Diagnostics for sediment not closed??

[schen]

Hi all,

I'm examining the budget of transport equation for sediments in a shallow idealized estuary. I have only one sediment class, and the domain of interest is constantly wet and dry due to tides. Strangely, with DIAGNOSTICS_TS turned on, the transport equation is not closed??? The salt and temperature transport equations are closed, as expected. Have anybody seen this before?

Here is how I did the budget:

mud_01_rate = mud_01_hadv + mud_01_vadv + mud_01_vdiff.

The RHS (righ-hand side) is consistently larger than LHS. There is an offset between LHS and RHS, but this offset is not constant in space and time.

Questions:

1. Should I expect the equation for sediment to be closed?? In step3d_t.F, it looks like the vertical settling flux is not included in diagnostics calculation. But, when I added a settling flux to mud_01_vadv, the transport equation is still not closed. Any suggestion is highly appreciated!!

[arango]

Yes, I will expect that. We haven't coded yet the contributions due to the source and sink terms in the sediment equations. Perhaps, we need volunteers to help us code these terms. I think it is not that difficult to code and test these contributions. Of course, it can get complicate if the contribution by processes is desired.

[schen]

Hernan,

Thanks for the clarification. Since vertical flux is what no fully represented in the sediment diagnostics, I tried to avoid it for now. So, I depth-integrated each term and expected the following to balance :

Integral (mud_01_rate) ~= Integral (mud_01_hadv) - d/dt (bed_thickness * 2650 * (1-porosity))

Integral means depth-integral. 2650 is sediment grain density.

The first two terms are available from the diagnostic output, and the last one is from the field variable (bed_thickness: meter). The last term represents the bed mass changes. I know that the time-derivative may introduce some errors, but I expect they should roughly balance.

Result:

They do not balance (sigh.....). Term 1 - Term 2 is roughly twice as big as the last term. Did I do something wrong?? Any suggestion is appreciated!! ---- Shih-Nan