Abstract

Satellite measurements of carbon monoxide (CO) are important for air quality monitoring and forecasting as well as in climate studies. MOPITT (the Measurements Of Pollution In The Troposphere instrument), a gas-filter correlation radiometer on board the NASA Terra platform, has been measuring CO ... Show moreSatellite measurements of carbon monoxide (CO) are important for air quality monitoring and forecasting as well as in climate studies. MOPITT (the Measurements Of Pollution In The Troposphere instrument), a gas-filter correlation radiometer on board the NASA Terra platform, has been measuring CO profiles and total CO column since early 2000, producing the longest global CO record to date. Global coverage is achieved every three days, approximately, with a ground instantaneous field of view at nadir of 22x22 km2. MOPITT derives tropospheric CO concentrations from cloud-free radiance measurements acquired in the reflected- and thermal-infrared regions (near 2.3 and 4.7 μm, respectively). MOPITT's unique capability for multispectral observations provides enhanced sensitivity near the surface. New satellite measurements are necessary to extend the global CO record. TROPOMI, the TROPOspheric Monitoring Instrument on board the ESA Copernicus Sentinel-5 Precursor satellite, was successfully launched in October 2017. It achieves global coverage daily, at a spatial resolution of 7x7 km2, approximately. TROPOMI is a spectrometer sensing ultraviolet, visible, and reflected-infrared radiances. Total CO column measurements are derived from the latter, making MOPITT and TROPOMI the only two satellite instruments currently retrieving CO from the 2.3 μm overtone band. TROPOMI retrieves full and partial CO columns over land (under clear and cloudy conditions) and partial CO columns over water (under cloudy conditions only). Here we present a comparison between CO retrievals from these two instruments, necessary to evaluate the continuity of the time series. Initial results indicate good agreement between the two datasets, with differences well within their accuracy requirements. Show less