[P-EM09_29AM2] VarSITI - Variability of the Sun and Its Terrestrial Impact

[PEM09-32] Recent observations by Rayleigh/Raman lidar and developments of tunable resonance scattering lidar system in JARE

*Mitsumu K. EJIRI¹, Takuo TSUDA¹, Takanori NISHIYAMA¹, Makoto ABO², Yoshihiro TOMIKAWA¹, Hidehiko SUZUKI³, Takuya KAWAHARA⁴, Masaki TSUTSUMI¹, Takuji NAKAMURA¹ (1.National Institute of Polar Research, 2.Graduate School of System Design, Tokyo Metropolitan University, 3.College of Science, Rikkyo university, 4.Faculty of Engineering, Shinshu University)

Keywords:Lidar, Resonance scatter, Rayleigh/Raman, Antarctic observation, Syowa Station

The National Institute of Polar Research (NIPR) is leading a six year prioritized project of the Antarctic research observations since 2010. One of the sub-project is entitled "the global environmental change revealed through the Antarctic middle and upper atmosphere". Profiling dynamical parameters such as temperature and wind, as well as minor constituents is the key component of observations in this project, together with a long term observations using existent various instruments in Syowa, Antarctica (69S, 39E). As a part of the sub-project, Rayleigh/Raman lidar was installed at Syowa Station in January, 2011 and has been operated at more than 350 nights (>3000 hours clear sky) by February, 2014. The Rayleigh/Raman lidar observes temperature and clouds in the mesosphere, the stratosphere and part of the troposphere, and providing seasonal and yearly variations of temperature profiles and data of gravity wave characteristics in the middle atmosphere, as well as high altitude clouds of PMC (polar mesospheric clouds) and PSC (polar stratospheric clouds). In order to extend the height coverage to include mesosphere and lower thermosphere region, and also to extend the parameters observed, a new resonance scattering lidar system with tunable wavelengths is developed at NIPR in Tachikawa (36N, 139E). The lidar transmitter is based on injection-seeded, pulsed alexandrite laser for 768-788 nm (fundamental wavelengths) and a second-harmonic generation (SHG) unit for 384-394 nm (second harmonic wavelengths). The laser wavelengths are tuned in to the resonance wavelengths by a wavemeter that is well calibrated using a wavelength-stabilized He-Ne laser. The new lidar has capabilities to measure density variations of minor constituents such as atomic iron (Fe, 386 nm), atomic potassium (K, 770 nm), calcium ion (Ca⁺, 393 nm), and aurorally excited nitrogen ion (N₂⁺, 390-391 nm) and temperature profiles in the mesosphere and lower thermosphere (MLT) region using resonance scatter of K. Currently, the fundamental laser pulses are transmitted with 120-160 mJ/pulse at approximately 25 Hz (i.e., 〜3-4 W) and the backscattered signal is received with a 35 cm diameter telescope. The new lidar system will be installed two years later at Syowa Station and provide information on the mesosphere and lower thermosphere as well as the ionosphere. This unique observation is expected to make important contribution to studies on the atmospheric vertical coupling process and the neutral and charged particle interaction. In this talk, current status of the research, observations, and system developments will be presented.