Matching WRF and MPAS physics

A

ArashC

New member
Hello,

Sorry for the basic question but I was a bit confused by MPAS manual. Is it possible to exactly match the physics options for WRF and MPAS? I already have a WRF namelist and I want to use the same physics schemes for my MPAS run. Thanks so much.

Best,
 
Hi,
Many of the same physics that are available for WRF are also available for MPAS, but not all. See this page, which describes supported physics suites, but if you scroll down further, information on the individual available physics options for MPAS are listed.
 
The physics suite "Mesoscale_reference" corresponds to the suite "Tropical" in WRF. However, some other options should also be set to make the physics consistent between the two models. Below is a detailed list:
config_o3climatology = True (MPAS) and O3input = 2 (WRF)
config_microp_re = True (MPAS) and use_mp_re = 1 (WRF)
config_gwdo_scheme = off (MPAS) and gwd_opt = 0 (WRF)
sfc_snowalbedo = true(MPAS) and rdmaxalb=true (WRF)
Please let me know if you ahve more questions. Thanks.
 
Thank you so much. Is there a way to also make "convection_permitting" in MPAS equal to physics in WRF?
 
Thanks so much. Do I need to implement the following as well?

config_o3climatology = True (MPAS) and O3input = 2 (WRF)
config_microp_re = True (MPAS) and use_mp_re = 1 (WRF)
config_gwdo_scheme = off (MPAS) and gwd_opt = 0 (WRF)
sfc_snowalbedo = true(MPAS) and rdmaxalb=true (WRF)
 
Hello again,

The options worked out ok for MPAS. Now my WRF looks like following and I get an error.

&physics
physics_suite = 'CONUS'
mp_physics = -1, -1,
cu_physics = -1, -1,
ra_lw_physics = -1, -1,
ra_sw_physics = -1, -1,
bl_pbl_physics = -1, -1,
sf_sfclay_physics = -1, -1,
sf_surface_physics = -1, -1,
radt = 15, 15,
bldt = 0, 0,
cudt = 0, 0,
icloud = 1,
num_land_cat = 21,
sf_urban_physics = 0, 0,
fractional_seaice = 1,
O3input = 2,
use_mp_re = 1,
gwd_opt = 0,
rdmaxalb =.true.,


------ ERROR while reading namelist physics ------
Maybe here?: use_mp_re = 1,
Maybe here?: gwd_opt = 0,
-------------- FATAL CALLED ---------------
FATAL CALLED FROM FILE: <stdin> LINE: 11540
ERRORS while reading one or more namelists from namelist.input.

I am using version 4.4. Please let me know how I should modify the physics.

Thanks so much.
 
Thanks so much. This is my last question. Is there a way to make WRF and MPAS vertical layers similar? If not exact, an approximation works too.
 
This is a good question. Yes you need to try to make the vertical levels close to each other between WRF and MPAS. We did so before when we compared WRF and MPAS performance. Unfortunately I didn't save the documents. You have to make it yourself, and I suppose this is not a hard issue.
 
Hello,

I hope all is well with you. This is a very late follow up question, but in my very first question I was asking about matching WRF and MPAS physics options, and later the response I got was "convection permitting" is equivalent to "CONUS", but I see not all of their schemes were equivalent. Could you please clarify how are they equivalent while some of their schemes are different in the manual? Is it because of those extra options you gave me? I appreciate your response as it is a bit urgent. Thanks so much.

Best,
 
HI,
Thanks for doule checking. I apologize for the incomplete information regarding physics_suite CONUS and convection_permitting. They are not exactly identical because different PBL/SFCLAY and cumulus schemes are used. In addition, GWD options can be turned on or off in CONUS, while it is always turned on in convection_permitting. For these reasons, these two suites cannot be treated as 'equivalent'.
Hope this is helpful for you. Please let me know if you have more questions.
 
Thanks for the response. No worries.
Earlier you gave me a flag to turn off GWD for MPAS as well. Did that also turn it off even though I had chosen convection_permitting? I am a bit confused with your last response.

Also, for WRF CONUS, do I have to set cumulus to zero if the resolution is 4km?
 
Please see my answers below:
ArashC said:
Thanks for the response. No worries.
Earlier you gave me a flag to turn off GWD for MPAS as well. Did that also turn it off even though I had chosen convection_permitting? I am a bit confused with your last response.
Click to expand...
GWD option should be manually set to be same for WRF and MPAS>
ArashC said:
Also, for WRF CONUS, do I have to set cumulus to zero if the resolution is 4km?
Click to expand...
4km is with the grey zone, and thus cumulus scheme can be either on or off depending on your specific research goals. It may be better to use scale-aware cumulus scheme such as GF (GFL in WRFV4.8.0), ntiedtke, etc.
 
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