Abstract:
[Text Source: NOAA/CPC and NOAA/ESRL/PSD]
Nino Regions - for data sampling of SSTs the tropical Pacific has been divided into a number of regions named Nino 1, 2,3, 4, and 3.4 (which is encompasses part of both region 3 and 4). Nino 1 is the area defined by 80W-90W and 5S-10S, Nino 2 by 80W-90W and 0S-5S, Nino 3 by 90W-150W and 5N-5S, Nino 4 by 150W-160E and 5N-5S, Nino 3.4 by 120W-170W and 5N-5S. (see:
http://ggweather.com/enso/nino_regions.gif)
The Climate Prediction Center has weekly data since 1990 and monthly since 1950. The Climate Diagnostics Center has monthly Nino 3.4 since 1948.
NCAR has Nino 3.4 data from Trenberth since 1871. (
http://www.cgd.ucar.edu/cas/catalog/climind/Nino_3_3.4_indices.html)
