Remote Sensing of Earth and the Oceans Guest Scientists: Dr' Christopher Small Dr' Gregory Mountain

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Remote Sensing of Earth and the OceansGuest
ScientistsDr. Christopher Small Dr. Gregory
Mountain

• Earth2Class Workshop for Teachers
• Originally presented 20 March 2004

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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.

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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.

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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.

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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.

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Most familiar remote sensing views come from
weather satellites
http//www.goes.noaa.gov/browse.html
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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
planets surface processes.
http//noaasis.noaa.gov/NOAASIS/ml/genlsatl.html
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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
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Observing Earth

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

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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.

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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
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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/
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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
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Over the past forty-plus years, many space
missions have added to our knowledgesome by the
data they sent back, some by their failures!

• NASAs 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

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Remotely sensing land features is one
thingremotely sensing under the sea is another!

• Light and radio wavesthe major portions of
  the EM spectrum used for most remote sensing
  technologiescannot penetrate though water. So
  different techniques must be used.

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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/bj
  ewell/ocean/hhocean/final/chall.htm

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Using Sound Waves to Sound the Sea Floor

• In the 1920s, a new techniqueSONAR-- 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.

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P(ic)assow
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• 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.

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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.

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http//marine.usgs.gov/fact-sheets/fs172-97/mappin
g.html
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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/
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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
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Next Generation JASON-1

• Recently, JASON-1 was launched to expand on these
  discoveries.
• JASON-1 belongs to the new series of NASA
  satellites monitoring our oceans

http//www.jpl.nasa.gov/missions/current/jason1.ht
ml
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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
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TRMM Tropical Rainfall Measuring Mission

• http//trmm.gsfc.nasa.gov/

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Today, satellites routinely monitor all of our
planet, including the ice-covered polar regions

• http//polar.ncep.noaa.gov/seaice/Analyses.htmlgl
  obal

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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.ed
u/esse/earthabove.html
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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/p
  rinciples.html
• http//jpl.nasa.gov

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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.ht
  ml
• Good source of information about satellites
• http//www.nodc.noaa.gov/
• NOAAs National Oceanographic Data Center

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To complete this part of todays workshop,
well learn more about what satellites can reveal
through the AMS Maury Projects Measuring Sea
Level from Space module. Following a break,
our guest scientists will share the excitement of
their investigations into the ocean floors
secrets.