Tropical Pacific Drifting Buoys
Rick Lumpkin / Mayra Pazos, AOML, Miami
SEPTEMBER 2011
During September 2011, 354 satellite-tracked surface drifting buoys, 49% with
subssurface 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 the climatological September value.
![](figa1.1.gif)
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 1993-2010 (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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