ECMWF >
ERA-40 Atlas >
Time series >

The PNA Index. A linear combination of 500hPa geopotential height anomalies m [blue] and normalised by their 45-year monthly standard deviation [red]

Click here to see this chart in a new browser window
 EPS (350kb)
 GIF (112kb)
   
ERA    The University of Reading    ECMWF    WCRP