The statistical description of atmospheric turbulence and laser propag
ation through the atmosphere is complicated by global intermittency, t
he slow variations in space and time of the basic turbulence parameter
s. The effects of global intermittency of atmospheric turbulence on th
e mutual coherence function and the irradiance spectrum are investigat
ed with numerical simulation. The effects of global intermittency are
negligible when the path length is of the order of 10 correlation scal
es of global intermittency. This condition is readily satisfied for ty
pical atmospheric parameters. The higher moments of irradiance appear
to be more sensitive to the effects of global intermittency.