River runoff problem

[javadi]

Dear all

I run the model but I have faced a problem. I have 4 rivers and define monthly discharge with salinity=3 and Temperature=12.

Here is the location of river points in my grid.

As my river comes from left to right, I define river transport as positive as mentioned here https://www.myroms.org/wiki/River_Runoff.

But after running, the model in the river runoff position shows more salinity compared to other points(top-left).

I cannot understand why?

The only thing that can be the wrong i,j? or transport?



please help me with your interesting comments

[jcwarner]

it could be i, j, or transport.
make sure the Q is positive for flow to the right.
look at the u values and ensure the rivers are coming from the correct locations.
those locations should be masked points. the river flow will overwrite the zero values at the masked locations.

-j

[javadi]

Hi

Thanks for your reply!


I have checked u velocity. It is here. I guess that the flow is towards the left.

The transport is positive so this can not be the problem.

With regard to i,j, I consider i=15 and j=295 in my file(for example). is it right? the result is based on this approach!

now should i define i=16 and j=295 or i=14 and j=295?

[jcwarner]

https://www.myroms.org/wiki/River_Runof ... _Eposition
is a good description of the river locations.
it needs to be coming out of the land masked cell.

[jivica]

A long time ago Rich Signell wrote very useful Matlab function called "map_rivers.m" (I can see you are using Matlab).
If you can't find it in the ROMS matlab repo or somewhere on the net, I will try to dig it out.

Hope this example (you are showing on the figures) is not something you want to use seriously, you need to define proper river inputs/model forcing/ grid etc...(this is the Adriatic Sea and there are publications with many studies related to ROFI and whole circulation is veeeery sensitive to all that...)

Good luck,
Ivica

[wilkin]

The function roms_plot_river_source_locations.m in my roms_wilkin tools https://github.com/johnwilkin/roms_wilkin will plot the sources in Matlab with symbols to indicate the flow direction.

[javadi]

Hi

Thanks!


I have a dilemma about one point.

In my case, I have 40 layers.

I should define V_shape (s_rho)from 1 to 40 or 0 to 39?

Another dilemma would be the least number would be for the bottom!

Best,

Javad

[wilkin]

river_Vshape has the properties ...

Code: Select all

        double river_Vshape(s_rho, river) ;
                river_Vshape:long_name = "river runoff mass transport vertical profile" ;
                river_Vshape:requires = "must sum to 1 over the s_rho coordinate" ;

so in your case dimension s_rho = 40. But whether you count from 0 to 39 or 1 to 40 depends only on the App you are using to read/write it. To distribute the river uniformly over all depths you want river_Vshape = 1/40 (i.e. = 0.025) for all values so it satisfies the property must sum to 1 over the s_rho coordinate.

If you want to weight the source toward the surface instead of being uniform, you make the weights larger toward higher values of s_rho because s_rho = 0 is the bottom and s_rho = (here 40) is the surface.

[javadi]

I try to define a profile thus I weigh in different layers. Here is it

I considered s_rho=1 to s_rho=40 is not right?


Do you mention that I should s_rho=0 to s_rho=40? It will be 41 layer?

[wilkin]

Here s_rho is just an index for the vertical dimension. You say you have 40 vertical layers, i.e. you have N = 40 in ROMS. If you are working in Python then the index is from 0 to 39, if you are in Matlab the index is from 1 to 40.

That plot is an oddly varying profile for river_Vshape. You do understand what river_Vshape does, right? It partitions the inflow river_transport into the vertical cells. This doesn't have a huge impact on the solution because ocean dynamics quickly adjust the profile.