What WRF will do if not setting nudging end hours

Topics specifically related to any of the WRF runtime options, such as SST update, DFI, nudging, restarts, global runs, adaptive time step, ndown.exe, tc.exe, moving nest, etc.
Post Reply
Jialiwang
Posts: 12
Joined: Wed May 22, 2019 8:20 pm

What WRF will do if not setting nudging end hours

Post by Jialiwang » Wed May 12, 2021 12:17 pm

Dear wrfhelp,

In the nudging section, if we setup nudging to 2 (spectral nudging), but do not setup end hours, will nudging start at all? If it starts, when it will end by default? The wrffdda_d01 is available for the entire time period.

For our test case, we did not setup nudging end hours, but in the rsl.error.0000 file every 3hr (our input frequency) we see these two lines:
Input data is acceptable to use: wrffdda_d01
Input data processed for aux input 10 for domain 1

Does this mean nudging is going?

Thanks
Jiali

Ming Chen
Posts: 1456
Joined: Mon Apr 23, 2018 9:42 pm

Re: What WRF will do if not setting nudging end hours

Post by Ming Chen » Wed May 12, 2021 11:41 pm

Jiali,
The default time of ending the nudging is set to zero. If you didn't set gfdda_end_h, then the nudging will not be conducted.
The message you have just tells you that the data is available and has been processed, but it is not used later.
WRF Help Desk

Jialiwang
Posts: 12
Joined: Wed May 22, 2019 8:20 pm

Re: What WRF will do if not setting nudging end hours

Post by Jialiwang » Thu May 13, 2021 2:53 pm

Thank you Ming. I figured this out. For other users' reference, if the nudging is effective, then in the namelist, there will be also these lines (ignore the numbers they are specific to our case):
D01 Spectral nudging read in new data at time = 5580.000 min.
D01 Spectral nudging bracketing times = 5580.000 5760.000 min.
D01 sample analysis values at i,k,j= 45 1 28 u_ndg_old= -7.5360

D01 sample analysis values at i,k,j= 45 1 28 v_ndg_old= -7.5360

D01 sample analysis values at i,k,j= 45 1 28 t_ndg_old= -7.5360

D01 sample analysis values at i,k,j= 45 1 28 ph_ndg_old= -7.5360
======

And you can also tell in the output, at the global attribution section:
GFDDA_END_H = 0 (if one doesn't set that gfdda_end_h line)

Post Reply

Return to “Special Running Options”