Scheduled Downtime
On Friday 21 April 2023 @ 5pm MT, this website will be down for maintenance and expected to return online the morning of 24 April 2023 at the latest

mp_microphysics with aerosol

This post was from a previous version of the WRF&MPAS-A Support Forum. New replies have been disabled and if you have follow up questions related to this post, then please start a new thread from the forum home page.


There are several mp_microphysics schemes which run with aerosol. The NSSL scheme (option 18) is said to be intended for idealized simulations in the userguide. Why does option 18 can not be used for a real case simulation? Is the CCN concentration in this scheme fixed?
The option 40 (Morrison double-moment scheme with CESM aerosol) must be used together with MSKF cumulus scheme. The cumulus scheme is usually turned off when grid space is small. Is this scheme recommended in a cloud permitting (1-3 km grid space) real case simulation?

Thanks very much!
Hi Emily,
The NSSL scheme (option 18) is more intended for convection-resolving simulations, and it surely works for real-data case.
The Morrison double moment scheme doesn't have to be used with the MSKF scheme. Yes it is one option for cloud-permitting real case simulation. However, I cannot say it is recommended because the performance of the scheme is always case dependent.
Fir high resolution runs with grid interval between 1-3km, you can turn off cumulus scheme.
Thank you for your reply. I have the question about NSSL microphysics scheme with aerosol as the WRF user guide emphasize that this is intended for idealized simulation. So I guess what the user guide mean is that option 18 (NSSL with aerosol) performs better when used for idealized run?
And for the option 40 (double-moment scheme with CESM aerosol, which is a new option in wrf version 4.0), the user guide also emphasize that option 40 must be used together with MSKF cumulus scheme. So I am curious about if I can use this morisson-aerosol scheme in a cloud permitting simulation as it has to be used together with MSKF cumulus scheme?

Thanks again!
Hi Emily,
The NSSL__2MOMCCN (option 18) is recommended for ideal case because CCN is specified to be a constant. It doesn't mean that it performs 'better'. We also run real case using this option with the option progn turned on.
I looked through the code of Morrison double moment scheme. I see no reason why this scheme must work with MSKF. Please try and let me know if the case doesn't work. Thanks.

NSSL scheme developer here (browsing through old posts). The scheme works fine in real data simulations, and the guide needs to be updated (i.e., I need to submit a change) to say that it is best for convection-resolving (or convection-allowing) simulations with dx <= 4 km or so. I also recommend using WENO or at least MONO advection for moist and scalars.

Ted M.
Thank you for the kind email. Would you please explain why WENO or at least MONO advection should be used with NSSL?
WENO or MONO is really a recommendation for any 2-moment scheme. This is because they reduce spurious values at the edges of storms, which can be hard to filter out.

Sorry, I guess I don't have notifications for these forums -- I just happened to see your question.... 4 months later.