介绍了利用差分像运动测量法测量光波到达角起伏方差来确定大气相干长度的方法,阐述了一种能对大气相干长度进行昼夜测量的日夜两用型大气相干长度仪的测量原理与结构,经过长期昼夜观测分析得知:整层大气湍流强度有随时间变化的趋势,这种趋势与近地面层的湍流强度的时间变化特征基本吻合,即在日出后和日没前两段时间内的相干长度值远大于其它时间段内的值.

The principle of atmospheric coherence length measurement via differential image motion measure of the optical wave's angle-of-arrival fluctuation is introduced. An instrument for the measurement of atmospheric coherence length both in the daytime and at night were described. The statistical characteristics of the atmospheric coherence length in the daytime and at night were analyzed from some primary observation results. It shows that the refractive index structure constant varies with the time in total layer, and the time-varying behavior is basically in accordance with that of the boundary layer, that is, the atmospheric coherence length during the period of sunrise and sundown is much larger than that in the other periods.