NINO3.4 Index

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  • SOI
  • NINO3.4
NINO3.4 Index

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.

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Signs indicating Australia's cool season arrival

16:15 AEST Mere hours after our Total Lightning Network went quiet over the Australian continent, the Himawari satellite captured a clear, textbook snapshot of the arrival of Australia's cool season.   A few distinguishing features should catch your eye:  A band of cloud streaming over northern WA and towards the nation's interior  A distinct clearing of cloud from most of the NT's Top End, and  A band of cloud crossing to the south of WA   Turns out, all three of these features point to one thing: winter is knocking at the door.  Image: Himawari satellite imagery and mean sea level pressure (ECMWF) over Australia on the morning of Saturday, April 27th, 2024.

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