Evaluation of tropospheric and stratospheric ozone trends over Western Europe from ground-based FTIR network observations

• Main Authors: Vigouroux, C., de Mazière, M., Demoulin, P., Servais, C., Hase, F., Blumenstock, T., Kramer, I., Schneider, M., Mellqvist, J., Strandberg, A., Velazco, V., Notholt, J., Sussmann, R., Stremme, W., Rockmann, A., Gardiner, T., Coleman, M., Woods, P.
• Other Authors: Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Institut d'Astrophysique et de Géophysique Liège, Université de Liège, Institut für Meteorologie und Klimaforschung - Atmosphärische Spurengase und Fernerkundung (IMK-ASF), Karlsruher Institut für Technologie (KIT), Chalmers University of Technology Göteborg, Institute of Environmental Physics Bremen (IUP), University of Bremen, Institut für Meteorologie und Klimaforschung - Atmosphärische Umweltforschung (IMK-IFU), National Physical Laboratory Teddington (NPL)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2008
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Ny-Ålesund; Kiruna; Ny Ålesund
• Online Access: https://hal.science/hal-00304029; https://hal.science/hal-00304029/document; https://hal.science/hal-00304029/file/acpd-8-5007-2008.pdf

International audience Within the European project UFTIR (Time series of Upper Free Troposphere observations from an European ground-based FTIR network), six ground-based stations in Western Europe, from 79° N to 28° N, all equipped with Fourier Transform infrared (FTIR) instruments and part of the Network for the Detection of Atmospheric Composition Change (NDACC), have joined their efforts to evaluate the trend of several direct and indirect greenhouse gases over the period 1995?2004. The retrievals of CO, CH 4 , C 2 H 6 , N 2 O, CHClF 2 , and O 3 have been optimized. Using the optimal estimation method, some vertical information can be obtained in addition to total column amounts. A bootstrap resampling method has been implemented to determine annual partial and total column trends for the target gases. The present work focuses on the ozone results. The retrieved time series of partial and total ozone columns are validated with ground-based correlative data (Brewer, Dobson, UV-Vis, ozonesondes, and Lidar). The observed total column ozone trends are in agreement with previous studies: 1) no total column ozone trend is seen at the lowest latitude station Izaña (28° N); 2) slightly positive total column trends are seen at the two mid-latitude stations Zugspitze and Jungfraujoch (47° N), only one of them being significant; 3) the highest latitude stations Harestua (60° N), Kiruna (68° N) and Ny-Ålesund (79° N) show significant positive total column trends. Following the vertical information contained in the ozone FTIR retrievals, we provide partial columns trends for the layers: ground-10 km, 10?18 km, 18?27 km, and 27?42 km, which helps to distinguish the contributions from dynamical and chemical changes on the total column ozone trends. We obtain no statistically significant trends in the ground?10 km layer for five out of the six ground-based stations. We find significant positive trends for the lowermost stratosphere at the two mid-latitude stations, and at Ny-Ålesund. We find smaller, but significant ...