What is Sudden Stratospheric Warming?
This spring, we will be seeing the effects of sudden stratospheric warming (SSW) in the Antarctic which will be driving a strong change in Australia's weather patterns over the springtime period.
This rare phenomenon occurs when the upper atmosphere approximately 30km above the Antarctic's sea level warms by between 25°C and 50°C.
The first occurrence of SSW on record since the 1950s occurred in September 2002. At the time, we did not have the technology to predict such an event. However, now, meteorologists are able to understand this change in weather pattern better. This year's SSW is expected to be the strongest on record, surpassing the effects of the warming in 2002 somewhat significantly. There has only been one other sudden stratospheric warming event, which occurred in September 2010.
While sudden stratospheric warming is not thought to be caused from climate change, it is important to note the effect it has on the climate, especially in relation to other climate related events.
During a period of SSW, Tasmania and South Australia will experience colder temperatures. However, New South Wales and Queensland will receive higher temperatures and a decrease in rainfall. These two states will also see an increase of heatwaves and fire risks over the period of SSW, which usually lasts between eight to sixteen weeks.
Currently, New South Wales and southern Queensland are experiencing one of the worst droughts on record, which is now being compounded by this SSW. The drought is likely to continue throughout spring, which will bring us into summer, a period of very low rainfall for the region. This means we must take action in our own lives to assist in drought relief for the people living in these areas, especially in remote and rural communities. To read more about the economic impacts of the drought in the eastern states of Australia, take a read of our blog post here.
While there are drawbacks of a period of sudden stratospheric warming, such as decreased rainfall and the Antarctic ice melting more rapidly, affecting wildlife in the area, there are also benefits to a period of SSW. This rare weather event actually reduces the size of the Antarctic ozone hole.
The chemical process which leads to the destruction of the ozone occurs when intensely cold polar stratospheric ice clouds are formed. The rapid increase in temperature due to sudden stratospheric warming will reduce or potentially prevent these ice clouds from forming. During a period of SSW, there is also a significant change in wind pattern, which is what causes many of the changes in weather over the course of the following months. This disrupted wind pattern tends towards carrying air from the tropics to the southern polar region. This air is more ozone-rich, helping repair the Antarctic ozone hole.