[ncl-talk] Doubt about interpolation from hybrid sigma level coordinate to height of 10m

[leilane.passos at inpe.br]

Hi, 

I need to interpolate the wind results from CCSM4(CAM) in
hybrid sigma level coordinate to height of 10 m. Then, I tried to use
the function wrf_user_intrp3d with the u, v and the geopotential height
(Z3), but the interpolated field has undefined values and I don't know
the reason. I have the following questions: 

1) I think that I should
find the interpolated values in the entire domain. But why did I find
undefined values in certain areas like Andes Chain? 

2) If I use the
command vinth2p to interpolate from hybrid to pressure coordinates, what
is a similar function that I could use to convert from pressure to
height of 10 m? 

; -------------- LOAD FUNCTIONS AND PROCEDURES
----------------

 load "/usr/share/ncarg/nclscripts/csm/gsn_code.ncl"

load "/usr/share/ncarg/nclscripts/csm/gsn_csm.ncl"
 load
"/usr/share/ncarg/nclscripts/csm/contributed.ncl"
 load
"/usr/share/ncarg/nclscripts/csm/shea_util.ncl"
 load
"/usr/share/ncarg/nclscripts/wrf/WRFUserARW.ncl"
 load
"/usr/share/ncarg/nclscripts/acentos.ncl"

 ; -------------- BEGINING OF
NCL SCRIPT ----------------

 begin

 outfile =
"test_U10mV10m.1985.20thC.nc"

 if (isfilepresent(outfile)) then

system("rm -rf "+outfile) ;-- make sure that file does not exist
 end
if

 ;-- open data file

 in_u =
addfile("224331.U.1985.20thC.U.nc","r")
 in_v =
addfile("224331.V.1985.20thC.V.nc","r")
 in_z =
addfile("239928.Z3.1985.20thC.Z3.nc","r")

 ;-- get variable t and its
dimensions and dimension sizes

 u = in_u->U ;(time, lev, lat, lon) ;--
get variable u
 v = in_v->V ;(time, lev, lat, lon) ;-- get variable v
 z
= in_z->Z3 ;(time, lev, lat, lon) ;-- get variable u

 time = in_u->time
;-- get dimension time
 lev = in_u->lev ;-- get dimension lev
 lat =
in_u->lat ;-- get dimension lat
 lon = in_u->lon ;-- get dimension lon


ntim = dimsizes(time) ;-- get dimension sizes of time
 nlev =
dimsizes(lev) ;-- get dimension sizes of lev
 nlat = dimsizes(lat) ;--
get dimension sizes of lat
 nlon = dimsizes(lon) ;-- get dimension sizes
of lon

 ;-- Interpolate u and v to 10m:
 ;u10m = u ;-- copy variable
and its dimensions and attributes
 u10m =
wrf_user_intrp3d(u,z,"h",10.0,0.,False) ;-- interpolate u
 u10m at units =
"m/s" ;-- define new units
 ;v10m = v ;-- copy variable and its
dimensions and attributes
 v10m =
wrf_user_intrp3d(v,z,"h",10.0,0.,False) ;-- interpolate v
 v10m at units =
"m/s" ;-- define new units
 ;print(u10m)


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;-- create new netCDF file
 fout = addfile(outfile,"c")

 ;-- begin
output file settings
 setfileoption(fout,"DefineMode",True) ;--
explicitly declare file definition mode

 ;-- create global attributes
of the file
 fAtt = True ;-- assign file attributes
 fAtt at title = "NCL
Efficient Approach to netCDF Creation"
 fAtt at source_file = "CCSM4.nc"

fAtt at Conventions = "CF"
 fAtt at creation_date = systemfunc ("date")

fAtt at history = "NCL script: ex_netcdf_2.ncl"
 fAtt at comment = "Convert
variable t: Kelvin to Celsius"
 fileattdef(fout,fAtt) ;-- copy file
attributes

 ;-- predefine the coordinate variables and their
dimensionality
 dimNames = (/"time", "lat", "lon"/)
 dimSizes = (/ -1 ,
nlat, nlon /)
 dimUnlim = (/ True , False, False/)

filedimdef(fout,dimNames,dimSizes,dimUnlim)

 ;-- predefine the the
dimensionality of the variables to be written out
 filevardef(fout,
"time" ,typeof(time),getvardims(time))
 filevardef(fout, "lat"
,typeof(lat), getvardims(lat))
 filevardef(fout, "lon" ,typeof(lon),
getvardims(lon))
 filevardef(fout, "u10m" ,typeof(u10m),
getvardims(u10m))
 filevardef(fout, "v10m" ,typeof(v10m),
getvardims(v10m))

 ;-- copy attributes associated with each variable to
the file
 filevarattdef(fout,"time" ,time) ;-- copy time attributes

filevarattdef(fout,"lat" ,lat) ;-- copy lat attributes

filevarattdef(fout,"lon" ,lon) ;-- copy lon attributes

filevarattdef(fout,"u10m" ,u10m) ;-- copy u10m attributes

filevarattdef(fout,"v10m" ,v10m) ;-- copy v10m attributes

 ;--
explicitly exit file definition mode (not required)

setfileoption(fout,"DefineMode",False)

 ;-- output only the data values
since the dimensionality and such have been predefined.
 ;-- The "(/",
"/)" syntax tells NCL to only output the data values to the predefined

;-- locations on the file.
 fout->time = (/time/) ;-- write time to new
netCDF file

 fout->lat = (/lat/) ;-- write lat to new netCDF file

fout->lon = (/lon/) ;-- write lon to new netCDF file
 fout->u10m =
(/u10m/) ;-- write variable to new netCDF file
 fout->v10m = (/v10m/)
;-- write variable to new netCDF file

end

Best regards, 

Leilane 
 
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