6:15 PM - 7:30 PM
[PEM27-P24] Measurements of Fe and Ca+ temperatures using by a frequency-tunable lidar
Keywords:Resonance scattering lidar, Mesosphere/Lower thermosphere, Ionospheric D/E region, Neutral temperature, Ion temperature
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.