  We develop a general polynomial chaos (gPC) based stochastic Galerkin (SG)
for hyperbolic equations with random and singular coefficients. Due to the
singu- lar nature of the solution, the standard gPC-SG methods may suffer from
a poor or even non convergence. Taking advantage of the fact that the discrete
solution, by the central type finite difference or finite volume approximations
in space and time for example, is smoother, we first discretize the equation by
a smooth finite difference or finite volume scheme, and then use the gPC-SG
approximation to the discrete system. The jump condition at the interface is
treated using the immersed upwind methods introduced in [8, 12]. This yields a
method that converges with the spectral accuracy for finite mesh size and time
step. We use a linear hyperbolic equation with discontinuous and random
coefficient, and the Liouville equation with discontinuous and random
potential, to illustrate our idea, with both one and second order spatial
discretizations. Spectral convergence is established for the first equation,
and numerical examples for both equations show the desired accu- racy of the
method.
