Evidence for solar‐cycle forcing and secular variation in the Armagh Observatory temperature record (1844–1992)

Abstract

Abstract. A prominent feature of previous long-term temperature studies has been the appearance of warming since the 1880s, this often being taken as evidence for anthropogenic-induced global warming. In this investigation, the long-term, annual, mean temperature record (1844-1992) of the Armagh Observatory (Armagh, North Ireland), a set of temperature data based on maximum and minimum thermometers that predates the 1880s and correlates well with northern hemispheric and global standards, is examined for evidence of systematic variation, in particular, as related to solarcycle forcing and secular variation. Indeed, both appear to be embedded within the Armagh data. Removal of these effects, each contributing about 8% to the overall reduction in variance, yields residuals that are randomly distributed. Application of the 1 O-year moving average to the residuals, furthermore, strongly suggests that the behavior of the residuals is episodic, inferring that (for extended periods of time) temperatures at Armagh sometimes were warmer or cooler (than expected), while at other times they were stable. Comparison of cyclic averages of annual mean temperatures against the lengths of the associated Hale cycles (i.e., the length of two, sequentially numbered, even-odd sunspot cycle pairs) strongly suggests that the temperatures correlate inversely (r =-0.886 at <2% level of significance) against the length of the associated Hale cycle. Because sunspot cycle 22 ended in 1996, the present Hale cycle probably will be shorter than average, implying that temperatures at Armagh over this Hale cycle will be warmer (about 9.31 + 0.23øC at the 90% confidence level) than average (= 9.00øC).

A prediction of the onset of solar cycle 24

“…The onset of cycle 24 should be in March 2007 ± 7 months with our technique. It is near to May 2007 according to Hanslmeier et al (1999), later than May 2006 according to Landscheidt (1999), and later than or near to January 2006 -May 2007 according to Wilson (1998). Incidentally, it is also close to the date, February 2007 ± 13 months, predicted from the relationship between the conventional T d and T a .…”

Relative humidity at Armagh Observatory, 1838–2008

“…We have previously found (Butler et al , 1998; 2005a; 2007) periodicities close to 7–8, 20–23 and 30 years in rainfall, sunshine, air temperature and soil temperatures from Armagh. Wilson (1998) also found evidence for a 22‐year periodicity in the Armagh temperature series. The 7–8‐year periodicity is believed to derive from the North Atlantic Oscillation (NAO), which contains power at a similar frequency (McHugh and Rogers, 2001; Butler et al , 2007).…”

Results of the Helsinki magnetic observatory 1844-1912

“…Rangarajan andBarreto, 2000;Mursula and Zieger, 2001;Mursula et al, 2003), studies on sunspot maximum predictions (Bounar et al, 1997;Kane, 1997;Wilson et al, 1998;Duhau and Chen, 2002;Duhau, 2003), and in solar flux studies, as well as in estimations of possible solar connections in the past and recent trends in the Earth's greenhouse effects (e.g. Wilson, 1998;Stamper et al, 1999;Lockwood et al, 1999;Pulkkinen et al, 2001;Lockwood, 2003). Alexandrescu et al (1995) have utilized Helsinki secular variation data (D) for studies on geomagnetic jerks.…”