how to specify river inflow

[azhang]

Hi, Modelers,

I use ROMS3.0 to do tidal simulation with constant T=15 and S=35, but I want to include some rivers. I am confused about how to specify river inflows for ROMS3.0. There are several rivers in my model domain. I like to let the freshwater flow in by providing discharges, temperature=15 and salinity=0 at river locations using CPP options of UV_PSOURCE and TS_PSOURCE. My qustions are,

1. what is difference between UV_PSOURCE and Q_PSOURCE
2. If the river flows in model domain from north to sourh or from east to west, should discharge be negative. For my experience, the negative discharge means flowing out the model domain.

3. Indeces of river location, I put the river on the water cells as follows,
if river flows in north-south direction (river_direction=1 in the forcing file), I put river on the water cells while the mask_v =1; if river flows in east-west direction (river_direction=0), I put river on the water cells while mask_u =1 on the cells.

I found that discharges at some rivers didn't flow in, and salinity values at some locations are too large.

Any help is appreciated.

Thanks

[kate]

You should be using UV_SOURCE. Q_SOURCE is for directionless sources at a rho point, but I'm not sure it was cleared up as being legal what with continuity and all.

Discharge should be negative in the cases you mention for flow into the water.

I'm not sure you are putting the sources in quite the right place. If a source goes east to west, its indices will be at a place with zero mask_u, since that is the land-sea boundary. In fact, any source should be where the mask_u or mask_v is zero, with land on one side and water on the other.

[abever]

From a previous post...

Posted: Sun Feb 25, 2007 5:55 pm Post subject:

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Try setting the point source to the middle of the grid, and ramping up the discharge so it is easy to see. Although not realistic, it allows you to make sure it is being set at the exact location you think, and is being discharged through the correct grid cell face (correct direction). Then, simply move it towards the location you want it specified at. If it never shows up that at least narrows any problems.

[azhang]

Thank you all for your replies. By following Kate's suggestion, I think I was able to put the river discharges correctly. For verification, I set my background salinity is 35 everywhere (in initial file), the salinity values are zeros at river input locations. I saw the freshwater flowed in near the river locations.

Thanks again for your help.