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Can PX LSM be used with ERA5?

H

Haorui Wang

New member
Hello everyone,

When I used the PX LSM with the ERA5, I had unusual temperatures around the shoreline and inland lakes. When I replace the ERA5 with the FNL, I don't have this problem. I also don't have a problem when I use the NOAH LSM with the ERA5. I am curious if the PX LSM can be used with the ERA5? I'd appreciate it if someone could give me some suggestions.

Related images and namelist have been uploaded.
PX LSM+ERA5.pngNOAH LSM+ERA5.png
 

Attachments

  • namelist.input
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Hi,
To my knowledge, this issue has not been reported previously. Are you using the "invariant fields" file with the ERA5 data? See How to Process ERA5 Data. If you're doing all of that correctly, can you let me know if it happens with any ERA5 (i.e. other dates) data, and different domains? Can you also let me know which version of WRF you're using? Thanks!
 
kwerner said:
Hi,
To my knowledge, this issue has not been reported previously. Are you using the "invariant fields" file with the ERA5 data? See How to Process ERA5 Data. If you're doing all of that correctly, can you let me know if it happens with any ERA5 (i.e. other dates) data, and different domains? Can you also let me know which version of WRF you're using? Thanks!
Click to expand...
Dear kwerner,

Thank you so much. I used WPS-4.6.0 and WRF-4.6.0. The resolution is 27km. I simulated according to the steps you provided, but the result is still the same as before. According to your suggestion, I simulated a total of 10 days from 2020-05-21 to 2020-05-31 and tried different domains. The results show that no matter which day or domain it is, the ERA5+PX LSM always shows a strange 2m temperature, while the ERA5+NOAH LSM and FNL+PX LSM are normal. Therefore, I think the ERA5 processing is correct (after all, ERA5+NOAH shows reasonable results), and the problem should lie in the coupling of ERA5 and PX LSM. Further I found that in the ERA5+PX LSM case, only the soil temperature, ground temperature and air temperature near the ground are abnormal, and the remaining variables are reasonable. I suspect that this may be related to the soil model of the PX LSM. I would appreciate any suggestions you may have!

Thanks again!

​

 
UPDATE:To rule out the computer environment, I used 2 different computers with the same results. I double checked every relevant variable in the input and output files of WPS and WRF.I found that the temperature anomalies near the shoreline and inland lakes are entirely due to anomalies in the deep soil temperatures. The ERA5 data always initialises the soil temperatures near the shoreline and inland lakes to 0 K (the FNL data does not lead to such temperature anomalies) and this is what I see from the wrfinput file, whether I am using the PX LSM or the NOAH LSM. The difference is that when using the NOAH LSM, the soil temperature quickly returns to normal as the simulation runs. When using PX LSM, on the other hand, as the simulation runs, the deep soil temperatures near the shoreline and inland lakes stay close to 0 K, resulting in anomalies in the shallow soil temperatures and air temperatures. Even when I manually initialise the deep soil temperature to a reasonable value, it rapidly becomes unreasonable as the model runs (temperature will be significantly higher or lower compared to the surrounding area). Overall, when ERA5 input data is used with PX LSM, it always produces unexpected soil temperatures near coastlines and inland lakes, no matter how I test. I suspect the problem is with the landsea-mask or with the PX LSM soil model. If someone can give me some advice or do some tests, I'd appreciate it.

If the soil temperature has not been initialized manually:
PX LSM+ERA5+no other operations.png


If the soil temperature has been initialized manually (Initialize according to the official tutorial at https://www2.mmm.ucar.edu/wrf/users/docs/PX-ACM.pdf):
PX LSM+ERA5+manually initialise.png
 
Thanks for doing that. It helps to rule out everything we can. Can you share your wrfinput_d01 file, and one or two of your met_em* files? These will likely be too large to attach to this post, so take a look at the home page of this forum for instructions on sharing large files. Thanks!
 
kwerner said:
Thanks for doing that. It helps to rule out everything we can. Can you share your wrfinput_d01 file, and one or two of your met_em* files? These will likely be too large to attach to this post, so take a look at the home page of this forum for instructions on sharing large files. Thanks!
Click to expand...
Dear kwerner,
Thank you for your help! I have uploaded the file to Nextcloud. The link is https://nextcloud.mmm.ucar.edu/index.php/s/n8in8C8PAAaYqAy/download?path=/&files=PX.tar
 
Thanks for sharing those files. It looks like you're missing the SOILHGT field in your met_em* files. That field should be included in the ERA5_INVARIANT file, along with a LANDSEA field (which you do have). Can you process the data again and make sure the SOILHGT field is included?
 
kwerner said:
Thanks for sharing those files. It looks like you're missing the SOILHGT field in your met_em* files. That field should be included in the ERA5_INVARIANT file, along with a LANDSEA field (which you do have). Can you process the data again and make sure the SOILHGT field is included?
Click to expand...
Dear kwerner,
Thank you so much! I have a question, if I am using ERA5 data, does the Land-Sea Mask variable have to be downloaded from ERA5 website as well？However, once I download the Land-sea mask from ERA5 website, metgrid.exe reports an error: ERROR: Cannot combine time-independent data with time-dependent data for field LANDSEA.mask. So, I did not include the Land-sea mask variable in my downloaded ERA5 data. I found in the forums that a user had previously reported this issue and resolved it by using the full global ERA5 data instead of the sub-region data. I tried downloading and using the global ERA5 data, but metgrid.exe still reports the same error as before. I'm guessing that the anomalous soil temperatures near the shoreline and inland lakes are because I haven't downloaded a Land-Sea Mask that matches the ERA5 data. Looking forward to any suggestions. Thanks again!（My ERA5 data was downloaded from the Climate Data Store in GRIB format.）
 
kwerner said:
Hi,
See the responses from Ming Chen on this forum thread. There are a few suggestions and information that could be useful, given your issue. Let me know if any of their suggestions work.
Click to expand...
Dear kwerner,
I apologize for the late reply. Thank you for your help. I tried the method described in the link you provided as well as many others. However, none of these methods solved my problem. Therefore, I am not going to use the PX LSM with ERA5. I will use NOAH and ERA5 which is working fine. If I find out anything further about PX LSM and ERA5, I'll report it here. Thanks.
 
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