El Nino and La Nina

Planet Earth is a dynamic system. To the average person, the Earth is just a normal planet just like the other eight planets in this universe. To people who want to learn more about Planet Earth and to people who study Planet Earth, they know that it is filled with many different systems, cycles, and subsystems. The four main interacting systems are the biosphere, the lithosphere, the atmosphere, and the hydrosphere. Some other very important cycles are the water cycle and the heating cycle. Some of the more famous cycles of Planet Earth are El Nino and La Nina. These cycles affect the whole Earth.

In a normal year, the trade winds blow westward, toward the West Pacific. These winds move the warm water. Since there is warm water in the West Pacific, then there is going to be a lot of rain. This happens because the warm water evaporates quicker and then condenses into rain. Then, the rain goes back into the ocean, and the cycle is repeated.

In the ocean, there are two different kinds of water; warm water that is higher and cold water that is lower. When the warm water moves away, the cold water is exposed. So, the warm water in the East Pacific moves to the West Pacific, cold water is left behind. All along the West Coast of the Americas (North, Central, and South), or in the East Pacific, the water is cooler than on the West Side of the Pacific.

When there is an El Nino year, big changes occur. An El Nino is a cycle of the Earth. It mostly affects the hydrosphere and the atmosphere. An El Nino happens when the westward blowing trade winds break down. Since these winds move the warm water, and now they aren't blowing, the warm water moves over to the East Pacific. The warm water moves along the equator. When the warm water has moved out of the West Pacific, cold water rises. Once the warm water reaches the coasts of the Americas, then it starts to move up and down the coastline. Around the equator, the water can be as warm as 85° F. Since the water is warm, it evaporates quicker and more often. The evaporated water condenses again and forms rain. That is why there is so much rain in an El Nino year, but only for the people who live on the east side of the Pacific. Then, the rainwater goes back into the ocean or lakes, and the cycle of evaporation and condensation starts all over again. Many people think that in an El Nino year, it rains a lot all over the world, but it doesn't. The West Coast of the Americas has a wet year because the warm water. Along the coastlines near the West Pacific, it is very dry, because they have cold water. This past El Nino in 1998 has made one of the driest years on the east coast of North America. The East Coast of the United States gets a smaller amount of rain and snow than normal.

El Nino has many affects on humans and animals. On the West Coasts of the Americas, there are a lot of mudslides due to all of El Nino's rain. All of the rain also affects beaches. The cliffs get eroded away by all the rain and by the fierce waves, which are also caused by El Nino. Many crops go to waste because the rain waters them too much. Fish can only live in cold waters. So, when the normally cold waters stay warm, the fish suddenly have a big problem. All that they can do is migrate north, to colder waters. Now, for animals that eat fish, such as the sea lions, they have no food to eat. Most of these animals die from famine. El Nino also causes a stop of upwelling. Upwelling brings the nutrients from the bottom of the sea, to the top. Fish eat the nutrients that are brought up. This happens when warm water moves out of an area and the cold water moves up. When the warm water stays in one area, the cold water can't move up, so there is no upwelling. El Nino pushes a huge mass of warm water to Peru's coast. This mass of water is about 1 ¸ the size of the United States. El Nino also moves the jet stream that runs through the middle of the United States up north, into Canada, and down into the southern United States.

La Nina is also a cycle. It mainly affects the hydrosphere and the atmosphere. Its affects on planet Earth are an opposite of what El Nino does, in some areas. In a La Nina year, the trade winds blow westward, above and below the equator, but not on the equator. So, the warm water that is north and south of the equator moves westward, toward Japan and China. A huge mass of cold water sits in the middle of the Pacific Ocean. It acts like a log in a river. A log in a river diverts the water to either side of it. The mass of cold water diverts all the storms north and south of it. This means that the northernmost and southernmost cities are going to get a lot of storms with a lot of rain (Seattle). Since there are no storms following the equator, the cities near the equator don't get a lot of rain during a La Nina year, a very dry year. There is high pressure near the equator. When there is cold water near the equator, so there isn't a lot of rain. Since the water is colder, it is harder for it to evaporate. In Indonesia, the long dry spell helped to create more wild fires. They also had a lot of typhoons. For people that live on the West Side of the Pacific Ocean, a normal year isn't much different than a La Nina year. In both years, they get a lot of rain.

Some people may think that a La Nina always comes after an El Nino. This isn't true. It was just a coincidence that this past El Nino had a La Nina the year after it. They are two totally different cycles. They are not linked together to form one big cycle.

El Nino and La Nina affect all of Earth's interacting systems. Earth's interacting systems are the Biosphere, the Lithosphere, the Atmosphere, and the Hydrosphere. El Nino affects the biosphere because the fish have to migrate; there is no upwelling to feed the fish. Then the sea lions and other animals that eat fish, die of hunger (only the animals that can't migrate with the fish). El Nino affects the lithosphere because of all of the rain that falls. Cliffs erode, there are a lot of mudslides, and sinkholes develop on streets. El Nino affects the atmosphere because of the warm water. It evaporates quicker, and more rain falls. This upsets jet streams, fronts, and other wind patterns. El Nino affects the hydrosphere because the water gets to be a lot warmer in the East Pacific and a lot colder in the West Pacific. The currents are also affected.

These are the affects of La Nina on Earth's interacting systems on the West Coast of the Americas, equatorial areas. La Nina affects the biosphere because it creates a dry spell for everything near the equator. All the wild fires kill the forests and plants. Other animals also die from the dry heat. Humans also suffer. In some places, crops don't get watered enough, so they dry out. This causes hunger in a lot of places. La Nina affects the lithosphere because the ground dries out, also. The soil gets to be very dry because very little water is getting to it. La Nina affects the atmosphere because there isn't a lot of moisture in the air. This happens because the water doesn't evaporate as quickly. La Nina affects the hydrosphere because the water is very cold in the east Pacific and in the middle of the Pacific, too.

One good site that I went to, to find out more information about El Nino is http://topex-www.jpl.nasa.gov/discover/intro.html. This page had a lot of information about the make-up of an El Nino. When you first get there, scroll down the page and click on El Nino. On the first page of this site, there are five little information boxes at the very bottom. Click on any of these to get more information about El Nino. Some of these boxes show great images of an El Nino, and others give good information about El Nino. Another good site that has great computer visualizations for an El Nino year, a La Nina year, and even a normal year is http://pmel.noaa. gov/toga-tao/el-nino/la-nina-pacific.html and http://www.elnino.noaa. gov/lanina_new_faq.html. Some of these images are in the back of this report.