Auroras, which are generated by the precipitation of energetic particles in the Earth's atmosphere in the polar regions, have complex structures and behavior. In spite of a long history of research many features of auroras still remain unexplained. The powerful radio waves of the PANSY radar can penetrate inside auroras, and detect their whole structure in high temporal and spatial resolution. The energy injection associated with auroras in the polar atmosphere and its effect on the Earth's atmosphere are revealed with the PANSY radar.
PMCs, also called noctilucent clouds, are observed in the 75-90km altitude range of the polar summer mesosphere. As PMCs are only mentioned in historical records after the Industrial Revolution, it is considered that PMCs are the result of human activity. PMCs, which are fairly sensitive to temperature, are regarded as the canary of Earth's climate change. Radar devices in the polar regions detect extraordinary strong echoes called Polar Mesosphere Summer Echos (PMSEs) related to PMCs. The high power of the PANSY radar allows us to explore the physics of PMCs by monitoring not only PMSEs, but also the background flow field of PMCs.
PSCs are clouds appearing in the polar winter stratosphere in the 20-30km altitude range, where the ozone layer exists. Even a small amount of water vapor contained in the lower stratosphere can condense into ice clouds at extremely low temperature in the polar regions. The PSCs are related to the formation of the Antarctic ozone hole. Simultaneous observation of atmospheric motions by the PANSY radar and clouds by lidar proivdes useful information on PSC physics.
Katabatic winds have a strong cold downward movement and flow along the slope of the Antarctic continent. They have significant effects not only in the Antarctic but also in the whole Southern Hemisphere. The PANSY radar can observe the circulation in the troposphere driven by katabatic winds with high time resolution. New insight into the transport of water vapor and aerosols can be obtained.
The accumulation of ozone in the polar regions by stratospheric circulation is maximized in the spring. However, ozone is destroyed photo-chemical reactions on the surface of PSCs, thus creating the ozone hole in the Antarctic. Prediction of the scale of the ozone hole requires accurate estimate of the stratospheric temperature controlling the amount of PSCs. The quantitative evaluation of gravity wave effects by the PANSY radar is critical for this task.