New research by scientists at the Universities of Melbourne and Exeter has linked wave like patterns in the winds of the northern hemisphere to extreme weather and climate change. The changes in the wind patterns are in the upper levels of the atmosphere and expose specific parts of North America, Asia and Europe to different extreme weather situations. The situations can lead to extended periods of unusual weather that can be dry, wet, cold or hot depending on the area and how the waves are arcing in a their north-south pattern.
Normally the wind patterns of the globe move in a west to east direction but are not linear. They have certain ebbs and flows to them like the waves of the ocean. Traditionally these wave patterns are know as the jet streams and have been thought to be rather fixed in place for certain periods of the seasons. They are responsible for drawing the warm air up from the tropics to cause heat waves or down from the northern Polar Regions to cause prolonged periods of cold, like the polar vortex situation the United States saw this winter.
A climatologist who was not in the study, Michael Mann from Penn State, has reported on the findings saying that like other recent studies this one looks at the “link between climate change and extreme weather and how large-scale atmospheric circulation patterns,” are affected by weather patterns. The study analyzed weather data over large sections of the globe from 1979-2012 to see when certain periods of cold, heat, drought and wet seasons were over a month long, and if the atmospheric patterns had an influence on the prolonged nature of the weather.
These wind patterns that move like a wave and are presumably linked to climate change and extreme weather, also have been found to affect certain global regions more frequently than others. For example the scientists exposed that central Asia and western North America are more susceptible to heat waves, while in contrast eastern North America receives extreme cold spells more frequently. Research also found that droughts are very common in central North America, Europe and central Asia, while extended wet periods are often found in western Asia.
Therefore the most important contribution of the findings is that these north-south waves actually slow down the weather patterns, because the distance to travel is greater, causing the weather stay over certain areas of the earth for more extended periods of time. This stagnation of weather patterns has been looked at by other studies. They found that by the late twenty-first century there could be more frequent air stagnation covering around 55 percent of the current global population.
This type of information can be very helpful for insurance companies, governments and people in general when they are looking at the risk of, and ultimately planning for, the impact of extreme weather events across the globe. Certain cities and countries could prepare better for extended droughts or long cold spells if they have better access to more consistent weather information. If these findings are true and extreme weather and climate change as a whole are linked to these wave like wind patterns then studying them in depth for longer periods of time could give scientists a better perception of the future.
By B. Taylor Rash