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Hurricanes and El Ninohttp://html.nbc5i.com/sh/idi/weather/hurricanes/index.htmlSea Surface Temperatureshttp://www.ssec.wisc.edu/data/sst/archive/Dry Soilshttp://soils.usda.gov/use/worldsoils/mapindex/desert.html
How does lightning form? Check out this site. http://www.nature.com/nsu/031110/031110-19.htmlActivity # 1 Optimum Conditions for Hurricane Formation After exploring cloud formation what conditions are optimum for cloud development? Find five places on the globe where you think hurricanes are likely to begin forming. Give the criteria for each location. If you are not sure about the results of your cloud experiment, go to Nasa's Observatorim and click on Hurricane Creation. NASA's Observatoriumhttp://observe.arc.nasa.gov/nasa/earth/hurricane/splash.htmlThinkquesthttp://library.thinkquest.org/CR0212082/hurstru.htm
Activity # 2 El Nino El Nino Info from NOAAhttp://www.pmel.noaa.gov/tao/elnino/nino-home.html
After you investigate NASA's Observatorium El Niño Web site,take the quiz at the end and write down your answers on a sheet of paper. http://observe.arc.nasa.gov/nasa/earth/el_nino/elnino1.html
To really understand the effects of an El Nino event, compare the normal conditions of the Pacific region and then see what happens during El Nino below.  Normal Conditions (Non El Nino)
La Niña is characterized by unusually cold ocean temperatures in the eastern equatorial Pacific, as compared to El Niño, which is characterized by unusually warm ocean temperatures in the Equatorial Pacific. In La Nina conditions, the trade winds blow stronger than in normal conditions, mving warm water even farther to the west.
It is believed that El Nino may have contributed to the 1993 Mississippi and 1995 California floods, drought conditions in South America, Africa and Australia. It is also believed that El Nino contributed to the lack of serious storms such as hurricanes in the North Atlantic which spared states like Florida from serious storm related damage. Unfortunately not all El Nino's are the same nor does the atmosphere always react in the same way from one El Nino to another. La Niña tends to bring nearly opposite effects of El Niño to the United States — wetter than normal conditions across the Pacific Northwest and dryer and warmer than normal conditions across much of the southern tier. The impacts of El Niño and La Niña at these latitudes are most clearly seen in wintertime. In the continental U.S., during El Niño years, temperatures in the winter are warmer than normal in the North Central States, and cooler than normal in the Southeast and the Southwest. During a La Niña year, winter temperatures are warmer than normal in the Southeast and cooler than normal in the Northwest.
modified fromhttp://www.pmel.noaa.gov/tao/vis/vis5d/sst-wind-cur-eqt-20c-med.html http://www.pbs.org/wgbh/nova/balloon/science/jetstream.htmlhttp://squall.sfsu.edu/gif/jetstream_init_00.gifhttp://squall.sfsu.edu/crws/map_info/jetstream_info.html
High-speed winds race around the globe between four and six miles above the earth, mostly from west to east. These rivers of air are often collectively referred to as the jet stream, and they form at the boundaries of warm and cold air. Speeds average between 50 and 100 mph, but reach 250 mph. There are actually three major jet streams over North America in winter (and sometimes two), stretching from Canada to the subtropics. These separate bands of wind snake about, separating and combining at various times. The course of the fast winds affect air masses, which in turn affect the course of the winds. Winter storms tend to track along the jet streams. A storm's energy, in the form of increased thunderstorm activity, alters the path of the jet stream, typically kicking it further north, where it can block air from moving into the East. El Nino or La Nina conditions cause vertical cloud formation to occur in different locations. These vertical clouds alter the path of the jet stream. modified from:http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hurr/grow/home.rxml
Hurricanes are formed from simple complexes of thunderstorms. However, these thunderstorms can only grow to hurricane strength with cooperation from both the ocean and the atmosphere. First of all, the ocean water itself must be warmer than 26.5 degrees Celsius (81°F). The heat and moisture from this warm water is ultimately the source of energy for hurricanes. Hurricanes will weaken rapidly when they travel over land or colder ocean waters -- locations with insufficient heat and/or moisture. Related to having warm ocean water, high relative humidities in the lower and middle troposphere are also required for hurricane development. These high humidities reduce the amount of evaporation in clouds and maximizes the latent heat released because there is more precipitation. The concentration of latent heat is critical to driving the system. The vertical wind shear in a tropical cyclone's environment is also important. Wind shear is defined as the amount of change in the wind's direction or speed with increasing altitude. When the wind shear is weak, the storms that are part of the cyclone grow vertically, and the latent heat from condensation is released into the air directly above the storm, aiding in development. When there is stronger wind shear, this means that the storms become more slanted and the latent heat release is dispersed over a much larger area.
http://www.nbc17.com/hurricanes/index.htmlLike all tropical cyclones, a hurricanes need the warm water of the tropics, which feeds the storms with energy. In a mature hurricane, wind picks up warmth and moisture from the ocean, circling inward ever faster from outer cloud bands to the inner eyewall, where winds are the strongest and where it finally rises rapidly and is pushed out the top. Here's a more detailed look at the process: In the beginning, a disturbance forms in the atmosphere, developing into an area of low atmospheric pressure. Winds begin to move into the center of the storm seedling from surrounding areas of higher air pressure. Warm water heats the air, and it rises as it nears the center. The ocean feeds warmth and moisture into the storm, providing energy that causes the warm air in the center to rise faster. It condenses high in the atmosphere, creating thunderstorms. The tropical depression develops (if conditions are favorable) into a tropical storm, then finally into a hurricane, which is not unlike a giant swirling mass of thunderstorms. As rising air in the storm's center condenses, it produces heat, forcing it to rise even faster. The air is pushed out the top -- much like smoke out the chimney of a fire -- and more air has to rush in at the surface to take its place. This kicks the ocean up more and, well, you can see that the storm essentially feeds on itself.
Hurricanes evolve through a life cycle of stages from birth to death. A tropical disturbance in time can grow to a more intense stage by attaining a specified sustained wind speed. The progression of tropical disturbances can be seen in the three images below.
Hurricanes can often live for a long period of time -- as much as two to three weeks. They may initiate as a cluster of thunderstorms over the tropical ocean waters. Once a disturbance has become a tropical depression, the amount of time it takes to achieve the next stage, tropical storm, can take as little as half a day to as much as a couple of days. It may not happen at all. The same may occur for the amount of time a tropical storm needs to intensify into a hurricane. Atmospheric and oceanic conditions play major roles in determining these events.
Hurricanes are Earth's strongest tropical cyclones. A distinctive feature seen on many hurricanes and are unique to them is the dark spot found in the middle of the hurricane. This is called the eye. Surrounding the eye is the region of most intense winds and rainfall called the eye wall. Large bands of clouds and precipitation spiral from the eye wall and are thusly called spiral rain bands.
The path of a hurricane greatly depends upon the wind belt in which it is located. A hurricane originating in the eastern tropical Atlantic, for example, is driven westward by easterly trade winds in the tropics. Eventually, these storms turn northwestward around the subtropical high and migrate into higher latitudes. As a result, the Gulf of Mexico and East Coast of the United States are at risk to experience one or more hurricanes each year.  In time, hurricanes move into the middle latitudes and are driven northeastward by the westerlies, occasionally merging with midlatitude frontal systems. Hurricanes draw their energy from the warm surface water of the tropics, which explains why hurricanes dissipate rapidly once they move over cold water or large land masses.
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