HR: 1340h
AN: A13A-0897    [Abstracts]
TI: Tidal Waves in the Middle Atmosphere and Their Modulation Caused by the 11-Year Solar Cycle
AU: Kitamura, M
EM: kita@geo.kyushu-u.ac.jp
AF: Department of Earth and Planetary Sciences, Kyushu University, 6-10-1, Hakozaki, Fukuoka, 812-8581 Japan
AU: * Hirooka, T
EM: hirook@geo.kyushu-u.ac.jp
AF: Department of Earth and Planetary Sciences, Kyushu University, 6-10-1, Hakozaki, Fukuoka, 812-8581 Japan
AU: Shibata, K
EM: kshibata@mri-jma.go.jp
AF: Meteorological Research Institute, 1-1, Nagamine, Tsukuba, 305-0052 Japan
AB: Atmospheric tides are mainly forced by diurnal variations of the heating due to absorption of solar radiation by ozone and water vapor. Since stratospheric ozone absorbs solar ultraviolet (UV) radiation, tidal waves could be modulated by the 11-year solar cycle through UV radiation changes. Hence, in this study features of atmospheric tides in the middle atmosphere and their modulation due to the solar cycle are examined by the use of a coupled chemistry-climate model (CCM) with sophisticated stratospheric chemistry developed at Meteorological Research Institute. We perform numerical simulations over four months from 1 May, i.e., in the solstitial season under solar maximum condition along with solar medium condition and investigate differences of the tidal wave activities. Results show that in both simulations diurnal tides are predominant in the stratosphere and lower mesosphere and are identified to the gravest external mode of diurnal tides based on the classical tidal theory. As regards the ozone field, corresponding diurnal components are predominant with a maximum around 70°N and 5 hPa. Daily changes of tidal waves are relatively small in the summer hemisphere and somewhat larger amplitudes are seen in the solar maximum simulation.
DE: 0341 Middle atmosphere: constituent transport and chemistry (3334)
DE: 3334 Middle atmosphere dynamics (0341, 0342)
DE: 3389 Tides and planetary waves
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005