Satellite oceanography
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Satellite Oceanography. Modified from a Presentation at STAO 2003 By Dr. Michael J. Passow. Ocean Satellites. Permit observations globally, especially useful where there are no ships or buoys

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Satellite Oceanography

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Satellite oceanography

Satellite Oceanography

Modified from a

Presentation at STAO 2003

By Dr. Michael J. Passow


Ocean satellites

Ocean Satellites

  • Permit observations globally, especially useful where there are no ships or buoys

  • Developed later than meteorological and other environmental sensing because electromagnetic radiation penetrates ocean water only to limited depths

  • Improved sensors permit inferences about ocean at greater depths


Satellite oceanography1

"Satellite Oceanography"

  • Surface topography, El Nino, and ocean winds are some of the areas investigated from space.

http://winds.jpl.nasa.gov/


Satellite oceanography applications

Satellite Oceanography Applications

  • Sea surface temperatures

  • Air-sea interactions

  • Sea Ice patterns

  • Monitoring ocean waves

  • Determining sea level variations

  • Analysis of ocean currents and eddies

  • Biological productivity

  • Precipitation patterns


Two basic satellite orbits

“Polar Orbiting”

(POES)

Takes about 90 minutes to make one revolution

Covers different areas each orbit as Earth rotates

Provides detailed images

Can produce time sequence

Geostationary (Geosynchronous)

(GOES)

Remains over same portion of planet by revolving with same period as Earth’s rotation

Can provide full disk or smaller views

Useful for weather and communication

Two basic satellite orbits


Satellite oceanography

http://www.iitap.iastate.edu/gcp/satellite/images/image7.gif


For more detailed studies we use polar orbiting satellites

For more detailed studies, we use “polar-orbiting” satellites

  • Polar-orbiting satellites are much closer to the surface (700 – 800 km) and make about 14 passes each day. They can provide good time sequence studies.

http://www.earth.nasa.gov/history/landsat/landsat4.html


Problem 2 how do you measure from a satellite

Problem 2—How do you measure from a satellite?

  • Satellites can detect what’s on Earth in two ways:

  • “passive” observation of energy reflected or radiated from the surface

  • “active” collection of signals beamed down from the satellite and reflected back

http://topex-www.jpl.nasa.gov/


Sea surface temperatures sst and thermal properties

Sea surface temperatures (SST) and thermal properties

  • Visible satellites can monitor difference between incoming solar radiation and reflected light

  • Infrared satellites can monitor IR energy emitted from surfaces

  • AVHRR (Advanced Very High Resolution Radiometer) measure SSTs

  • Also monitored with MODIS (Moderate Resolution Imaging Spectroradiometer)


Sst images link through dstreme ocean

SST Images[link through DStreme Ocean]

http://www.cdc.noaa.gov/map/images/sst/sst.gif


Sea surface temperature anomalies ssta

Sea Surface Temperature Anomalies (SSTA)

  • Images constructed by measuring difference between “observed” and “expected” values – anomalies

  • Better approach to recognizing “what is unusual,” not just “what is”

  • Especially useful for El Nino/La Nina studies—example: http://orbit-net.nesdis.noaa.gov/orad/sub/sst_anomaly_2m.html


Ssta images

SSTA images

http://www.osdpd.noaa.gov/PSB/EPS/SST/climo.html


Satellite oceanography

  • SeaWIFS has allowed us to monitor the links between physical and chemical conditions and marine biology

  • Biological response to climate changes

http://seawifs.gsfc.nasa.gov/SEAWIFS.html


Sea surface topography

Sea Surface Topography

  • Variations in sea surface heights caused by gravity variations (sea floor topography and geology)

  • Also seasonal changes in atmospheric and ocean circulation patterns

  • Radar altimeters aboard TOPEX/Poseidon and Jason satellites

  • AMS “Measuring Sea Level from Space”


Topex poseidon is

TOPEX-Poseidon is…

  • a partnership between the U.S. and France to monitor global ocean circulation, discover the tie between the oceans and atmosphere, and improve global climate predictions. Every 10 days, the TOPEX/Poseidon satellite measures global sea level with unparalleled accuracy.

http://topex-www.jpl.nasa.gov/mission/mission.html


Topex has been especially useful in understanding

TOPEX has been especially useful in understanding…

  • Variations in sea surface temperatures. This has been the most important instrument for observing El Nino/ La Nina changes in the Pacific Ocean, and all the effects on climate

http://topex-www.jpl.nasa.gov/elnino/elnino.html


Satellite oceanography

Jason 1 is a follow-on mission to TOPEX-

Poseidon

Monitors global ocean circulation, studies ties between the oceans and atmosphere, improves global climate forecasts and predictions, and monitors events such as El Niño conditions and ocean eddies.

http://www.jpl.nasa.gov/missions/current/jason1.html


Sea ice extent

Sea Ice Extent

  • Areal extent, amount, and thickness important for oceanographers and operationally

  • Visible images not feasible during winter

  • POES microwave sensors provide operational ice analyses

  • The next slide shows an example of sea ice cover in the Northern Hemisphere


Satellite oceanography

http://polar.wwb.noaa.gov/seaice/Analyses.html


Canadian sea ice imagery

Canadian Sea Ice Imagery

Ice conditions monitored by satellite and ships are available at http://ice-glaces.ec.gc.ca/App/WsvPageDsp.cfm?ID=1&Lang=eng


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