Rivers numerical noise

[briochemc]

In the river tutorial, if I change the first solution plot to

cmap = :RdYlBu_4
plothorizontalslice(s, grd, zunit=u"μmol/m^3", depth=0, color=cmap, clim=(-1,1))

I get to see numerical noise at the Amazon outlet and other major rivers at the surface.

With OCIM2:

OCIM1:

OCCA:

[briochemc]

I reckon smoothing would solve the problem.

For the record, this is the raw river data on a histogram, showing how large a contribution the Amazon is compared to the other rivers: