| ertical transport of CO out of the boundary layer by one weak, one average-strength, and one strong wintertime mid-latitude cyclone were simulated using the RAMS hydrodynamic model with a coarse grid of 100 km horizontal grid resolution covering most of North America, and two nested grids with 25 km and 6.25 km grid size.;Comparisons of vertical CO transport between runs with and without nested grids and use of a filtering technique to separate out mean and fluctuating components of vertical CO flux determined that synoptic scale motions with horizontal scales greater than 400 km were responsible for 85-90% of the total transport of CO out of the boundary layer for all three cyclones. Motions with horizontal length scales of 6.25-25 km, 100-400 km, and 25-100 km caused 1-5%, 1-5%, and 5-10% of the total transport, respectively.;Changing vertical grid spacing from 300 m to 100 m changed total vertical transport out of the boundary layer by less than 5% for the average strength and strong cyclones, and caused a 20% increase for the weak cyclone. Accurate modeling of surface CO concentrations required 200 m vertical grid spacing or finer.;Total transport of CO to the free troposphere from the boundary layer for the weak, average-strength, and strong cyclones was ;During the one month period Feb. 15-March 15, 1993,... |
