Background:
Hurricanes are storms that have their beginning off the coast of Africa and travel across that Atlantic Ocean to the Caribbean and the East coast of the United States. Hurricanes can cause millions of dollars of damage to property and in some cases the loss of lives. From June to November every year hundreds of people and pieces of equipment are put into action to watch the Atlantic Ocean for signs of a hurricane brewing. Once one is sighted, it is tracked so that people can be warned if they happen to be in the way of one of nature's most devastating storms.
PREDICTING HURRICANES
A new science has come out of hurricanes. It is looking for patterns in climate to predict what type of hurricane season it will be. One person who works with his research team to predict the hurricane season is Professor William Gray from Colorado State University.
Professor Gray uses many different parameters to predict the Atlantic Hurricane season. One of those parameters is rainfall in Africa. Professor Gray and his research team study the amount of rainfall the West Sahel area of Africa receives. The West Sahel of Africa is the area of North Africa from the Atlantic Coast to around 7 West, and includes the countries of Mauritania, Senegal, the Gambia, Guinea-Bissau, Guinea, Sierra Leone, and Mali.
http://www.lib.utexas.edu/Libs/PCL/Map_collection/middle_east_and_asia/N_Africa_Mid_East_pol_95.jpg
The West Sahel receives approximately 15-20 inches of rain a year. It's rainy season is June to September. Professor Gray and his team have discovered that when the Sahel has a drier than average year, the winds in the troposphere blow off of the Africa coast and prevent the top of the storms from forming thus cutting down on the ability of the storm to become a hurricane. When the Sahel has a normal or above average rainfall, the winds do not blow off the coast and the storms have a better chance to become a hurricane as they pass over the Atlantic.
Background:
The student should have a working knowledge of the following skills:
- position of continents
- location of oceans
- graphing
Procedure:
1. Read the introduction on hurricanes.
2. Answer question one on your worksheet.
3. Click here to collect the hurricane data. Follow the steps below to find and collect the data.
- A. Scroll down to the Buttons for each year.
- B. Choose the button you wish to use. For this investigation you will need to get the data for the years 1950 to 1996.
- C. Click on the button of the year you want.
- D. Scroll down to "Individual Storm Summary".
- E. Create a data sheet to put your information on. The data sheet will need a column for the year, a column for the number of tropical storms, column for number of hurricanes, and a column for each intensity level (1-5) so that you can list down the number of hurricanes for each year in each intensity level.
- F. Copy down the following information for each year
- 1. The year
- 2. Number of Tropical Storms
- 3. Number of Hurricanes
- 4. Hurricane Intensity Category; i.e. how many hurricanes were 1,2,3,4,5
- G. Once the data is copied, click on the "Back" button and choose the next year you wish to collect the data. Repeat steps F.
4. Create two graphs from your data sheet.
- Graph one- graph only the hurricane data for each year. When you graph the number of hurricanes for each, color code the bar to match how many hurricanes were at each hurricane intensity. (Ex. for 1950- 1 block red for intensity 0ne, 2 blocks green for intensity Two, 5 blocks yellow for intensity Three, 2 blocks orange for intensity Four, and 1 block purple for intensity Five) Make sure you put a key on your graph. Draw a line for the average number of hurricanes which is 6.
- Graph two- graph both the tropical storms and the hurricanes combined for each year. Color key the graph by using one color for tropical storms and another color for hurricanes. Make sure you include a key. Draw a line for the average number of storms per year which is 10.
5. Answer questions 2 and 3 on your answer sheet.
http://typhoon.atmos.colostate.edu/forecasts/1997/97sahel_jun97/
6.Follow these steps to download and print out a copy of this graph.
- A. Scroll down to the graph "Central and West Sahel Rainfall".
- B. Place the cursor into the center of the graph and click and hold down.
- C. Choose "Save this Image As..."
- D. Save Image on the Desktop- will save as a JPeg file.
- E.Open up ClarisWorks or other word processing program. The following steps are for ClarisWorks. Open up the JPeg folder. Go to Edit and select Copy. Go to ClarisWorks and open up the Draw Program. Paste in the JPeg file. Go under ARRANGE and select TRANSFORM and select rotate 90. This will turn the image horizontally. Click one side of the image and drag to stretch out the image to fill the page. Save and print out. Make sure you have checked Page set-up to make sure the direction of the page is horizontal. This graph shows you rain patterns for West and Central Sahel. The graph does not show you the amount of rainfall for the year but if the rainfall was below average, average, or above average. Zero is the average rainfall. You will be looking at the data for the West Sahel which is the green bars if printed in color, or light gray if in black and white.
7. Answer questions 4 and 5.
8. Compare the rainfall graph to the combined tropical storm-hurricane graph. Answer question 6.
9. Compare the rainfall graph to the hurricane graph. Answer question 7.
10. Complete the rest of the questions on your answer sheet.
Coding:
Maryland Core Learning Goals: 1.1, 2.1, 2.2, 3.1, 3.2
National Standards (Science): A, E, F.3
National Standards (Geography): 1, 2.3
National Standards (Mathematics): 1.2, 1.4, 1.6, 2.1, 2.4, 4.4, 8.2, 10.2
Extensions:
- 1. Read the article at the following site http://usatoday.com/weather/wgrayhow.htm Explain why hurricane predicting is a difficult activity.
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| Cold phase |
Neutral phase |
Warm phase |
| (La Nina) |
|
(El Nino) |
| 1889 |
1890 |
1896 |
| 1892 |
1891 |
1899 |
| 1893 |
1894 |
1902 |
| 1903 |
1895 |
1904 |
| 1906 |
1897 |
1905 |
| 1908 |
1898 |
1911 |
| 1909 |
1900 |
1913 |
| 1910 |
1901 |
1918 |
| 1916 |
1907 |
1925 |
| 1922 |
1912 |
1929 |
| 1924 |
1914 |
1930 |
| 1938 |
1915 |
1940 |
| 1942 |
1917 |
1951 |
| 1944 |
1919 |
1957 |
| 1949 |
1920 |
1963 |
| 1954 |
1921 |
1965 |
| 1955 |
1923 |
1969 |
| 1956 |
1926 |
1972 |
| 1964 |
1927 |
1976 |
| 1967 |
1928 |
1982 |
| 1970 |
1931 |
1986 |
| 1971 |
1932 |
1987 |
| 1973 |
1933 |
1991 |
| 1975 |
1934 |
1997 |
| 1988 |
1935 |
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1936 |
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1937 |
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1939 |
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1941 |
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1943 |
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1945 |
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1946 |
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1947 |
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1948 |
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1950 |
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1952 |
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1953 |
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1958 |
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1959 |
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1960 |
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1961 |
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1962 |
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1966 |
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1968 |
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1974 |
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1977 |
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1978 |
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1979 |
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1980 |
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1981 |
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1983 |
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1984 |
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1985 |
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1989 |
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1990 |
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1992 |
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1993 |
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1994 |
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1995 |
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1996 |
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- 2. To your graph of tropical storms and hurricanes, add the El Nino years and see how adding another parameter to hurricane prediction changes your understanding, i.e. if it was a wet year for the Sahel but low activity for the Atlantic Ocean, is that because it was an El Nino year.
- 3. Search the net to find information on the other parameters named in the USA Today article and add to the graph of Atlantic storm activity to see if as you add more parameters if the prediction becomes more accurate.
- 4. Search the net to find the information of the hurricane prediction parameters named in the USA Today article and see if you can predict what type of Hurricane season we will have. Keep track of the Hurricane activity and see how close you came.
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- Credits:
Cheryl Overington, Principal Investigator
- Jeff Cottingham
Connie Lenhart
Marilyn Tupis