Year: 2025
Type: article
Abstract: We provide trend estimates for total, stratospheric, and tropospheric ozone columns over Reunion (21.1°S, 55.5°E) from 1998 to 2021, using only Système d’Analyze par Observation Zénithale and Southern Hemisphere Additional OZonesonde observations. Trends are derived using Trend‐Run, a multiple linear regression model, and a dynamic linear model (DLM) to identify potential turning points. Overall, total ozone exhibits a positive trend (3.0 1.5 DU/decade), with increases in both stratospheric (1.1 1.6 DU/decade) and tropospheric ozone (2.2 1.0 DU/decade). DLM identifies a turning point in stratospheric ozone in 2008, with a clear decrease in stratospheric ozone before this point and an increase afterward. We also determined changes in the lapse rate tropopause (LRT), the subtropical barrier position, and ERA5 wind and geopotential fields during the same period to investigate possible links between mid‐tropospheric ozone increase and transport‐related perturbations. Although trends in LRT height and temperature are barely significant, they suggest a recent deepening of the troposphere, indicative of climate change. Intensification of the anticyclonic gyre over Southern Africa and a weakening of the Mascarene anticyclone are found. This suggests that, independent of possible changes in ozone precursor emissions over Africa or South America, dynamics are driving increases of ozone and ozone precursors over Reunion from 1998 to 2021. Furthermore, the rate of Reunion's free tropospheric trends exceeds that observed at all other southern hemisphere ozonesonde stations, including those in tropical, subtropical and mid‐latitude regions.
Source: Earth and Space Science
DOI: 10.1029/2025ea004398
Institutions: Centre National de la Recherche Scientifique, University of Reunion Island, Laboratoire de l'Atmosphère et des Cyclones, Institut de Recherche pour le Développement, Agence Nationale de l'Aviation Civile et de la Météorologie, Universidade Federal do Oeste do Pará, Université de Versailles Saint-Quentin-en-Yvelines, Sorbonne Université, Institut Pierre-Simon Laplace, Laboratoire atmosphères, milieux, observations spatiales, Observatoire des Sciences de l'Univers de la Réunion, Goddard Space Flight Center, Science Systems and Applications (United States), University of Maryland, Baltimore County
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: gold
Estimated APC paid: $2,650
OpenAlex ID: W4416945437