Measuring Carbon Monoxide With TROPOMI: First Results and a Comparison With ECMWF-IFS Analysis Data

The Tropospheric Monitoring Instrument (TROPOMI) was launched onboard of the European Space Agency's (ESA) Sentinel-5P satellite. One of the mission's key products is the total column density of carbon monoxide, inferred from TROPOMI's 2.3m measurements. Using the operational processing algorithm, we analyze six subsequent days of measurements during the commissioning phase. The TROPOMI product is compared with CO fields from the European Centre for Medium-Range Weather Forecasts (ECMWF) assimilation system. Globally, a small mean difference between the data sets of 3.2 5.5% with a correlation coefficient of 0.97 is found. The daily global coverage of TROPOMI enables it to capture day-to-day evolution of the atmospheric composition. As an example, we discuss the air pollution event of India in November 2017 with high carbon monoxide (CO) concentrations, which partly dispersed when the CO polluted air was transported north alongside the Himalaya to China. The striking agreement and also regional differences with ECMWF indicate new exciting applications for the TROPOMI CO data product.