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HYSPLIT for Mars

PostPosted: November 6th, 2013, 5:48 pm
by davidbruggeman815
I am conducting a study on Mars using HYSPLIT for dust trajectories, which obviously needs to be corrected for Mars. The changes I am assuming that need to be made would be the radius and topography, however, I was wondering if other constituents would need to be modified in the source code to achieve this?
Thank you.

Re: HYSPLIT for Mars

PostPosted: November 8th, 2013, 4:02 pm
by ariel.stein
This is a really unique application for HYSPLIT!
Here are some thoughts that can help you. During the calculation the model implicitly uses a standard atmosphere air density, so that needs to be modified. However, that might not be the only required modification. For instance, if you are letting the model calculate the gravitational settling then you need to modify the gravity constant. Also, when calculating the vertical dispersion the model relies on parametrizations that use gravity and other Earth related constants. As you can see it might require some involvement with the code to make it applicable to the Mars atmosphere.
Please keep us posted on the development of this application!!

Re: HYSPLIT for Mars

PostPosted: November 25th, 2013, 6:18 pm
by alibridger
Jumping in here (as the advisor!), our 1st step will be to run the pure trajectory code (no dispersion etc.) So what we are trying to do is figure out what to edit and where to edit it! For example: (1) in searching the code (in /library) for the planet's radius, we have found that to be set to 6371 km in several locations. Does that seem right (as opposed to being defined in just one location)? Either way, we can edit that for Mars. (2) If we keep sedimentation, we'll have to do the save for gravity. (3) The next thing is terrain: is there ONE location/routine in which terrain is read in (so that we can override and input Mars' terrain data)? And (4): is there ONE location in the code at which meteorological data is read in? Ideally, we can then slot in our own read statements to ingest wind output from the Mars GCM (as opposed to convincing the Mars GCM to output data in a form hysplit already knows).

Any help with these source code questions would be great! Final example: is there a subset of the code which is for trajectory calculation ONLY (so we could ignore the rest for now)??

Re: HYSPLIT for Mars

PostPosted: December 2nd, 2013, 3:01 pm
by ariel.stein
Here are some comments/answers:
1) Yes, there might be several locations where gravity is defined throughout the code.
3) If no terrain height is provided by the meteorological data (see below), the model will read it from a file called TERRAIN.ASC under the bdyfiles directory.
4) Yes, the model reads the meteorological fields needed to run a trajectory (including terrain height, if available) through the advection subroutine (advpnt.f) . The source code for the trajectory calculation is called hymodelt.F and you can find it under the source directory.