A Second-Generation Laser Radar

Abstract A brief discussion of the laser-radar method for investigating atmospheric properties above the troposphere is given. A detailed description is then presented of a large new system which has been constructed in Jamaica. The system is designed to have a telescope receiver whose collecting area is 16 m2, made up of a mosaic of spherical mirrors each of 30 inch diameter with an 80-ft focal length. The photomultiplier systems in use are designed to achieve a quantum efficiency of about 15% with the 0.6943-μm ruby laser light. The equipment is about three orders of magnitude more sensitive than the usual laser-radar system. The problems which were met in the design and construction of such an equipment and the ways in which they were overcome are discussed. The results of a typical operation sequence are given. These show that the equipment can, in the absence of aerosols, make measurements of atmospheric density up to about 100 km with a relative accuracy of ∼10%.