Meaning of 'wind_speed_level1_max' in the diag output

[Peiyang]

I'm trying to figure out how to produce 10m max wind speed using MPAS, which is similar to the variable 'WSPD10MAX' in WRF. I noticed there is a diagnostic output called 'wind_speed_level1_max'. I'm wondering if this is what I should use, or if there is any difference between 'wind_speed_level1_max' and 10m max wind speed. Any help would be greatly appreciated.

 

[Ming Chen]

Hi,
'wind_speed_level1_max' is the Maximum wind speed in lowest model level during the current output interval.

 

[Peiyang]

Hi,
'wind_speed_level1_max' is the Maximum wind speed in lowest model level during the current output interval.

Thank you for your quick response. May I ask a naive follow up question?

As stated in Section 7.2.2 of the User's Guide, number of vertical levels is controlled by config_nvertlevel (default is 55). But is there any instruction on how to manually set the vertical coordinates? When I used the default (55) vertical layers setup, how do I determine the thickness of the first model layer?

 

[Ming Chen]

in the initial and output files, you will find the variable zgrid, which is the height of (full) model levels. You can always derive the thickness of model layers based on zgrid.

You can manually set the height of each vertical level, and save the file in a .txt file. Suppose you bhave a file named 'lev.txt', and the format can be like:

0.0
45.0
100.
170.
250.
...
...

Then in your namelist.init_atmosphere, you need to specify

config_specified_zeta_levels = lev.txt

In this case, MPAS will read 'lev.txt' and use the levels in this file.