The NINO3.4 index is one of several El Niņo/Southern Oscillation (ENSO) indicators based on sea surface temperatures.
NINO3.4 is the average sea surface temperature anomaly in the region bounded by 5°N to 5°S, from 170°W to 120°W. This region has large variability on El Niņo time scales, and is close to the region where changes in local sea-surface temperature are important for shifting the large region of rainfall typically located in the far western Pacific.
An El Niņo or La Niņa event is identified if the 5-month running-average of the NINO3.4 index exceeds +0.4°C for El Niņo or -0.4°C for La Niņa for at least 6 consecutive months.
For those among us wanting to balance out our participation in Earth Hour, the Vivid Light, Music and Ideas Festival opens in Sydney this on Friday.
Australia's Bureau of Meteorology (BoM) has released modelling showing the latest El Nino cycle is over, but could now lead to a wet winter after a devastating 14 months of drought and famine across the Pacific.
As drought bites hard on large parts of remote Australia, taking its toll on the health and finances of isolated communities, the Royal Flying Doctor Service (RFDS) is more important than ever.