How Blows the Wind? Charlsie Allen, NBCT OKAGE Teaching Consultant Purpose To locate and identify wind patterns of the world; to describe their effect on the environment; and To identify and describe how humans have adapted life to these wind patterns. PASS 7th Grade Standard 3.1 Recognize regional climatic patterns … prevailing winds…. Standard 5.0 The student will examine the interactions of humans and their environment. Standard 5.2 Evaluate the effects of human … adaptation to the natural environment…desertification…. A Legend… The Ancient Greeks used to think that wind was the Earth breathing in and out. We now know that it is just… air on the move. Global Wind Patterns Air moves between different areas around the world. Air moves at different heights in the atmosphere. Global Wind Patterns Colder air from the poles tends to sink and move towards the equator closer to the surface of the Earth. Warm air from the equator rises and moves towards the poles high in the atmosphere because it is lighter. Coriolis Effect Causes distinct pattern of winds around the world. In the northern hemisphere, winds blow to the right. In the southern hemisphere, winds blow to the left. Major Wind Patterns Westerlies Trade winds Roaring Forties The Doldrums Wind Patterns Wind patterns occur all over the world and these patterns have names given by local residents. Chinook Winds Location: North America Chinook Winds Source of wind: Cold arctic winds from northern Canada. Chinook Wind Chinook Winds Effects on environment Colder than usual winters throughout the United States Chinook Winds Impact on Humans: Colder winters cause higher heating bills. Cattle are lost in harsh winters Businesses lose money during bad winters. El Niño and La Niña Location: Pacific Ocean El Niño and La Niña Source of wind: Winds blowing East to West across the Pacific weaken and change course. The large warm air mass near Australia begins to move east toward South America. El Niño and La Niña La Niña El Niño El Niño and La Niña Incidence: In the past, every 4 to 5 years Recently, more often El Niño and La Niña Effects on environment: Severe storms in North and South America. Drought in Australia Polar jet stream moved north. Eastern United States has warmer winter. El Niño and La Niña Effects (continued) The Pacific jet stream moves further south than usual. Fierce storms hit California’s coast which usually has mild, sunny weather. El Niño and La Niña Impact on Humans: Thousands of deaths Billions of dollars lost around the world Monsoons Location: South Asia Monsoons Source of wind: Summer – Wet Monsoons begin in the Indian Ocean between India and Africa. Winds move northeast across India toward the Himalayas. Monsoons Incidence: Regularly each year Summer Monsoon – May to September Winter Monsoon – October to April Monsoons Effects on environment: Before the summer Monsoon rains, land mass heats to 120° F. Winter Monsoons bring cool land, mild temperatures, low humidity. Monsoons Impact on Humans: Monsoons are key to farming success. Seeds planted before Monsoon develop roots before the rains come. Monsoons Impact on Humans (continued) If Monsoons are late, young plants die, and famine follows. If Monsoons are early or too severe, young plants wash away, and famine follows. Mistral Location: Rhone Valley, France Mistral Source of Wind: Cold, north-westerly wind that blows down the Rhone valley. Mistral Incidence: 100 days a year Mistral Effect on environment: Winds blow 40 to 80 mph 100 days per year Trees grown permanently bent Mistral Impact on Humans: Homes have windows only on the southeast side for protection from the cold, dry wind that blows through the Rhone Valley. Sirocco Location: Wind blows from North Africa to Italy. Sirocco Source of wind: Over north Africa, winds become hot and dry and blow toward Italy Sirocco is a hot, dust-and-sand-laden wind especially common in summer blowing from Algeria northward. Sirocco Wind Sirocco Winds Sirocco Incidence: Spring and Summer Sirocco Effect on environment: Supports the Mediterranean Climate with sunny, mild summers. Cool moist fall and winter replaces Sirocco. Sirocco Impact on Humans: Italy Encourages rain Climate allows Italian farmers to grow crops Sirocco Extension: What might happen to farmers if the Sirocco wind blew all year long? How might the climate of Italy be affected if there were no Sirocco wind? Sirocco Impact on Humans: Algeria Soil erosion from overgrazing Other poor farming practices; Desertification; Inadequate supplies of potable water Harmattan Location: South of Sahara West coast of Africa Algeria, Guinea, Guinea-Bissau Harmattan Source of Wind: Dry, dusty wind which blows south from the Sahara in winter. Brings dust storms and very dry air. Harmattan Incidence: Blows in winter Harmattan Effect on environment: Generally hot and humid; Monsoonal-type rainy season (June to November) with southwesterly winds; Dry season (December to May) with northeasterly Harmattan winds Harmattan Impact on humans: Hot, dry, dusty Harmattan haze may reduce visibility during dry season Inadequate supplies of potable water Desertification Discussion Questions Extension: Is there a connection between the Sirocco and the Harmattan? Both begin in the Sahara Sorocco blows north in summer Harmattan blows south in winter Other Named Winds The Levante: an easterly Mediterranean wind bringing mild, moist air to Gibraltar and the mainland of Spain and Africa. Other Named Winds The Pampero: a very cold south westerly wind in Argentina formed in the middle of the continent blowing across the Pampas grasslands. Resources http://www.rcn27.dial.pipex.com/cloudsrus/activities.html Games and activities on weather, winds, and climate. http://www.rcn27.dial.pipex.com/cloudsrus/wind.html Definitions of winds and wind patterns. http://www.rcn27.dial.pipex.com/cloudsrus/features.html Weather and climate patterns. http://www.cia.gov/cia/publications/factbook/geos/gv.html Facts and maps on most countries of the world.