Impact of the Stratospheric Ozone on the Northern Hemisphere Surface Climate During Boreal Winter

Abstract

In this study, we examine the impact of stratospheric ozone on the Northern Hemisphere (NH) surface climate during boreal winter by analyzing the two experiments using Global/Regional Integrated Model system-Chemistry Climate Model (GRIMs-CCM) (i.e., LINOZ-on/-off experiments) and eight Atmosphere Model Inter-comparison Project (AMIP) climate models. In LINOZ-on, ozone concentration in the upper troposphere and lower stratosphere (UTLS) varies with latitudes, being low in the tropics and high in the mid-to-high-latitudes, by adopting a linearized ozone scheme. The LINOZ-off, however, prescribes constant ozone concentration throughout all latitudes. Cooler surface temperatures over the Eurasian and Asian continents in boreal winter are simulated in LINOZ-on than that in LINOZ-off. A reduced mean UTLS temperature gradient in LINOZ-on, due to the difference of climatological mean ozone concentration, causes a weakened mean zonal wind in the lower stratosphere compared to the LINOZ-off. This mean wind difference is extended all the way to the surface, resulting in a negative Arctic Oscillation (AO)-like mean state in the mid-to-high latitudes in the LINOZ-on. Subsequently, it causes cool surface temperatures over the Eurasian and Asian continents by altering horizontal winds. This result is also supported by the comparison between AMIP models with a relatively high and low stratospheric ozone concentration in the mid-to-high latitudes. Therefore, a careful attention should be paid to the climatology of stratospheric ozone concentration in climate models to correctly simulate surface climate in the NH in the past and future climate.