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Guidelines on Setting Hysplit Level 1 Height
Posted: July 12th, 2023, 7:33 pm
by Thunder23
If I am creating a back trajectory for a sample that is located 5m AGL, should I enter that as my Level 1 Height? I am struggling to find any information on what to do if you are tracing back from a landing spot. Also, If I want to run a back trajectory for a particle gathered over a week, would a run time of 24 hours with a trajectory started every 24 hours with a maximum of 7 trajectories be correct?
Thank you!
Re: Guidelines on Setting Hysplit Level 1 Height
Posted: July 20th, 2023, 8:56 am
by alicec
It is hard to answer these questions without knowing the details of your application.
Many different techniques for using backwards trajectories for source determination have been developed
so I suggest starting with a literature search to see what others working in your field have done.
This review article from 1998 may be a good starting place.
https://www-sciencedirect-com.proxy-um. ... 1097004573
In general the trajectories are representing the path of an air mass. Over time it is expected that
any material within the boundary layer will become well mixed up to the boundary layer height and thus utilizing several trajectories from
near to the ground up to the mixing layer height may be appropriate.
Simply utilizing trajectories at the receptor height which is often very close to the ground is usually not effective.