  Recently, De Pontieu et al. (2007b) discovered a class of spicules that
evolves more rapidly than previously known spicules, with rapid apparent
motions of 50--150 km s${}^{-1}$, thickness of a few 100 km, and lifetimes of
order 10--60 seconds. These so-called type II spicules have been difficult to
study because of limited spatio-temporal and thermal resolution. Here we use
the IBIS instrument to search for the high velocities in the disk counterpart
of type II spicules. We have detected rapidly evolving events, with lifetimes
that are less than a minute and often equal to the cadence of the instrument
(19 secs). These events are characterized by a Doppler shift that only appears
in the blue wing of the Ca II IR line. Furthermore the spatial extent,
lifetime, and location near network, all suggest a link to type II spicules.
However, the magnitude of the measured Doppler velocity is significantly lower
than the apparent motions seen at the limb. We use Monte Carlo simulations to
show that this discrepancy can be explained by a forward model in which the
visibility on the disk of the high-velocity flows in these events is limited by
a combination of line-of-sight projection and reduced opacity in upward
propelled plasma, especially in reconnection driven jets that are powered by a
roughly constant energy supply.
