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UP: Fachverband Umweltphysik

UP 4: Poster Session

UP 4.3: Poster

Tuesday, March 8, 2016, 16:00–17:30, Foyer H41

Mean age of stratospheric air in the Bremen CTM — •Evgenia Galytska, René Hommel, and John P. Burrows — Institute of Environmental Physics, University of Bremen, DE

To analyse the variability and strengths of the Brewer-Dobson circulation (BDC), the mean age of air (AoA) conceptual model has been implemented in a 3D chemistry transport model (CTM), driven by ERA-INTERIM (EI) reanalysis. The concept defines idealized particles as time increments that accumulate during simulation depending on their transient time within the BDC. The resulting transient time (AoA) is investigated with respect to the initial time of the particle's release at the lower boundary.

We aim to understand possible changes in the transport characteristics of our CTM over the last 2.5 decades resulting from changes in model parametrizations for the treatment of advection, radiation, and chemistry. We relate our findings to the ongoing discussion about potential changes of the BDC. We conducted 26-year simulations from 1986-2011 with the CTM from different development branches. The spatial resolution is 2.5° x 3.75° (lat/lon), with 29 levels of potential temperature (335-2726 K). Horizontal transport has been calculated from EI wind fields and the vertical transport from EI diabatic heating rates. This study is a necessary step to further evaluate capabilities of our CTM in order to adequately model important transport pathways into and within the stratosphere, which are still debated.