Atmospheric effects on millimeter radio waves

This report is a short survey intended to present the atmosphere's effect on millimeter waves. The emphasis is on rain and raindrop-size distributions. This emphasis is appropriate because rain (the most common nongaseous constituent of the lower atmosphere) also has the greatest effect on millimeter waves, and raindrop-size distribution is needed to compute the theoretical and measured extinction of radio waves. The pressing need to acquire short-time data on raindrop-size distribution, particularly in the smallest size classes, is emphasized. Likewise, the acquisition of data on atmospheric fluctuations will determine how well millimeter-wave propagation through turbulence will be understood.