Cooperative Observation of Equatorial Atmosphere Dynamics

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This research project is devoted to the study of cumulous convection and atmospheric waves in the equator by the observations carried out in equatorial Indonesia under cooperations between Japan, Indonesia and Australia.Near Jakarta, in Jawa Island, a boundary layr radar and a meteor radar, which were installed in 1992, were continuously operated and the winds and turbulences below 5km altitude and wind velocities and temperature fluctuations at 70-110km altitudes have been recorded. At Bandung, Jawa, radiosondes were launched every day in order to observe wind, temperature and humidity up to 35km in the troposphere and stratosphere. At Pontianak in Kalimantan Island, New MF radar was built and operated since November 1995, which can observe winds at 70-100km altitudes. Simultaneous radiosonde and MF radar observation was carried out at Pontianak in a rainy season, in order to measure the dynamics throughout the troposphere and the middle atmosphere, simultaneously.Below 2km, good agre … More ement between radar wind and objective analysis was found. Frequency spectrum of wind fluctuation has smaller slope than that in mid-latitudes. Strong 10 day and 4 day oscillations were found in zonal and meridional wind component, respectively. Modeling of boundary layr dynamics was also successful which accounts for the observed characteristics. Near the tropopause, strong activity of the Kelvin waves was detected with significant modification of tropopause heights, which suggests troposphere/stratosphere exchange by the equatorial waves. In the mesosphere, quasi-biennial variability of MSAO (mesospheric semi-annual oscillation) and diurnal tides have been clearly recognized. Significant 2-day and Kelvin waves were observed and global structures have been studied, which indicates significant momentum fluxes of these waves in the equator. All these results clarified that the activity of the equatorial troposphere significantly drives the general circulation in the middle atmosphere, which affects the global environmental changes. Less