The goals of the International Team activity "Stratospheric Age-of-Air: Reconciling Observations and Models (ISSI-AoA)" are consolidation of the method to derive mean AoA from trace gases; identification of complementary diagnostics of stratospheric transport; and evaluation of the ability of models to simulate transport. All goal focus towards the answer to the question whether the current discrepancy in mean AoA trend estimates between models and observations can be resolved.

Contribution of IMK-ASF: Global ten-year data set of AoA derived from MIPAS/Envisat observations and methods to transform trace gas distributions into AoA (Stiller et al. 2012; Haenel et al., 2015); provision of effective transport velocities as alternative metrics for stratospheric residual transport derived within the ANCISTRUS project from MIPAS trace gas distributions (von Clarmann und Grabowski, 2016; 2021; von Clarmann et al., 2021); comparative analyses of all data sets and contribution to the planned two review papers.