The loading pattern of the AO is defined by CPC as the leading mode of Empirical Orthogonal Function (EOF) analysis of monthly mean 1000mb height during 1979-2000 period.

Time Interval: Monthly
Time Coverage: 1950 to Sep 2020
Update Status: Periodically updated

Get Data:

AO: Standard PSL Format (What is standard format?)
AO: Original

Source:
Data is from NOAA/CPC at http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index.htmll
References:

1. list at NOAA/CPC

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