ACE1 Model BoM GASP/HYSPLIT back trajectory data from the C-130
flights have been put together into a single composite file.
The 52 separate files are demarked in the composite file by 
a Start and End message next to the original file name. 
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Backtrajectories are calculated with the NOAA HYSPLIT 3.2 code using 
the Australian Bureau of Meteorology (ABoM) GASP model.  This model has
approximately 5 degree horizontal resolution and 18 levels in the 
vertical.  These data are then interopolated onto omega fields for use
with HYSPLIT.  

For each series of trajectories we provide
an ASCII file which contains the time, lat, lon, pressure, U, V, vertical 
velocity in pressure, temperature, relative humidity and surface pressure. 
These fields come from the GASP data set.  

Trajectories will fail if the track hits the surface, rises above approx
500 HPa or flows off the restricted domain of the GASP data.  Also, the 
lowest interpolated GASP data is to the 0.991 omega level.  This corresponds
to roughly 110 meters height.  Trajectories below this level are not 
accurate.  Most likely they will be moving too quickly as they do not 
reflect the physics of the surface drag on the air flow.  They still provide 
a good estimate of the air motion for the first 12-24 hours.  

These trajectories are designed to aid in the analysis of 
the C-130 observations in missions based of Hobart in which 
the C-130 ran circles in the boundary layer.  These are ACE 
missions 11 through 28 inclusive with the exception of flights
14, 17 and 27.  Flight 21 was broken into two source locations.

For each selected mission, a point/time was identified when the
aircraft was in the midst of a circle.  Backwards and forwards
trajectories are run from this location.  Each series of 
trajectories has source altitudes of 100, 500 and 2000m.  

Please contact steve siems (s.siems@sci.monash.edu.au) 
regarding questions.