Atmospheric O-2, CO2 and delta C-13 measurements from aircraft sampling over Griffin Forest, Perthshire, UK

Regular vertical aircraft sampling has been performed in the lower troposphere above Griffin Forest, near Aberfeldy, Perthshire, UK (56 degrees 37N, 3 degrees 47'W), between February 2003 and May 2004, for analysis of O-2/N-2, CO2 and delta(13)C of CO2. We sampled flasks between 800 and 3100 m above sea level. The peak-to-peak amplitude of the seasonal cycle Of O-2/N-2 decreases from 171 per meg at 800 m to 113 per meg at 3100 m. Furthermore, the seasonal cycle is shifted from low to high altitudes with a lag of about 1 month. The same features are observed for CO2 with a decrease in the peak-to-peak amplitude of the seasonal cycle from 17.6 ppm at 800 m to 11.4 ppm at 3100 m. The vertical profiles show decreasing O-2/N-2 ratios in summer and increasing O-2/N-2 ratios in wintertime with increasing sampling height, due to surface exchange of oxygen with the land biosphere and the ocean. The O-2:CO2 exchange ratios of the vertical profiles vary between -1.5 and -2.4 mol O-2/mol CO2. Copyright (C) 2005 John Wiley & Sons, Ltd.