Did you know that strong winds in South America can lead to heavy monsoons in India? Read on to discover how this is possible and learn how La Nina could affect you.
The Butterfly Effect and La Nina
Have you ever heard of the butterfly effect? The idea is that a butterfly flapping its wings in South America can affect the surrounding air and lead to a flood in Australia. In other words, a small occurrence in one part of the planet can have a lasting effect in another. While this may be a bit of an exaggeration, this idea is actually quite an apt metaphor for La Nina.La Nina is a weather pattern defined by the cooling of the ocean surface along the tropical Pacific coast of South America. The tropical Pacific refers to the area of the Pacific Ocean in between the Tropic of Cancer to the north and the Tropic of Capricorn to the south. (On the map below, the Tropic of Cancer and Tropic of Capricorn are just inside the pink lines marked at 30 degrees N and S.
) La Nina events occur approximately every two to seven years, and the effects can last for as long as two years.
So, here is how the sequence plays out. The easterly trade winds blow more strongly than usual. (These are the butterfly wings.
Yes, strong winds will have a much larger effect on the environment than a butterfly.) This pushes the warm surface waters of the Pacific Ocean westward, making room for the cold, deep, ocean waters to emerge.The effect starts to pick up steam, snowballing into consequences all around the globe. The trade winds continue pushing the warm surface waters of the Pacific west.
This leads to warmer-than-usual waters in the western Pacific (Southeast Asia and Australia) and cooler-than-usual waters in the eastern Pacific (the Americas).
The Effects of La Nina on the Western Pacific
The warm waters in the western Pacific warm the surrounding air. As this air rises, it starts to cool, creating condensation and rain clouds. If you were reading the weather report, this would be referred to as a low pressure system. And, as you may have guessed, low pressure systems often lead to rain.
During La Nina, the summer monsoons in Southeast Asia and India are stronger and bring more rainfall than usual. Southeast Africa and northern Brazil also experience wetter-than-normal conditions. In Australia, La Nina is often linked to major flooding. In 2011, the Queensland floods left 38 people dead.
|Butterflies its original size. That would be like