1 deg vs 0.5 deg GDAS data - backward trajectories

[jhoelzemann]

Hi,

We did an intercomparison with 10 day backward trajectories (online-model) using 1 deg GDAS data and 0.5 GDAS data.
With the 0.5 deg GDAS data, the trajectories only went half way back (approximately half of the distance compared to the 1 deg-GDAS simulation).
Independent from the GDAS resolution the covered distance to the starting point within the same amount of days should be the same, or are we missing something?

Thanks,
Judith

[ariel.stein]

Hi Judith,
When running trajectories using the GDAS 0.5 degree you are only running backwards for 7 days since the web version only allows 7 meteorological files. For the GDAS 0.5 we have daily files. If you want to run with GDAS 0.5 for longer periods (e.g 10 days or more) I would recommend downloading the PC or Mac versions of the model in your own machine.