Linking solar and long baseline terrestrial neutrino experiments

We show that in the framework of three light neutrino species with hierarchical masses and assuming no fine tuning between the entries of the neutrino mass matrix, one can use the solar neutrino data to obtain information on the element $U_{e3}$ of the lepton mixing matrix. Conversely, a measurement of $U_{e3}$ in atmospheric or long baseline accelerator or reactor neutrino experiments would help discriminate between possible oscillation solutions of the solar neutrino problem.