Plotting meteorology data along a trajectory

[koko_a]

Hi,
I'm using the PC version of Hysplit with meteorology data downloaded from ERA-Interim reanalysis (ECMWF).

I tried to plot meteorology data along a matrix of backtrajectories.
I succeeded in plotting the relative humidity and Theta, but not the specific humidity or other meteorological parameters (they are seem as constant 0; an example attached below).

The meteorology file includes a field of specific humidity.

What should I do...?

Thanks

spcHum.PNG (9.42 KiB) Viewed 6362 times

[barbara.stunder]

The meteorology values plotted should be the values in the last column of the trajectory endpoints file. Open the trajectory endpoints (text) file in Notepad. Confirm specific humidity is the last column, and that they are non-zero. The Help file (c:\hysplit4\html\s614.htm) through the GUI at Advanced / Configuration Setup / Trajectory / (6) / Help gives information.

You could do one trajectory using ECMWF to verify the plot of specific humidity as a contrast to a matrix of trajectories.

[koko_a]

Hi Barbara and thank you for your answer.
The trajectory endpoints file shows 0 too, and it is the same if I calculate for a matrix or a single trajectory.

I also checked the meteorology file I've loaded and it seems fine (using meteoInfo software; and there are values in the specific humidity field).

Any suggestions?

[barbara.stunder]

The plot is just showing the values of zero that are in the tdump file. The theta and temperature values are also zero, which is not right. In meteoinfo are you plotting the ARL/HYSPLIT-formatted file? Or your 'raw' EMCWF data? I wonder if the convert-to-arl didn't work. You could also try plotting these meteorology fields in the ARL-formatted file through the HYSPLIT GUI - Meteorology / Display Data / Contour Map.

[koko_a]

I plotted the 'raw' EMCWF data, and indeed, the ARL/HYSPLIT-formatted file isn't showing other meteorological fields (both in meteoInfo and in HYSPLIT GUI).
So if it is a problem with the conversion to ARL, what could be the problem?
Is there another way to perform the conversion?

The 3D fields that I have from ERA-Interim are:
129.128/131.128/132.128/135.128/157.128/133.128
which are:
Geopotential/U component of wind/V component of wind/Vertical velocity/Relative humidity/Specific humidity

[alicec]

How are you doing the conversion currently?

Thanks,
Alice

[koko_a]

How are you doing the conversion currently?

Thanks,
Alice

I've downloaded the 3D fields that was mentioned earlier, 2D surface data and invariant data and in the HYSPLIT GUI:
Meteorology->convert to ARL->ECMWF ERA, and I change the "Numb levels" to 37.

In general the conversion works, but not for the specific humidity

[alicec]

Ok, I see that you are not downloading the temperature (130.128).
The conversion programs are made to be frugal. They won't save the RELH and SPHU because they consider
this information to be redundant. They will preferentially save the RELH if both are present in the meteorological file.
Then, if you ask for SPHU, HYSPLIT will compute it using the RELH. However, since you don't have the temperature field,
the sphu cannot be computed.
I would highly recommend downloading the temperature field.
An alternative is to download only the sphu and not the relh. Then you will be able to get the sphu but not the relh.

Cheers,
Alice

[koko_a]

Hi alice, thank you very much - it's working now!