Business / Agriculture / Environmental Protection Agency (EPA): An independent federal government agency established in 1970 and charged with coordinating effective governmental action concerning the environment, including setting standards, promulgating and enfor MORE
Technology / Radar / Reflectivity Factor (Z): Integral over the backscatter cross-section of the particles in a pulse volume. For particles small compared to the wavelength the scatter cross-section is d6, where d is the diameter of the particle. MORE
Science / Weather / Crepuscular Rays: Contrasting, alternating bright and dark rays in the sky. Sunlight is scattered by molecules and particles rendering these bright rays visible. Contrast is enhanced by haze, dust, or mist. These rays MORE
Science / Weather / Backscatter: A radar echo that is reflected, or scattered, at 180 degrees to the direction of the incident wave. Also the scattering of radiant energy into space before it reaches the earth's surface. MORE