[Wrf-users] about "RAINC" and "RAINNC"

[Eric Altshuler]

Hello Wen, 


Some of these questions have no simple answer. RAINC is produced by the cumulus parameterization. There are several cumulus schemes available in WRF, so you need to know which one is being used. Each scheme is described in one or more papers, but these may be difficult to understand for those not familiar with cloud dynamics. RAINNC is produced by the cloud microphysics scheme and any other processes that generate precipitation on the grid scale. On scales > 10 km, this is mostly from stratiform clouds. At high resolution < 5 km, grid scale may resolve some cumulus clouds and their precipitation will be included in RAINNC. For domains with resolution < 2-5 km, you should not use any cumulus scheme because most or all convection will be resolved at the grid scale. In this case, RAINC=0. The microphysics schemes are also described in the literature but you need a good understanding of cloud physics. 


Best regards, 




Eric L. Altshuler 
Research Scientist 
Center for Ocean-Land-Atmosphere Studies 
253 Research Hall, Mail Stop 6C5 
George Mason University 
4400 University Drive 
Fairfax, VA 22030 USA 

E-mail: ela at cola.iges.org 
Phone: (703) 993-5725 
Fax: (703) 993-5770 

----- Original Message -----
From: "wen" <wenguanhuan at 163.com> 
To: "wrf-user-list" <wrf-users at ucar.edu>, "wrfhelp" <wrfhelp at ucar.edu> 
Sent: Tuesday, August 13, 2013 3:41:06 AM 
Subject: [Wrf-users] about "RAINC" and "RAINNC" 


Hi all， 



I found there were two type of precipitation in wrf-output, which are "RAINC " and "RAINNC". I have some questions about these precipitations. I hope you can help. Thank you! 


1) The description of "RAINC" is "ACCUMULATED TOTAL CUMULUS PRECIPITATION". Does it mean that "RAINC" is from cumulus parameterization? If so, how the cumulsus scheme calculate the precipitation? Is there any detailed description about the calculation? What is the major factor influencing the "RAINC". 


2) The description of "RAINNC" is "ACCUMULATED TOTAL GRID SCALE PRECIPITATION". I do not know really what does it mean. How is "RAINNC" calculated? What is the major factor influencing the "RAINNC"? 


3) What is most difference between these two type of precipitation? What are differences between the major factors influence these two type of precipitation? 




-- 

Best regards, 
Guanhuan Wen 


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