The location of the initial nucleation in the SSPHE was
found to depend on the Richardson number. The effects of
buoyancy, supercooling degree and forced velocities effect
interact leading to an initial localized nucleation over the
subcooled plate (Ri> 0.02) or to a global fluid volume
nucleation (Ri< 0.02). The detected supercooling amplitude
was found to be a good indicator of the fluid mixing inside
the SSPHE upper side.