The observed trend in the Southern Annular Mode: is it the ozone hole or is it greenhouse gases?
- đ¤ Speaker: Howard Roscoe, BAS
- đ Date & Time: Tuesday 29 January 2008, 11:00 - 12:00
- đ Venue: British Antarctic Survey, Room 307
Abstract
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.
Series This talk is part of the British Antarctic Survey series.
Included in Lists
- All Talks (aka the CURE list)
- Biology
- British Antarctic Survey
- British Antarctic Survey, Room 307
- Cambridge Environment
- Climate Science Seminars within Cambridge
- Featured lists
- Life Sciences
- Life Sciences
- ME Seminar
- my_list
- ob366-ai4er
- other talks
- Queens' College Politics Society
- School of Physical Sciences
- Talks related to atmosphere and ocean dynamics and climate science
Note: Ex-directory lists are not shown.
![[Talks.cam]](/static/images/talkslogosmall.gif)

Howard Roscoe, BAS
Tuesday 29 January 2008, 11:00-12:00