ADRIGOLE

Period of Record

Trends

The ALE site at Adrigole, Ireland, was operated under the supervision of J.E. Lovelock of Reading University and P.G. Simmonds of the University of Bristol. The site is located on the west coast of Ireland about 400 m from Bantry Bay and 50 m above mean sea level. Measurements at the site began in July 1978 and continued through December 1983. Although generally receiving clean oceanic air from the westerly sector, the site at times (particularly in winter) received polluted air from eastern Ireland, Great Britain, and continental Europe. Altogether, about one-third of the measurements made at this site showed some evidence of pollution.

The monthly mean mixing ratio of CFC-11 increased from 158.2 parts per trillion (ppt) in July 1978 to 201.3 ppt by the end of 1983. The mixing ratio of CFC-12 increased from 284.4 to 380.5 ppt during the same period. For both CFC-11 and CFC-12, the increases were nearly linear during the period of measurement, averaging 8.1 ppt/year for CFC-11 and 17.5 ppt/year for CFC-12. In each case, the trend is highly significant (P < 0.0001).

The time series of the monthly mean mixing ratios of N₂O is interrupted from February 1979 through March 1980. Data collected during this period were discarded because of instrumental problems indicated by large variability in the analyzed N₂O values from the calibration gas (Prinn et al. 1983). Although the scatter is considerable, the remaining values nevertheless show a highly significant (P < 0.0001) trend. The monthly mixing ratio of N₂O increased from 301.5 parts per billion (ppb) in July 1978 to 302.9 ppb in December 1983. Prinn et al. (1990) calculated that the mixing ratio of N₂O increased on average 0.76±0.17 ppb/year for the 10-year period July 1978 through June 1988. (This calculation employed data from Adrigole for the period 1978-83 and additional data from Mace Head, the successor site to Adrigole for GAGE, for an 18-month period during 1977-78.) No significant periodic oscillation was evident. Throughout the period of record, the daily N₂O variability was generally larger than that at equatorial and Southern Hemisphere sites.

Adrigole
Bantry Bay, Ireland
52° N, 10° W
50 m above MSL

Adrigole Mixing Ratios Graph

• Monthly average CFC-11, CFC-12, and N₂O mixing ratios at Adrigole