Earth2Class Workshop for Teachers Originally presented 20 March 2004

1. Remote Sensing of Earth and the OceansGuest Scientists:Dr. Christopher Small Dr. Gregory Mountain Earth2Class Workshop for Teachers Originally presented 20 March 2004

2. How can we observe objects we cannot reach? We can use energy waves they emit or reflect. Everything in the Universe emits energy. When we use the appropriate instruments to detect those wavelengths, we can learn more about the object.

3. “Passive” Sensing Most of the time, we use light, heat, or other wavelengths emitted or reflected by an object to detect our world. For instance, you are using your eyes to receive the light wavelengths emitted or reflected off the screen (depending on whether you are reading this on a computer or seeing the large screen presentation.) You are just “passively” receiving the energy.

4. “Passive” Sensing Satellites and spacecraft can detect energy emitted or reflected from Earth or other objects in the solar system in a similar way, if they are sensitive to the appropriate wavelengths.

5. “Active” Sensing Another way to detect the environment is to send out a signal and detect its “echo.” This is the basis for sonar and radar. Satellite- and spacecraft-based radar instruments have enabled us to learn much about our planet and our partners in the solar system, even when visible light is blocked by clouds or other phenomena.

6. Most familiar “remote sensing” views come from weather satellites http://www.goes.noaa.gov/browse.html

7. Examples of Observing Earth from Space Weather satellites, such as that shown here, capture visible, infrared, and other wavelengths emitted to space, then send their data back to Earth to be assembled into valuable images of our planet’s surface processes. http://noaasis.noaa.gov/NOAASIS/ml/genlsatl.html

8. Other Environmental Satellites Polar-orbiting satellites, such as the TIROS-N shown here, orbit the Earth at lower altitudes than weather satellites to provide much more detail about Earth processes. http://noaasis.noaa.gov/NOAASIS/ml/genlsatl.html

9. Observing Earth • NOAA’s National Environmental Satellite, Data, and Information Service (NESDIS) has primary responsibility for operating our nation’s weather satellites. • Military, commercial , and governmental agencies in the US and abroad also operate satellites for a variety of purposes, such as telecommunications.

10. USGS Remote Sensing The US Geological Survey utilizes a wide variety of satellites to observe resources and hazards on land. “Landsat” provided some of the first images more than 30 years ago. Today, much of this is done through the National Mapping Program. Their web site, http://mapping.usgs.gov/ , provide many valuable links about remote sensing for teachers and students.

11. Landsat The “Landsat” program is the longest-running program to observe Earth from space. Landsat 1 was launched in 1972. Landsat 7, launched in 1999, has added to the millions of remote-sensed images of our planet. http://landsat7.usgs.gov/index.php

12. Of course, long before and after satellite imaging, aerial photos provided interesting views of familiar objects from remote viewing locations. http://terraserver.homeadvisor.msn.com/

13. Even earlier, hot air balloons provided views from above that greatly changed the way in which we viewed our world. http://www.aeragon.com/03/03-28.html

14. Over the past forty-plus years, many space missions have added to our knowledge—some by the data they sent back, some by their failures! NASA’s Jet Propulsion Laboratory has had primary responsibility for many of these missions. Their web site provides an excellent account of past, present, and future missions www.jpl.nasa.gov

15. Remotely sensing land features is one thing—remotely sensing under the sea is another! Light and radio waves—the major portions of the EM spectrum used for most remote sensing technologies—cannot penetrate though water. So different techniques must be used.

16. Going back to ancient times, sailors measured depth with weighted lines “HMS Challenger,” the first true oceano-graphic research vessel, used piano wire, rather than the heavier ropes usually used for “soundings.” http://www.wshs.fcps.k12.va.us/academic/science/bjewell/ocean/hhocean/final/chall.htm]

17. Using Sound Waves to Sound the Sea Floor • In the 1920s, a new technique—SONAR-- was developed. • Sound Navigation and Ranging provided a rapid method of looking through water to identify features in the water beneath a vessel and on the sea floor. • The next slide represents how a ship can send down a signal and detect the echo.

18. P(ic)assow

19. SONAR was widely employed in WW II, first for anti-submarine warfare, and routinely used after the war. Many sonar records became available after the war, revealing hitherto unknown features of the ocean bottoms. Dr. Bruce Heezen and Marie Tharp here at Lamont developed techniques beginning in the 1950s to change these 2-D records into 3-D physiographic charts, a drawing technique developed by their Columbia professors E. Raisz and A. K. Lobeck.

20. Modern Technologies • New shipboard and airborne techniques for mapping the ocean floors include “side scan sonar” and high-resolution seismic profiling. The next slide provides examples of such images, which are great advances over the 2-D images from the original echo-sounders. More about these techniques will be explained by our guest scientist.

21. http://marine.usgs.gov/fact-sheets/fs172-97/mapping.html

22. Focus in on Satellite Oceanography • The French-American TOPEX- Poseidon satellite launched in the early 1990s provided extensive data about the oceans. http://sealevel.jpl.nasa.gov/

23. TOPEX altimeters can measure… …variations in sea surface heights on the scale of meters, showing “hills” and “valleys” that exist even when the effects of waves and winds are removed. http://neptune.gsfc.nasa.gov/~krachlin/opf/ocean1.html

24. Recently, JASON-1 was launched to expand on these discoveries. JASON-1 belongs to the new series of NASA satellites monitoring our oceans Next Generation: JASON-1 http://www.jpl.nasa.gov/missions/current/jason1.html

25. Others in this new generation of “eyes in the sky” include: SeaWifs Aqua http://eos-pm.gsfc.nasa.gov/ http://seawifs.gsfc.nasa.gov/SEAWIFS.html

26. TRMM – Tropical Rainfall Measuring Mission • http://trmm.gsfc.nasa.gov/

27. Today, satellites routinely monitor all of our planet, including the ice-covered polar regions • http://polar.ncep.noaa.gov/seaice/Analyses.html#global

28. To learn more about satellite studies: Claire L. Parkinson Earth from Above: Using Color-Coded Satellite Images to Examine the Global Environment University Science Books, Sausalito CA ISBN 0-935702-41-5 Online images from the book: http://mirage.usra.edu/esse/earthabove.html

29. Some additional interesting web sites about satellite studies: http://home.att.net/~dkvangemert/ This is an excellent web page with lots of information about rocketry. NASA has many educational pages for students and teachers: http://spacelink.nasa.gov/products/Rockets/ http://quest.arc.nasa.gov/space/teachers/rockets/principles.html http://jpl.nasa.gov

30. Additional useful web sites http://asd-www.larc.nasa.gov/SCOOL/orbits.html Another good NASA source of general information and classroom activities http://octopus.gms.org/surfing/satellites/index.html Good source of information about satellites http://www.nodc.noaa.gov/ NOAA’s National Oceanographic Data Center

31. To complete this part of today’s workshop, we’ll learn more about what satellites can reveal through the AMS Maury Project’s “Measuring Sea Level from Space” module. Following a break, our guest scientists will share the excitement of their investigations into the ocean floor’s secrets.