Display of Other Along-Traj Variables

Topics about the HYSPLIT trajectory model.
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hurricanemolina
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Joined: June 6th, 2017, 6:04 pm
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Display of Other Along-Traj Variables

Post by hurricanemolina » June 6th, 2017, 6:11 pm

I have a question regarding advanced configuration of HYSPLIT. 

I am currently using NARR data in ARL format and everything is working great so far for basic trajectory generation. I know how to access/modify the SETUP file. How can I make it so that HYSPLIT displays latent/sensible heat flux variables as along-trajectory variables? These variables are already in the NARR ARL files I am using (LHTF, SHTF). 

Additionally, would the displayed LHTF/SHTF be relative to the air parcel or the environment? Or am I misunderstanding the basic concepts of Latent/Sensible heat with this question?

Thank you for your time and for all you do!!

ariel.stein
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Joined: November 7th, 2012, 3:14 pm
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Re: Display of Other Along-Traj Variables

Post by ariel.stein » June 7th, 2017, 5:15 pm

Unfortunately, the trajectory program does not include the extraction of those variables along the trajectory. However, the following variables can be extracted along the trajectory if they are available in the meteorological file:

Potential Temperature in degrees Kelvin
Ambient Temperature in degrees Kelvin
Precipitation rainfall in mm per hour
Mixing Depth in meters
Relative Humidity in percent
Specific Humidity in g/(kg air)
Water Vapor Mixing Ratio in g/(kg dry-air)
Solar Radiation downward solar radiation flux in watts per square meter
Terrain Height in meters required for the trajectory plot to show underlying terrain

These variables reflect the state of the environment.The trajectory does not modify any of these variables as it gets transported through the meteorological fields.

hurricanemolina
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Joined: June 6th, 2017, 6:04 pm
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Re: Display of Other Along-Traj Variables

Post by hurricanemolina » June 7th, 2017, 11:40 pm

Thank you so much for your reply.

I completely misunderstood page 55 of the HYSPLIT User's Manual (Revised January 2017) which lists LHTF and SHTF as parameters that the model can read. What is that referring to? Is that referring to the ARL formatting of data?

If I were to attempt to modify my desktop HYSPLIT version to extract those variables along the trajectory -- Which application(s) would I be modifying?

Thanks again for your time!

ariel.stein
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Joined: November 7th, 2012, 3:14 pm
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Re: Display of Other Along-Traj Variables

Post by ariel.stein » June 8th, 2017, 9:28 am

The model will read those fluxes but it will use them to calculate the turbulent dispersion when using the model for concentration calculations.

Including the extraction of these variables along the trajectory will require the modification of the hysplit source code. If you are proficient in fortran, you can modify the code and we can share it the rest of the user community.
On the other hand, you could also use the GUI under Meteorology/Display Data/Text Profile to look at the value of the fluxes at fixed latitude and longitudes.

yaqiang
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Re: Display of Other Along-Traj Variables

Post by yaqiang » June 8th, 2017, 10:35 am

Another option is to write MeteoInfoLab script to extract the variable values from meteorological data along trajetory. There is a online example: http://www.meteothinker.com/examples/me ... _data.html .

hurricanemolina
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Joined: June 6th, 2017, 6:04 pm
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Re: Display of Other Along-Traj Variables

Post by hurricanemolina » June 8th, 2017, 6:24 pm

Thank you both for your responses and for the provision of the MeteoInfoLab along-traj code, which is very useful! I will also go ahead and try to modify my Hysplit fortran code over the next couple of weeks/months. I will most certainly share if I am successful.

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