A numerical study is presented with results from a sensitivity study of wave front spatial coherence. Specifically, the influence of small‐scale (order of tens of meters to tens of centimeters) water‐column turbulence on vertical coherence of a direct path, LFM chirp at a source–receiver separation of 500 m is examined. Parameters chosen as variable included turbulence strength, spectral cut‐off scale (and combined rms value), source depth, receiver sub‐array depths, and background sound speed structure. Preliminary analysis suggests that the background profile may play a more significant role than originally anticipated. The generality of this is considered in the context of measures of profile ‘‘smoothness’’ and ‘‘curvature,’’ as previously quantified by others. Potential implications include the use of background profile knowledge to arrange source–receiver geometry for optimal signal reception when coherent processing is advantageous (e.g., comms, active detection, etc.). The model results also show that the Fresnel scale of the turbulent pertubations may dominate the coherence structure, as predicted by theory. The impact of turbulence strength and frequency appear to behave as expected. [Work supported by ONR.]