Modelling the abundance of 18O18O in the atmosphere and its sensitivity to temperature and O3 photochemistry

Atmospheric temperature and ozone photochemistry are recognised to play dominant roles in setting the abundance of ¹⁸O¹⁸O isotopologues (expressed via Δ₃₆) of atmospheric oxygen. Here, we use the AC-GCM EMAC to simulate the abundance of atmospheric ¹⁸O¹⁸O in a most consistent to date kinetic chemistry modelling framework.

Extensive model diagnostics allow us quantifying contribution of various factors into changes in Δ₃₆ since the last 60 years. It is shown that atmospheric dynamics is another fundamental ingredient of atmospheric Δ₃₆ distribution.

We discuss potential applications of clumped O₂ composition for quantifying various atmospheric processes like decadal changes in tropospheric O₃ abundance or tropopause warming due to volcanism.