Presentation on theme: "What Causes Our Weather?. From the Sun to Our Earth! Global movement of matter is driven by the properties of water and energy Heat Transfer: – Radiation."— Presentation transcript:
What Causes Our Weather?
From the Sun to Our Earth! Global movement of matter is driven by the properties of water and energy Heat Transfer: – Radiation – Conduction – Convection Convection is the primary mechanism of energy transfer in the atmosphere, oceans and asthenosphere
What Causes Climate and Seasons The shape of the planet and the tilt Milankovitch Cycles: Like a top the Earth wobbles and the length of the elliptical orbit changes every 100,000 years as well as the tilt, causing different latitudes to receive more or less sunlight
What are the Major Global Convection Cells? Hadley Cells: Start at equator and rise to about N/S latitude (trade winds) Rainforests form where air rises Deserts form where air descends
Convection Cells Ferrel Cells: Exist from degrees latitude N/S (Westerlies) Polar Cells: Cold, very dry dense air (Polar Easterlies) Jet Streams: Extremely fast moving winds found at boundaries of convection cells
What is the Coriolis Effect?
How do our oceans affect weather?oceans Trade winds created by the Coriolis Effect apply friction to the surface of the ocean and drag water in the same direction. Thermohaline currents: Temperature and salinity affect density of the ocean consequently causing currents (cold salty water is denser) Twice a day the gravitational pull from the moon causes high tides
What is El Nino-Southern Oscillation (ENSO) ? Rise in temperature of 0.5 Celsius degrees more than normal in the Eastern Pacific Ocean near the equator, usually beginning around December (hence the name, Christ Child) Occurs at irregular intervals of 2-7 years and has usually lasted one or two years, but has been coming more frequently. Disrupts global weather patterns Triggered by Southern Oscillation
What are the Effects of El Nino The deeper, warmer water in the east limits the amount of nutrient-rich deep water normally surfaced by the upwelling process Since fish can no longer access this rich food source, many of them die off
What happens in the atmosphere? Tropical thunderstorms are fueled by hot, humid air over the oceans The hotter the air, the stronger and bigger the thunderstorms The east coast of southern Africa and Australia often experiences drought during El Nino Describe economic consequences!