Japan Geoscience Union Meeting 2015

Presentation information


Symbol P (Space and Planetary Sciences) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM27] Physics and Chemistry in the Atmosphere and Ionosphere

Tue. May 26, 2015 6:15 PM - 7:30 PM Convention Hall (2F)

Convener:*Yuichi Otsuka(Solar-Terrestrial Environment Laboratory, Nagoya University), Takuya Tsugawa(National Institute of Information and Communications Technology), Seiji Kawamura(National Institute of Information and Communications Technology)

6:15 PM - 7:30 PM

[PEM27-P24] Measurements of Fe and Ca+ temperatures using by a frequency-tunable lidar

*Takuo TSUDA1, Mitsumu K. EJIRI2, Takanori NISHIYAMA2, Makoto ABO3, Takuya KAWAHARA4, Takuji NAKAMURA2 (1.The University of Electro-Communications, 2.National Institute of Polar Research, 3.Tokyo Metropolitan University, 4.Shinshu University)

Keywords:Resonance scattering lidar, Mesosphere/Lower thermosphere, Ionospheric D/E region, Neutral temperature, Ion temperature

We are developing a new resonance scattering lidar system to be installed at Syowa Station (69S, 39E) in Antarctica. For the new lidar system, we have employed a tunable alexandrite laser covering the resonance scattering lines of two neutral species, which are atomic potassium (K, 770 nm) and atomic iron (Fe, 386 nm), and two ion species, which are calcium ion (Ca+, 393 nm) and aurorally excited nitrogen ion (N2+, 390 nm, 391 nm). Thus the new lidar system will provide information on the mesosphere and lower thermosphere as well as the ionosphere. Using the new resonance scattering lidar together with colocated other instruments, we will conduct a comprehensive ground-based observation of the low, middle, and upper atmosphere above Syowa Station. 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 presentation, we will report current status on test observations of the iron atom layer at National Institute of Polar Research (NIPR) at Tachikawa, Japan (36N, 139E). In order to obtain the iron resonance line at 386 nm, we operate the fundamental laser (i.e. the tuneable alexandrite laser) at 772 nm, which is shifted by 2 nm from the potassium resonance line at 770 nm, and then obtain the pulsed 386 nm laser using nonlinear crystal based on the second harmonic generation (SHG) technique. On 14 August 2013, we successfully detected first signals from the iron atom layer, with one-frequency mode for Fe number density measurement. The observed iron number density would be fairly comparable to that from the previous observations at Illinois (40N, 88W). After that, we have prepared three-frequency mode for Doppler temperature measurements. Based on a theoretical calculation, we have determined good combination of the three laser frequencies to minimize the temperature error, and then performed operations of the three-frequency mode on 5 and 18 Augsut 2014. The obtained temperature data will be compared with those from NRLMSISE-00 model and satellite observations. Furthermore, we will show a challenge of observing Ca+ temperature.