Long term trends and stratospheric profiles of three fluorosulfur gases: SO2F2, SF5CF3 and SF6

• Main Authors: Sturges, William, Laube, Johannes, Hogan, Christopher, Buys, Zac, Mani, Francis S., Engel, Andreas, Martinerie, Patricia, Brenninkmeijer, Carl
• Format: Text
• Language: unknown
• Published: 2010
• Subjects: QD Chemistry; Greenland; Ice cap
• Online Access: http://repository.usp.ac.fj/7039/; http://repository.usp.ac.fj/7039/1/EGU2010%2D12188%2D1.pdf; http://meetingorganizer.copernicus.org/EGU2010/EGU2010-12188-1.pdf

Measurements have been made of three industrially-produced fluorosulfur gases in 18old air 19 collected from deep firn on the Greenland ice cap (collected as part of the North Eemian ice drilling project), from a balloon-borne cryosampler, and from aircraft measurements. The oldest firn air dates back to the middle of the last century, and contained no measurable amounts of the gases, consistent with them having no significant natural sources. Whereas we have previously shown that SF5CF3 and SF6 were growing at the same rate up until at least 1999, it is evident that SF5CF3 is now rising at a significantly lower rate than SF6; calling in to question the earlier assertion that they share a common origin. All three gases show only slight declines in concentration with altitude in the stratosphere,confirming that they have long stratospheric lifetimes. Interhemispheric gradients in the upper troposphere were significant for SF6 and SO2F2, but not SF5CF3, consistent with a reduction in the growth rate of the latter.