Trajectories near North Pole and 0/360 longitude

[ps1729]

Dear all, I am trying to calculate back trajectories in the Arctic using a longitude-latitude grid using model output from the community atmospheric model. I am running into two related problems: (1) when trajectories get too close to the north pole and (2) when a trajectory tries to cross the 0/360 longitude - in both cases the trajectory terminates. Looking at the forums and user manual, I am a bit confused about which coordinates to transform to and how. Any help would be appreciated. Best, Pratap.

[barbara.stunder]

I am not familiar with the community atmospheric model. What program are you using to convert it to ARL/HYSPLIT format? Is your grid global?