Sodium temperature lidar measurements of the mesopause region over Syowa Station, Antarctica

Observation of mesospheric temperature profiles with a new sodium lidar has started at Syowa Station (69° 00'S, 390° 3 5'E) since February, 2000. The transmitter is composed from injection seeded Nd:YAG lasers of 1064 nm and 1 3 1 9 nm, producing sodium resonance line at 589 nm by sum frequency generation. The advantage of this instrument is the transmitter is simple thus transportable, and a reliable solid state system requiring less maintenance compared with ordinary type of dye laser transmitters. The 589 nm laser bandwidth is well narrowed less than 100 MHz, pulse width is 40 nsec, and the energy is 40 mJ/pulse. The 589 nm wavelength is controlled by a personal computer with monitoring a seed laser wavelength using a wavemeter with an accuracy of 0. 1 pm. Temperature structures were measured by two frequency technique and by sodium D2 Doppler profile filling. Both results were in good agreement and consistent with model temperature structure.