  We study effects of eccentricity fluctuations on the elliptic flow
coefficient v_2 at mid-rapidity in both Au+Au and Cu+Cu collisions at
sqrt{s_{NN}}=200 GeV by using a hybrid model that combines ideal hydrodynamics
for space-time evolution of the quark gluon plasma phase and a hadronic
transport model for the hadronic matter. We find that the effect of
eccentricity fluctuation is modest in semicentral Au+Au collisions but
significantly enhances v_2 in Cu+Cu collisions.
