Tropical Pacific Drifting Buoys
Rick Lumpkin / Mayra Pazos, AOML, Miami
JANUARY 2008
During January 2008, 288 satellite-tracked surface drifting buoys, 74% with
subsurface drogues attached for measuring mixed layer currents, were reporting
from the tropical Pacific. Westward anomalies were observed throughout nearly
all of the tropical Pacific basin, with the strongest anomalies of 20-30 cm/s
along the NEC at 10N and in the weakened NECC at 6-8N. Cold anomalies of
-0.5 to -1.5 C were measured in the band 20N-20S by most drifters east of 160W,
with -1.5C to -3.0C anomalies at 140-150W. Warm anomalies of +0.5 to +3.0C
were common in the region 120E-160W, 20-30N, the southern edge of the
northern hemisphere subtropical gyre.

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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