Tropical Pacific Drifting Buoys
Rick Lumpkin / Mayra Pazos, AOML, Miami
SEPTEMBER 2009
During September 2009, 452 satellite-tracked surface drifting buoys,
81% with subsurface drogues attached for measuring mixed layer currents,
were reporting from the tropical Pacific. Across the basin, surface
currents speeds were near their normal climatological September values;
strong anomalies at 120-130W were due to instability waves. Most drifters
between 10N and 10S measured SST warmer by +0.5 to +3.0C than normal.
Warm anomalies of +1.5 to +3.0C were also measured by many drifters in the
Kuroshio Current and recirculation region.
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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