In this correction, we fix the mismatch that existed between model and observational annual averages. When calculating annual averages from model output, seasonal means were averaged, resulting in a given year being the average from December through November. When calculating annual averages from observational data, monthly means were averaged, resulting in a given year being the average from January through December. To correct for this 1 month mismatch, all annual mean temperatures derived from observations are calculated as December to November means, subject to the threshold criterion described in Libardoni and Forest [2011]. Because decadal mean temperatures are used for the surface temperature diagnostic, the 1 month shift in the averaging window has minimal impact on the resulting observational time series. Across all five decades and four zonal bands, the temperature differences due to the 1 month shift are at most 0.05C. The revised time series are not shown.

© 2013 American Geophysical Union