The relative importance of various NOx sources including lightning, aircraft, and surface emissions on upper tropospheric total odd nitrogen (NOy) is illustrated as a first application of the three-dimensional Stretched-Grid University of Maryland/Goddard Chemical-Transport Model (SG-GCTM). The SG-GCTM is an extension of the uniform-grid GCTM. The SG-GCTM allows uses of detailed chemical emission data for a region of interest. For this simulation, the stretched-grid was chosen so that its maximum resolution (0.625 degrees E-W, 0.5 degrees N-S) is located over eastern North America and the North Atlantic. The grid's minimum resolution (2.5 degrees E-W, 2 degrees N-S) is located on the opposite side of the globe. A two month simulation, October-November 1997, is run by driving the SG-GCTM with 46-layer Goddard Earth Observing System STRAT (GEOS-STRAT) assimilated data. Model-calculated upper tropospheric NOy and NOy measurements during SONEX (the SASS (Subsonic Assessment) Ozone and Nitrogen Oxides Experiment) are compared. The comparison shows that the SG-GCTM is a useful tool for studying the relative importance of NOx sources. In addition, the simulation is used to highlight the importance of deep convective mixing and to assess the algorithm used to calculate lightning NOx emissions in the SG-GCTM
Symposium on Interdisciplinary Issues in Atmospheric Chemistry