ENSO & SST

ENSO and Sea Surface Temperatures

Climate Models show El Niño likely to weaken in the Autumn of 2003

Equatorial Pacific SSTs intensified during December

El Niño-related temperature and wind anomalies in the Equatorial Pacific continue to propagate eastwards in December, as the event came close to maturity. The NINO3 SST anomaly (+1.7°C) is now significantly higher than the NINO4 anomaly (+1.3°C) for the first time in this event. Threemonth (Oct-Dec) means are about +1.5°C and +1.4°C for NINO3 and 4, respectively. Westerly zonal wind anomalies extend to near 140°W, and the region of enhanced Equatorial convection has strengthened near the dateline. The area of suppressed convection in the west affects northern Australia and also the Coral Sea, New Caledonia and southeast towards northern New Zealand. Equatorial subsurface temperature anomalies appear to be weakening east of the dateline, but are still above +2°C across most of the eastern Pacific mixed layer. The SOI strengthened slightly in December to near – 1.3, bringing the 3-month mean to –1.0.

Most Global Climate Models (8 out of 11) are predicting a return to neutral conditions during autumn 2003.

Sea surface temperature anomalies (°C) for December 2002

Mean sea surface temperatures (°C) for December 2002