WRF Running Error optical value exceed the threshold

[Zongrun Li]

Hi, I have run a case which coupled WRF-Chem with WRF-Fire. The simulation has error after 40 hours running.

mieaer /refr/ outside range 1e-3 - 10 refr=     0.14358E+02

I have found that WRF suggests set the threshold to 15 for module_optical_averaging.F when the value slightly higher than 10. I am not sure whether it is fine or not. I use RADM2 with GOCART for the simulation and I do not set the aerosol optical option. My question is why this module is used even I do not care about the optical property? Also, why WRF use 10 as the maximum in the code?

[Mary Barth]

Hello Zongrun,

The high values from the aerosol optical driver are often caused by erroneously high aerosol concentrations. It's an issue that has come up before.

However, you say that you have not turned on the aerosol optical calculation. I am not sure why the error has occurred. I'd suggest checking chem_driver.F code to make sure that the logic for calling the optical_driver is as you expect.

An optical depth of 10 is fairly high (one can barely see the sun with tau=10). However, I can imagine there are air pollution events where tauaer > 10. If you think that's reasonable for your case, then you could adjust the threshold to a higher value.

Mary

-- 
^--^--^--^--^--^--^--^--^--^--^--^--^--^--^--^--^--^--^--^--^--^
Mary Barth                                Phone:  303-497-8186
Senior Scientist                          email: bar...@ucar.edu

National Center for Atmospheric Research                        
P.O. Box 3000                  
Boulder, CO 80307           

https://staff.ucar.edu/users/barthm  
DC3 Web Site:  http://www2.acom.ucar.edu/dc3/
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+

[Rajesh Kumar]

Hello Zongrun,

This is not the aerosol optical depth but rather the real part of the refractive index that exceeds 10 in some cases. We are aware of this issue and will have a discussion among the WRF-Chem developers later this week. We hope to post a solution to this problem sometime next week. 

As Mary said, look at your chem_driver.F to see why optical_averaging subroutine is called even if you do not set the aerosol optical option.

Rajesh

--

Rajesh Kumar, Project Scientist III

Research Applications Laboratory 

National Center for Atmospheric Research 

E-mail: rku...@ucar.edu

Phone: +1-303-497-1413

Web: https://staff.ucar.edu/users/rkumar