3) columns measured by the Infrared Atmospheric Sounding Interferometer (IASI), onboard th..." /> 3 3

Decrease in tropospheric O3 levels in the Northern Hemisphere observed by IASI

Citations of this article
Mendeley users who have this article in their library.


<p><strong>Abstract.</strong> In this study, we describe the recent changes in the tropospheric ozone (O<span class="inline-formula"><sub>3</sub></span>) columns measured by the Infrared Atmospheric Sounding Interferometer (IASI), onboard the Metop satellite, during the first 9 years of operation (January 2008 to May 2017). Using appropriate multivariate regression methods, we differentiate significant linear trends from other sources of O<span class="inline-formula"><sub>3</sub></span> variations captured by IASI. The geographical patterns of the adjusted O<span class="inline-formula"><sub>3</sub></span> trends are provided and discussed on the global scale. Given the large contribution of the natural variability in comparison with that of the trend (25–85&amp;thinsp;% vs. 15–50&amp;thinsp;%, respectively) to the total O<span class="inline-formula"><sub>3</sub></span> variations, we estimate that additional years of IASI measurements are generally required to detect the estimated O<span class="inline-formula"><sub>3</sub></span> trends with high precision. Globally, additional 6 months to 6 years of measurements, depending on the regions and the seasons, are needed to detect a trend of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>|</mo><mn mathvariant="normal">5</mn><mo>|</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="15pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="d2e91589cdc40bafcf79b75df8aa10f6"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-18-6867-2018-ie00001.svg" width="15pt" height="13pt" src="acp-18-6867-2018-ie00001.png"/></svg:svg></span></span>&amp;thinsp;DU&amp;thinsp;decade<span class="inline-formula"><sup>−1</sup></span>. An exception is interestingly found during summer at mid- and high latitudes of the Northern Hemisphere (NH; <span class="inline-formula">∼</span>&amp;thinsp;40 to <span class="inline-formula">∼</span>&amp;thinsp;75<span class="inline-formula"><sup>∘</sup></span>&amp;thinsp;N), where the large absolute fitted trend values (<span class="inline-formula">∼</span>&amp;thinsp;<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M14" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>|</mo><mn mathvariant="normal">0.5</mn><mo>|</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="198cdf2540281af9ec160aa95d892909"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-18-6867-2018-ie00002.svg" width="24pt" height="13pt" src="acp-18-6867-2018-ie00002.png"/></svg:svg></span></span>&amp;thinsp;DU&amp;thinsp;yr<span class="inline-formula"><sup>−1</sup></span> on average) combined with the small model residuals (<span class="inline-formula">∼</span>&amp;thinsp;10&amp;thinsp;%) allow for detection of a band-like pattern of significant negative trends. Despite no consensus in terms of tropospheric O<span class="inline-formula"><sub>3</sub></span> trends having been reached from the available independent datasets (UV or IR satellites, O<span class="inline-formula"><sub>3</sub></span> sondes, aircrafts, ground-based measurements, etc.) for the reasons that are discussed in the text, this finding is consistent with the reported decrease in O<span class="inline-formula"><sub>3</sub></span> precursor emissions in recent years, especially in Europe and USA. The influence of continental pollution on that latitudinal band is further investigated and supported by the analysis of the O<span class="inline-formula"><sub>3</sub></span>–CO relationship (in terms of correlation coefficient, regression slope and covariance) that we found to be the strongest at northern midlatitudes in summer.</p>




Wespes, C., Hurtmans, D., Clerbaux, C., Boynard, A., & Coheur, P. F. (2018). Decrease in tropospheric O3 levels in the Northern Hemisphere observed by IASI. Atmospheric Chemistry and Physics, 18(9), 6867–6885. https://doi.org/10.5194/acp-18-6867-2018

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free