SITII is an observation and modeling project aimed at elucidating the physical mechanisms underlying the interaction of tides, boundary layer inertial oscillations and non-linear mechanics of sea ice. These high frequency processes are not fully included or succesfully simulated in most ice-ocean circulation models. Yet a semi-diurnal period to ice drift and divergence has been observed in several studies, in several Arctic locations.

For example: The figures below show spectra of divergence, shear or velocity of pack ice estimated for arrays of point measurements during (a) AIDJEX (Hibler et~al. 1974), (b) MIZEX (Lapparante & Hibler 1987), (c) CEAREX (Pease et al. 1995), and (d) AWI IABP contributions (Heil & Hibler 2002). Note the semi-diurnal peak in these spectra, indicating sea ice deformation rate and ice motion displays consdierable power at tidal or inertial frequencies, in the Beaufort Sea, Greenland Sea Margional ice zone and the Barents Sea.