We study the dynamics of excitation pulses in a modified Oregonator model for the light-sensitive Belousov-Zhabotinsky (BZ) reaction assuming that the intensity of the applied illumination is a spatiotemporal stochastic field with finite correlation time and correlation length. We find enhancement of coherence resonance for suitable chosen correlation time. Based on this observation, we propose a mechanism for noise-enhanced propagation of pulse trains in excitable media subjected to external fluctuations.