inconsistency between input ediment.in and output history fi

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CBian
Posts: 39
Joined: Mon Dec 28, 2009 4:01 pm
Location: Ocean University of China

inconsistency between input ediment.in and output history fi

#1 Unread post by CBian »

Dear ROMS developers,

I set the sediment parameters in the sediment.in file:

! Particle settling velocity (mm/s).

SAND_WSED == 0.06 0.60 6.00 0.06 0.60 6.00 12.0 24.4


However, in the output history file, it said:

double Wsed(NST) ;
Wsed:long_name = "sediment particle settling velocity" ;
Wsed:units = "millimeter second-1" ;
data:
Wsed = 6e-05, 0.0006, 0.006, 6e-05, 0.0006, 0.006, 0.012, 0.0244 ;


the settling velocity in the history file is 1000 time big as the sediment.in file. The critical erosion stress also has the same problem.
the output file also has the same problem.

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arango
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Re: inconsistency between input ediment.in and output histor

#2 Unread post by arango »

Actually, the NetCDF values for these variable should be 1000 times smaller. All the units inside of ROMS are MKS. So we divide the input values (millimeter/second) for Wsed by a thousand to have meter/second. The computations are fine. We just have the units NetCDF attribute wrong for Wsed and Sd50 in the output files.

The critical erosion stress tau_ce and tau_cd are divided by RHO0 to convert it to kinematic stress from N/m2 to m2/s2. All the stresses inside ROMS are kinematic. So the values in the output NetCDF files are divided by RHO0. The units NetCDF attribute for these variables should be meter-2 second-2.

Notice that the values reported to standard out are in the same units as in the input script. They are scaled after they are reported. Therefore, your computations are correct. It is just that we have the wrong units attribute in the NetCDF files.

Thank you for bringing this to my attention :!: I corrected this problem. See the following :arrow: trac ticket for details. Please update.

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