Carbon monoxide (CO) and ethane (C 2 H 6 ) trends from ground-based solar FTIR measurements at six European stations, comparison and sensitivity analysis with the EMEP model

• Published in: Atmospheric Chemistry and Physics
• Main Authors: R. Sussmann, C. Servais, U. Raffalski, A. K. Petersen, J. Notholt, M. De Mazière, E. Mahieu, F. Hase, F. Forster, P. Duchatelet, T. Borsdorff, T. Blumenstock, J. E. Jonson, D. Simpson, J. Mellqvist, J. Angelbratt, T. Warneke, C. Vigouroux
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2011
• Subjects: Physics; QC1-999; Chemistry; QD1-999; Kiruna; Ny-Ålesund; Ny Ålesund
• Online Access: https://doi.org/10.5194/acp-11-9253-2011; https://doaj.org/article/e8485f246b3e420d84de3585b010963d

Trends in the CO andC 2 H 6 partial columns ~0–15 km) have been estimated from four European ground-based solar FTIR (Fourier Transform InfraRed) stations for the 1996–2006 time period. The CO trends from the four stations Jungfraujoch, Zugspitze, Harestua and Kiruna have been estimated to −0.45 ± 0.16% yr −1 , −1.00 ± 0.24% yr −1 , −0.62 ± 0.19 % yr −1 and −0.61 ± 0.16% yr −1 , respectively. The corresponding trends for C 2 H 6 are −1.51 ± 0.23% yr −1 , −2.11 ± 0.30% yr −1 , −1.09 ± 0.25% yr −1 and −1.14 ± 0.18% yr −1 . All trends are presented with their 2-σ confidence intervals. To find possible reasons for the CO trends, the global-scale EMEP MSC-W chemical transport model has been used in a series of sensitivity scenarios. It is shown that the trends are consistent with the combination of a 20% decrease in the anthropogenic CO emissions seen in Europe and North America during the 1996–2006 period and a 20% increase in the anthropogenic CO emissions in East Asia, during the same time period. The possible impacts of CH 4 and biogenic volatile organic compounds (BVOCs) are also considered. The European and global-scale EMEP models have been evaluated against the measured CO and C 2 H 6 partial columns from Jungfraujoch, Zugspitze, Bremen, Harestua, Kiruna and Ny-Ålesund. The European model reproduces, on average the measurements at the different sites fairly well and within 10–22% deviation for CO and 14–31% deviation for C 2 H 6 . Their seasonal amplitude is captured within 6–35% and 9–124% for CO and C 2 H 6 , respectively. However, 61–98% of the CO and C 2 H 6 partial columns in the European model are shown to arise from the boundary conditions, making the global-scale model a more suitable alternative when modeling these two species. In the evaluation of the global model the average partial columns for 2006 are shown to be within 1–9% and 37–50% of the measurements for CO and C 2 H 6 , respectively. The global model sensitivity for assumptions made in this paper is also analyzed.