traj.gs

[Berny Bisselink]

Dear GrADS-users,

I am working with the script traj.gs to draw backward trajectories. At
every timestep traj.gs draws a dot. At the end point of the trajectories I
make calculations for the evaporation rates. The end point of the
trajectories is (almost) the end of the given domain, but not exactly (goes
with exact timesteps). The trouble is that I have to know the trajectory
until the exact end of the domain (between the timesteps).
For example: I have a domain 6-27degr E; 44-52 degr N. In that domain I
draw the backward trajectory for a point till the moment it reaches almost
the end of the domain (e.g t=3). The next step (t=2; backwards)is a point
outside the domain. Because of this the trajectory stops at t=3 and reaches
not exact the domain edges.
Does anybody know how to adapt traj.gs in a way it calculates the
trajectory exactly till the end of the domain, so that it stops at e.g. 52
degr N (somewhere between t=3 and t=2) and I can make calculations at this
point?

I appreciate any suggestions a lot,
Best Regards, Berny