Sodium temperature lidar system for measuring the Antarctic mesopause region at Syowa station in 1999, 2000, and 2001

We are planning to measure the Antarctic mesopause region by a sodium temperature lidar at Syowa station (69 degrees 00' S, 39 degrees 35' E) for three years, 1999 - 2001 as a part of the 5th Campaign of Japanese Antarctic Research Expedition (JARE 40 - 42). The objective of this campaign is to clarify the mechanism of energetic interaction between the lower thermosphere and the upper mesosphere through the mesopause region over Antarctica. Lidar measurements will be made cooperatively with a MF radar and a Fabry-Perot Doppler imager. The pulse laser tuned to the sodium D2 resonance line (589 nm) can be obtained by a sum frequency of two injection seeded Nd:YAG lasers (1064 nm and 1319 nm) with a narrow spectral width below 0.2 pm. The temperature measurement can be made by detecting the Doppler broadening of sodium D2 fluorescence spectrum by tuning laser wavelength alternately at two points of its spectrum. Scattered photons are collected by a Dall-Kirkham Cassegrain telescope of 0.5 m in diameter and detected in photoncounting mode with a gated photomultiplier tube (PMT). The photons are integrated with a range-gated multichannel scaler and processed with a personal computer. Daytime measurements will be made by using an extremely narrow band Faraday filter.