%0 Journal Article %A Konopka, P. %A Grooß, J.-U. %A Günther, G. %A Plöger, F. %A Pommrich, R. %A Müller, R. %A Livesey, N. %T Annual cycle of ozone at and above the tropical tropopause: observations versus simulations with the Chemical Model of the Stratosphere (CLaMS) %J Atmospheric chemistry and physics %V 10 %@ 1680-7316 %C Katlenburg-Lindau %I EGU %M PreJuSER-7675 %P 121 - 132 %D 2010 %Z Record converted from VDB: 12.11.2012 %X Multi-annual simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS) were conducted to study the seasonality of O-3 within the stratospheric part of the tropical tropopause layer (TTL), i.e. above theta = 360K potential temperature level. In agreement with satellite (HALOE) and in-situ observations (SHADOZ), CLaMS simulations show a pronounced annual cycle in O-3, at and above theta = 380 K, with the highest mixing ratios in the late boreal summer. Within the model, this cycle is driven by the seasonality of both upwelling and in-mixing. The latter process occurs through enhanced horizontal transport from the extratropics into the TTL that is mainly driven by the meridional, isentropic winds. The strongest in-mixing occurs during the late boreal summer from the Northern Hemisphere in the potential temperature range between 370 and 420 K. Complementary, the strongest upwelling occurs in winter reducing O-3 to the lowest values in early spring. Both CLaMS simulations and Aura MLS O-3 observations consistently show that enhanced in-mixing in summer is mainly driven by the Asian monsoon anticyclone. %K J (WoSType) %F PUB:(DE-HGF)16 %9 Journal Article %U <Go to ISI:>//WOS:000274224600011 %R 10.5194/acp-10-121-2010 %U https://juser.fz-juelich.de/record/7675