为了研究随高度变化的大气湍流外尺度对斜程路径点目标回波闪烁指数的影响，基于修正Rytov方法，将斜程路径下双基系统及单基系统点目标回波的闪烁指数模型拓展至中度及强起伏湍流区域。该模型不仅包含内尺度因素，而且考虑了随高度变化的外尺度因素。数值模拟结果表明：当湍流起伏较弱时，外尺度对于闪烁指数的影响远小于内尺度；但当系统处于中度及强起伏湍流时，随高度变化的外尺度因素的影响作用明显，不可忽略。在激光通信、激光探测等系统中，可利用该研究结果对系统所处湍流区域引起的闪烁效应进行预测，以调整系统至最佳配置。

Based on the modified Rytov method, a model of scintillation index of echo wave from the point target in slant atmospheric turbulence is proposed. The model extends the scintillation index from weak fluctuation regimes to the moderate and strong fluctuation regimes in both monostatic system and biastatic system. Besides the inner scale, the model also contains the outer scale which changes with altitude. Numerical analysis results show that the outer scale affects the scintillation index little in the weak regime but plays an important role in the strong regime. The results above can be used for forecasting the influence of atmospheric turbulence on laser communication systems or laser detection systems.