Tropical Pacific Drifting Buoys
Rick Lumpkin / Mayra Pazos, AOML, Miami
During February 2012, 282 satellite-tracked surface drifting buoys, 44% with
subsurface drogues attached for measuring mixed layer currents, were reporting
from the tropical Pacific. Strong eastward anomalies of O(50 cm/s) were seen by
a few near-equatorial drifters near 110W; more observations such as moored
records from TAO are needed to evaluate the robustness and scale of this
signal.Elsewhere, westward anomalies of O(10-20 cm/s) were observed across
most of the basin. As seen since December 2011, many drifters north of 10N and
west of the dateline measured SSTs warmer than normal by 0.5-3.0C, while
drifters to the south and east measured SSTs at or slightly cooler (0-1.5C)
than climatological February values. Cold anomalies were most prevalent
between 20S to 20N, east of the dateline. A few very warm (1.5-3.0C) anomalies
were measured by near-equatorial drifters east of 120W.
Top:Movements of drifting buoys in the tropical Pacific Ocean during feb12.
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.