MAXIMUM AND MINIMUM TEMPERATURES AT ARMAGH-OBSERVATORY, 1844-1992, AND THE LENGTH OF THE SUNSPOT CYCLE

The question of whether or not the Earth's climate is influenced by so lar activity has received considerable attention since the mid-ninetee nth century. Most investigations have adopted the sunspot number as th e parameter of solar activity. Recently, however, it has been shown by Friis-Christensen and Lassen (1991) that the mean northern hemisphere temperature, from 1861-1990, follows a strikingly similar trend to th e length of the sunspot cycle, suggesting that the recent global warmi ng could, at least in part, arise from changes in solar activity. In v iew of the importance of this result, we have examined a set of contin uous meteorological records, maintained at Armagh Observatory since 18 44, to assess, first, whether data from a single site can give meaning ful information on global trends, and second, whether the data from th is particular site for the period 1844-1866 can be used to extend the baseline of the comparison with solar activity. We find that both are indeed the case and that there is a strong correlation between the sol ar cycle length and the mean temperature at Armagh over the past 149 y ears.