ACE‐FTS measurements across the edge of the winter 2004 Arctic vortex

Abstract

Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE‐FTS) solar occultation measurements have been used to create volume mixing ratio (VMR) profiles of H2O, CH4, and N2O inside and outside the 2004 Arctic vortex. Using derived meteorological quantities such as potential vorticity, we have classified 450 occultations (from February and March 2004 spanning 0 to 79.8°N) as vortex, vortex edge, or extravortex. We plot [CH4] versus [N2O] correlations to display the distinct patterns observed for measurements of different air masses and use these correlations to further classify the extravortex occultations as tropical, subtropical, or midlatitude. Using comparisons between high latitude profiles of [N2O], [CH4], and [H2O] inside and outside the Arctic vortex, we estimate upper stratospheric and lower mesospheric descent rates and find that descent in the winter 2004 Arctic vortex was rapid, with evidence of descent at higher altitudes than in past years.