日本地球惑星科学連合2018年大会

講演情報

[EE] ポスター発表

セッション記号 P (宇宙惑星科学) » P-EM 太陽地球系科学・宇宙電磁気学・宇宙環境

[P-EM10] Coupling Processes in the Atmosphere-Ionosphere System

2018年5月22日(火) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:Liu Huixin(九州大学理学研究院地球惑星科学専攻 九州大学宙空環境研究センター)、Chang Loren(Institute of Space Science, National Central University)、大塚 雄一(名古屋大学宇宙地球環境研究所)

[PEM10-P02] Kelvin waves in the stratosphere and the MLT region during 2009-2010

*Chen-Jeih Pan1Wei-Sheng Chen1Uma Das2 (1.Institute of Space Science, National Central University, Taiwan、2.Department of Physics, Indian Institute of Information Technology, Kalyani, India)

キーワード:atmospheric Kelvin wave, TIMED/SABER

This study investigated slow Kelvin waves (SKWs) in the stratosphere and ultra-fast Kelvin waves (UFKWs) in the mesosphere and lower thermosphere (MLT) region during the strong El Niño period, 2009-2010. Some studies indicated that strong convection during El Niño may inspire more SKWs activities in the stratosphere. On the other hand, the variation of UFKWs in the MLT region during El Niño is still not clear. Therefore, this study compared SKWs in the stratosphere and UFKWs in the MLT region to get more detail about Kelvin wave’s upward propagation. To extract wave's properties, temperatures from TIMED/SABER (Thermosphere Ionosphere Mesosphere Energetics Dynamics/Sounding of the Atmosphere using Broadband Emission Radiometry) observations and ECMWF (European Centre for Medium-Range Weather Forecasts) reanalysis during 2009-2010 were used. Temperatures between -10 and +10 latitudes were firstly gridded into the day-altitude-longitude data cube, and then removed its background to get equatorial temperature fluctuations. For each altitude, the two-dimensional FFT was applied to each 96-day data segment and stepped forward in time by 1 day. Fourier spectra, the output of FFT, were analyzed to get primary wave periods and amplitude variation. The results show that UFKWs dominate the MLT region but SKWs dominate the stratosphere. SKWs show large amplitude in the quasi-biennal oscillation (QBO) easterly phase. However, UFKWs are not so active as SKWs in the same period. It seems that strong El Niño does not inspire more UFKWs activities in the MLT region.