Air temperatures at Armagh Observatory, Northern Ireland, from 1796 to 2002

Abstract

Three independent mean temperature series for Armagh Observatory, covering the period 1796-2002 have been calibrated and corrected for the time of reading and exposure. Agreement between the three series is good in regions of overlap. With a short gap in the Armagh data from 1825 to 1833 filled by data from two stations in Dublin, the resulting series is the longest for the island of Ireland and one of the longest for any single site in the British Isles.Over the past 207 years, we note that temperatures in Armagh, in all seasons, show a gradual overall trend upwards. However, there are seasonal differences: summer and spring temperatures have increased by only half as much as those in autumn and winter. This is partly due to the exceptionally cold winters and autumns experienced prior to 1820. Relative to the overall trend, warm periods occurred in Ireland, as in other parts of Europe, in the mid-19th century, in the mid-20th century and at the end of the 20th century. Relatively cool temperatures prevailed in the early 19th century, in the 1880s and in the 1970s. Thus, if the baseline against which current temperatures are compared were moved from the late 19th century to include the earlier warm period, the apparent warming at the end of the late 20th century would be correspondingly reduced.A gradual decline in the daily temperature range at Armagh since 1844 may have resulted from higher minimum temperatures associated with increased cloudiness.A 7.8 year periodicity is identified in winter and spring mean temperatures at Armagh, which is probably a consequence of the North Atlantic oscillation.

The long-term temperature record from Markree Observatory, County Sligo, from 1842 to 2011

“…Mean global surface temperature has increased by 0.768C from the mid-nineteenth century until 2005(IPCC 2007. Current trends in Irish temperature closely follow global patterns, with numerous studies having focused on climate amelioration at the beginning of the twentieth century and the accelerated warming since the 1990s (Vincent and Gullet 1999, Zhai and Ren 1999, McElwain and Sweeney 2003, 2007.…”

“…Of the climate records that extend into the nineteenth century, the vast majority are found in Europe (Butler et al 2005). Consequently, for much of the globe, the spatially complete instrumental period is quite short (Klingbjer and Moberg 2003), limiting the time scale involved in climate research.…”

“…According to Donnelly et al (2004), an understanding of climate at the regional and local scale is imperative to adequately examine potential impacts of future climate change. Although a number of studies have examined fluctuations at a regional Irish scale (Butler 1994, Sweeney et al 2002, McElwain and Sweeney 2003, 2007, Butler et al 2005, geographic coverage of Ireland is not complete. This paper presents an analysis of a previously unexplored temperature record from Markree Observatory located in County Sligo in the northwest of Ireland.…”

“…Although the introduction of a new long-term temperature series offers an extended regional chronology, most historic instrumental records do suffer from a degree of imperfection in portions of the series (Butler et al 2005). Records must conform to a number of criteria in order to adequately narrate a climate story.…”

“…The majority of meteorological records lack one or more of these criteria, making the climate reconstruction inadequate. To date in Ireland only a small number of temperature series fill these absolute rules (Butler et al 2005). Markree is one such record.…”