Abstract: Atmospheric optical turbulence seriously affects the normol operation of optical systems. The acquisition of the profile of atmospheric refractive index structure constant C2 n is the basis for calculating the effect of atmospheric turbulence, however, the research of the refractive index structure constant C2 n profile is usually under 30 km presently. In order to study the C2 n profile on higher altitude, the C2 n profile in Gobi area is estimated in two parts taking 30 km as the boundary based on the conventional meteorology parameters obtained from meteorological rocket sounding, and regarding to the the C2 n profile above 30 km, Tatarskii optical turbulence parameterization scheme and outer scale model HMNSP99 are used tentatively. The results show that under 30 km, the magnitude order and changing trend of estimated C2 n are consistent with those of historical data, and at the altitude above 30 km, assuming that the homogenous and isotropic turbulence is satisfied, the estimated C2 n decreases steadliy with the increase of altitude, with the average magnitude order decreasing from 10-20 to 10-23. Because of the lack of basic theory about turbulence, the estimation of C2 n above 30 km in this work is tentative, however, it provides another idea and reference for further understanding the characteristics of the C2 n profile above the stratosphere.

Key words: atmospheric optics, refractive index structure constant, turbulence profile, meteorological rocket, conventional meteorology parameters