12th Conference on Middle Atmosphere

Wednesday, 6 November 2002
Descent rate in the Antarctic vortex estimated by ADEOS/ILAS trace gases and its relation to dynamical fields
Nozomi Kawamoto, National Space Development Agency of Japan (NASDA), Tokyo, Japan; and H. Kanzawa and M. Shiotani
We analyzed long-lived trace gas data (N2O, CH4, and H2O) observed by ADEOS/ILAS to study the stratospheric descent rate in the Antarctic vortex. Clear downward motion is seen from February to June 1997. In addition, it has large time variations with a period of about 10 days, which are related to those of dynamical fields. Small warmings and large negative values of DF (Eliassen-Palm Flux Divergence) are seen when the descent rate becomes large. Moreover, the correlation map in the latitude-height section between the vertical flow and temperature time variation (dT/dt) has an interesting feature: It shows warming below 10 hPa and cooling above 10 hPa in the polar region (70S-90S), and the opposite pattern in the mid-latitude (40S-70S). It is just like the meridional circulation in response to DF induced by planetary waves, which was first illustrated by the Matsuno's stratospheric sudden warming theory.

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