extract data from GDAS

[scarlett.boiardi]

Hi,

I would need to obtain the relative humidity (RH2m) and the temperature at 2 m level (T02m) that HYSPLIT uses to compute the backtrajectories (done with the GDAS meteorological files). To be more precise, I would like to know if it's possible to output in the tdump file the T02m and the RH2m.
I'm sorry in advance if it's very straightforward, but I'm very new to this and I don't know at all how to do it.

Thanks for you time and help,
Best wishes,

Scarlett

[barbara.stunder]

Please see the trajectories sections in the Tutorial. Use the link for the "PC HYSPLIT Tutorial" at http://www.ready.noaa.gov/HYSPLIT.php.

Relative humidity (RH2M) and temperature (T02M) at 2 m are not used in the trajectory calculation.

If you want to know the RH2M and T02M along a trajectory, in the PC version, go to Advanced / Configuration Setup / Trajectory, and choose #6 Add METEOROLOGY output along trajectory. The analogous choice of terrain is shown in the Tutorial in section 4.10.

The Tutorial also has information on the HYSPLIT meteorology files.

[scarlett.boiardi]

Thanks for the answer.

Okay, if it's not possible to get the RH2m and T02m along the trajectory, is it possible to get them from the GDAS file ? Basically, I have many backtrajectories and I would like to be able to obtain the sea surface temperature and RH at the sea surface temperature at particular points (where there is moisture uptake along the trajectory), from the same data files as the ones used to compute the backtrajectories (so from GDAS). Assuming T02M can be considered as being SST, I would need to extract T02M from the different GDAS files at specific lon and lat. Does anyone know how to do this ?

Thanks again !

[glenn.rolph]

You can output these fields in the tdump file as long as they exist in the meteorology file. You need to follow the steps outlined in the last post to add them to the tdump along the trajectory through the Advanced menu tab.