Development of a Local Urban Climate model and its application to the Intelligent Design of cities

Cities worldwide already face the challenge of increased thermal burdens due to the combined effect of global warming and urban heat island effects.

As half of the world population is now living in urban areas, there is an increasing awareness of how the local climate should inform urban design decisions.

According to current climate change projections, UK summers are expected to be longer and hotter, coupled with wetter and windier winters. The effects of extreme events have already been experienced in the UK; the 2003 heat wave posed a significant risk to the health and comfort of the UK. Importantly, overheating will be further exacerbated in large urban areas due to heat island effects.

The wider picture should also be considered - whilst urban warming in the UK will result in increased summertime cooling loads in buildings and increased heat-related mortality, it will also lead to decreased winter heating loads and fewer cold related deaths. The net effects of such phenomena need to be better understood. Appropriate tools, able to identify and quantify the effectiveness of various planning, building, energy and health policies need to be developed. Prior to the LUCID project, no practical methods for assessing and quantifying the impact of specific design decisions on the local climate had been established.

The tools and methodologies developed in the LUCID project have enabled the related impacts to be better understood, quantified and addressed. The work has involved the gathering and preparation of data to both drive and test the LUCID models, the development of urban climate models at a range of scales, the development of impact (comfort, health and energy) models, and the application of the models via a series of case studies at different scales.

People

PI: Michael Davies

Co-Is: Michael Batty, Phillip Steadman, Ben Croxford

Rs: James Milner, Zhihui Ye, Ian Hamilton, Anna Mavrogianni, Eleni Oikonomou and Christine Demanuele 

Output

A suite of local urban climate models was developed, spanning three scales; citywide, neighbourhood and street. Site-specific weather data from the local urban climate models was fed into a suite of impact assessment models:

• Energy – A housing stock energy model was developed to assess the impact of the London heat island on variations in domestic heat demand.
• Comfort – Dynamic thermal modelling was used to quantify the impact of the heat island on indoor summer thermal comfort in free-running buildings.
• Health – The LUCID project also investigated the impact of the London heat island on mortality and the determinants of spatial variations in outdoor temperature during heat waves and preventable mortality.

The development of the methodological frameworks described above and their findings have been presented in over 30 peer-reviewed academic publications. A Summary for Policymakers highlighting the key messages emerging from the project was also produced. 

Impact

The LUCID work has been used by the Greater London Authority (GLA) to inform the development of the draft replacement London Plan and London’s Climate Change Adaptation Strategy, the final versions of which were published in 2011.

The LUCID project has helped the GLA to begin to develop better evidenced-based policies and programmes with respect to increasing resilience of the London built environment to a changing urban climate. For example, the outcomes of LUCID have informed the GLA’s urban greening programme, demonstrating that increasing green cover in the most developed areas of London can help to reduce the higher temperatures associated with the urban heat island effect. This has assisted the GLA in beginning to optimise the best mix of adaptation and mitigation measures and to target limited funding to where it will have most effect.

The LUCID team has also engaged with individual Local Authorities through the provision of high spatial resolution external temperature maps at the borough level. The project findings were included in the 2012 DEFRA Climate Change Risk Assessment: Built Environment Sector Report. 

Links

Read more about the LUCID project

For further information please contact: Michael Davies and Anna Mavrogianni