Ambient-noise seismology is of fundamental importance to high-resolution crustal imaging, thanks to the unprecedented dense data coverage it affords in regions of little seismicity. In this work, using spectral-element and adjoint methods with a realistic 3D Earth model, I quantify the sensitivity of ambient-noise cross correlations from central Europe with respect to its origin and shear wavespeed structure. This highlights the potential importance to consider localized noise distributions for tomographic imaging and forms the basis of a gradient-based inversion scheme in which the distribution of noise sources may be treated as a free parameter.