The TEKS Know that climatic interactions exist among Earth, ocean, and weather systems. • 8.10 (A) recognize that the Sun provides the energy that drives convection within the atmosphere and oceans, producing winds and ocean currents; CONVECTION Transfer of heat by the movement of warmed fluid (air or liquid) Warm fluid rises (less dense) Cool fluid sinks (more dense) CONVECTION CONVECTION CONVECTION Moves air in the atmosphere! Moving Air = Winds Convection in the atmosphere is the main cause of the wind. Where does the Energy for Convection come from on Earth? THE SUN!!! CONVECTION CONVECTION causes deep ocean currents! CONVECTION Wind over the shore changes direction because of EARTH’S UNEVEN WARMING & COOLING! Hot Air is Less Dense! Atmospheric Density How high is the atmosphere? 99% is within 30 km / 18 miles of the surface of the Earth Half the atmosphere is 5 km / 3.5 miles above the surface of the Earth Air Pressure – the weight of the air pressing on the surface at a give location What is most dense SINKS! Atmospheric Movement MOSTLY CAUSED BY: - Temperature differences - Pressure differences - Coriolis Effect (due to Earth’s rotation) Air Movement Gas molecules move from high density to lower density The TEKS Know that climatic interactions exist among Earth, ocean, and weather systems. • 8.10 (B) identify how global patterns of atmospheric movement influence local weather using weather maps that show high and low pressures and fronts; We would expect… Coriolis Effect breaks up Global Circulation • On Earth the large circulation cell breaks up into 3 smaller ones, moving diagonally • Other worlds have more or fewer circulation cells depending on their rotation rate The Coriolis effect • The Coriolis effect – Is a result of Earth’s rotation – Causes moving objects to follow curved paths: • In Northern Hemisphere, curvature is to right • In Southern Hemisphere, curvature is to left – Changes with latitude: • No Coriolis effect at Equator • Maximum Coriolis effect at poles The Coriolis effect on Earth • As Earth rotates, different latitudes travel at different speeds • The change in speed with latitude causes the Coriolis effect Figure 6-9a Global Winds - winds that blow steadily in paths for thousands of kilometers Total Atmosphere Circulation Role of the Ocean • Slowly absorbs and slowly releases heat energy helping keep Earth’s temperatures relatively stable • Oceans heat or cool the air above them and transport heat around the globe in currents. • Hurricanes form over warm ocean water, drawing their energy from the water’s heat. Ocean Currents Currents • large scale water movements – occur everywhere in ocean – both surface and deep • 2 main types: surface currents (10%) and subsurface currents (90%) – surface currents are primarily wind driven – deep currents are density driven – other forces affecting currents Coriolis effect friction gravity thermal expansion geologic shape of ocean basin Major oceanic circulation systems Current Gyres Gyres are large circular-moving loops of water Five main gyres (one in each ocean basin): • North Pacific • South Pacific • North Atlantic • South Atlantic • Indian • Generally 4 currents in each gyre • Centered about 30o north or south latitude Wind-driven surface currents Lost at Sea Duckie Progress •January 1992 - shipwrecked in the Pacific Ocean, off the coast of China •November 1992 - half had drifted north to the Bering Sea and Alaska; the other half went south to Indonesia and Australia •1995 to 2000 - spent five years in the Arctic ice floes, slowly working their way through the glaciers •2001 - the duckies bobbed over the place where the Titanic had sunk •2003 - they were predicted to begin washing up onshore in New England, but only one was spotted in Maine •2007 - a couple duckies and frogs were found on the beaches of Scotland and southwest England. Other Effects of Wind on Water Movement a) Downwelling – results when two wind-driven surface currents collide OR when a wind-driven surface current collides with a land mass two surface currents colliding surface current colliding with land mass b) Upwelling - results when two wind-driven surface currents move away from each other OR when a wind-driven surface current moves away from a land mass two surface currents pushed in opposite directions surface current pushed away from land mass Surface and Deep-Sea Current Interactions Unifying concept: “Global Ocean Conveyor Belt” http://seis.natsci.csulb.edu/rbehl/ConvBelt.htm The Water Cycle Four Types of Fronts Cold Fronts A cold front forms when cold air moves underneath warm air, forcing the warm air to rise. Cold Front On Weather Map How can you tell which direction the front it moving from the map? Four Types of Fronts Warm Fronts - A warm front forms when warm air moves over cold air. What kind of weather forms at a warm front? Warm Front On Weather Map How can you tell which direction the front it moving from the map? Stationary Fronts Where the warm and cool air meet, water vapor in the warm air condenses into rain, snow, fog, or clouds. Occluded Fronts When a cold air mass and a cool air mass come together, the warm air caught between them is forced upward. Reading Weather Maps http://0.tqn.com/d/weather/1/0/B/-/-/-/weathersymbolssummary.jpg Read the Legend!!! Radar http://www.crh.noaa.gov/arx/?n=jul2409 Local Weather…. http://www.wunderground.com/maps/#?type=Fronts The TEKS Know that climatic interactions exist among Earth, ocean, and weather systems. • 8.10 (C) identify the role of the oceans in the formation of weather systems such as hurricanes. http://www.weatherwizkids.com/weather-hurricane.htm What Happens On Land? • Landfall After a few hours over land, a hurricane will weaken rapidly. WHY? • Without the moisture and heat sources provided by the ocean, the storm can no longer produce thunderstorms near the eye. Without this convection, the storm's energy dissipates. Recommended Resources… • Edheads – Reading a Weather Map Tutorial & Interactive Game • http://edheads.org/activities/weather/index.shtml • Current Weather Maps – (different maps for temp, pressure, moisture, etc) • http://weather.rap.ucar.edu/surface/ • Weather - Easy Interactive Barometer • http://kids.earth.nasa.gov/archive/air_pressure/barometer.html • Air Force Association that Flies Into Hurricanes to Collect Data! • http://www.hurricanehunters.com/ • Short video clip about their mission http://oceantoday.noaa.gov/hurricanehunters/welcome.html • NOAA – Education Resources • http://www.education.noaa.gov/ • Bill Nye – Storms • http://www.gamequarium.org/cgi-bin/search/linfo.cgi?id=7827 Other Files You Might Like… • • • • Edusmart BrainPop – Weather Unit Organizer Bill Nye – Storms – check out the clearest, most fun explanation of El Nino ever!! (also has Winds, Atmosphere,etc) • Evaporation & Condensation Lab • STEMscopes • Texas STAAR Coach