a a a Display Options Cymraeg
Follow Ofcom on Facebook Follow Ofcom on Twitter Subscribe to the Ofcom RSS Follow Ofcom on YouTube Follow Ofcom on YouTube

Independent regulator and competition authority
for the UK communications industries.

Search Ofcom

Modelling Rain-Rate Maps for Fixed-Link Frequency Assignment Procedures

Analysis of rainfall records for all of the UK from 1990 to 2010 shows an upward trend in the rain rate exceeded for 0.01% time, a parameter used for fixed-link assignments. The rate of change tends to increase from north to south.

When Ofcom's current rain map was brought into use in 2001 it tended to over-estimate the 0.01% rate compared to the 20-year trends found in this study. Since then the degree of over-estimation has decreased due to rising 0.01% rates. By 2015 the Ofcom map is expected still to over-estimate the 0.01% rate over most of the UK, although by then there will be smaller but increasing areas where it under-estimates.

A new UK rain map has been prepared of the rain rate expected to be exceeded for 0.01% time in the year 2015, based on the trends found in the analysis.

The 0.01% rate is increasing sufficiently rapidly, approaching 0.8 mm/h per year in some places, that it would be advisable to update the analysis of rainfall data on a regular basis. This would be facilitated by standardising the format in which the required data can be downloaded from the agencies involved in making the measurements.

Back to top