Research goals of the PANSY project
Observation of unique energy inflows in the polar region
The ionosphere, the uppermost part of the Earth's atmosphere, is in contact with the outer space. Particularly in the polar regions, electrons and ions from space precipitate down to the atmosphere, and cause the aurora and severe disturbances. PANSY radar has the unique ability to measure the ionosphere in two ways: incoherent scattering observations, which can measure velocity and other parameters, and coherent scattering observations, which can measure density fluctuations, allowing us to get a detailed picture of the impact of space on the Earth's atmosphere.
Study of Polar Mesospheric Clouds (PMCs)
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.
Study of Polar Stratospheric Clouds (PSCs)
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.
Study of katabatic winds
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.
Accurate estimation of stratospheric temperature
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.