Tropical Highlights - October
Surface and sub-surface oceanic conditions across the Tropical Pacific
continued to trend towards a weak warm episode during October 2003 (Table
T2), while atmospheric features continued to reflect ENSO neutral
conditions (Table T1). Sea surface temperatures (SSTs) and anomalies
increased across the entire equatorial Pacific, with anomalies in both the
Niņo 3.4 and Niņo
4 regions reaching their highest values since March 2003 (Table
T5). SST anomalies remained more than 1°C
above normal in the equatorial west Pacific, while slightly warmer than
normal SSTs were observed across the rest of the equatorial Pacific (Fig.
Oceanic thermocline depths, as measured by the depth of the 20°C
isotherm (Figs. T15, T16) remained slightly deeper than average
across most of the equatorial Pacific during October. Consistent with these
conditions, oceanic temperatures at thermocline depth were 1-2°C
above average across most of the equatorial Pacific (Fig. T17).
The low-level and upper-level equatorial winds remained near average
across the Pacific during October (Table T1, Figs.
and the Tahiti-Darwin SOI remained near zero (-0.3) during the month (Table
T1, Fig. T1). In addition, relatively weak outgoing longwave radiation (OLR)
anomalies were observed throughout much of the global Tropics during October
(Fig. T25). None of these indicators has exhibited any trend towards
warm or cold episodes during the past five months and all are consistent
with near neutral conditions across the Tropical Pacific.