First year of Sulfur Dioxide Retrievals from Sentinel-5 Precursor TROPOMI instrument and comparison with independent satellites and ground-based datasets

Abstract

The Sentinel-5 Precursor (S5P) platform was launched from Northern Russia on October 13, 2017 carrying the TROPOspheric Monitoring Instrument (TROPOMI). With a spatial resolution of 7x3.5 km², TROPOMI provides improved information on natural and anthropogenic emissions of trace gases and aerosols, with an unprecedented level of details. BIRA-IASB and DLR have the joint responsibility of developing and maintaining the SO2 retrieval algorithm and its implementation into the S5P operational processor (Theys et al., 2017). In this paper, we introduce the algorithm, present the first year of TROPOMI SO2 results for several degassing volcanoes and anthropogenic sources. Compared to the current OMI, OMPS and GOME-2 sensors, we observe a step change in satellite ability to monitor and quantify global SO2 point emissions sources. The improvements and new opportunities offered by TROPOMI are illustrated and discussed, and first validation results of the TROPOMI SO2 product with available concurrent satellite and ground-based measurements are presented. The retrieval challenges associated with higher resolution measurements are also addressed and plans for future work are outlined.