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Laser remote sensing
techniques provide a most important extension of our ability
to measure the physical and chemical properties and processes
of our atmosphere. Lidar is the name given to the application
of radar principles at optical wavelengths. At radio
frequencies, the scattering processes allow tracking of large
targets, raindrops, and even the larger particles in clouds.
At the higher optical frequencies, in the infrared, visible
and ultraviolet regions of the spectrum, we are able to
measure the properties of molecules based upon their
absorption and scattering. The absorption and scattering at
these wavelengths provides unique signatures, which allow us
to investigate fundamental atmospheric processes, measure
profiles of the meteorological properties, follow the detail
dynamics of the atmospheric motions, and measure the
concentrations of the natural chemical species of the
atmosphere, as well as those air pollutants added from various
sources. The lidar techniques developed until this time in
research laboratories are now beginning to find their way to
use as primary measurement tools for meteorology, industrial
processes, air quality, detection of hazardous gases,
detection of gas pipeline leaks, and many more applications.
The developments of lasers, detectors and a wide range of
electro-optical devices have provided the critical elements
for the development of the present capabilities.
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