HYSPLIT Forum: hysplitbbs.arl.noaa.gov

Dear Hysplit Team and Hysplit Users

I was wondering how accurate the terrain/elevation model used in Hysplit is? I am running back trajectories over Antarctica using NCEP reanalysis MET and outputting trajectories with height above ground level.

Will the "ground" height/elevation be correct over the central continent plateau of Antarctica?

How well is the Antarctic Peninsula captured?

What about ice shelves? Do they count as "ground" in the model?

Finally - how much can I trust the trajectory height? Only in the boundary layer? Or could I trust, for example a trajectory start height of 4000m AGL above the South Pole (~7000m ASL). This is important in interpreting ground based atmospheric chemistry measurements, since at those heights, in this region, one might expect to see the chemical signatures of stratospheric exchange.

Any information and/or advice on the matter would be greatly appreciated.

Kind regards,
Thomas

This particular meteorological dataset has a horizontal resolution of 2.5 degrees and the terrain height is derived from the surface pressure. From the attached figure you can see that the elevated areas (low pressure areas) over Antarctica can be distinguished at this resolution. However, many finer details about the ice shelves will not be captured. For that you will need a higher horizontal resolution.

The NCEP reanalysis vertical resolution is also very coarse. The vertical levels that the model are as follows:
Levels (hPa): 1000,925,850,700,600,500,400,300,250,200,150,100,70,50,30,20,10.
However, I do not see any reason why not to trust trajectories starting above the boundary layer.
More information about the NCEP reanalysis data can be found at:
http://www.ready.noaa.gov/gbl_reanalysis.php
http://www.cpc.ncep.noaa.gov/products/w ... lysis.html