Tidal Waves in the Upper Stratosphere and Lower Mesosphere as Inferred From Coupled Chemistry-Climate Model Simulations

HR: 09:20h
AN: A51F-09 [Abstracts]
TI: Tidal Waves in the Upper Stratosphere and Lower Mesosphere as Inferred From Coupled Chemistry-Climate Model Simulations
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: 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: Shibata, K
EM: kshibata@mri-jma.go.jp
AF: Meteorological Research Institute, 1-1, Nagamine, Tsukuba, 305-0052, Japan
AU: Akiyoshi, H
EM: hakiyosi@nies.go.jp
AF: National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba, 305-8506, Japan
AB: Atmospheric tides are mainly forced by diurnal variations of the heating due to absorption of solar radiation by ozone and water vapor. Features of atmospheric tides in the region from the upper stratosphere to lower mesosphere are examined by the use of coupled chemistry-climate models (CCMs) with sophisticated stratospheric chemistry developed at the Center for Climate System Research of the University of Tokyo (CCSR) / National Institute for Environmental Studies (NIES) and MRI (Meteorological Research Institute). Results show that in both simulations diurnal tides are clearly seen in summer hemispheres of the stratosphere and lower mesosphere. The global structure is identifiable with the gravest external mode of diurnal tides based on the classical tidal theory: The maxima appear around 0.1 hPa at 40° in both summer and winter hemispheres, which travel westward behind the sun by about 6 hours. The maximum amplitude is larger in summer hemispheres than in winter hemispheres by a factor of 2. As regards the ozone field around the forcing region of tides, corresponding diurnal components are also predominant, having two maxima around 1 hPa and 5 hPa at 70° in summer hemispheres; they travel westward behind the sun by about 13 hours and 5 hours, respectively. The formation mechanism of the distinctive structure in the ozone field will be discussed in the presentation.
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: 2007 Fall Meeting