Tropical Pacific Drifting Buoys
Rick Lumpkin / Mayra Pazos, AOML, Miami
MARCH 2010
During March 2010, 449 satellite-tracked surface drifting buoys, 68% with
subsurface drogues attached for measuring mixed layer currents, were
reporting from the tropical Pacific. The dramatic El Nino anomalies seen
in the last several months were more disorganized in March. Strong eastward
anomalies were seen by a few drifters close to the dateline, but westward
anomalies were measured by drifters at 140-160W and 160-170E. Warm anomalies
of +0.5C to +1.5C were common in the southern hemisphere west of 130W, and
cold anomalies of -0.5C to -1.5C were measured by several drifters north of
10N, between the dateline and 150W. Elsewhere temperatures were near their
climatological March values.

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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