Intercomparison between ozone-broadening parameters retrieved from millimetre-wave measurements by using different techniques

Abstract

For atmospheric purposes, the N 2- and O 2-, or Air-broadenings of selected transitions of ozone have been investigated in the 195–300 K temperature range. More precisely, the following 13 transitions in the 280–345 GHz frequency range have been studied: the 2 2,0 ← 2 1,1 (279.5 GHz), 24 2,22 ← 24 1,23 (286.2 GHz), 3 2,2 ← 3 1,3 (286.3 GHz), 5 2,4 ← 5 1,5 (293.2 GHz), 13 4,10 ← 14 3,11 (300.7 GHz), 14 0,14 ← 13 1,13 (301.8 GHz), 7 2,6 ← 7 1,7 (303.2 GHz), 26 2,24 ← 26 1,25 (315.9 GHz), 5 3,3 ← 6 2,4 (317.2 GHz), 20 1,19 ← 20 0,20 (320.0 GHz), 26 6,20 ← 27 5,23 (343.2 GHz), 26 2,24 ← 25 3,23 (343.2 GHz), and 4 3,1 ← 5 2,4 (343.5 GHz) lines. Systematic errors are known to be the principal error source and recent intercomparisons of line-broadening coefficients showed differences up to 20%, thus a large effort in minimizing systematic error sources has been taken and cross check measurements with different techniques have been carried out. The conclusion of the intercomparison performed indicates an excellent agreement of the results and that an uncertainty less than 3%, which also takes into account the systematic errors, can be claimed for the line-broadening parameters.