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Tropical Pacific Drifting Buoys
Rick Lumpkin / Mayra Pazos, AOML, Miami
NOVEMBER 2008
During November 2008, 383 satellite-tracked surface drifting buoys, 90% with
subsurface drogues attached for measuring mixed layer currents, were reporting
from the tropical Pacific. Strong westward anomalies (25-50 cm/s
basin-averaged) were measured by many drifters in the latitude band 2-6S,
with the largest anomalies seen at 130-150W, suggesting an acceleration of
this band of the SEC. Westward anomalies at 10N were consistent with a southward
shift of the NEC/NECC separation latitude from its climatological November
location. SSTs were close to climatological November values in the center of
the basin, with warm anomalies of +0.5 to +1.5C common west of the dateline and
north of 10N, a persistent pattern over the last several months. Very warm
anomalies (+1.5 to +3.0C) were measured by many drifters north of 20N and west
of the dateline. In the southeastern tropical Pacific, many drifters measured
cold anomalies of -0.5 to -1.5C.

FIGURE A1.1
a) Top: Movements of drifting buoys in the tropical Pacific Ocean.
The linear segments of each trajectory represent a one week displacement.
Trajectories of buoys which have lost their subsurface drogues are gray; those with
drogues are blue.
b) Middle: Monthly mean currents calculated from all buoys 1993-2002 (gray),
and currents measured by the drogued buoys this month (black) smoothed by an
optimal filter.
c) Bottom: Anomalies from the climatological monthly mean currents for this month.
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