Wednesday, 6 November 2002
Descent rate in the Antarctic vortex estimated by ADEOS/ILAS trace gases and its relation to dynamical fields
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.
Supplementary URL: