[ncl-talk] error using vinth2p on CCSM4 PI winds

[Dennis Shea]

[1] When reading an entire array,
     Use
           und= f1->U
     Not
           und= f1->U(:,:,:,:)

     The former is more efficient. If you want to explicitly note that U is
4D, I'd suggest adding a commebt

         und= f1->U                           ; 4D or (:,:,:,:)

[2] There is an odd mix of units for the P0, plev and ps variables.
      I speculate your 'P0u' is in Pa when it should be in mb (hPa).

P0u = f1->P0
ps   = f4->PS      ; Pa

P0u = P0u*0.01
P0u at units = "mb"




On Fri, Feb 27, 2015 at 12:18 PM, Lisa Murphy <lmurphy at rsmas.miami.edu>
wrote:

>  Hi -
>
>  I'm using NCL version 6.1.2. I'm working with the CMIP5 CCSM4 PI
> simulation data. The surface U and V winds are not archived so I tried
> using the the vinth2p function to interpolate to either 850mb or 925 mb.
> However, when I do so the winds are very strong and seem to be offset. I
> checked the lat and lon coordinates and things seem to be fine. I'm not
> extrapolating (extrap = False), but this shouldn't be an issue when I
> interpolate to 850 mb.  I also tried both the linear and log interpolation
> (interp = 1 or 2).
>
>  The file size is large (13 Gb). Could this be the issue?
>
>  Please see the attached image file, and a subset of my script
> below. Thanks for any help.
>
>  Lisa
>
>  und= f1->U(:,:,:,:)
> lat = f1->lat
> lon = f1->lon
> time = f1->time
> P0u = f1->P0
> ps = f4->PS
>
>  ; for comparison with another model interpolate the model data to these
> ; 25 constant pressure levels
> plevs = (/70.,100.,150.,200.,250.,300.,350.,400.,450.,500.,550., \
>          600.,650.,700.,750.,800.,825.,850.,875.,900.,925.,950.,975., \
>                                 990.,995.,1000./)
> plevs at units = "mb"
> plevs at positive = "down"
>
>  interp = 2  ;1 = linear, 2 = log, 3 = loglog
> extrap = False
>
>  hyam = f1->hyam
> hybm = f1->hybm
>
>  ui = vinth2p(und,hyam,hybm,plevs,ps,interp,P0u,1,extrap)
> printVarSummary(ui)
>
>  uil = ui(:,17,:,:)
> copy_VarCoords(ui,uil)
> copy_VarAtts(ui,uil)
> printVarSummary(uil)
>
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