ENCYCLOPEDIA OF Espionage, Intelligence, and Security Volume ...

Emergency Response Teamsto the planet’s albedo—its reflective power, or the proportionof incoming radiation that it reflects. Another 25% ofsolar radiation is absorbed by the atmosphere, whileabout 45% is absorbed at the planetary surface by livingand non-living materials. This energy is later re-radiated tospace in degraded form, that is, at a longer wavelength.The atmosphere and its current conditions have apowerful effect on the amount of visible light reflected,and this—along with the loss of electromagnetic energyfrom the sun—places constraints on the observationalabilities of remote-sensing equipment.Detecting images. There is a continuous distribution ofelectromagnetic energy levels, from extremely low toextremely high, that together constitutes the entire electromagneticspectrum of energy. At the lowest level areradio waves, then microwaves (the section of the spectrumacross which television transmission takes place).Higher in frequency and energy levels are such forms oflight as infrared, visible, and ultraviolet. Still higher are xrays, and highest of all are gamma rays, which have anextremely small wavelength and extremely high frequency.Of most interest in remote sensing are the energylevels near the middle of the spectrum: microwaves, infrared,visible light, and ultraviolet light. Remote sensingsatellites measure the EMR reflected from features onEarth back into space. Photographic cameras on remotesensingsatellites are capable of detecting light from thenear infrared to the near ultraviolet. Remote sensing equipmenttypically divides the infrared portion into relativelylow-energy near-infrared images, and higher energy thermalinfrared images. The satellite may have a thermalscanner that operates in the thermal infrared portion, or amulti-spectral scanner operating across a range from ultravioletto thermal infrared. There may also be passivemicrowave and active radar systems operating in themicrowave portion of the spectrum.Scanning and processing images. Satellites equipped withmulti-spectral scanners can make precise measurementsacross a number of narrow bands. These scanners may beof the oscillating or “wisk-broom” type, which scan alonga line perpendicular to that of the satellite’s trajectory, orof the “push-broom” type, which detect entire scanlines at once.These multi-spectral scanners record electromagneticradiation as electrical signals, convert them to digitalformat, and transmit the information to an Earth receivingstation. The latter interprets various numbers as brightnessvalues on a gray scale. Depending on the needs of theobserving agency, images may be adjusted for resolution.For example, spatial resolution improves the detail forsmaller objects, while radiometric resolution allows forthe greatest levels of contrast. The analyzing agency may,in the digital image processing phase, add false color toenhance the readability of images for specific data—forEncyclopedia of Espionage, Intelligence, and Securityexample, red to indicate heat levels at areas where weaponsare being tested.❚ FURTHER READING:BOOKS:Chen, C. H. Information Processing for Remote Sensing.River Edge, NJ: World Scientific, 1999.Dehqanzada, Yahya A., and Ann Florini. Secrets for Sale:How Commercial Satellite Imagery Will Change theWorld. Washington, D.C.: Carnegie Endowment for InternationalPeace, 2000.Firschein, Oscar, and Thomas M. Strat. RADIUS: ImageUnderstanding for Imagery Intelligence. San Francisco,CA: Morgan Kaufmann Publishers, 1997.Krepon, Michael. Commercial Observation Satellites andInternational Security. New York: St. Martin’s Press,1990.ELECTRONIC:“Earthshots: Satellite Images of Environmental Change(U.S. Geological Survey).” (February 26, 2003).“Remote Sensing Data and Information.” (February 26, 2003).“Satellite Remote Sensing.” University of Waterloo Facultyof Environmental Sciences. (February 26, 2003).“Visualization of Remote Sensing Data.” (February 26, 2003).SEE ALSOSatellites, SpyEmergency Response TeamsEmergency response teams are the front line of the EnvironmentalProtection Agency (EPA) Emergency ResponseProgram, which is in turn at the center of the nationalinfrastructure for responding to environmental hazardssuch as oil spills. The Emergency Response Programbrings together a wide range of activities directed towardensuring appropriate, timely responses in the event of anemergency involving the release of oil or hazardous substances.After state and local first-responder capabilitieshave been exceeded, emergency response teams provideadditional support to see that all hazards are dealt with inaccordance with federal guidelines for the safety of humanpopulations and the natural environment.The larger framework. The EPA response system is part of alarger national framework designed to respond to hazardssuch as the release of toxic chemicals and oil. Among thekey facilities is the National Response Center operated bythe Coast Guard, which is the first point of contact for393