Tropical Pacific Drifting Buoys
Rick Lumpkin / Mayra Pazos, AOML, Miami
During September 2011, 354 satellite-tracked surface drifting buoys, 49% with
subsurface drogues attached for measuring mixed layer currents, were reporting
from the tropical Pacific. Few drifters measured near-equatorial currents in
the western half of the basin. Very strong northward anomalies measured by
three near-equatorial drifters at 129W are likely associated with a tropical
instability wave. Between 110W and the date line, strong equatorial westward
anomalies of O(50 cm/s) were measured by a number of drifters between the
equator and 5S. Most drifters between 10N and 10S measured SSTs cooler by
0.5 to 1.5C than the climatological September value.
Top:Movements of drifting buoys in the tropical Pacific Ocean during sep11.
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.