Trajectory option

[gracy.hm]

Hi,
when we plot trajectories which option we should take to plot trajectories. Iscentropic trajectories calculation or Sigma calculation for trajectories calculation.
In my case when I am running iscentripic trajectories I am getting strong westerlies while as when I am calculation using sigma coordinated my air masses are circulating around my location. So our interpretation of results will be entirely different in both the cases, which option to select.
RED colour shows -Iscentropic trajectories
BLACK colour shows- SIGMA
other settings are same for both of them


Thanks
Gracy

[ariel.stein]

Using the sigma option forces the model to keep the trajectories at the same vertical level and there is no vertical motion for the duration of the run. I would not recommend using this option unless you do it for model evaluation purposes.
Please refer to the following link for further information about trajectories vertical motion.
http://www.meteozone.com/home/tutorial/ ... _vert.html