The storm-laden westerly winds blow across the Southern Oceans and brush New Zealand all year round. Their meanderings to the south and to the north have become known as the ‘Southern Annular Mode’ or SAM. SAM dominates changes in the weather from one month to the next, bringing long spells of settled and fine weather to New Zealand when the westerlies head south, and bringing cool and stormy conditions when the westerlies come our way. Knowing what SAM is doing helps us understand how the weather is varying and if this is a good week for getting the washing out on the line.

This talk, hosted by Lower Hutt Cafe Scientifique, will explain how the SAM works and what effect it has on our weekly weather. We will then go on to look at how human influence is pushing the SAM around, and whether the SAM is likely to bring us lots of sunshine or an excess of storms over the coming decades.


Dr. James Renwick is a professor in the School of Geography, Environment and Earth Sciences, Victoria University of Wellington. He is fascinated by the general circulation of the atmosphere – how the atmosphere transports energy and momentum, what it does to achieve this, and how this affects storm tracks and jet streams. He also has an interest in Antarctic climate, especially the growth and decay of Antarctic sea ice, and how it is linked to tropical influences. James is also involved in climate prediction work, and has been involved with the Intergovernmental Panel on climate change process for several years.

Venue: Wholly Bagels, 34 Knights Road, Lower Hutt

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