TY  - JOUR
AU  - Punge, H.J.
AU  - Konopka, P.
AU  - Giorgetta, M.A.
AU  - Müller, R.
TI  - Effects of the quasi-biennial oscillation on low-latitude transport in the stratosphere as derived from model driven trajectory calculations
JO  - Journal of geophysical research / Atmospheres
VL  - 114
SN  - 0022-1406
CY  - Washington, DC
PB  - Union
M1  - PreJuSER-1723
SP  - D03102
PY  - 2009
N1  - This work was supported by the European Commission within the 6th Framework Integrated Project SCOUT-O3. The authors greatly acknowledge the technical support given by Nicole Thomas and valuable comments by Gebhard Gunther.
AB  - The quasi-biennial oscillation (QBO) of stratospheric zonal winds induces a secondary meridional circulation (SMC) consisting of QBO variations in meridional and vertical winds. In this work, we investigate how these instantaneous meridional circulation anomalies add over time to variations of stratospheric transport. To that end, we compute backward parcel trajectories on the basis of the output of a chemistry-climate model (CCM). At the equator, the trajectories show the strongest vertical parcel displacement over a seasonal timescale when the QBO progresses toward easterly phase in the middle stratosphere. During the solstitial seasons a large number of parcels come from the summer hemisphere, causing in addition a QBO variation in the spread of the total ascent among equatorial parcels. A QBO effect on meridional transport is diagnosed from PV gradients during summer in the easterly phase of the QBO, which suggests a variation of the tropical-subtropical barrier strength. Analyses of the parcel trajectories and CCM trace gas distributions confirm this finding. We suggest that this variation is due to the combined effects of QBO and annual variation in meridional advection and in wave-induced eddy transport.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000263175400003
DO  - DOI:10.1029/2008JD010518
UR  - https://juser.fz-juelich.de/record/1723
ER  -