Consistency of tropospheric ozone observations made by different platforms and techniques in the global databases

Abstract

A large quantity of tropospheric ozone observations are conducted all over the world using different platforms and techniques for different purposes and goals. These observations are commonly used to derive seasonal cycles, interannual variations and long-term trends of ozone in the troposphere. In addition, they are used for comparison with three-dimensional chemistry-transport models to evaluate their performance and hence to test our current understanding of the tropospheric ozone variability. It is still challenging to provide robust tropospheric ozone trends throughout the world because of the great variability of ozone, its complex photochemical reactions, the rarity of long-term records, the diversity of measurement techniques and platforms, and the issues with data quality. In this work, we evaluated, with emphasis on the lower troposphere, the consistency of tropospheric ozone observations made by means of multiple platforms, including surface sites, sondes and regular aircraft, that are publicly available in the global databases, but excluding space-borne platforms. Concomitant observations were examined on an hourly basis (except for ±3 hours for sonde versus aircraft) for pairs of locations at less than 100-km distance. Generally, we found good agreement between sonde and surface observations. We also found that there was no need to apply any correction factor to ozonesonde observations except for Brewer–Mast sondes at Hohenpeissenberg. Because of a larger distance between the site pairs, the correlations found between the aircraft and surface measurements were poorer than those between sonde and surface measurements. However, a relatively simple wind segregation improved the agreement between the aircraft versus surface measurements. We found also that due to diurnal cycles, the sonde launching at a fixed local time led to positive or negative biases against the surface observations, suggesting that great attention should be paid to local time and diurnal variations when using ozonesonde in the analysis of seasonal cycles, long-term trends and interannual variations of lower tropospheric ozone. The comparison of surface data at Mt. Happo to regular aircraft data over Tokyo/Narita showed a relatively reasonable agreement, ensuring regionally representative ozone data sets in this region for trend analysis.

• tropospheric ozone
• MOZAIC
• IAGOS
• WDCGG
• WOUDC

This paper is part of a Special Issue on MOZAIC/IAGOS in Tellus B celebrating 20 years of an ongoing air chemistry-climate research measurement from airbus commercial aircraft operated by an international consortium of countries. More papers from this issue can be found at http://www.tellusb.net

This paper is part of a Special Issue on MOZAIC/IAGOS in Tellus B celebrating 20 years of an ongoing air chemistry-climate research measurement from airbus commercial aircraft operated by an international consortium of countries. More papers from this issue can be found at http://www.tellusb.net

Acknowledgements

We acknowledge the following data centres. For ozonesondes: the World Ozone and Ultraviolet Radiation Data Centre (WOUDC, www.woudc.org) operated by Environment Canada, Toronto, Ontario, Canada, under the auspices of the WMO; for surface data: the World Data Centre for Greenhouse Gases (WDCGG, www.gaw.kishou.go.jp/wdcgg) maintained by the Japan Meteorological Agency, Tokyo, Japan, in cooperation with the WMO. Ushuaia ozone data were provided by the Global Atmosphere Watch Station of Ushuaia, managed by the National Weather Service of Argentina (SMN), in agreement with the National Institute of Aerospace Technology of Spain (INTA) and the State Meteorological Agency of Spain (AEMet). The data at Tsukuba and Syowa were provided by Aerological Observatory and Office of Antarctica Observation, respectively, of Japan Meteorological Agency. The data at Egbert and Saturna were provided by Air Quality Research Branch, Environment Canada. The data at Hohenpeissenberg and Neuglobsow were provided by the German Meteorological Service and Federal Environmental Agency of Germany, respectively. The data at Izana were provided by the Meteorological State Agency of Spain, at Trinidad Head by NOAA, and at Cape Point by the South African Weather Service. We also acknowledge the strong support of the European Commission, Airbus, and the Airlines (Lufthansa, Air-France, Austrian, Air Namibia, Cathay Pacific, Iberia and China Airlines so far) who carry the MOZAIC or IAGOS equipment and perform the maintenance since 1994. MOZAIC is presently funded by INSU-CNRS (France), Météo-France, CNES, Université Paul Sabatier (Toulouse, France) and Research Center Jülich (FZJ, Jülich, Germany). IAGOS has been and is additionally funded by the EU projects IAGOS-DS and IAGOS-ERI. The MOZAIC-IAGOS data are available via CNES/CNRS-INSU Ether website www.pole-ether.fr.

We also thank the German Weather Service (Meteorological Observatory at Hohenpeissenberg), the National Space Development Agency of Japan and NASA (Wallops Island Flight Facility) for providing their data through the WOUDC. Funding for research was provided partly by the Global Environment Research Fund of the Ministry of the Environment, Japan (S-7-1 and 2-1505). H.T. thanks Kimiko Suto and Haruka Yamagishi at NIES for technical support, and Dr. Edit Nagy-Tanaka at NIES for editing the manuscript. We thank two anonymous reviewers for their valuable comments for improving the paper.

Notes

This paper is part of a Special Issue on MOZAIC/IAGOS in Tellus B celebrating 20 years of an ongoing air chemistry-climate research measurement from airbus commercial aircraft operated by an international consortium of countries. More papers from this issue can be found at http://www.tellusb.net