HYSPLIT Forum: hysplitbbs.arl.noaa.gov

Like another user, I only getting partial results for a back trajectory calculation. I am using the Mac-based downloaded HYSPLIT model and the GUI. I am trying to run a 168 hour back trajectory, but when I run the model, it only back simulates back as little as 5 hours for some simulations. For other dates, I am able to conduct the entire 168 hour back trajectory simulation, so I don't think I'm setting the run up incorrectly.

I have used two data sets, NCEP-NCAR Renalysis data and GDAS 1 deg res data, but both produce the same result.

I have made sure that I have enough meteorological data loaded so that the simulation is not stopped because of insufficient temporal resolution.

I successfully ran the back trajectory for 168 hours on the web-based HYSPLIT model using the above data, so I know it's possible.

Thoughts and solutions welcome.

You need to make sure you have 168 hours of backward in time data in the meteorological data sets you are including in your CONTROL file. The NCAR Global reanalysis files only have data for one month in them, whereas the GDAS 1 degree files only have at most 1 week of data (some files such as those ending in w5 may only have a few days at the end of a month in them). You many need to include several meteorological files in your CONTROL file so that the trajectory can go all the way back 168 hours.