The CO2Image mission: quantifying localized emissions of carbon dioxide and methane

Space-based measurements of carbon dioxide (CO2) are the backbone of the global and national-scale carbon monitoring systems currently being developed to support and verify greenhouse gas emission reduction measures. In Europe, the CO2M Mission aims to constrain national and regional-scale emissions down to scales of urban agglomerations and large point sources with emissions in excess of ~10 MtCO2/year. We report on the status of the DLR demonstrator mission “CO2Image”, which aims to complement these measurements by zooming in on facility-scale emissions, detecting and quantifying emissions from point sources as small as 1 MtCO2/year. The key feature of the mission is a target region approach, measuring approximately 75 tiles of size ~50 x 50 km2 per day at a resolution of 50 x 50 m2. Thus, CO2Image will be able to resolve plumes from individual localized sources, essentially providing super-resolution nests for survey missions such as CO2M. Through the choice of the spectral window, detection of point sources of methane as small as 100 kg CH4/hr will also be possible, as well as the retrieval of carbon monoxide. This presentation focuses on the selection of targets, which is relevant for any mission aiming to maximize the number of cloud-free scenes given a limited number of targets per orbit. This is particularly important for persistently cloudy regions, such as the Tropics. For this we are using forecast cloud cover, which is compared to actual observed cloudiness measured by existing sensors. Using Brazil as an example region, we compare the benefit of using forecast data with different lead times, ranging from one to five days. The target selection algorithm also considers additional factors such as wind speed, shortwave radiation, measurement geometry, and surface albedo. As a publicly-funded mission, CO2Image aims to provide public, transparent information about anthropogenic greenhouse gas emissions from space.