Water plays a crucial role on the earths radiation budget and its stratospheric variation could drive global surface climate change on a dccadal scale (Solomon et al., 2010).The Soundings of Ozone and Water in the Equatorial Region (SOWER) has been making efforts to establish the climatology and variabilities in the tropical stratospheric water concentrations (Fujiwara et al., 2010) since its initiation in 1998.