Page 1 of 1

Hysplit Tragectory in Windows - issue with starting day

Posted: September 18th, 2016, 11:58 am
by Anne70
Hello, I am a home user of Hysplit, and I am running it on a PC laptop, Windows 32 bits (Vista).

In relation to the Gordon Bennett Gas Balloon competition, I would like to run Hysplit Trajectory. I know I can do it online, but I was only able to run the online model a few times, then I was unable to connect to the server again. Well I guess it's busy :-)

Ok so I downloaded everything on my laptop and so far so good. I was able to get the meteorological model, etc.

First issue: I was unable to enter a later time than the meteorological model to start the calculation. I am using the gfslrf (2.5 degrees) and downloaded the latest available which is the 06 UTC (I thought I could get the 12 UTC, but it seems it was not available yet). Even if I enter time 22 UTC (same day, that is today) to start the model calculation, it does not work. I got error message that my starting time is -prior- to starting time of the meteorological model, which is not the case.

After reading the User Guide, I saw that if I leave all to '00' in the time and date field, the trajectory calculation would start at the same time as the meteorological model is starting. So I did that and I got a first result which seemed to make sense (it displayed in GSview properly).

I wanted to re-run the trajectory model with a longer time window, and here problems started: the starting day of the trajectory calculation is BLOCKED on the 28th of September! I tried everything (starting again, deleting the parameter files and starting from scratch, downloading again the meteorological model), nothing helped. I can't get the start date changed to anything else than 28th of September.

I am stuck now, so I hope that somebody can help me with this issue :-)

Have a nice evening everybody,
Stavanger. Norway

Re: Hysplit Tragectory in Windows - issue with starting day

Posted: September 19th, 2016, 8:08 am
by barbara.stunder
Please see You should use both the gfsf (forecast hours +0 to +240) and gfslrf (forecast hours +240 to +384).

Re: Hysplit Tragectory in Windows - issue with starting day

Posted: September 19th, 2016, 4:00 pm
by Anne70
Hello Barbara and thank you for your help. Indeed, by downloading the 1 degree GFSF model, I was able to run my trajectory from the present time.

I hadn't realized that GFSFlr was for 'long range'. I thought the GFSF models were only different is spatial resolution (0.5, 1 and 2.5 degrees). But of course it makes sense when one wants to calculate a pollutant trajectory to have another model from 10+ days and ahead. Very interesting.

I just recalculated a trajectory for the Gordon Bennett Cup balloons, and found that they might head to Greece... Let's see how this works out :)

Have a nice day,