Relative parameter change vs absolute change

[Mike]

Hi,

I understand that some parameters vary spatially in the model, so during calibration, they must have relative changes.  Examples are soil parameters and curve number.  Are there any others that should only change relatively?  OV_N, for example, represents manning's n for overland flow.  This sounds like a parameter that depends on land cover, and so will vary by HRU, so I imagine it should change relatively.  

Thanks,

~Mike

[Sushant Mehan]

Hi Mike, 

Did you get the answer for your question, i am also looking for the same? 

Regards

Sushant

[Thayse Dourado]

Hi Mike and Sushant,

One easy way to verify the spatial variability of the parameters is checking your tables in TablesIn swat folder. For example, if you have doubts in a .mgt parameter (like CN2, for example), check in the mgt table if it is constant or not.

Hope this help.

Thayse

[Sushant Mehan]

Hi Thayse 

This was what my observation was, but i am still confused with relative and replace, For instance take Heat_Units, they are crop dependent and geography also decides this, ( Albedo, Sun many things) shall we take this under relative or replace for agricultural land with different land use proportion?

Regards

Sushant

[Thayse Dourado]

Hi Sushant,

I understand your questions and I could be wrong, but I think you should observe parameters behavior in SWAT model. What I am saying is in the Tables you can see if the model is considering the parameters variability in its equations (geographic, crop... dependency). Otherwise, even if you use relative changes it will not vary among the different land use proportions.

Hope it can help...

Thayse