HR: 0800h
AN: A21B-0723    [Abstracts]
TI: Sensitivity of Age-of-air and Ozone to Vertical Resolution in a Chemical Transport Model Coupled With a GCM
AU: * Deushi, M
EM: mdeushi@mri-jma.go.jp
AF: Metorological Research Institute/Japan Meteorological Agency, 1-1, Nagamine, Tsukuba-shi, Ibaraki-ken, 305-0052 Japan
AU: Shibata, K
EM: kshibata@mri-jma.go.jp
AF: Metorological Research Institute/Japan Meteorological Agency, 1-1, Nagamine, Tsukuba-shi, Ibaraki-ken, 305-0052 Japan
AB: We evaluated stratospheric transport characteristics of an off-line chemical transport model coupled with a general circulation model which were developed at the Meteorological Research Institute/Japan Meteorological Agency. Two versions used here had vertically 45- and 68-level which had a vertical spacing of about 2 and 0.5 km respectively in the stratosphere; and the same T42 spectral truncation horizontally. The transport module was a hybrid semi-Lagrangian scheme, which was formulated in an ordinal semi-Lagrangian scheme horizontally and a mass-conserving flux-form vertically. As a diagnostic of transport characteristics in the stratosphere, we calculated the age-of-air with using assimilated atmospheric fields to ERA40 re-analysis for the period 1981-2000. The 68-level model was better able to capture the observed mean ages than the 45-level model. And we applied the simple leaky tropical pipe model in the tropical lower stratosphere to the age-of-air results; and revealed that the 68-level model reduced the numerical vertical diffusion in this region than the 45-level model. The vertical diffusion of the 68-level model was the same order of the one estimated from observations. And also, we conducted full-chemistry runs for the period 1991-2000. The climatology of ozone and several long-lived trace gases were compared with observations. In the tropical and mid-latitude lower stratosphere, ozone profiles of the 68-level model were remarkably better agreement with observations. This indicated that the transport of long-lived trace gases due to the Brewer-Dobson circulation was closely depend on the vertical resolution.
DE: 3334 Middle atmosphere dynamics (0341, 0342)
DE: 3319 General circulation
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting