3.6 Other methods
Alternatives to full 2-dimensional inversions are the so-called “1.5-dimensional” approach, in which
1-dimensional radial inversions are carried out separately for each of the coefficients describing the
latitudinal rotation variation, and “1d1d” inversions in which the radial and latitudinal variations of the
rotation rate are integrated separately. For details of many of these methods, please see Schou et al. (1998)
and references therein.