO-related changes in the Atlantic Ocean were indeed responsible for the observed variations in North American summer climate, and whether - in addition - there were impacts on other regions, is therefore an important challenge. We have carried out experiments with an atmospheric GCM to investigate the impact of multidecadal changes in the Atlantic Ocean on boreal summer climate. Through quantitative comparisons between the model results and observations we find compelling evidence that the Atlantic was an important driver of variations during the twentieth century in the summertime climate of both North America and western Europe. Our findings have implications for the interpretation of past instrumental and proxy climate records, and for decadal climate predictions.
UR: http://www.met.rdg.ac.uk/~rowan
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 4513 Decadal ocean variability (1616, 1635, 3305, 4215)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005