In this paper, several models of the vertical profile of C 2 n were given using home made high sensitivity micro temperature apparatus. We discussed mainly the effect of atmosphere turbulence on the finite bandwidth of a wavefront compensative system when the wavefront phase of the plane wave went through the atmospheric turbulence in summer or in winter. The Strehl ratios for various bandwidths of the wavefront compensative system were given when a closed loop transfer function H(f) was used as a model of a closed-loop control system that processed the turbulence-induced wavefront distortions. For the low control bandwidth fc=40 Hz, the Strehl ratio could be large than 0.85. Although the wind speed of the free atmosphere in the winter was 40.0 m/s, much stronger than in summer, the difference of the Strehl ratio in the two seasons was small.