The Development of a Local Urban Climate Model and its Application to the Intelligent Development of Cities (LUCID)

Lead Research Organisation: University College London
Department Name: Bartlett Sch of Graduate Studies


This project will develop world leading methods for calculating local temperature and air quality in the urban environment. The impact on energy use and the consequences for health of a changing climate will then be explored. The implications for urban planning will be considered in detail. Such methods applied to urban areas would contribute greatly to the generation of guidance in planning process and such modelling is seen as essential to estimate and predict the transition from the present unsuitable practices to more sustainable urban communitiesThere is overwhelming consensus that the climate is warming and an increasing recognition that decisions made now need to be informed by how the local climate will change. Current projections for the UK are for longer, hotter summers and wetter, windier winters, with the South-East warming by between 2.5oC and 4 oC by the 2080s. A change of this magnitude, particularly in summer will lead to much increased prevalence of overheating inside buildings. Humidity is also predicted to increase during the summers limiting the ability to cool buildings through natural ventilation. The frequency of summer days when there are very warm temperatures above 30oC will increase and associated urban heat island effects will lead to frequent extreme temperatures especially in large urban areas. Adapting to and ameliorating such dangerous conditions, whose deadly affects have recently been experienced, for instance in Chicago in 1995, in Greece in 2001 and in France in 2003, will require appropriate policies of urban planning, housing and transport. But before these policies can be developed, quantitative tools are required to identify and quantify the effectiveness of mitigation and adaptation strategies.Increased mortality clearly represents an extreme consequence of rising temperatures. However, it is clear that the proportion of the time that people will feel 'uncomfortable' has the potential to increase. This raises the possibility of a large increase in the use of mechanical cooling systems and a consequent rise in energy use, particularly in urban areas. Higher temperatures associated with the urban heat island are expected to make things worse. In particular, one strategy for passive cooling of buildings is through storing heat within the building fabric during the day and cooling through ventilation at night. But this method relies on the night time temperatures being sufficiently low. The urban heat island is typically most pronounced at night, and so it is important to know whether or not this method remains viable. Buildings both respond to and contribute to the local microclimate. Effective building design requires a knowledge of, and ways of dealing with, this microclimate. What is the way ahead? Currently, methods exist to estimate the broad magnitude of excess temperatures in urban areas and there have been some measurement campaigns. However, there are no established practical methods or tools for assessing the impact of local planning decisions (land use, building-layout orientation and design, size of open spaces or parks) on the fine details of the local climate. This project then will develop and test state-of-the-art methods for calculating local climate and air quality in the urban environment. The impact on the internal built environment, energy use and the consequences for health will then be explored. The implications for urban planning will be considered in detail.This proposal brings together a new consortium of meteorologists, building scientists, urban modellers, planners, urban and building designers and epidemiologists to research how cities can adapt to a changing climate. The proposal effectively unites two consortia / model developers and model users / in a most coherent manner.
Description There is overwhelming scientific consensus that the climate is changing. Many cities worldwide already face the challenge of increased thermal burdens due to the combined effect of global warming and urban heat island (UHI) effects. As half of the world's 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 recently been experienced in the UK; the 2003 heat wave posed a significant risk to the health and comfort of the UK population and the increase in excess heat-related deaths during the heat wave period was 17% in England and Wales. By the 2050s, increased ambient air temperatures are projected to result in 'heat wave periods' occurring during most summers. This warming places an increasing burden on demands to maintain safe and comfortable temperatures within buildings.

Importantly, overheating will be further exacerbated in large urban areas due to heat island effects. A study of daily mortality in all regions of England and Wales between 1993 and 2003 found that whilst risk of mortality was observed for heat exposure in all regions, the strongest heat effects were in London. 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 thus enabled the related impacts to be better understood, quantified and addressed. The work has involved:
(1) the gathering and preparation of data to both drive and test the LUCID models
(2) the development of urban climate models at a range of scales
(3) the development of 'impact' (comfort, health and energy) models
(4) the application of the models via a series of case studies at different scales

The main messages that evolved from the urban climate modelling component of LUCID are:
• Urban land-use distribution is key to urban temperatures
• London's current scattered greening cools London
• Advection is important
• To affect the city-scale UHI the greening needs to be on a large scale
• Building form has a moderate impact on urban temperatures
• Anthropogenic heating is likely to be important
• Increasing the albedo of urban surfaces leads to daytime cooling

The key messages that evolved from the 'impact' modelling component of LUCID are:
- The UHI currently has a significant net energy benefit for London.
- This balance will depend critically on future uptake of air conditioning
- The thermal quality of dwellings seems more important than the location within the UHI area
- The current stock is vulnerable to heat
- There is some relationship between overheating and distance from centre
- There is a significant impact of very local microclimatic effects
- UHI has significant impact on mortality
- There are indications however, that the geometry and thermal quality of a building are of greater importance than the location of the building within the UHI
Exploitation Route Stakeholder view: Greater London Authority

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 Mayor's vision for London is for the capital to be the 'best big city in the world'. A key part of achieving the Mayor's vision is our commitment to tackle climate change - both by reducing London's carbon emissions by 60% by 2030 and preparing London for the impacts of climate change and extreme weather. Achieving this vision will be challenging as we work with the legacy of Victorian buildings and infrastructure, a planning system that has little influence on existing development and a climate of financial efficiency savings in the public sector.
A key element of reducing London's carbon emissions and increasing our resilience to climate change is to improve the energy and water efficiency of London's existing buildings. The Mayor has developed a number of large-scale programmes to tackle both domestic and non-domestic buildings. The RE:NEW programme unites the London Boroughs to work with the GLA on retrofitting up to 1.2 million homes by 2015, the RE:FIT programme looks at retrofitting public sector buildings and the RE:CONNECT programme works in 10 areas to create low carbon communities. We are also working with the 16 biggest commercial landlords in London to improve their estates.
We also need to ensure that we are adapting the city to warmer, wetter winters and hotter, drier summers, and that the current emphasis on reducing emissions doesn't foreclose any adaptation options, or increase our vulnerability. We need to understand how to manage the urban heat island at citywide, neighbourhood, street and individual building scales. Our urban greening programme seeks to increase the amount of greencover in London to help cool the city and absorb rainwater, but we need to ensure that it is targeted where most effective.
The LUCID project has helped us to begin to develop better evidenced-based policies and programmes with respect to the above. For example, the outcomes of LUCID have informed our 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. Research from the LUCID project has assisted us in beginning to optimise the best mix of adaptation and mitigation measures and to target limited funding to where it will have most effect.
Sectors Construction,Energy,Environment

Description The LUCID work has been used by the Greater London Authority (GLA) to inform the development of the versions of the London Plan and London's Climate Change Adaptation Strategy that were published in 2011.
First Year Of Impact 2011
Sector Environment
Impact Types Societal

Title Modelling of London's Heat Island Impacts 
Description A suite of local urban climate models was developed, spanning three scales: a) citywide, b) neighbourhood and c) street level. Citywide scale The London Unified Model (LondUM) is a set-up of the Met Office Unified Model (MetUM) - a numerical weather prediction model. LondUM tiles represent the earth's surface with different types of vegetated and non-vegetated surfaces - then calculates the impact that the surface properties (e.g. albedo, emissivity and thermal heat capacity) have on the local climate. LondUM can model the London urban heat island, including the effect of variables like urban materials, land use and anthropogenic heat. The London Site Specific Air Temperature (LSSAT) prediction model is composed of a series of Artificial Neural Network (ANN) models that predict site specific hourly air temperatures within the Greater London area, compared to Heathrow weather. Neighbourhood scale The Atmospheric Dispersion Modelling System (ADMS) calculates profiles of the mean airflow and turbulence in the atmospheric boundary layer, taking into account local variations in terrain height and geometry and accounts for local diurnal storage of heat. Street scale OutdoorROOM is a Surface Energy Balance (SEB) model intended to be used for smaller scale studies, for example sensitivity studies for building and development design. It is based on a combination of a thermal resistance model used to examine thermal comfort in internal building spaces and an urban canyon air flow model. 
Type Of Material Computer model/algorithm 
Provided To Others? No  
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. 
Description Stakeholder meeting 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Policymakers/politicians
Results and Impact A diverse group of stakeholders discussed how the outputs from the LUCID project could be tailored to suit their needs.
Year(s) Of Engagement Activity 2010