Work

Nineteenth- and twentieth-century semi-quantitative surface ozone along subtropical European to tropical Africa Atlantic coasts

Year: 2025

Type: article

Abstract: . Tropospheric ozone (O3) plays a key role in the climate system. Studying pre-industrial tropospheric O3 implies two important challenges: i) the lack of observational records prior to the late 19th century, which hampers understanding long-term climate trends, given O3 crucial role, ii) and the uncertainties on their quantitative values in a non-polluted atmosphere across the planet. The ozonoscope was the first instrument used to measure ozone. It offers semi-quantitative estimates of surface O3 when no other measurements were available. Despite their potential value, the digitisation, curation and publication of ozonoscope data remains largely unexplored. In this work, we initiate an effort to rescue surface O3 ozonoscope records with a new data collection. We include data from 23 observatories covering Portugal and the African Atlantic regions, providing a latitudinal span from the extratropics in the northern hemisphere to the tropics in the southern hemisphere. This record represents the most extended ozonoscope data series to date, spanning 50 years of daily data and 58 years of monthly data, from 1855 to 1913.

Source: Earth system science data

DOI: 10.5194/essd-17-2437-2025