Arctic Oscillation modulation of the Northern Hemisphere spring tropospheric ozone

This study identifies the Arctic Oscillation (AO) signature on the interannual variability of tropospheric ozone, with an emphasis on spring ozone over the North American and European continents. The analysis is first performed on ozonesonde data. It is shown that the variability in AO explains up to 50% of the tropospheric ozone variability in the lower troposphere over North America during the spring months. Chemistry-transport model simulations in which the meteorology varies from year to year, but the emissions and net stratospheric production of ozone remain the same show similar results. The model results indicate the role of the AO in modulating stratosphere-troposphere exchange and in regulating the transport of ozone and its precursors from North America, Europe and Asia.