The ITU Radiocommunication Assembly considering:a) that the characteristics of the tropospheric radio channel depend on a variety of meteorological parameters;b) that statistical predictions of radiopropagation effects are urgently required for planning and design of radiocommunication and remote sensing systems;c) that, for the development of such predictions, knowledge of all atmospheric parameters affecting channel characteristics, their natural variability and their mutual dependence is needed;d) that the quality of measured and suitably analysed radiometeorological data is one of the determinants of the ultimate reliability of propagation prediction methods that are based on meteorological parameters;e) that an accurate knowledge of the clear-sky level on a satellite-to-ground link is important in developing the margin required to enable a telecommunications service to operate satisfactorily under adverse propagation conditions;f) that the clear-sky level on a satellite-to-ground link can fluctuate significantly both diurnally and seasonally due to solar heating and atmospheric effects;g) that interest exists in extending the range of frequencies used for telecommunication andremote sensing purposes;h) that propagation conditions should be known as well as possible during the process of bringing into service (BIS) of radio-relay equipment.