Precipitation simulation with angles when using ERA5 input

[aurorrmok]

Hello, I am planning to run WRF3.9 model to simulate the rainfall. I used ERA5 grib data as the initial meteorological field input. No errors were reported at each step, but the wrfout file were strange. That is near the coast, the precipitation is distributed at some angles.

I am confused with this results. Can anyone help me please?

I have a rainfall case (2023-09-06_18:00:00' to '2023-09-09_00:00:00') and use three domains simulation. The red rectangle is my research area.

1. I have downloaded ERA5 data. Please see my download_era5_grib.txt. I download data from 2023-09-06 to 2023-09-09 and those data as my input era5 data:
./link_grib.csh /GPUFS/yt_ust_suhui_3/uwincm/DATA/Black_storm_era5/era5 (are my ERA5 data and namelist.wps reasonable to simulate my case)
I can successfully create met_em.d01*, met_em.d02* and met_em.d03* files.

2. Then I ln -sf met_em.d0* files to WRF/run directory and ./real.exe. I can get wrfinput_d01, wrfinput_d02, wrfinput_d03 and wrfbdy_d01. Then I run ./wrf.exe. Then wrfout files can be generated at all times. But the results look really weird. There is an angle of rainfall simulation near the coastal part. What should I do?


Thank you so much for your help in advance!

 

[kwerner]

Hi,
First, apologies for the delay in response. We've been busy conducting our tutorial and have been out of the office some. I'm not sure I can see an issue with the precipitation output. If you're still experiencing this issue, can you point out exactly where the problem is, and explain in a bit more detail what you mean by an "angle of rainfall?" Thanks.

 

[aurorrmok]

Hi,
First, apologies for the delay in response. We've been busy conducting our tutorial and have been out of the office some. I'm not sure I can see an issue with the precipitation output. If you're still experiencing this issue, can you point out exactly where the problem is, and explain in a bit more detail what you mean by an "angle of rainfall?" Thanks.

Thank you for your reply. I am still encountering difficulties with this problem. As shown in the attached picture, the angle within the red circle appears unusual. Using the same parameters, if the input is based on FNL data, this kind of situation does not occur. However, if ERA5 data is used as the input, this strange phenomenon appears.

 

[kwerner]

Although that does seem to be a sharp right angle, I believe it's just a coincidental product of the simulation results when using ERA5 for this particular date, time, and namelist settings. It's just an area of precipitation that is jutting out further than other parts in the line of storms. If the resolution were higher, you would possibly see that it's not quite so perfect of a line. I don't think it's anything to be concerned about. Different data inputs are going to provide results. I would just advise to use whatever type provides the results closest to what you expect.