The Handbook on Radiometeorology supplies background and supplementary information on radiowave propagation effects, and serves as a companion volume and guide to the Recommendations that have been developed by Study Group 3 (SG3) Working Party 3J (Propagation Fundamentals) of the ITU Radiocommunication Sector (ITU-R). It provides general information on radiometeorology for those who use the ITU-R P series of Recommendations, those who wish to have a more detailed understanding of the Recommendations and those who wish to contribute to their development.