Intercomparison of Tropospheric OH Measurements by Different Laser Techniques during the POPCORN Campaign 1994

• Published in: Journal of atmospheric chemistry 1998-10, Vol.31 (1-2), p.227-227
• Main Authors: Hofzumahaus, A, Aschmutat, U, Brandenburger, U, Brauers, T, Dorn, H-p, Hausmann, M, Heßling, M, Holland, F, Plass-dülmer, C, Ehhalt, D H
• Format: Article
• Language: English
• Subjects: Absorption spectroscopy; Correlation coefficient; Diurnal variations; Rural environments; Spectrum analysis; Statistical analysis
• ISSN: 0167-7764; 1573-0662
• DOI: 10.1023/A:1006014707617

In-situ OH measurements by laser-induced fluorescence (LIF) spectroscopy and folded long-path differential optical absorption spectroscopy (DOAS) were carried out in a rural environment in North-East Germany as part of the field experiment POPCORN in August 1994. The large set of OH data obtained allowed an intercomparison of both techniques based on relative diurnal profiles and simultaneously measured absolute concentrations. Most of the time the two OH instruments encountered the same air and agreed well in the measured relative diurnal variations. Only on a few occasions the measurements significantly disagreed due to a perturbation of the DOAS measurements by a local OH source in the north-western wind sector. Excluding data from this wind direction, the statistical analysis of 137 data pairs yields a correlation coefficient of r = 0.90 and a weighted linear fit with a slope of 1.09 ± 0.12. The correlations are carefully analyzed. The comparison of both instruments is discussed in the light of newly published effective absorption cross-sections for H2O and O2 that affect the calibration of LIF.[PUBLICATION ABSTRACT]