Shown are zonal mean time series of zonal mean temperature and eastward wind calculated with the ECMWF global weather forecast model for 1 September 1957 onward.
They are based on 2.5x2.5 degree daily (12 h UT) analyses on pressure levels, either from the ERA40 reanalysis (September 1957-August 2002) or from operational analyses after 2002.
The first 15 years of ERA40 are yellow, the second 15 years from ERA40 are lightblue, and the third 15 years form ERA40 are orange. The operational analyses from 2002 onward have varying colours. The red line is the current year (2011).
The temperature is expressed in degrees K(elvin) = degrees C(elsius) + 273
| Temperature | Eastward wind | |
|---|---|---|
| Northern Hemisphere | T 50 hPa North Pole | v 60 N 10 hPa |
| Southern Hemisphere | T 50 hPa South Pole | v 60 S 10 hPa |
