Merged SAGE II, Ozone_cci and OMPS ozone profile dataset and evaluation of ozone trends in the stratosphere

Abstract

Abstract. In this paper, we present a merged dataset of ozone profiles from several satellite instruments: SAGE II on ERBS, GOMOS, SCIAMACHY and MIPAS on Envisat, OSIRIS on Odin, ACE-FTS on SCISAT, and OMPS on Suomi-NPP. The merged dataset is created in the framework of the European Space Agency Climate Change Initiative (Ozone_cci) with the aim of analyzing stratospheric ozone trends. For the merged dataset, we used the latest versions of the original ozone datasets. The datasets from the individual instruments have been extensively validated and intercompared; only those datasets which are in good agreement, and do not exhibit significant drifts with respect to collocated ground-based observations and with respect to each other, are used for merging. The long-term SAGE-CCI-OMPS dataset is created by computation and merging of deseasonalized anomalies from individual instruments.The merged SAGE-CCI-OMPS dataset consists of deseasonalized anomalies of ozone in 10 • latitude bands from 90 • S to 90 • N and from 10 to 50 km in steps of 1 km covering the period from October 1984 to July 2016. This newly created dataset is used for evaluating ozone trends in the stratosphere through multiple linear regression. Negative ozone trends in the upper stratosphere are observed before 1997 and positive trends are found after 1997. The upper stratospheric trends are statistically significant at midlatitudes and indicate ozone recovery, as expected from the decrease of stratospheric halogens that started in the middle of the 1990s and stratospheric cooling.

Total ozone trends from 1979 to 2016 derived from five merged observational datasets – the emergence into ozone recovery

“…Our results are also largely consistent with more recent profile trend studies Sofieva et al, 2017;Steinbrecht et al, 2017) that basically show mostly insignificant trends at lower stratosphere altitudes.…”

“…The latter would mean that the BDC is getting stronger in the SH, which would result in larger SH extratropical lower stratospheric ozone trends as compared to the NH. However, the recent stratospheric ozone profile trend studies do not indicate such a hemispheric trend asymmetry in the lower stratosphere Steinbrecht et al, 2017;Sofieva et al, 2017).…”

“…(1), is considered the standard MLR that is commonly applied for determining trends from ozone profile data (e.g., Bourassa et al, 2014Harris et al, 2015;Tummon et al, 2015;Sofieva et al, 2017;Steinbrecht et al, 2017). The extra term P (t) in Eq.…”

Drift-corrected Odin-OSIRIS ozone product: algorithm and updated stratospheric ozone trends

“…The decreasing trend in the tropical lower stratosphere, found previously by Sioris et al (2014) and Bourassa et al (2014), remains statistically significant in these updated and pointing-corrected results, although with slightly reduced extent. The trend results are very consistent with those presented by Steinbrecht et al (2017) and Sofieva et al (2017), which also use this drift-corrected OSIRIS data in combination with SAGE II, OMPS, and other limb data records.…”

An updated version of a gap-free monthly mean zonal mean ozone database

“…Systematic comparisons between the databases showed that the applied merging technique plays a role in the representation of realistic long-term stratospheric ozone trends and variability , in addition to the choice of data sources. Recognizing these sensitivities, a second generation of most of these databases has already been developed, with reprocessed data sources and improved merging techniques (e.g., Bourassa et al, 2018;Sofieva et al, 2017;Zawada et al, 2018). However, these updated databases still have limited coverage in the troposphere.…”