Most of the waves that the average person is used to seeing are those on the surface of a lake. These are mechanical waves and as their restoring force (a characteristic of all waves) is provided by gravity they are often specified as surface gravity waves or just gravity waves. Although these waves are very common there is another type of wave very literally hiding under the surface. Inertial waves are waves that are produced in rotating fluids and their restoring force is provided by the Coriolis effect. They are actually produced in the interior of the fluid and so don’t exist at the surface where we would normally see them. There is one very important group of inertial waves that exist high up in the atmosphere called Rossby waves and it is these that today’s paper is studying.
Over the last twenty years there has been a spate of extreme summers. The 2006 European and North American heat wave; the Australian “angry summer” in 2012-2013; 2015’s middle eastern heat wave killing thousands; and California’s almost constant droughts are just a few examples. Obviously global warming theory predicts that a rise of global temperature would induce some of these effects and affect their frequency. This explanation is good but recent evidence seems to imply that these conditions are just a bit too extreme to be explained in this way and there is probably a more complicated process behind the scorching weather. The theory suggested is that Rossby waves in the northern hemisphere may somehow be connected and so a series of atmospheric models were designed to investigate this. The researchers decided to cut any unnecessary parts out of these computer models leaving only the features considered most accurate so the computing power could be spent on investigating them. It was found that there is a statistical connection between the formation of standing high amplitude Rossby waves in specific latitudes and an extreme summer condition. It is believed that the Rossby waves act to resonate and trap other types of pressure waves resulting in concentrations of heat building up, eventually leading to the unfortunate climate conditions.