North Atlantic Thermal Persistence and Coherent Evolution
Gidon Eshel
Journal of Geophysical research (Oceans), Vol. 108(C2), 3029, doi:10.1029/2001JC001180, 2003
Abstract
North Atlantic thermal persistence and coherent evolution are
examined. A region near Cape Cod and the Gulf of Maine is identified
as the North Atlantic (NA)'s most thermally persistent, with a unique
combination of high-amplitude, long-lasting sea surface temperature
(SST) anomalies. A mechanism is advanced, whereby that region's
surface ocean reflects deep upper ocean dynamics, with thermal
evolution that tracks heat advection by the slowly evolving upper
ocean. This is consistent with the subtropical gyre playing an active
and central role in NA climate variability. The proposed
interpretation is supported by broad, high lag correlations between
the Bermuda potential vorticity time series (representing the
subtropical gyre state) and surface anomalies. Using the Bermuda
potential vorticity time series as a "dynamical filter", successive
lag correlation patterns reveal surface oscillations that are not
apparent in the raw surface data.