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

[Lisa Murphy]

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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