Sensitivity Experiments and Data Issues

[aurorrmok]

Dear Sir or Madam,

I am simulating the rapid intensification phase of Typhoon SAOLA in 2023 (from 2023082812 to 2023090300). I have set up three domains with resolutions of 12 km, 4 km, and 1.3 km and I am using a two-way nested setup, with one wrfinput file. I want to conduct some sensitivity experiments, but I have encountered some issues during this process. Could you please help me?


(1) Because ERA5 data severely underestimates the wind speed during these period, the model cannot simulate the rapid intensification phase. Therefore, I only want to read the met_em file for the first time step, namely 2023082812, and then let the model evolve on its own without reading the time-varying meteorological input files. In this case, should I set INTERVAL_SECONDS=475200 (covering the entire simulation period) in both namelist.wps and namelist.input? If this approach is incorrect, what should I do instead?

(2) I want to multiply my wind speed by 2.5 or 3 to identify the effect of UV wind. Should I directly modify the ERA5 data, the met_em file, or the wrfinput? What are the differences in modifying these three types of files?

 

[kwerner]

Apologies for the delay in response while our team tended to time-sensitive obligations. Thank you for your patience.

(1) Because ERA5 data severely underestimates the wind speed during these period, the model cannot simulate the rapid intensification phase. Therefore, I only want to read the met_em file for the first time step, namely 2023082812, and then let the model evolve on its own without reading the time-varying meteorological input files. In this case, should I set INTERVAL_SECONDS=475200 (covering the entire simulation period) in both namelist.wps and namelist.input? If this approach is incorrect, what should I do instead?

I believe that may work. You can test it out to see.

(2) I want to multiply my wind speed by 2.5 or 3 to identify the effect of UV wind. Should I directly modify the ERA5 data, the met_em file, or the wrfinput? What are the differences in modifying these three types of files?

You can modify any of those files, but if it were me, I'd modify the wrfinput file since it's the furthest along in the process. There is less chance of some part of the program overriding the values you want to use.