  We develop commutator estimates in the framework of Besov-Morrey spaces,
which are modeled on Besov spaces and the underlying norm is of Morrey space
rather than the usual $L^{p}$ space. As direct applications of commutator
estimates, we establish the local well-posedness and blow-up criterion of
solutions in Besov-Morrey spaces for the incompressible Euler equations and
ideal MHD system. Main analysis tools are the Littlewood-Paley decomposition
and Bony's para-product formula.
