open access

https://hdl.handle.net/2115/64860

Role of the equatorial Kelvin wave in stratosphere-troposphere exchange in a general circulation model

英語

2001-10-16

American Geophysical Union

Journal of Geophysical Research: Atmospheres

106(D19)

22763-22780

Large-scale disturbances which cause the variations of ozone and water around the equatorial tropopause are investigated with a general circulation model incorporating a simplified ozone photochemistry, realistic topography, and seasonal cycle of the sea surface temperature. Eastward moving large-scale equatorial gravity waves are found to be dominant to modulate the minor constituents' distribution around the equatorial tropopause. A case over the Indian Ocean in the northern summer was investigated in detail. The disturbance had the characteristics of the equatorialK elvin wavea t the tropopausele vel, coupledw ith organizeda ctive convections in the troposphere. Associated with the downward displacement (and suppressed-convectiopnh)a seo f this system,d ry, ozone-richs tratospheric air moved downward into the upper troposphere. At the opposite phase, physical and dynamical processes above the organized active convections prevented the lower stratosphere from accumulating excess water. Thus the dryness around the equatorial tropopausei s maintained during the passageo f sucha system. Analysis of 4-year integration data reveals that such disturbances are especially active over the Indian Ocean during the northern summer through autumn. This is probably related to the development of the summer monsoon circulation over south Asia. This model has also simulated the zonal wave one structure of tropical tropospheric ozone and suggested the important contribution of convective transport to the structure.

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Copyright 2001 American Geophysical Union.

0148-0227