p_top_request and input data

[Deleted member 3607]

Hello WRF Community,

I was wondering if someone could explain the relationship between p_top_request and the ERA5 input data height?

I am working on a project that needs to resolve up to the stratosphere and possibly mesosphere and I'm not sure if my p_top_request value needs to change.

Looking at the default value in the namelist.input it is set to 5000 which is equivalent to 20km.

So if I need to look up to the 60-70km range what would be p_top value be?

Thanks for any help.

 

[jordanschnell]

Will,

From the ARW user guide:



Also, sometimes what you need is in the Registry (Registry/Registry.EM_COMMON - units listed):
rconfig real p_top_requested namelist,domains 1 5000 irh "p_top_requested" "Pa" ""

As for what to use, a value of 1 Pa would be a good start, but you may need to adjust - Note that your input data needs to be resolved up to this level.

 

[wcheng]

Hello WRF Community,

I was wondering if someone could explain the relationship between p_top_request and the ERA5 input data height?

I am working on a project that needs to resolve up to the stratosphere and possibly mesosphere and I'm not sure if my p_top_request value needs to change.

Looking at the default value in the namelist.input it is set to 5000 which is equivalent to 20km.

So if I need to look up to the 60-70km range what would be p_top value be?

Thanks for any help.

I am working on a similar problem...you need to set p_top to 7 Pa. Also, WPS needs to be modified:

ungrib/src/read_namelist.F

! =================================
!pmin = 100. ! default is 1 hPa (48 km)
pmin = 1 ! 1 Pa
! =================================

I created wrfinput wrfbdy files w/o issues but my run died within a 2 time steps. I had 134 levels as
well as 75 levels...all crashed.

 

[Ming Chen]

If your model top reaches the top of stratosphere, then p_top_requested should be around 1 mb (100pa). if you need to further extend upward to mesosphere, then p_top_requested may need to be around 0.01mb.
However, not many data products provide information at such a high level. We also don't have many experiences running WRF with the model top located at mesosphere. Please keep us updated about any issues/progresses. Thanks in advance.

 

[tyfcwgl]

I am working on a similar problem...you need to set p_top to 7 Pa. Also, WPS needs to be modified:

ungrib/src/read_namelist.F

! =================================
!pmin = 100. ! default is 1 hPa (48 km)
pmin = 1 ! 1 Pa
! =================================

I created wrfinput wrfbdy files w/o issues but my run died within a 2 time steps. I had 134 levels as
well as 75 levels...all crashed.

Is there any further experimental experience?