Comparison of ozone data from Cape Verde and the AMMA cruise with back trajectories.
Top plot: Hourly ozone data from the Cape Verde station (black squares) are plotted with the 15-min shipborne ozone data (colored circles) from 6 May 2008 to 16 May 2008. The color-coding of the shipborne ozone measurements represents the distance between the ship and station. The purple ellipses correspond to the ship data (right) and the matching station data (left) shifted by 48 h, the approximate transport time between both measurement sites. Bottom plot: Back-trajectories every 12 h are shown along the cruise track near Cape Verde. The solid red line is the AMMA cruise track. The 144-h back trajectories are the black, blue, pink, and green lines. The colors and symbols are used to differentiate various trajectories for ease of viewing. Symbols are placed on the trajectory lines every 12 h. Day of year is labeled next to each second trajectory.