Experimental investigation of laser transmission at 1.06 μm in horizontal atmosphere under fine and haze-fog conditions of summer

With two sets of experimental instruments, laser transmission was investigated through horizontal atmosphere at 1.06 mu m under fine and haze-fog events. One set of the instruments is an indirect transmission meter used to measure visibility and the other one is a direct transmission meter used to measure the attenuation of laser power. Results show that the variation of transmittance got from laser power (T-p) and that obtained by visibility (T-vis) are highly correlated. For relative humidity (RH) below 85%, the curve of T-vis fits that of T-p very well. While the RH is above 85%, the T-vis is more likely smaller than T-p under fine meteorological condition, but under haze-fog condition T-vis is larger than T-p on the contrary. For different weather condition, the relation efficient between extinction coefficient and visibility is different. Even for similar visibility, the extinction coefficient of haze-fog event is larger than that of fine event.