The amount of precipitation changes during El Niño in many areas of the world. The map above shows precipitation anomalies during El Niño for Northern Hemisphere winter.
Click on image for full size
Courtesy of NOAA
Teleconnections: Changes in Weather Linked Together
Changes in the atmosphere in one place can affect weather over 1000 miles away. Scientists are trying to sort out how this works so that they can better understand and predict weather patterns worldwide. They call these patterns teleconnections.
Teleconnection patterns are caused by changes in the way air moves around the atmosphere. The changes may last from a few weeks to many months. Teleconnection patterns are natural. However, they may be changed as Earth’s climate warms.
There are a number of different teleconnection patterns. Here are two examples:
El Niño is a major teleconnection pattern created by El Niño-Southern Oscillation (ENSO) changes to the atmosphere and ocean. During El Niño events cold and dry air is blown into places that typically have warm and moist air. This causes a big change in the weather. For example, the amount of clouds in one area could lead to changes in precipitation elsewhere. Changes in the temperature of the ocean surface in the tropical Pacific Ocean also affect the weather.
Other areas are affected by El Niño, too. Southern Alaska, for example, can become warmer than usual. And the U.S. Gulf Coast can be cooler and more rainy than usual. El Niño even has an impact as far away as West Antarctica. There is evidence from ice cores that during the strong El Niño event from 1939-1942 temperatures in West Antarctica were 5-7 C (9-13 F) warmer than normal.
The North Atlantic Oscillation
A teleconnection pattern with roots in the Atlantic causes unusual weather in the Northern Hemisphere. The cause is the North Atlantic Oscillation (NAO) - changes in the intensity of a low pressure system over Iceland and a high pressure system in the subtropical Atlantic. During the winter of 1995-96 the changes in pressure caused cold and snowy weather in eastern North America, bitter cold in Northern Europe, and wet weather in southern Europe and northern Africa.
Last modified September 18, 2008 by Lisa Gardiner.
Shop Windows to the Universe Science Store!Cool It!
is the new card game from the Union of Concerned Scientists that teaches kids about the choices we have when it comes to climate change—and how policy and technology decisions made today will matter. Cool It! is available in our online store
You might also be interested in:
Antarctica is unique. It is the coldest, windiest, and driest continent on Earth. The land is barren and mostly covered with a thick sheet of ice. Antarctica is almost entirely south of the Antarctic Circle...more
Sometimes there is a change in the way air moves through parts of the atmosphere. And there are sometimes changes in the way water moves through the ocean too. This disturbs typical weather patterns, or...more
Looking for online content that can be used for a climate change education course or module? Pages linked below can be used to support an introductory climate change education for either a unit or a full...more
Rainbows appear in the sky when there is bright sunlight and rain. Sunlight is known as visible or white light and is actually a mixture of colors. Rainbows result from the refraction and reflection of...more
The Earth travels around the sun one full time per year. During this year, the seasons change depending on the amount of sunlight reaching the surface and the Earth's tilt as it revolves around the sun....more
Scientists sometimes travel in specially outfitted airplanes in order to gather data about atmospheric conditions. These research aircraft have special inlet ports that bring air from the outside into...more
An anemometer is a weather instrument used to measure the wind (it can also be called a wind gauge). Anemometers can measure wind speed, wind direction, and other information like the largest gust of wind...more