Tropical Pacific Drifting Buoys
Rick Lumpkin / Mayra Pazos, AOML, Miami
During May 2011, 421 satellite-tracked surface drifting buoys, 64% with
subsurface drogues attached for measuring mixed layer currents, were reporting
from the tropical Pacific. As seen since September 2010, the westward SEC was
stronger than normal, with westward anomalies of 5-10 cm/s present in a broad
latitude range from 5-20S. Between 10-20N, the westward NEC was also faster
than average by ~5 cm/s. Cold SST anomalies of -0.5 to -1.5C were measured
by many drifters east of 160W from 20S to 30N, a pattern seen since February.
Top:Movements of drifting buoys in the tropical Pacific Ocean during may11.
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 black.
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.
Bottom: Anomalies from the climatological monthly mean currents for this month.