Atmospheric radar for the 0.5-110 km region

Radar can be used to make measurements of the dynamics and structure of the atmosphere by detecting irregularities in refractive index due to variations in humidity and temperature in the lower atmosphere (0-20 km), and due to variations due to fluctuations in electron density in the mesosphere lower thermosphere (MELT) region of the upper atmosphere (50-110 km). MF and HF radars have been used to routinely investigate the MLT for over 50 years. Wind profiling radars operating in the VHF band have been used for about 25 years to investigate the stratosphere troposphere (ST) region, but only routinely in the last 15 years. Considerable development has occurred within the past decade. In particular, great attention has been paid to interferometric and imaging techniques, to a re-examination and extension of MF radar techniques, to the application of VHF radars developed for atmospheric research to meteor studies, and finally, a rebirth of dedicated meteor radars has occurred. Here we briefly describe some of these recent improvements.