  A purely atomic immigration superprocess with dependent spatial motion in the
space of tempered measures is constructed as the unique strong solution of a
stochastic integral equation driven by Poisson processes based on the excursion
law of a Feller branching diffusion, which generalizes the work of Dawson and
Li (2003). As an application of the stochastic equation, it is proved that the
superprocess possesses a local time which is Holder continuous of order
$\alpha$ for every $\alpha< 1/2$. We establish two scaling limit theorems for
the immigration superprocess, from which we derive scaling limits for the
corresponding local time.
