GDAS terrain height?

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GDAS terrain height?

Post by ryanxia » July 18th, 2019, 8:52 pm


I am using GDAS 1 deg resolution data for HYSPLIT back trajectory modeling. In the traj output, there is a column of terrain height asl. What's the resolution of this "terrain" height data? Is it also 1 deg? If so, finer scale peaks or mountains might be smoothed out. Is the elevation the same for the whole 1 degree grid?

I am curious how the terrain height is treated by HYSPLIT. I saw previous posts that NCEP/NCAR terrain height is inferred from pressure fields, not real elevation asl. I am considering to use HYSPLIT trajectory end point coordinates as input to DEM raster to read the real "elevation" from the exact coordinates. Do you caveat on this?


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Re: GDAS terrain height?

Post by barbara.stunder » July 19th, 2019, 8:31 am

All the fields in a HYSPLIT meteorology file are on the same grid, so yes, the GDAS1 terrain height is at 1 degree resolution. There is no finer resolution.

The NCEP/NCAR reanalysis archive does not have terrain height, so HYSPLIT uses the surface pressure, which is in the file, to estimate the height.

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