surface temperature (SST) anomalies remained negative in the eastern
tropical Pacific during December 2005, with a December value of -0.6 in the
Niņo 3.4 region and -0.7 in the Niņo 1+2 region (Fig. T18,
Table T2). The
- Darwin SOI (latest value -0.2, Table T1, Fig.
T1) was slightly negative, primarily in
response to higher-than-average pressure over
. Meanwhile, the equatorial SOI for December is +2.2 (Fig. T2).
The equatorial SOI has been greater than or equal to +0.5 since September
oceanic thermocline, measured by the depth of the 20°C
isotherm along the equator, featured near-average depth in the central
Pacific and slightly shallower-than-average depth in the eastern Pacific
during December (Figs. T15, T16).
Consistent with these conditions, equatorial oceanic temperatures at
thermocline depth were near average throughout most of the Pacific and 2-3oC
below average in the eastern Pacific (Fig. T17).
December, near-average low-level winds were observed over the eastern
equatorial Pacific while low-level easterly anomalies (more than 3.0 m s-1)
were observed over the central and western equatorial Pacific (Fig. T20).
In the global tropics, enhanced convection (above-average rainfall amounts)
was observed over the eastern
as well as over the northeastern
T26 and E3).