Back Trajectories

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 that are accessible from the table below.  The gif files are located on our ftp server (saga.pmel.noaa.gov/pub/indoex/data) to facilitate downloading each entire set.
 
AEROSOLS-Leg 1 Norfolk-Cape Town 15 Jan - 8 Feb DOY 15-39 Trajectory Plots Data File
AEROSOLS-Leg 2 Cape Town-Mauritius 10 Feb - 19 Feb DOY 41-50 Trajectory Plots Data File
INDOEX-Leg1 Mauritius-Male 22 Feb - 28 Feb DOY 53-59 Trajectory Plots Data File
INDOEX-Leg2 Male-Male 4 Mar - 23 Mar DOY 63-82 Trajectory Plots Data File
INDOEX-Leg3 Male-Male 26 Mar - 30 Mar DOY 85-89 Trajectory Plots Data File

The trajectory data files are accessible as a tar-gzip (.tar.gz) data file for each leg.  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,l ongt, height (meters), pressure (mbar).  A complete description of the data format can be found on page 21 of  the HYSPLIT_4 User's Guide, available in PDF format from the ARL server.
 
 
Cruise Leg Plots

Plots for each cruise leg are available below.  Each cruise leg show the back trajectories (in blue) that arrived at the ship on 00Z each day at 500m, 2500m (~750mb) and 5500m (~500m).  The numbers in each trajectory show where the air masses were on that number of days (24 hour periods) back from arrival at the ship position.  The cruise track is shown in red.  These plots do not show the vertical motion of the back trajectories.  The vertical motions are in the plots from the table above
 
 
AEROSOLS-Leg 1 Norfolk-Cape Town 15 Jan - 8 Feb DOY 15-39 500m plot 2500m plot 5500m plot
AEROSOLS-Leg 2 Cape Town-Mauritius 10 Feb - 19 Feb DOY 41-50 500m plot 2500m plot 5500m plot
INDOEX-Leg1 Mauritius-Male 22 Feb - 28 Feb DOY 53-59 500m plot 2500m plot 5500m plot
INDOEX-Leg2a Male- 4 Mar - 11 Mar DOY 63-70 500m plot 2500m plot 5500m plot
INDOEX-Leg2b   - Male 11 Mar - 23 Mar DOY 70-82 500m plot 2500m plot 5500m plot
INDOEX-Leg3 Male-Male 26 Mar - 30 Mar DOY 85-89 500m plot 2500m plot 5500m plot