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MPAS Post-processing

Monica

New member
Hi all,

I am currently using ncl to post-process the output file history*.nc of mpas. I want to draw some wind field diagrams, but I found that in the history*nc file, only u(time,nEdges,nVertLevels), there is no v. How should I draw the wind field diagram with ncl? Can you give me some simple example?

char xtime(Time, StrLen) ;
xtime:units = "YYYY-MM-DD_hh:mm:ss" ;
xtime:long_name = "Model valid time" ;
float u(Time, nEdges, nVertLevels) ;
u:units = "m s^{-1}" ;
u:long_name = "Horizontal normal velocity at edges" ;
float w(Time, nCells, nVertLevelsP1) ;
w:units = "m s^{-1}" ;
w:long_name = "Vertical velocity at vertical cell faces" ;
float pressure(Time, nCells, nVertLevels) ;
pressure:units = "Pa" ;
pressure:long_name = "Pressure" ;

Thanks
 
Although it's quite old and I haven't used it for a while, I've attached an example NCL script that overlays wind barbs on a plot of a scalar field. If you look in the script beginning with the comment
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; BEGIN WIND BARB PLOTTING
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
you'll find the code to interpolate the winds to a regular lat-lon grid and to plot them.
 

Attachments

  • atm_barbs.ncl.txt
    4.3 KB · Views: 27
Hi, mandachasteen, mgduda,
Thank you both for your advice and code, which got me now that the problem is fully resolved.
Thanks
 
Although it's quite old and I haven't used it for a while, I've attached an example NCL script that overlays wind barbs on a plot of a scalar field. If you look in the script beginning with the comment

you'll find the code to interpolate the winds to a regular lat-lon grid and to plot them.
Hi, mgduda
I now know how to use the uReconstructZonal(Time, nVertLevels, latitude, longitude) and uReconstructMeridional(Time, nVertLevels, latitude, longitude) in the history*.nc to plot a horizontal wind field figure. But another problem is, I need to plot the wind field on a specific 500hPa. But the 'nVertLevels' dimension does not seem to be isobaric surfaces. So what do I need to do? Do I need to do vertical interpolation and How?

Best
 
For the specific case of 500 hPa zonal and meridional winds, these are already available in the default diagnostics stream as 'uzonal_500hPa' and 'umeridional_500hPa'. More generally, though, this forum post illustrates how SciPy's interp1d can be used to vertically interpolate fields to an isobaric surface: Plot moist potential temperature at 500 hPa .
 
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