Bug in traj-module: incorrect interpolation on glorim
When performing trajectory calculations using the traj-module there is an issue with the interpolated values optionally defined in traj.inp:
- Trajectory positions are likely correctly calculated, e.g. LON, LAT and THETA
- Units TEMP and PRESS can be interpolated optionally, but do not correspond to the initially provided values
This is certainly correct for the first iteration (first column in 'time'), and most likely incorrect for all others as well, as per inplausibilities in an analysis I performed. The issue has occurred when using traj on glorim and might be an issue with the local installation. I attached a file documenting the situation. The core issue I found is as follows:
- Provided values for temperature and pressure (temp1, press1) on some locations, I can calculate values for the potential temperature (theta1)
- Tracking these initial locations yields directly provided potential temperature theta2 (as per default output)
- I request to have temperature and pressure to be interpolated and saved as well (temp2, press2)
- For the first value (initial time), I find press1 != press2 and temp1 != temp2, but theta1 == theta2
- Moreover, potential_temperature(press2, temp2) == theta2; values for press2, temp2 are incorrect, but strangely matchingly incorrect