Improving Knowledge of Surface Emissions Using Observations from Satellite and Aircraft Campaigns

Abstract : Recent satellite and aircraft observations have been integrated to better quantify the distribution and temporal variability of surface emissions at global and regional scales. This presentation will give examples of approaches using a combination of space-borne instruments, aircraft data collected during field campaigns, and atmospheric modeling. These methods have also been used to assess the capability of future space missions to provide a better understanding of emissions. We discuss several case studies demonstrating an approach to evaluate NOx emissions at a sector level by comparing satellite retrievals and in-situ aircraft sampling to regional and global chemical-transport model calculations of NO2 columns. These studies address impacts of NOx emissions controls at US power plants and the quantification of NOx emissions from motor vehicles, industrial facilities, and ports in US cities and in megacities around the globe. Space-borne instruments in geostationary (GEO) orbit will soon monitor major air pollutants across North America, Europe, and Asia. We investigate the possibility that GEO observations of formaldehyde (HCHO) columns can provide information about urban volatile organic compound (VOC) emissions. Aircraft observations constrain model simulations of the emissions of primary VOC species and their atmospheric oxidation to form HCHO. Model simulations of tropospheric HCHO columns are then compared with retrievals from current satellite instruments in low earth orbit and from proposed GEO instruments. We conclude with a discussion of how better knowledge of surface emissions of atmospheric compounds can be integrated into the GEIA (Global Emissions InitiAtive, http://www.geiacenter.org) international project. GEIA provides access to information on global and regional emissions datasets through the ECCAD (Emissions of atmospheric Compounds and Compilation of Ancillary Data, http://eccad.sedoo.fr) database