ASSURE: Across-Scale processeS in URban Environments

Lead Research Organisation: University of Reading
Department Name: Meteorology


Local and global consequences of climate change (enhanced urban heat islands, worsening environmental conditions) affect most of the world's urban population, but only recently have cities been represented, albeit crudely, in weather forecast models. To manage and develop sustainable, resilient and healthy cities requires improved forecasting and observations that cross neighbourhood-influenced scales which the next generation weather forecast models need to resolve. ASSURE addresses the critical issue of which processes need to be parameterised, and which resolved, to capture urban heterogeneity in space and time.

We will advance understanding to develop new approaches and parameterisations for larger-scale urban meteorological and dispersion models by combining the results of field observations, high-resolution numerical simulations and wind tunnel experiments. Field work and modelling will focus on Bristol, as its physical geography provides suitably high levels of complexity and allows whole-city approaches. With mid-sized cities being large sources of greenhouse gases, and where large numbers of people live, it is critical agencies can provide predictions of weather and climate variability across cities of this scale as they need this information to manage and provide their services. ASSURE will include idealised simulations and theoretical analyses to ensure generic applicability.

The ASSURE objectives are:
* To understand how sources of urban heterogeneity (physical setting, layout of buildings and neighbourhoods, human activities) combine to influence the urban atmosphere in space and time.
* To quantify effects of urban heterogeneity at different scales (street to neighbourhood, to city and beyond) on flow, temperature, moisture and air quality controlling processes and to determine how these processes interact.
* To develop a theoretical framework that captures key processes and feedbacks with reduced complexity to aid mesoscale and larger model parameterisations.
* To inform the development priorities of current weather and climate models that have meso-scale capabilities and are used in decision-making processes (e.g. integrated urban services).

The ASSURE high-fidelity simulations and carefully designed experiments will allow us to explore implications of urban heterogeneity in isolated and combined configurations; interpret and integrate field observations (e.g. 3D meteorological and city-scale tracer dispersion experiments); integrate different approaches to understand the magnitude, source, and geographical extent of uncertainties in process models at different scales; synthesize the new knowledge to conduct theoretical analyses; develop algorithms reflecting this analysis.

Novel in ASSURE are simulations resolving street to city-scale features that are linked to mesoscale models; field observations capturing vertical and horizontal variations in the urban boundary- and canopy-layers, including novel multi-source gas tracer experiments; and wind tunnel simulations across atmospheric stabilities and model resolution. New insights will be gained on the role of variations in the building morphology (or form), local topography, and human activities (e.g. waste heat, and AQ emissions).

ASSURE will produce detailed datasets; in-depth understanding across the scale of atmospheric processes involved; high-fidelity multiscale urban modelling tools; theoretical models taking account of multiscale effects; improved assessment of current meso-scale model skill and the data used by practitioners to explore future urban scenarios as city form and function change.

We will work with local and international organisations and companies to ensure the project benefits a broad range of society. They include: Avon Longitudinal Study of Parents and Children, CERC, COWI, ECMWF, Met Office, Delft University of Technology, Stanford University, University Hannover, RWDI, Surrey Sensors and UKCRIC.


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Melo A (2023) Influence of wind direction and source location on peak-to-mean concentration ratios in urban environments in Journal of Wind Engineering and Industrial Aerodynamics

Description ALSPAC (Avon Longitudinal Study of Parents and Children) 
Organisation University of Bristol
Department Avon Longitudinal Study of Parents and Children (ALSPAC)
Country United Kingdom 
Sector Academic/University 
PI Contribution We are providing data on airflow through the Bristol urban airshed and this will help ALSPAC interpret their datasets.
Collaborator Contribution ALSPAC have a database on health outcomes of over 4000 people and their children living in Bristol from ca. 1990. These data, coupled with data we will generate on air flow and air pollution in Bristol will allow us to carry out air- pollution - health studies.
Impact On-going as project just started
Start Year 2022
Description Bristol City Council 
Organisation Bristol City Council
Country United Kingdom 
Sector Public 
PI Contribution Bristol City Council have an air quality unit that set policy for the city regarding air pollution. The data from this project will inform them regarding on-going policy
Collaborator Contribution Bristol City Council make measurements of air pollutants throughout the city and these data will be made available. In addition, access to sites to use to house measurement equipment.
Impact None yet
Start Year 2022
Description ECMWF 
Organisation European Centre for Medium Range Weather Forecasting ECMWF
Country United Kingdom 
Sector Public 
PI Contribution Model Development Model runs
Collaborator Contribution Model Evaluations Observations
Impact Stretton: Publications Frid: ASSURE:
Start Year 2017
Description Met Office 
Organisation Meteorological Office UK
Country United Kingdom 
Sector Academic/University 
PI Contribution Model evaluation Model development Observations
Collaborator Contribution Model development Model output data
Impact ASSURE - preparation for model evaluation AerFO
Start Year 2007
Description Magazine article 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Activity: interview leading to magazine article in Building Engineer titled "Measuring and mitigating city microclimates".
Year(s) Of Engagement Activity 2022
Description Partner Meeting 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Activity: Online set of presentations
Intended purpose: Outline the ASSURE project and get Partners engaged
Outcome: more detailed discussion of possible interactions/activities
Year(s) Of Engagement Activity 2022
Description urbsiphere and Partners in Bristol 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Bristol partners and International partners
- visited many sites
- learnt about many data sets partners have gathered
- encourage international partner to work in Bristol
Year(s) Of Engagement Activity 2023