Overview and update of the SPARC Data Initiative: Comparison ofstratospheric composition measurements from satellite limbsounders

Abstract. The SPARC Data Initiative (SPARC, 2017) performed the first comprehensive assessment of currently available stratospheric composition measurements obtained from an international suite of space-based limb sounders. The initiative's main objectives were (1) to assess the state of data availability, (2) to compile vertically resolved, monthly zonal mean trace gas and aerosol climatologies, and (3) to perform a detailed inter-comparison of these climatologies, summarising useful information and highlighting differences among datasets. The vertically-resolved climatologies of 26 different atmospheric constituents extending over the region from the upper troposphere to the lower mesosphere (300–0.1 hPa) are provided on a common latitude-pressure grid and include most major long-lived trace gases (O3, H2O, N2O, CH4, CCl3F, and CCl2F2), transport tracers (HF, SF6, HCl, CO, HNO3, NOy), and shorter-lived trace gases important to stratospheric chemistry including nitrogens (NO, NO2, NOx, N https://doi.org/10.5281/zenodo.4265393 ).