Tropospheric ozone distribution and variability from satellite sounding at multiple wavelengths

Tropospheric ozone has been retrieved from satellite uv sounders commencing with ESA's Global Ozone Monitoring Experiment (GOME) on ERS-2. The scheme devised by RAL (Munro et al. 1998, Miles et al. 2015) resolves the surface - 450hPa layer and has subsequently been developed and applied to five uv sounders (GOME, SCIAMACHY, GOME-2A, GOME-2B and OMI) to produce multi-year global data sets from 1995-2018 for ESA's Climate Change Initiative and EU's Copernicus Climate Change Service; several of which have been assimilated in ERA-5 and contributed to Tropospheric Ozone Assessment Report (TOAR). Existing data sets are being used in conjunction with chemical transport and coupled chemistry climate models in studies of interannual variability on global and regional scales (eg NAO and summer 2018 European heatwave).

Research is underway to reconcile data sets from these uv sounders to produce a self-consistent, unified set spanning 1995-present. Tropospheric ozone has also been retrieved jointly with water vapour, temperature and surface spectral emissivity by RAL's Infrared and Microwave Scheme (IMS) from IASI, MHS & AMSU-A on MetOp. Current developments aim to combine co-located measurements in the ozone uv, ir and visible bands to improve vertical resolution and sensitivity in the lower troposphere. In addition to MetOp GOME-2 and IASI, combined wavelength approaches would be applicable also to Sentinel-5 Precursor and Suomi-NPP CrIS and to planned satellite missions in polar (MetOp-SG Sentinel-5 and IASI-NG) and geostationary (GEMS & GIIRS, TEMPO, MTG-S Sentinel-4 & IRS) orbit. This paper will outline the current status and near-term plans for ozone retrieval, data production and scientific exploitation.