Evidence of lightning NOx and convective transport of pollutants in satellite observations over North America

Column observations of NO2 by GOME and CO by MOPITT over North America and surrounding oceans for April 2000 are analyzed using a regional chemical transport model. Transient enhancements in these measurements due to lightning NOx production or convective transport are examined. Evidence is found for lightning enhancements of NO2 over the continent and western North Atlantic and for convective transport enhancements of CO over the ocean. The two independent satellite measurements show consistent enhancements related to convective events. Model results suggest that the enhancements are particularly large in the lower troposphere due to convective downdrafts of lightning NOx and shallow convection of CO, implying that low-altitude aircraft in situ observations are potentially critical for evaluating the model simulations and validating satellite observations of these transient features.