NOx During Ozone Depletion Events in the Arctic Troposphere at Ny-Ålesund, Svalbard

Harald J. Beine, Daniel A. Jaffe, Frode Stordal, Magnuz Engardt, Sverre Solberg,
Norbert Schmidbauer, Kim Holmén

Submitted to Tellus, May 1996.

Abstract. Measurements of NOx, ozone, non-methane hydrocarbons (NMHC), and other atmospheric constituents during the spring of 1994 were made at the Zeppelin-mountain atmospheric research station near Ny-Ålesund, Svalbard. On a few occasions we observed tropospheric ozone depletion events with minimum ozone mixing ratios of 4 ppbv that typically lasted for several hours. This paper presents the first measurements of NOx during ozone depletion. The objective of this work is to explore the role of NOx and NMHCs during those periods.

During depletion periods mixing ratios of NOx, total NMHC, and acetylene dropped to minima of 2.3 pptv, 6.4 ppbCv, and 202 pptv, respectively. These mixing ratios are significantly lower than the means for the entire campaign, which were 27.8 pptv, 14.3 ppbCv, and 614 pptv, respectively.

Because NO2 would quickly scavenge the BrO radical, the low observed NOx mixing ratios are consistent with proposed mechanisms involving catalytic destruction of ozone by the Br radical. A mechanism involving NOx to recycle Br radicals seems unlikely.