Abstract
The classical oceanographic problem of deducing the unknown constant in the dynamic method—the problem of the "level of no motion"—may be treated as a geophysical inverse problem. The unknown "barotropic" velocity may be chosen to satisfy an arbitrary number of conservation laws, subject to perfect geostrophic balance and with explicit use made of the relative errors in the observations. The solution obtained is one of minimum energy. A western North Atlantic region is used to demonstrate the power of the method.