D. Keith Wilson
Dept. of Appl. Ocean Phys. and Eng., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543
The usual error maps computed for underdetermined tomographic images can be very misleading for two reasons. First, the spatial correlation function of the actual field usually differs from the correlation function used to solve the inverse problem. Second, the effect of smoothing by the projections is neglected. Numerical examples are used to demonstrate these points, and methods for improving the inverse reconstructions are suggested. Tomographic imaging of flow fields is also discussed. Although it can be proven that the irrotational part of the flow that is interior to the array is invisible to the measurements, this is shown not to be a fundamental impediment for flow tomography using the methods usually applied by geophysical tomographers, largely because they assume a priori statistics of the spatial structure.