albedo for the surface covered by C3 unmanaged crop

[AndrewY]

Hello all,

I want to validate the modifications I made to the percent coverage of a specific PFT. I wonder if there is a value range for albedo when the land surface is covered by C3 unmanaged crop? Would the value 0.2 (the maximum snow-free canopy albedo of C3/C4 grasses in MOSES/TRIFFID) be a reasonable estimate?

Thank you very much!

 

[oleson]

If you are asking what value of albedo the model produces for a C3 unmanaged crop, it is difficult to say. It will depend on whether it is a visible, or nir, or broadband albedo, the canopy density in terms of leaf and stem area, and the type of underlying soil, etc. One suggestion is to setup a single point simulation that only has the C3 unmanaged crop type and experiment with various setting of canopy density, soil, etc.
As a very rough estimate, the leaf visible and nir reflectances are 0.11 and 0.35, which averages to 0.23, so 0.2 broadband for a dense canopy might not be too far off.