  Helioseismic inversions, carried out for several years on various
ground-based and spatial observations, have shown that the solar rotation rate
presents two principal regimes: a quasi-rigid rotation in the radiative
interior and a latitude-dependent rotation in the whole convection zone. The
thin layer, named solar tachocline, between these two regimes is difficult to
infer through inverse techniques because of the ill-posed nature of the problem
that requires regularization techniques which, in their global form, tend to
smooth out any high gradient in the solution. Thus, most of the previous
attempts to study the rotation profile of the solar tachocline have been
carried out through forward modeling. In this work we show that some
appropriate inverse techniques can also be used and we compare the ability of
three 1D inverse techniques combined with two automatic strategies for the
choice of the regularization parameter, to infer the solar tachocline profile
in the equatorial plane.
  Our work, applied on LOWL (LOWL is an abbreviation for low degree denoted by
L) two years dataset, argue in favor of a very sharp (0.05+/-0.03R_sun)
transition zone located at 0.695+/-0.005R_sun which is in good agreement with
the previous forward analysis carried out on Global Oscillations Network Group
(GONG), Big Bear Solar Observatory (BBSO) and LOWL datasets.
