Simultaneous measurements of OClO, NO 2 and O 3 in the Arctic polar vortex by the GOMOS instrument

We present the first nighttime measurements of OClO from a limb-viewing satellite instrument in the Arctic polar vortex. The relationship between OClO, NO 2 and O 3 slant column densities in the Arctic polar vortex are analyzed from the GOMOS measurements. The retrieval process is based on a differential optical absorption spectroscopy (DOAS) method applied on the weighted median GOMOS transmittances. A study of the longitudinal distributions of OClO, NO 2 and O 3 above 65° north in January 2008 is presented. It shows a strong halogen activation in the lower stratosphere and a strong denoxification in the entire stratosphere inside the Arctic polar vortex. Time series of temperatures and OClO, NO 2 and O 3 slant column densities for the winters 2002/2003 to 2007/2008 are also presented. They highlight the correlation between temperature, OClO and NO 2 . The GOMOS instrument appears to be a very suitable instrument for the monitoring of OClO, NO 2 and O 3 in the stratosphere during nighttime.