Do GPP (gC/m^2/s) and GRAINC (gC/m^2) have something with the percent patch on the cropland?

[mengqi]

Hi,

I noticed that the unit of GPP is gC/m^2/s, which means that GPP has nothing to do with the crop area.

I did two simulations: one is corn with 30% (i.e., the percent corn patch on the cropland), and the other is corn with 60%. Other variables are kept consistent. However, I found their GPPs are different.

In addition, I also did two corn simulations associated with GRAINC (gC/m^2). But I also found their GRAINC are different.

I was wondering if my understanding is right or not.

Thanks!

 

[slevis]

When you say, "GPP has nothing to do with the crop area" I think you mean because it's per unit area, right?

However, I think you are looking at grid-average GPP and GRAINC. If so, these will change when you alter the subgrid composition of the grid cell. If you were looking at pft-level output, then maybe they would not change, but I'm not sure.