Most special purpose meteorological radars operate at millimeter wave frequencies. Those described in this paper include both ground and space based applications. Most have been built in single sets but they provide useful tools for special meteorological research.
Stephen L. Johnston,
"Millimeter wave meteorological radars", Proc. SPIE 1514, 15th International Conference on Infrared and Millimeter Waves, 15145T (1 December 1990); doi: 10.1117/12.2301619; https://doi.org/10.1117/12.2301619