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SUMMARY:Dynamical attribution of recent variability in Atlantic overturnin
 g - Helen Johnson (Earth Sciences\, University of Oxford)
DTSTART:20160215T130000Z
DTEND:20160215T140000Z
UID:TALK63807@talks.cam.ac.uk
CONTACT:Doris Allen
DESCRIPTION:Attributing observed variability of the Atlantic Meridional Ov
 erturning Circulation (AMOC) to past changes in surface forcing is challen
 ging but essential for detecting any influence of anthropogenic forcing an
 d reducing uncertainty in future climate predictions. Here we obtain quant
 itative estimates of wind and buoyancy-driven AMOC variations at 25◦N by
  projecting observed atmospheric anomalies onto model-based dynamical patt
 erns of AMOC sensitivity to surface wind\, thermal and freshwater forcing 
 over the preceding 15 years. We show that local wind forcing dominates AMO
 C variability on short timescales\, whereas subpolar heat fluxes dominate 
 on decadal timescales. The reconstructed transport time series successfull
 y reproduces most of the interannual variability observed by the RAPID-MOC
 HA array. However\, the apparent decadal trend in the RAPID-MOCHA time ser
 ies is not captured\, requiring improved model representation of ocean adj
 ustment to subpolar heat fluxes over at least the past two decades\, and h
 ighlighting the importance of sustained monitoring of the high latitude No
 rth Atlantic. 
LOCATION:MR5\, Centre for Mathematical Sciences
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