Constructing design weather data for future climates

We develop a method, here called ‘morphing’, to produce design weather data for building thermal simulations that accounts for future changes to climate. Morphing combines present-day observed weather data with results from climate models. The procedure yields weather time series that encapsulate the average weather conditions of future climate scenarios, whilst preserving realistic weather sequences. In this sense the method ‘downscales’ coarse resolution climate model predictions to the fine spatial and temporal resolutions required for building thermal simulations. The morphing procedure is illustrated by application to CIBSE design weather years and climate change scenarios for the UK. Heating degree days calculated from the weather series morphed to future climates show a marked reduction compared to present day, by an amount that agrees well with results calculated directly from the climate model. This agreement gives confidence that the morphing technique faithfully transforms the weather sequences. Practical application: There is overwhelming consensus amongst the scientific community that the Earth's climate is warming. This warming will have implications for building services in the UK that should be considered now. This article describes a method for producing weather data with best current estimates of future climate that can be used to quantify the risk of building overheating.