Atmospheric neutrinos - present and future -

Atmospheric neutrinos have been playing a major role in studying neutrino oscillations. The present data are consistent with pure 2 flavor v(mu) -> v(tau) oscillations. The allowed v(mu) -> v(tau) oscillation parameter region is sin(2) 2 theta(23) > 0.92 and 1.5 < Delta m(23)(2) < 3.4 x 10(-3) eV(2) at 90%C.L. Recent data from an LIE analysis showed that the v, disappearance probability obeys the sinusoidal function as predicted by neutrino oscillations. Future of Delta m(23)(2) atmospheric neutrino experiments are also discussed emphasizing the measurement of theta(13) and the sign Delta m(23)(2).