Hemispheric surface air temperature variations: A reanalysis and an update to 1993

The present study is a reanalysis of both the existing and the newly available temperature datasets to produce a grid-box dataset of 5° × 5° temperature anomalies. The reanalysis not only uses over 1000 more stations (2961 in total), principally covering the period from the 1920s to about 1990, but also arrests the decline of stations incorporated in real time for the latest years. Two hundred and fifty-two more stations are used in this analysis for the 1991-1993 period, compared with earlier analyses. The purpose of the reanalysis however, is not just to calculate hemispheric averages. The improvements in station numbers used mean that the grid-box dataset should better estimate time series for small subcontinental scales.