Gravity-topography coherence
= Gravity-topography coherence
For cross-spectrum $S_{gh}$ and autospectra $S_{gg},S_{hh}$, squared coherence is $|S_{gh}|^2/(S_{gg}S_{hh})$. It measures the fraction of spectral association between <gravity> and topography. Low coherence can signal uncorrelated internal loading, noise or shortcomings of a simple surface-load model; interpreting it as <elastic thickness> requires a loading model.