Millimeter-wave Environmental Remote Sensing of Earth's Atmosphere

introduction It is well known to the scientific community that the spectral properties of the gases that make up the Earth’s atmosphere play a major role in determining the environment in which we live. For example, the temperature at the Earth’s surface is determined by the balance between the solar radiation absorbed at the Earth’s surface and the infrared radiation emitted by the Earth into space. The infrared re-radiation is controlled by the wavelengths and intensities of the absorption lines, and bands of the gases that make up the Earth’s atmosphere. As a second example, the environmental level of ultraviolet radiation in which life has evolved is controlled by the amount of ozone in the stratosphere. Ozone is very effective at absorbing biologically damaging solar ultraviolet radiation between 285 and 315 nanometers, UV-B radiation. Therefore, the environmentdetermining physical properties of the atmosphere depend on its chemical composition. Over the past two decades, scientists have realized in ever-increasing numbers that the balance of chemical and physical processes that determine the atmospheric composition, and hence the environment at the surface, is delicate and subject to perturbation by gases released as a result of human activities. This realization has driven greatly expanded efforts to understand the physics and chemistry of the atmosphere and predict the effects of man-made pollutants. These efforts include improved computer modelling of atmospheric ;:?+..:::