How is height converted to pressure when using hybrid sigma-pressure levels?

Topics about the HYSPLIT trajectory model.
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khartig
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How is height converted to pressure when using hybrid sigma-pressure levels?

Post by khartig » June 23rd, 2020, 8:41 am

My input data is on hybrid sigma-pressure levels, similar to ECMWF (vertical coordinate system flag 4). How is the final column of the trajectory endpoints file, 'PRESSURE', calculated? I would like to be able to plot my source data in either height or pressure coordinates, but I want to make sure the conversion I'm using on my data matches that used in the trajectories so that they line up correctly.

Fantine
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Joined: November 8th, 2012, 3:41 pm

Re: How is height converted to pressure when using hybrid sigma-pressure levels?

Post by Fantine » June 23rd, 2020, 8:59 am

You may use the hypsometric equation to compute the pressure from temperature and geopotential height.
https://en.wikipedia.org/wiki/Hypsometric_equation or you can find it in any meteorological textbook.

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