Tropical Pacific Drifting Buoys
Rick Lumpkin / Mayra Pazos, AOML, Miami
AUGUST 2010
During August 2010, 453 satellite-tracked surface drifting buoys,
71% with subsurface drogues attached for measuring mixed layer currents,
were reporting from the tropical Pacific. As seen in the last two months,
dramatic 50 cm/s westward anomalies were measured by many near-equatorial
drifters, although this was primarily seen at longitudes of 140-180W.
In July, this pattern was present across the basin. These westward anomalies
are an intensification of the pattern seen since March. Equatorial drifters
in the center of the basin measured cold SST anomalies of -1 to -3C.
Off-equatorial drifters measured SSTs at or slightly above normal July
values west of 160-170W, and at or slightly below normal east of this.
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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