Effects of rain must be taken into account in propagation prediction methods used in service planning. Two examples are given:
Rec. P.530 for LOS microwave links
Rec. P.618 for Earth-space paths
Both contain well-known rain attenuation prediction method based on concept of deriving the effective length of the path through the rain – the effective path taking account of the spatial non-uniformity of rain, both horizontally and vertically, along the path.
For XPD, model based on relation with co-polar attenuation.
Recs also address frequency scaling of attenuation and depolarisation effects when measurement data are available at one frequency but required for another.
Rec. P.452 gives a prediction method for signals scattered from rain cells. This mode must be taken into account in a detailed assessment of potential interference mechanisms between two points on Earth’s surface – i.e. along with modes such as super-refractivity and ducting.
In all cases, prediction methods refer to Rec. P.837 as source of rain intensity data.
