SEMINAR: AOML Seminar - Sept. 17, 2012 - 2:00 p.m. - Dr. Shane Elipot - “Observed basin-scale response of the North Atlantic Meridional Overturning Circulation to wind stress forcing”

[Aoml.Receptionist <aoml.receptionist@noaa.gov>]

AOML Seminar

 

DATE:              Monday, Sept. 17, 2012

TIME:               2:00 p.m. – refreshments at

                           1:45 p.m.

Location:     AOML First Floor

                           Conference Room

SPEAKER:      Dr. Shane Elipot

                             National Oceanography Center

 Liverpool, United Kingdom

TITLE:             “Observed basin-scale response of the North Atlantic Meridional 
Overturning Circulation to wind stress forcing”

 

Abstract: The response to wind stress forcing of the Atlantic Meridional Overturning Circulation (AMOC) is investigated from an observational standpoint, using four
time series of overturning transports below 1000 m spanning 3.7 years. These time series are derived from four moored arrays located on the western boundary of the
North Atlantic basin: the RAPID WAVE array (42.5 N), the Woods Hole Oceanographic Institution Line W array (39 N), the RAPID MOC array (26.5 N), and the MOVE
array (16 N). Mode decompositions of the analytic cross-covariance between these transport time series and scaterrometer wind stress over the North Atlantic suggest that
basin-scale variability of atmospheric wind stress significantly drives the AMOC on relatively short time scales. First, the arrangement of the phases of the transport time series
at semi-annual and annual time scales is shown to be statistically linked to basin-wide seasonal patterns of wind stress and wind stress curl. This predominant mode of co-variability
between overturning transports and wind stress is interpreted in terms of rapid basin-scale adjustments in the form of two counter-rotating meridional overturning Ekman cells
centered on the tropics and the subtropical gyre. A second mode of co-variability is found which is associated with anomalous patterns of wind stress and wind stress curl correlated
with the North Atlantic Oscillation. This mode acts to modulate the strength of the horizontal gyre circulations, and to reinforce and weaken at times an inter-gyre overturning cell.