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


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.


New member
Hi, I would like to know if an analysis/spectral nudging technique will be added in the next version of MPAS. In a recent article I have seen that analysis nudging has already been tested (Bullock et al., 2018) but is not yet operational. I would also like to know if you plan to introduce passive tracers in future versions. Thank you.
At present there are no plans to incorporate either grid nudging or spectral nudging in the next MPAS-Atmosphere release. Although the code supplement for the Bullock et al. 2018 paper is based on MPAS v4.0, it might be worth contacting Russ Bullock to see whether the EPA might share any updated version of that code.

Regarding passive tracers, you could take a look at the "Adding Passive Tracers" lecture slides from the most recent MPAS-Atmosphere tutorial as well as Section 6 of the tutorial exercises.

There are also a few code branches that demonstrate how to add passive tracers with varying levels of sophistication:
Dear Users,
I would like to calculate the nudging time step (fgdt). I did not set anything for "fgdt". As per the manual the default is 0 and computes at every step. Does this every step mean at the model time step? For my case the time_step=60 seconds.

Any suggestions and help in this regard is highly appreciated.

Thank you.
@lpasmanoranjan This section of the forum is for the MPAS-Atmosphere model. If your question is about the WRF model, could you post it in one of the WRF sections of the forum?