Scope

Rainfall rate statistics with a 1-min integration time are required for the prediction of rain attenuation in terrestrial links (e.g. Recommendation ITU-R P.530) and Earth-space links (e.g. Recommendation ITU-R P.618).

When reliable long-term local rainfall rate data is not available, Annex 1 of this Recommendation provides a rainfall rate prediction method for the prediction of annual and monthly rainfall rate statistics with a 1 min integration time. This prediction method is based on: a) total monthly rainfall data generated from the GPCC Climatology (V 2015) database over land and from the European Centre for Medium-Range Weather Forecast (ECMWF) ERA Interim re analysis database over water, and b) monthly mean surface temperature data in Recommendation ITU-R P.1510.

When reliable long-term local rainfall rate data is available with integration times greater than 1-min, Annex 2 of this Recommendation provides a method for converting rainfall rate statistics with integration times that exceed 1-min to rainfall rate statistics with a 1-min integration time.