The anomalous 2019 polar stratospheric chemistry in GMAO’s assimilation experiments

At the end of August 2019, a rare sudden stratospheric warming (SSW) commenced in the Southern Hemisphere as a result of anomalously high wave activity, which led to a significant tilting and shrinking of the polar vortex and a rapid rise of the vortex temperature through adiabatic compression resulting from accelerated sinking of air within the polar vortex. As a result, the 2019 ozone hole was the smallest since the late 1980s and closed in early November, about one month earlier than usual.

Using the new Constituent Data Assimilation System (CoDAS) developed at the GMAO, we conducted an analysis of the dynamical and chemical evolution of the 2019 polar vortex and ozone depletion. This animation shows the evolution of ozone, the chlorine reservoir compound HCl, water vapor and N2O at four selected potential temperature levels over the southern high latitudes between 1 July and 31 October 2019. It is readily seen that chemical composition of the polar vortex (marked by a black contour in each panel) differed dramatically from that at midlatitudes. Read more.