How to modify the albedo data in usr_nl_cam?

[jialiu]

I want to modify the albedo of certain regions in the coupled model. Is it feasible to specify the values of albedo using grid points in user_nl_cam?

 

[slevis]

From the land model perspective, please see this thread:

How to modify the albedo data in a latitude and longitude range?

I want to modify the surface albedo in a latitude and longitude range, but I do not find any data directly representing the albedo in the input data. So I modified the restart file in the run file ***.clm2.r.0061-01-01-00000.nc but the mode did not run successfully, the log file shows： ERROR...

bb.cgd.ucar.edu

 

[katec]

Hi there, does this answer your question, or are you looking for different albedos?

 

[jialiu]

Hi there, does this answer your question, or are you looking for different albedos?

Hi, I have looked into the method slevis mentioned, but it seems that it may not work if I want to modify the surface albedo of a specific area to a specific value. Do you have any other methods?

 

[jialiu]

Hi, I have looked into the method slevis mentioned, but it seems that it may not work if I want to modify the surface albedo of a specific area to a specific value. Do you have any other methods?

By the way, I want to modify the surface albedo within a coupled model.

 

[katec]

Since this is about the land surface albedo, I'm going to move the thread to the CTSM forum. Perhaps you can get other opinions there, but I think the answer here is probably the best answer.

 

[slevis]

@katec is right: the link provided above is the best answer that we have to offer. You are welcome to come up with a different solution for your specific application.

 

[jialiu]

@katec is right: the link provided above is the best answer that we have to offer. You are welcome to come up with a different solution for your specific application.

Thank you for your answer, slevis. I found that in the surfdata, it is distinguished by soil classes. If I only know the total surface albedo, how can I find the corresponding soil color type.

 

[oleson]

You would have to experiment with different soil color classes since the soil albedo is a function of radiation band (vis and nir) and soil moisture. Maybe pick a soil color class where your total albedo is midway between the vis and nir albedos and dry and saturated albedos. But, as we've mentioned before, the soil albedo is just one component of the total surface albedo. Vegetation properties are an important determinant of this.
As we've also mentioned before, one way forward might be to look at the code of "SLIM", the Simple Land Interface Model. One can replace the calculated surface albedo in CLM with a prescribed albedo using SLIM. I don't know the details but you can find information on SLIM here:

GitHub - marysa/SimpleLand: Simple Land Model for CESM --- *** IN DEVELOPMENT *** --- please contact for more info. See supplemental information of https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0812.1 for a description of SLIM physics. Imple

Simple Land Model for CESM --- *** IN DEVELOPMENT *** --- please contact for more info. See supplemental information of https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0812.1 for a descripti...

github.com

 

[oleson]

See also this for more information:

GitHub - ESCOMP/SimpleLand: Simple Land Model for CESM --- *** IN DEVELOPMENT *** --- please contact for more info. See supplemental information of https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0812.1 for a description of SLIM physics. Imple

Simple Land Model for CESM --- *** IN DEVELOPMENT *** --- please contact for more info. See supplemental information of https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0812.1 for a descripti...

github.com

 

[jialiu]

See also this for more information:

GitHub - ESCOMP/SimpleLand: Simple Land Model for CESM --- *** IN DEVELOPMENT *** --- please contact for more info. See supplemental information of https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0812.1 for a description of SLIM physics. Imple

Simple Land Model for CESM --- *** IN DEVELOPMENT *** --- please contact for more info. See supplemental information of https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0812.1 for a descripti...

github.com

Hi Oleson, thanks for your speedy reply and help! I will try it.