> Question on the starting height to make the trajectories and the correction factor for MAGL
I have a question regarding what start height to make the trajectories and the correction factor for MAGL...
For my case,
MSLP=1026 mb
PRSS=995 mb
Difference = 1026 - 995 = 31mb
Multiplying 31 times 10 gives 310 m
The actual terrain height at that location is 244 m
244 - 310 = -66
This means that I would start a trajectory at 66 m below the start
height that I choose for this site. All of your examples in the
frequently asked questions suggest that the start heights be adjusted by
adding not subtracting height. Is subtracting 66 m from the start height
valid?
The case you described is a valley. The large-scale average terrain
is higher than the actual location of interest. There is no correct answer in
terms of what you should do. If the valley is relatively wide and large,
then I would ignore the terrain issue and start the trajectory at the same
height above model terrain as above the actual surface. If the valley is
narrow, then you should probably start at ground-level regardless of height.
