pattern of tropical sea surface temperature (SST) anomalies during December
2006 featured warmer-than-average temperatures across the central and
eastern Pacific (Fig. T18). Accordingly, the SST anomalies
in the Niņo 4 and Niņo 3.4 regions remained positive (latest values of 1.2
and 1.3, respectively) (Table T2).
The SST anomalies in the far eastern equatorial Pacific have decreased
slightly, with a December value of 0.5 in the Niņo 1+2 region (Fig. T18,
Table T2). Meanwhile,
Darwin SOI is
negative (latest value: -0.5), primarily in response to
higher-than-average pressure over
, which has observed persistent positive SLP departures since May 2006 (Table
T1, Figs. T1 and T19).
oceanic thermocline, measured by the depth of the 20ēC isotherm along the
equator, featured above average depth over most of the eastern Pacific
during December (Figs. T15, T16).
Consistent with these conditions, oceanic temperatures at thermocline
depth were 2-4ēC above average throughout most of the eastern equatorial
Pacific (Fig. T17).
December 2006, low-level easterly anomalies (more than 3.0 m s-1)
were observed over the central equatorial Pacific and across
T20). Enhanced convection (above-average
rainfall amounts) was observed across the
as over the central equatorial Pacific, while
suppressed convection (below-average rainfall amounts) was seen across
(Figs. T25 and
E3). These wind and convection anomalies
reflect an intensification of Madden-Julian Oscillation (MJO) activity, not
the ongoing El Niņo.