Viewed from space, the oceans give Earth its "blue

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Corey Erika Carpenter
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TOPEX/Poseidon altimeter data reveal our Ocean Planet Viewed from space, the oceans give Earth its "blue marble" appearance, setting our planet apart from all others in the solar system.

1 TOPEX/Poseidon altimeter data reveal our Ocean Planet Viewed from space, the oceans give Earth its "blue marble" appearance, setting our planet apart from all others in the solar system. This cloak of life-giving water that covers more than percent of Earth's surface area controls our planet's climate. Studying the oceans, scientists are using TOPEX/Poseidon satellite altimeter data to learn how heat from the Sun is transported around the globe by ocean circulation patterns. Altimeter data over the oceans are used primarily to determine the sea-surface-height. From this data researchers have an improved understanding of the role of the oceans in the phenomenon known as El Niño, their role in controlling seasonal variations and longer-term climate changes. TOPEX/ Poseidon data are also used for operational purposes, such as monitoring eddies and their impact on human activities and marine life. The radar altimeter sends out short pulses of microwave energy; the round-trip time of the pulses is used to calculate the sea- surface topography. Corrections are made for a variety of factors including the precise satellite orbit, gravitational topography, atmospheric effects and ionospheric effects and tides. Scientists and engineers have worked to improve the corrections with the result that sea-surface height measurements are now accurate to. cm. TE AS topex/ Backside Panel from the poster Rise and Fall of the 9-98 El Nino As Tracked By Jointly sponsored by the National Aeronautics and Space Administration (NASA) and the French space agency Centre National d'etudes Spatiales (CNES), TOPEX/Poseidon has continuously surveyed the oceans' surface with radar altimeters since launch in 99. The satellite orbits Earth, times per year, and engineers are optimistic that the mission will continue to collect data through the year. The Jet Propulsion Laboratory (JPL) of the California Institute of Technology manages the TOPEX/Poseidon mission for NASA.

2 TOPEX/Poseidon Earth s Oceans Topography Experiment Objectives High-Gain Antenna (. m dia.) Solar Array Global Positioning System Antenna Six-year global view of Earth s oceans Improved understanding of ocean currents Improved forecasting of global environment Satellite Bus. m Highlights Attitude Control Module U.S. France (Centre National d Études Spatiales CNES) program Propulsion Module 8.9 m Launched August, 99, on Ariane P launch vehicle Power Module Sensors: Altimeters (NASA, CNES) Doppler Tracking Antenna (DORIS). m Altimeter Antenna Laser Retroreflector Assembly Microwave Radiometer Instrument Module Wet mass: kg Dry mass: kg Microwave radiometer (NASA) Global Positioning System (GPS) receiver (NASA) Laser retroreflector (NASA) Doppler tracking receiver (CNES) Orbits Earth at -km altitude, - degree inclination Launch 8//9 TOPEX/POSEIDON Measurement System GPS Satellite -day repeat of ground tracks (± -km accuracy) Covers 9% of the ice-free oceans every days Engineering Assessment Completed 9//9 Verification Phase Completed //9 Prime Mission Years Satellite Orbit DORIS Beacon Laser Ranging Station Radar Altimeter Signal..... Gravity s Influence on Sea Level Ocean Topography Unprecedented accuracy: sea-level measurements to within cm Has measured sea levels, mapped basinwide current variations, monitored effects of currents on global climate change; studied El Niño phenomenon Extended Mission Through.. Backside Panel from the poster Rise and Fall of the 9-98 El Nino As Tracked By

3 El Niño An El Niño is a disruption in the normal ocean circulation that affects the weather worldwide. Relatively small changes in ocean temperature over large area can make very big changes in the weather patterns. An El Niño is a natural event which occurs every - years. The term El Niño is used by those who fish the waters off the coasts of Ecuador and Peru to refer to the warm current that appears around Christmastime, causing a decline in the fish population. How does it work? In a normal year, the easterly (westward-blowing) trade winds push warm surface water against the western boundary of the Pacific Ocean near Australia and Indonesia, while nutrientrich cold water wells up along the west coast of South America, helping fish thrive. TOPEX/ Poseidon has tracked this LOW RAINFALL buildup of warm water in the western Pacific Ocean, which can be as much as meter higher than the eastern Pacific. As a result, there is little for fish to eat and, in turn, few fish for people to eat. The ocean also affects the atmosphere. With the warm ocean, there is an increase in evaporation and subsequent precipitation over the mountains in that area. The effects of the El Niño reach considerably further than the area surrounding the tropical Pacific; jet streams are altered all over the world and many places have weather that is very different from normal. The change in the trade winds which leads to El Niño has yet to be fully understood. The trade winds are controlled by the interaction between the atmosphere and the ocean, with seasurface temperature an especially important factor. Scientists are working to understand how and why the trade winds change so that we can better predict El Niño's. HIGH RAINFALL An El Niño occurs when the trade winds over the equator weaken and even reverse direction, that is, they blow from west-toeast. This allows the warm "pile" of water normally held against the western shore of the Pacific to move eastward along the equator. When this bulge of warm water reaches South America it moves north and south along the coast for hundreds of miles. When the warm water bulge is against the shore of South America, the normal upwelling of cool nutrient-rich water is prevented. warm water weak trade winds Indonesia South America Backside panel from the poster Rise and Fall of the 9-98 El Nino As Tracked By

4 = PURPLE - = BLUE cm = GREEN = YELLOW = RED = LT BLUE = ORANGE MAR 9 MAY 9 NOV 9 Activity. Color the El Niño TE AS Backside panel from the poster Rise and Fall of the 9-98 El Nino As Tracked By

5 = PURPLE - = BLUE cm = GREEN = YELLOW = RED = LT BLUE = ORANGE JAN 98 FEB 98 MAY 98 Activity. Color the El Niño (continued) TE AS Backside panel from the poster Rise and Fall of the 9-98 El Nino As Tracked By

El Niño Impacts The 99-998 El Niño altered weather patterns all over the globe. Because people and animals pattern their lives on average weather, most of the impacts were negative.

6 El Niño Impacts The El Niño altered weather patterns all over the globe. Because people and animals pattern their lives on average weather, most of the impacts were negative. Some of the major impacts are listed below: Severe drought lowered crop yields in regions of Africa, Southeast Asia, Australia, and South America. Over % of Algeria's wheat crop was lost, drought sent food prices soaring in Uganda, % of North Korea's maize crop failed with more than rain-free days with temperatures near 9 deg. F. ( deg. C) Flooding caused loss of life and road and property damage in central and southern South America. Some locations in central Chile received the amount of their total yearly rainfall in a single day. The increase in rainfall was due to increased moisture picked up over the eastern Pacific Ocean that changed the path of the jet streams. Atlantic tropical storms and hurricanes were dramatically reduced in 99. This decrease was partly caused by abnormally strong high-level winds that blew from the eastern Pacific across the tropical Atlantic to the Sahel region of Africa. The strength of hurricanes was increased in the eastern Pacific. Hurricane Nora was the strongest hurricane on record for the eastern Pacific. Hurricane Pauline was also very strong and it hit Mexico's Pacific resort coast with winds of up to miles per hour. These hurricanes were fed by high ocean temperatures. Ice storms in eastern Canada and New England caused some areas to be without power for over a month as rain froze on contact with objects such as power pylons, telephone poles, wires and trees. The weight of ice caused pylons to crumple and wires break. The Canadian army was deployed to help in cities and on farms. Sea lions and other marine mammals starved off the California coast because warm water blocked the normal upwelling of cold nutrient-rich coastal water. Some of the more fortunate were rescued and nursed back to health. The lack of nutrients in the ocean resulted in less abundant plankton, organisms which are the foundation of this marine food chain. Forest fires in Indonesia, started by people clearing land in an area suffering from prolonged drought, blazed out of control because vegetation was so dry. Smoke polluted air over thousands of miles caused health problems and is blamed for the crash of a jetliner that killed over a hundred people. Relatively warm temperatures across much of southern Canada and northern USA was good news to golfers but poor news for skiers. Demand for heating fuels decreased dramatically and there were lower fuel prices elsewhere in the USA. Backside panel from the poster Rise and Fall of the 9-98 El Nino As Tracked By

Activity. Track the El Niño Color the TOPEX/Poseidon images that show the rise and fall of the 99-998 El Niño so that areas of similar height are the same from one month to the next.

High areas correspond to warm water, low areas correspond to cold water. Use a color scheme that gives you a map that is easy to interpret.

The El Niño was at a maximum in November. How can we know that? How long did it take for the El Niño to reach a maximum? How long did it take for the El Niño to disappear?

7 Activity. Track the El Niño Color the TOPEX/Poseidon images that show the rise and fall of the El Niño so that areas of similar height are the same from one month to the next. These maps show the sea-surface height anomaly which is the difference between the height during that particular -day period and the average height for that time of year. High areas correspond to warm water, low areas correspond to cold water. Use a color scheme that gives you a map that is easy to interpret. Learn More About the El Niño APR 9 There is a lot that you can discover about the El Niño by looking at your map. () () () () () () Which way did the warm water travel? The El Niño was at a maximum in November. How can we know that? How long did it take for the El Niño to reach a maximum? How long did it take for the El Niño to disappear? Look at a map of the United States, how far north were coastal waters affected by the El Niño? How big was the area of warm water compared to your state or country? NOV 9 MAR 98 Backside panel from the poster Rise and Fall of the 9-98 El Nino As Tracked By

8 Activity. Hills and Valleys of the Sea Surface The surface of the sea is not flat; It consists of hills and valleys high and low levels of water that make up its ocean topography. (Select one of the maps of Activity, and ask your friends to choose other maps from the same series.) Build an Ocean Topography Model () Collect the materials you will need: colored ocean topography maps from plate or, tracing paper, pencil, thin cardboard, card stock, scissors, glue, paint (optional). () Enlarge the map on a photocopy machine if you want to have a bigger model. () Place the tracing paper on top of the map you have selected. Trace the contours of the surface by outlining each of the different colors on the image (You will be following the contour lines or the print). Use the scale to determine the height of each area. () Trace the line of each contour onto a separate sheet of card stock, then cut out each contour outline. (Optional: Use different color card stock for each contour level. You may buy colored stock, or paint what you have.) () Cut small pieces of cardboard to place between each layer. (The cardboard provide a means of indicating the relative height of each contour.) () Position cardstock and cardboard on the tracing paper, glue the cardstock cutouts one on top of each other to build the model of the sea surface. () Display the series of models to show the rise and fall of the El Niño. Discover More About Oceans and El Niño; Look Carefully at Your Models When Answering These Questions: () What is the difference between the highest and the lowest points of the ocean surface, and how did this difference vary with time? () How does the sea-surface topography compare to land topography? Are they very similar or very different? Why? () How might the ocean topography affect ocean currents? Hint: think about which way the water will flow, and look at meteorological maps. () What other measurements from satellites, ships, or buoys might help scientists to understand El Niño conditions? The above material is adapted from the CD-ROM Visit to an Ocean Planet. See the CD-ROM for more in-depth activities: Backside panel 8 from the poster Rise and Fall of the 9-98 El Nino As Tracked By

9 LEARN MORE!! Visit our TOPEX/Poseidon website at (Science and education pages with links to related sites.) On the Web El Niño JPL; (Science and education pages with links to related sites.) NOAA El Niño; (El Niño and La Niño pages with data from satellites and buoys.) NOAA Forecasts; (Maps on anomalies and tutorials.) TOPEX/Poseidon Education Outreach topex/ (Great pages with activities and information from the Center for Space Research and the Texas Space Grant Consortium.) (Lesson plans and featured oceanographic topics from Texas A&M.) Resources for Oceanography and Earth Science Educators (A page,on-line document, also available in hardcopy.) Bulletin boards and Ask a scientist (Outreach Bulletin Board); topex/tpask.html (Ask a Scientist.); Ask_Dr._Bob.html (Ask Dr. Bob.) CD-ROMs: Two CD-ROMs are available through Perspectives on an Ocean Planet (Informational) Visit to an Ocean Planet (Educational ) Slide Set The El Niño slide set is available from the Finley-Holiday Film Corporation. Telephone: Hard Copy Materials Posters, brochures, lithographs and other hard copy materials are available upon request from topex@jpl.nasa.gov, or from TOPEX/Poseidon Project Outreach Office Mail Stop -8 8 Oak Grove Drive Pasadena, CA 99. Backside panel 9 from the poster Rise and Fall of the 9-98 El Nino As Tracked By

Warm Up Vocabulary Check

Warm Up Vocabulary Check Surface current Coriolis Effect global winds upwelling Gulf Stream deep current climate El Nino convection current continental deflection 1.The apparent curving of the path of