The NAO is traditionally defined as the normalized pressure difference between a station on the Azores and one on Iceland. An extended version of the index can be derived for the winter half of the year by using a station in the southwestern part of the Iberian Peninsula (Hurrell, 1995). Here we give data for SW Iceland (Reykjavik), Gibraltar and Ponta Delgada (Azores). The NAO calculated from Gibraltar and SW Iceland is also given (Jones et al., 1997).
See also :
December 2000: The values for Gibraltar have been altered. New documentation will be in a paper currently in preparation by Jones, Briffa and Osborn.
|File format (NAO)|
for year = 1821 to 2000 format(i5,12f7.2,f8.2) year, 12 * monthly value, annual value
|Missing values represented by -99.99|
|File format (Station pressure)|
format(i1,i5,i5,a) ?,startyear,endyear,name for year = startyear to endyear format(i5,12i6) year, 12 * monthly value
Missing values represented by -10
Divide by 10 for millibars
|nao_azo.dat||10 kilobytes||Pressure data for Ponta Delgada, Azores|
|nao_gib.dat||14 kilobytes||Pressure data for Gibraltar|
|nao_ice.dat||14 kilobytes||Pressure data for South-West Iceland|