[ncl-talk] Missing outputs from the function int2p

[Wei-Jen Tseng]

Dear NCL users,
I use the function "int2p" to interpolate data to the specified pressure
levels.
I expect that there is no missing value in my output.

But I found something strange:
[1] There are 3 or 4 missing outputs but they all have values before
interpolate.
[2] Some output become missing when I change the range of interpolation.
(new pressure level set 237.5)


This is data:
pressure (FillValue 9999):
(0) 1008
(1) 1002.5
[SNIP]
(524) 48.1
(525) 47.8

altitude (FillValue 99999):
(0) 4
(1) 52.5
[SNIP]
(524) 20839.2
(525) 20884.3


This is my script:
begin
;--- load data ---;
iFil = addfile("sounding_zc081041.nc","r")
p_in = iFil->pressure
a_in = iFil->altitude

;--- new pressure levels ---;
p_out1 = fspan(87.5,987.5,37)
p_out2 = fspan(112.5,987.5,36)

;--- interpolate to new pressure levels ---;
a_out1= int2p(p_in,a_in,p_out1,2)
a_out2= int2p(p_in,a_in,p_out2,2)

;-- results ---;
print("Result: 1")
print(p_out1+" "+a_out1)
print(" ")
print("Result: 2")
print(p_out2+" "+a_out2)
end
;---end of the script ---;

This is the output.
Most of the outputs looks well.
I use the brackets to highlight strange outputs.

(0) Result: 1
(0) 87.5 17311.2
(1) 112.5 15936.5
[SNIP]
(5) 212.5 12072.7
(6) 237.5 99999 <=== [1,2]
(7) 262.5 10648.4
(8) 287.5 10014.1
(9) 312.5 9419.78
(10) 337.5 99999 <=== [1]
(11) 362.5 8336.37
(12) 387.5 99999 <=== [1]
(13) 412.5 7364.7
[SNIP]
(24) 687.5 3296.85
(25) 712.5 99999 <=== [1]
(26) 737.5 2708.44
[SNIP]
(35) 962.5 414.551
(36) 987.5 187.77
(0)
(0) Result: 2
(0) 112.5 15936.5
(1) 137.5 14779.8
[SNIP]
(4) 212.5 12072.7
(5) 237.5 11330 <=== [2]
(6) 262.5 10648.4
(7) 287.5 10014.1
(8) 312.5 9419.78
(9) 337.5 99999 <=== [1]
(10) 362.5 8336.37
(11) 387.5 99999 <=== [1]
(12) 412.5 7364.7
[SNIP]
(23) 687.5 3296.85
(24) 712.5 99999 <=== [1]
(25) 737.5 2708.44
[SNIP]
(34) 962.5 414.551
(35) 987.5 187.77

And I checked the source data.
The source data looks well.

$ ncl
 NCAR Command Language Version 6.3.0
ncl 0> f=addfile("sounding_zc081041.nc","r")
ncl 1> p=f->pressure
ncl 2> a=f->altitude
ncl 3> print(p+" "+a)
(0) 1008 4
(1) 1002.5 52.5
[SNIP]
(82) 715.4 2964
(83) 712.5 2998.3 <===
(84) 709.5 3034.1
[SNIP]
(219) 389.2 7804.3
(220) 387.5 7839 <===
(221) 385.6 7875.7
[SNIP]
(245) 339.4 8821.9
(246) 337.5 8863.1 <===
(247) 335.4 8908.6
[SNIP]
(305) 239.1 11286.2
(306) 237.5 11330 <===
(307) 236 11375
[SNIP]
(524) 48.1 20839.2
(525) 47.8 20884.3

I uploaded my data to ftp.cgd.ucar.edu.
File name is "sounding_zc081041.nc".

I also put same data on the dropbox.
https://www.dropbox.com/s/lj3l1lj70r2n95w/sounding_zc081041.nc?dl=0

Thank you for any suggestion.

best regards,
Wei-Jen

-- 

Wei-Jen Tseng

Department of Atmosphere Sciences, National Taiwan University

Email: tseng.weijen at gmail.com
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