ENSO and Sea Surface Temperatures
The tropical Pacific Ocean exhibited a weak El Niño state, but the atmosphere remained uncoupled from the ocean during October. The NINO3.4 average anomaly was +0.9°C again in October (as in September), and +0.8°C for August to September (up from +0.6 in July to September). The subsurface temperature profile shows a region of positive anomalies (+2°C or more) near the surface at the South American coast. Sea surface temperature (SST) anomalies have become positive right across the eastern Equatorial Pacific in the last two weeks. Positive zonal wind anomalies were evident at times during October. However, the Southern Oscillation Index (SOI) remained weak at -0.5 for October, with the August to September 3-month mean at –0.6. October outgoing longwave radiation (OLR) and the Tropical Rainfall Measuring Mission (TRMM) rainfall anomalies show anomalous convection in the region of the Solomon Islands, with suppressed convection over Southeast Asia and Indonesia. However, Southwest Pacific convective anomalies do not show El Niño-like characteristics as yet.
Most available models indicate (weak) El Niño conditions into early 2005, with about half indicating El Niño conditions persisting into autumn of 2005. No model is predicting substantial cooling in the equatorial Pacific over the next nine months.
Sea surface temperature anomalies (°C) for October 2004
Mean sea surface temperatures (°C) for October 2004
