7-day Back trajectories to the ship have been calculated using the HYSPLIT 4 model.  A description of HYSPLIT  can be found on the NOAA ARL web server.  The model runs were made using Global FNL grided data.  Vertical motions were calculated from the data vertical velocity (omega) field. Trajectories were calculated at 6-hour intervals for trajectories arriving at the ship location at altitudes of 500 (green), 2500 (red) and 5500 (black) meters (nominally 950, 750 and 500 mbar).  The numbers on each line are the number of days (24 hour periods) back at that location from the arrvial time at the ship location.  The trajectories were plotted with FERRET and the plots have been converted to gif files.  The gif files are available in the table below.  The "Large Region" shows the trajectories plotted as in above left, the "small region" shows the same trajectories ploted onto a smaller region as in above right.  The entire set of trajectorie gif files can be downloaded in one "tar" file as  rhb_traj_gifs.tar .  Filenames indicate the date and time of each trajectory

The trajectory data files are accessible as a tar-gzip (.tar.gz) data file: rhb_traj_data.tar.gz.  The individual data files are named with the date and hour in the file name followed by a 9,7 or 5 for the three heights.  After the first five header lines the data fields are: traj number, met grid number, year, month, day, hour, minute, forecast hour, age of trajectory (negative for back trajectory), lat, longt, height (meters), pressure (mbar).  A complete description of the data format can be found on page 31 of  the HYSPLIT_4 User's Guide, available in PDF format from the NOAA-ARL server.

Back Trajectory Plots