Re: fatal:Div: operator failed, can't continue

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Mon Jan 31 2011 - 09:24:28 MST

I am sure that if you print the minimum value
of RH you will see that it is zero.

eg

print("min(RH)="+min(RH)+" max(RH)="+max(RH))
min(RH)=0 max(RH)=.....

Hence,

qs = (qv/RH)*100

will fail.

You can use the "where" function

http://www.ncl.ucar.edu/Document/Functions/Built-in/where.shtml

Please read the "Description" section. In particular, the
"Caveat" section

Good luck

On 1/31/11 9:07 AM, wei huang wrote:
> Thanks for your cooperation, kindly, I have changed the pressure hPa to
> Pa but still it does not working and giving the same error: Any help
> will be appreciated.
> thanks
>
> P= a->P; perturbation; Pa
>
> Pb = a->PB; base state pressure; Pa
>
> P= P + Pb; total pressure
>
> T = a->T; perturbation potential temperature
>
> tk = T + 300.
>
> qv = a->QVAPOR; water vapor mixing ratio(kg/kg)
>
> RH = wrf_rh (qv, P, tk)
>
> printVarSummary(RH)
>
> qs = (qv/RH)*100
>
> printVarSummary(qs)
>
> Error:
>
> fatal:divide: Division by 0, Can't continue
>
> fatal:Div: operator failed, can't continue
>
> fatal:Execute: Error occurred at or near line 17 in file
>
>
>
> On Mon, Jan 31, 2011 at 11:36 PM, Dennis Shea <shea@ucar.edu
> <mailto:shea@ucar.edu>> wrote:
>
> Please read the documentation:
> http://www.ncl.ucar.edu/Document/Functions/Built-in/wrf_rh.shtml
>
> ==
> "qv" must be kg/kg , you are passing "g/kg"
> "P" must be "Pa", you are passing "hPa"
>
>
>
> On 1/31/11 7:09 AM, wei huang wrote:
>
> Dear NCL users,
>
> I got an error to calculating saturated mixing ratio from the
> wrf water
> vapor mixing ratio. I donít know my assumption is correct or
> not. Could
> anyone help me to figure out the problem or any advice about it?
>
> Thanks
>
> wei
> a = addfile("wrfout_02.nc <http://wrfout_02.nc/>
> <http://wrfout_02.nc <http://wrfout_02.nc/>>","r")
>
>
> P= a->P; perturbation
>
> Pb = a->PB; base state pressure
>
> P= P + Pb; total pressure
>
> T = a->T; perturbation potential temperature
>
> tk = T + 300.
>
> qv = a->QVAPOR/1000; water vapor mixing ratio(g/kg)
>
> RH = wrf_rh (qv, P*.01, tk) ;P*0.01 converts Pa to hPa
>
> printVarSummary(RH)
>
> qvs = (qv/RH)*100; saturated water vapor mixing ratio(g/kg)
>
> printVarSummary(qvs)
>
> end
>
> ;*****************************************
>
> Variable: RH
>
> Type: float
>
> Total Size: 102667500 bytes
>
> 25666875 values
>
> Number of Dimensions: 4
>
> Dimensions and sizes:[24] x [39] x [south_north | 160] x
> [west_east | 105]
>
> Coordinates:
>
> Number Of Attributes: 2
>
> units :%
>
> description : Relative Humidity
>
> fatal:divide: Division by 0, Can't continue
>
> fatal:Div: operator failed, can't continue
>
> fatal:Execute: Error occurred at or near line 16 in file
>
>
>
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>
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Received on Mon Jan 31 09:24:33 2011

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