Wind blows west across the tropical Pacific, from the Americas to Asia. During La Niña years, water at the ocean’s surface moves along with the wind, warming up in the sun as it goes. So, warm water collects at the ocean’s surface off the coast of Asia. This makes more clouds and rainstorms there.
But sometimes the westward winds weaken enough for the warm water in the western Pacific sloshes back east! Then we get an El Niño. This makes for more clouds and rain in the eastern Pacific—that’s when we get floods in Southern California.
You can actually see the warm surface water moving back and forth in this animation! The height is greatly exaggerated, of course. This was made by the TAO/TRITON array, about 70 devices anchored to the floor of the Pacific Ocean. These measure winds, sea surface temperature, relative humidity, air temperature, and subsurface temperature at 10 depths in the upper 500 meters. All this information is sent in real time to the Argos System - six satellites that follow polar orbits at an altitude of about 850 kilometers, 50 receiving stations on the ground, and two data processing centers. This has been going on since 1985.
But why do the westward winds weaken enough for an El Niño to occur? That's what my blog post is about:
http://johncarlosbaez.wordpress.com/2014/06/24/el-nino-project-part-2/
As you'll see, it's complex and fascinating! It involves underwater waves at the boundary of the hot and cold ocean water, and also the Madden-Julian Oscillation, a repeating pulse of storms that moves east across the Indian and Pacific oceans at 4-8 meters/second.
El Niños happen roughly every 4 to 7 years, in a rough cycle. But it's quite hard to predict El Niños more than 6 months ahead of time. That's what the El Niño Project is going to tackle. In my next post I'll talk about how.
#El_Niño
But sometimes the westward winds weaken enough for the warm water in the western Pacific sloshes back east! Then we get an El Niño. This makes for more clouds and rain in the eastern Pacific—that’s when we get floods in Southern California.
You can actually see the warm surface water moving back and forth in this animation! The height is greatly exaggerated, of course. This was made by the TAO/TRITON array, about 70 devices anchored to the floor of the Pacific Ocean. These measure winds, sea surface temperature, relative humidity, air temperature, and subsurface temperature at 10 depths in the upper 500 meters. All this information is sent in real time to the Argos System - six satellites that follow polar orbits at an altitude of about 850 kilometers, 50 receiving stations on the ground, and two data processing centers. This has been going on since 1985.
But why do the westward winds weaken enough for an El Niño to occur? That's what my blog post is about:
http://johncarlosbaez.wordpress.com/2014/06/24/el-nino-project-part-2/
As you'll see, it's complex and fascinating! It involves underwater waves at the boundary of the hot and cold ocean water, and also the Madden-Julian Oscillation, a repeating pulse of storms that moves east across the Indian and Pacific oceans at 4-8 meters/second.
El Niños happen roughly every 4 to 7 years, in a rough cycle. But it's quite hard to predict El Niños more than 6 months ahead of time. That's what the El Niño Project is going to tackle. In my next post I'll talk about how.
#El_Niño
