Correlation of N2O and ozone in the southern polar vortex during the Airborne Antarctic Ozone Experiment

N 2 O mixing ratios, measured in situ by an airborne laser spectrometer (ATLAS), have been used along with in situ ozone measurements to determine the correlation of N 2 O and ozone in the Antarctic stratosphere during the late austral winter. N 2 O and ozone measurements on five transit flights between Ames Research Center, California (37°N), and Punta Arenas, Chile (53°S), were used to determine the correlation of N 2 O and ozone between 13 and 20 km in the mid‐latitudes. The mid‐latitude correlation is negative (≤−0.5). However, poleward of 53°S, N 2 O and ozone often show a strong positive correlation which approximately coincides with the wind speed maximum surrounding the Antarctic vortex. Strong zonal winds appearing between 60°S and 70°S are colocated with strong potential vorticity gradients, indicating that the wind speed maximum is a good marker for the vortex boundary. Flight tracks penetrating well beyond the wind maximum show a return to negative correlation. With few exceptions, regions in the vortex with positive N 2 O and O 3 correlation are colocated with total water mixing ratios of greater than 2.9 ppmv, and negatively correlated regions with water mixing ratios of less than 2.9 ppmv. The driest regions appear to be colocated with the greatest ozone loss. Because positive correlation between N 2 O and O 3 cannot be explained by horizontal or vertical transport (below 35 km), positive N 2 O/O 3 correlations appear to be a sensitive indicator of chemical loss of ozone.