HR: 1340h
AN: A13A-0896    [Abstracts]
TI: Phase relationship between chemical species and dynamical quantities in the QBO simulated with MRI coupled chemistry-climate model
AU: * Shibata, K
EM: kshibata@mri-jma.go.jp
AF: Meteorological Research Institute, 1-1 Nagamine, Tsukuba, 305-0052 Japan
AU: Deushi, M
EM: mdeushi@mri-jma.go.jp
AF: Meteorological Research Institute, 1-1 Nagamine, Tsukuba, 305-0052 Japan
AB: The ozone QBO is known to precede the zonal wind QBO by about a quarter-cycle in the lower stratosphere, while the phase relation is reversed, i.e., the ozone QBO is retarded by similar time-lag, above about 15 hPa (28km). To investigate this phase relationship between chemical species including ozone and dynamical quantities, chemistry-climate model (CCM) of Meteorological Research Institute is used, which can reproduce a realistic QBO of 31-month period. The dynamical module is a spectral global model of T42 truncation with 68 layers extending from the surface to 0.01 hPa (about 80 km), wherein the vertical spacing is 500m in the stratosphere. Hines gravity wave (GW) drag is incorporated with enhanced GW source in the tropics to reproduce the QBO in zonal wind. Further, the horizontal diffusion is weakened to 180 hrs at the maximum wavenumber of 42 in the middle atmosphere, while a conventional value of 18 hrs is used in the troposphere. The chemistry-transport module treats 34 long-lived species including 7 families, and 15 short-lived species with 79 gas phase reactions, 34 photochemical reactions and 9 heterogeneous reactions on polar stratospheric clouds and sulfate aerosols. Transport scheme is a flux form semi-Lagrangian type in the vertical and, at once, a simple semi-Lagrangian type in the horizontal with cubic interpolation. It is found that the model successfully reproduces the observed phase relationship between ozone and zonal wind. The lag-correlation coefficient between them attains maximum and minimum in the middle stratosphere in 20-30 hPa: a maximum of about 0.6 at -4 months lag and a minimum of about -0.6 at 9 months lag below 15 hPa, above which the coefficients are oppositely singed. These features are very similar to those based on observations, wherein the precedent phase lag is referred to as about several months or a quarter cycle.
DE: 0340 Middle atmosphere: composition and chemistry
DE: 0341 Middle atmosphere: constituent transport and chemistry (3334)
DE: 3319 General circulation (1223)
DE: 3334 Middle atmosphere dynamics (0341, 0342)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005