Check SS fluxes are reasonable

[JamesSample]

The new model uses coefficients from Bogen (1996) to estimate suspended sediment (SS) yields from woodland, upland and glacial areas. At national scale, sediment yields estimated in this way seem quite high, and I find it difficult to gauge whether they are reasonable. Retention of sediment in lakes should also be high, in which case the total accumulated fluxes may be OK.

To do:

1. When Vollenweider coefficients for SS are available, try accumulating fluxes allowing for retention and comparing to observed fluxes of SS to see whether simulated values are plausible
2. Check the literature for other studies to confirm/improve on the Norwegian estimates from Bogen (1996). For reference, the median values from Bogen currently used in TEOTIL3 are shown in the table below

land_class	yield
wood_ss_kg/km2	2000
upland_ss_kg/km2	23000
glacier_ss_kg/km2	131000

@LeahJB Any suggestions for other literature values based on the review you did for SS during the forprosjekt? Ta :-)

[JamesSample]

NIBIO have some interesting data considering SS losses from woodland areas in Norway and Finland - see the presentation sent by Marianne on 21.08.2023 at 16.16 and especially the plot below:

Based on this, the value from Bogen (1996) of 2 kg/da/year seems plausible, but probably a bit on the high side. In f828f95, I have therefore changed the coefficient for woodland SS from 2000 kg/km2 to 1000 kg/km2.