[Wrf-users] ZERO Precipitaion

[Ehsan Beigi]

Dear Sir/Madam,

Happy New Year :)

thanks for your previous help. i am using CAM2WRF code to convert ccsm
format to WPS intermediate format , the problem is that the ccsm doesn't
have relative humidity (RH), and instead they have specific humidity
(SPECHUMD) and i just replaced the RH with SPECHUMD in CAM2WRF code, and
also my met_file does include SPECHUMD, but after running WRF the
precipitation become zero . if this method is incorrect, could i calculate
RH from specific humidity using this equation before running CAM at WRF code (
by assuming constant values for *ρws** = density of water vapor** and ρ** =
density of the moist or humid air (kg/m3)**)*

*x = 0.622 φ ρws / (ρ - ρws) 100%**         (1)*

*where*

*x** = specific humidity of air vapor mixture (kg/kg)*

*φ** = relative humidity (%)*

*ρws** = density of water vapor (kg/m3)*

*ρ** = density of the moist or humid air (kg/m3)*


I appreciate your help in advance.


Best Regards,


Ehsan Beigi




On Thu, Dec 29, 2011 at 6:48 PM, Ehsan Beigi <ebeigi3 at tigers.lsu.edu> wrote:

> Thanks for your help. my met_file does include SPECHUMD(please take a look
> at attach files), but in the CAM2WRF code, i just replaced the RH with
> SPECHUMD that you mentioned it is incorrect, this code only convert the
> format from ccsm to wps intermediate format,   could you please help me
> with that? i also attached the CAM2WRF code , you can see how i changed RH
> with SPECHUMD ? thanks again
>
>
> Best Regards,
>
>
>
>
>
>
> On Thu, Dec 29, 2011 at 11:48 AM, wrfhelp <wrfhelp at ucar.edu> wrote:
>
>>  If there is no RH, then you should include SPECHUMD in your met-em file.
>> When real.exe is running, it will calculate QVAPOR based on SPECHUMD. It is
>> incorrect to change SPECHUMD to be RH.
>>
>> On 12/27/2011 1:27 PM, Ehsan Beigi wrote:
>>
>>
>> Thanks for your help and Merry Christmas again!  you mentioned a good
>> point about zero precipitaion, the problem is that the ccsm input data
>> doesn't have RH, and they only have  specific humidity (SPECHUMD) instead ,
>> so i had to rename the RH in CAM2WRF code to SPECHUMD , and as a result, in
>> my met_em* files i don't have RH which i think it leads to zero
>> precipitation, i attahced the ncdump -h output of my met_em file and also,
>> the specific humidty, could you please take a look at it, and help me with
>> that?, i really appreciate your help, and my research have been stopped at
>> this point for more than three months because of this problem.
>>
>> Bests,
>>
>>
>>
>> --
>> *Ehsan Beigi*
>> *PhD Student*
>> *Department of Civil and and Environmental Engineering
>> 2408 Patrick F. Taylor Hall
>> Louisiana State University
>> Baton Rouge, LA, 70803*
>>
>>
>>
>>
>
>
> --
> *Ehsan Beigi*
> *PhD Student*
> *Department of Civil and and Environmental Engineering
> 2408 Patrick F. Taylor Hall
> Louisiana State University
> Baton Rouge, LA, 70803*
>
>
>


-- 
*Ehsan Beigi*
*PhD Student*
*Department of Civil and and Environmental Engineering
2408 Patrick F. Taylor Hall
Louisiana State University
Baton Rouge, LA, 70803*
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