HALOE observations of the Arctic Vortex during the 1997 spring: Horizontal structure in the lower stratosphere



In late March, 1997, HALOE observed very low ozone (less than 1 ppmv at 48OK), low HCl, generally high NOx, and normal levels of H2O within the Arctic vortex. Trajectory mapping techniques show that the lower stratospheric Arctic vortex was locally chemically perturbed during this period. Regions of low HCl and low NOx mixing ratios found within the Arctic vortex indicate that partitioning within the odd chlorine family had been shifted from reservoir species to active species. Low O3 mixing ratios within these regions strongly suggest that chlorine-catalyzed photochemical destruction of O3 had recently taken place. Regions of low HCl and higher NOx mixing ratios are also observed within the Arctic vortex. Correlations of O3, H2O, NOx and HCl with HF are used to quantify the changes in these constituents during March and early April, 1997. Temporal changes in the correlation of HCl and NOx with HF indicate increases in these species. No trend in the correlations of H2O or O3 with HF was found in the lower stratosphere.