Changes in the annual cycle of heavy precipitation across the British Isles within the 21st century
We investigate future changes in the annual cycle of heavy daily precipitation events across the 
British Isles in the periods 2021–2060 and 2061–2100, relative to present day climate. Twelve 
combinations of regional and global climate models forced with the A1B scenario are used. 
The annual cycle is modelled as an inhomogeneous Poisson process with sinusoidal models 
for location and scale parameters of the generalized extreme value distribution. Although the 
peak times of the annual cycle vary considerably between projections for the 2061–2100 
period, a robust shift towards later peak times is found for the south-east, while in the 
north-west there is evidence for a shift towards earlier peak times. In the remaining parts of the 
British Isles no changes in the peak times are projected. For 2021–2060 this signal is weak. 
The annual cycle’s relative amplitude shows no robust signal, where differences in projected 
changes are dominated by global climate model differences. The relative contribution of 
anthropogenic forcing and internal climate variability to changes in the relative amplitude 
cannot be identified with the available ensemble. The results might be relevant for the 
development of adequate risk-reduction strategies, for insurance companies and for the 
management and planning of water resources