Tropical Pacific Drifting Buoys
Rick Lumpkin / Mayra Pazos, AOML, Miami
During December 2015, 398 satellite-tracked surface drifting buoys, 69% with
subsurface drogues attached for measuring mixed layer currents, were reporting
from the tropical Pacific. As seen since August, across the basin a number of
drifters measured very strong eastward anomalies between 5S and 5N. These
anomalies were ~20 cm/s in December, weaker than in previous months. In the
eastern Pacific, a number of drifters indicated a narrower than normal NECC.
This current normally spans 4-10N, but was not present at 8.5-10N in December.
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 1993-2010 (gray),
and currents measured by the drogued buoys this month (black) smoothed by an
c) Bottom: Anomalies from the climatological monthly mean currents for this month.