sea surface temperature (SST) anomalies persisted across the central and
east-central equatorial Pacific during January 2005.
The SST anomalies in the eastern equatorial Pacific have decreased
slightly, with a January value of -0.1 in the Niņo 1+2 region (Fig. T18,
The pattern of tropical SSTs during January featured positive
anomalies greater than +1.0°C between 160°E and 150°W (Fig. T18).
The SST anomaly in the Niņo 3.4 region decreased to 0.6 (Table T2).
Meanwhile, atmospheric features continued to show month-to-month
variability associated with intraseasonal (Madden-Julian Oscillation - MJO)
activity (Figs. T11, T12,
T13, Table T1).
- Darwin SOI (latest value 0.3, Table T1,
Fig. T1) was positive for the first time since
oceanic thermocline, measured by the depth of the 20°C
isotherm, remained deeper than average across most of the equatorial Pacific
during January (Figs. T15, T16).
Consistent with these conditions, oceanic temperatures at thermocline depth
above average across most of the equatorial Pacific (Fig. T17).
monthly low-level (850-hPa) and upper-level (200-hPa) equatorial zonal wind
indices, the Tahiti-Darwin SOI and the outgoing longwave radiation (OLR)
index have all exhibited considerable variability since January 2004 in
association with intraseasonal (Madden-Julian Oscillation) activity (Table
low-level winds were observed over most of the tropical regions during
January 2005, except that low-level westerly anomalies (more than 3.0 m s-1)
were observed over the western equatorial Pacific and
, and low-level easterly anomalies (more than 3.0
m s-1) over central equatorial Pacific
(Fig. T20). The global Tropics
featured near-average convection, with the exception of enhanced convection
over the western equatorial Pacific and over portions of the tropical
(Fig. T25), where
extreme flooding occurred in
during the last half of January.