University of Cambridge > Talks.cam > British Antarctic Survey > The observed trend in the Southern Annular Mode: is it the ozone hole or is it greenhouse gases?

The observed trend in the Southern Annular Mode: is it the ozone hole or is it greenhouse gases?

Add to your list(s) Download to your calendar using vCal

If you have a question about this talk, please contact Deb Shoosmith.

Open to non-BAS; please contact Deb Shoosmith (drsho@bas.ac.uk or 221702) if you would like to attend.

I will present results of multiple regressions of the leading mode of atmospheric variability at southern high latitudes: the Southern Annular Mode (SAM). It is regressed against indices with large inter-annual variability, and one of several trend indices in order to determine which trend term gives the optimum fit. There is a significant linear trend in SAM , but there is a major increase in significance using chlorine from CFCs, and a further increase using the mass deficit of ozone in the ozone hole. We make no direct attempt to identify cause and effect, but if the trend is due to human influence then ozone loss is at least 9 times more likely the principle cause of the trend in SAM than greenhouse gases, though a simultaneous contribution from a small linear trend cannot be excluded. Other evidence is consistent with a stratospheric cause of the tropospheric effect.

This talk is part of the British Antarctic Survey series.

Tell a friend about this talk:

This talk is included in these lists:

Note that ex-directory lists are not shown.

 

© 2006-2020 Talks.cam, University of Cambridge. Contact Us | Help and Documentation | Privacy and Publicity