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Papers by Christine Susan B Grimmond
International Journal of Climatology, 2007
Urban Air Quality — Recent Advances, 2002
Recent advances in understanding of the surface energy balance of urban areas, based on both expe... more Recent advances in understanding of the surface energy balance of urban areas, based on both experimental investigations and numerical models, are reviewed. Particular attention is directed to the outcome of a COST-715 Expert Meeting held in April 2000, as well as experiments initiated by that action. In addition, recent complete parameterisations of urban effects in meso-scale models are reviewed. Given that neither the surface energy balance, nor its components, normally are directly measured at meteorological stations, nor are there guidelines for the setup of representative meteorological stations in urban areas, this paper also provides recommendations to close these gaps.
Understanding Urban Metabolism addresses the gap between the bio-physical sciences and urban plan... more Understanding Urban Metabolism addresses the gap between the bio-physical sciences and urban planning and illustrates the advantages of accounting for urban metabolism issues in urban design decisions. Urban metabolism considers a city as a system, and distinguishes between energy and material flows as its components. Based on research from the BRIDGE project, this book deals with how the urban surface exchanges and transforms energy, water, carbon and pollutants in cities. This book also introduces a new method for evaluating how planning alternatives can modify the physical flows of urban metabolism components and how environmental and socioeconomic components interact. The inclusion of sustainability principles into urban planning provides an opportunity to place the new knowledge provided by bio-physical sciences at the centre of the planning process, but there is a strong need to bridge knowledge and practice, as well as for a better dissemination of research results and exchan...
Theoretical and Applied Climatology, 2011
Abstract The solar and longwave environmental irradiance geometry (SOLWEIG) model simulates spati... more Abstract The solar and longwave environmental irradiance geometry (SOLWEIG) model simulates spatial variations of 3-D radiation fluxes and mean radiant temperature (T mrt) as well as shadow patterns in complex urban settings. In this paper, a new vegetation scheme is included in SOLWEIG and evaluated. The new shadow casting algorithm for complex vegetation structures makes it possible to obtain continuous images of shadow patterns and sky view factors taking both buildings and vegetation into account. For the calculation of 3- ...
Quarterly Journal of the Royal Meteorological Society, 2010
† The contribution of Martin Best was written during the course of his employment at the Met Offi... more † The contribution of Martin Best was written during the course of his employment at the Met Office, UK and is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland For an increasing number of applications, mesoscale modelling systems now aim to better represent urban areas. The complexity of processes resolved by urban parametrization schemes varies with the application. The concept of fitness-forpurpose is therefore critical for both the choice of parametrizations and the way in which the scheme should be evaluated. A systematic and objective model response analysis procedure (Multiobjective Shuffled Complex Evolution Metropolis (MOSCEM) algorithm) is used to assess the fitness of the single-layer urban canopy parametrization implemented in the Weather Research and Forecasting (WRF) model. The scheme is evaluated regarding its ability to simulate observed surface energy fluxes and the sensitivity to input parameters. Recent amendments are described, focussing on features which improve its applicability to numerical weather prediction, such as a reduced and physically more meaningful list of input parameters. The study shows a high sensitivity of the scheme to parameters characterizing roof properties in contrast to a low response to road-related ones. Problems in partitioning of energy between turbulent sensible and latent heat fluxes are also emphasized. Some initial guidelines to prioritize efforts to obtain urban land-cover class characteristics in WRF are provided.
Journal of Applied Meteorology and Climatology, 2011
Recent developments to the Local-scale Urban Meteorological Parameterization Scheme (LUMPS), a si... more Recent developments to the Local-scale Urban Meteorological Parameterization Scheme (LUMPS), a simple model able to simulate the urban energy balance, are presented. The major development is the coupling of LUMPS to the Net All-Wave Radiation Parameterization (NARP). Other enhancements include that the model now accounts for the changing availability of water at the surface, seasonal variations of active vegetation, and the anthropogenic heat flux, while maintaining the need for only commonly available meteorological observations and basic surface characteristics. The incoming component of the longwave radiation (L↓) in NARP is improved through a simple relation derived using cloud cover observations from a ceilometer collected in central London, England. The new L↓ formulation is evaluated with two independent multiyear datasets (Łódź, Poland, and Baltimore, Maryland) and compared with alternatives that include the original NARP and a simpler one using the National Climatic Data Ce...
Journal of Applied Meteorology and Climatology, 2010
A large number of urban surface energy balance models now exist with different assumptions about ... more A large number of urban surface energy balance models now exist with different assumptions about the important features of the surface and exchange processes that need to be incorporated. To date, no comparison of these models has been conducted; in contrast, models for natural surfaces have been compared extensively as part of the Project for Intercomparison of Land-surface Parameterization Schemes. Here, the methods and first results from an extensive international comparison of 33 models are presented. The aim of the comparison overall is to understand the complexity required to model energy and water exchanges in urban areas. The degree of complexity included in the models is outlined and impacts on model performance are discussed. During the comparison there have been significant developments in the models with resulting improvements in performance (root-mean-square error falling by up to two-thirds). Evaluation is based on a dataset containing net all-wave radiation, sensible ...
International Journal of Climatology, 2011
To bridge the gaps between traditional mesoscale modelling and microscale modelling, the National... more To bridge the gaps between traditional mesoscale modelling and microscale modelling, the National Center for Atmospheric Research, in collaboration with other agencies and research groups, has developed an integrated urban modelling system coupled to the weather research and forecasting (WRF) model as a community tool to address urban environmental issues. The core of this WRF/urban modelling system consists of the following: (1) three methods with different degrees of freedom to parameterize urban surface processes, ranging from a simple bulk parameterization to a sophisticated multi-layer urban canopy model with an indoor-outdoor exchange sub-model that directly interacts with the atmospheric boundary layer, (2) coupling to fine-scale computational fluid dynamic Reynolds-averaged Navier-Stokes and Large-Eddy simulation models for transport and dispersion (T&D) applications, (3) procedures to incorporate highresolution urban land use, building morphology, and anthropogenic heating data using the National Urban Database and Access Portal Tool (NUDAPT), and (4) an urbanized high-resolution land data assimilation system. This paper provides an overview of this modelling system; addresses the daunting challenges of initializing the coupled WRF/urban model and of specifying the potentially vast number of parameters required to execute the WRF/urban model; explores the model sensitivity to these urban parameters; and evaluates the ability of WRF/urban to capture urban heat islands, complex boundary-layer structures aloft, and urban plume T&D for several major metropolitan regions. Recent applications of this modelling system illustrate its promising utility, as a regional climate-modelling tool, to investigate impacts of future urbanization on regional meteorological conditions and on air quality under future climate change scenarios.
International Journal of Climatology, 2013
Where a licence is displayed above, please note the terms and conditions of the licence govern yo... more Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.
Urban Ecosystems, 1997
This paper is a review of research in Chicago that linked analyses of vegetation structure with f... more This paper is a review of research in Chicago that linked analyses of vegetation structure with forest functions and values. During 1991, the regions trees removed an estimated 5575 metric tons of air pollutants, providing air cleansing worth 9.2 million. Each year they sequester an estimated 315 800 metric tons of carbon. Increasing tree cover 10% or planting about three
Global Change Biology, 2002
Bulletin of the American Meteorological Society, 2013
Atmospheric Chemistry and Physics, 2011
Quarterly Journal of the Royal Meteorological Society
Sensible heat flux (QH) is a critical driver of surface and boundary layer meteorological process... more Sensible heat flux (QH) is a critical driver of surface and boundary layer meteorological processes, especially in urban areas. Aerodynamic resistance methods (ARM) to model QH are promising because, in principle, all that is needed is surface temperature (T0), air temperature (TA) and an aerodynamic resistance term (rH). There are significant challenges in urban areas however, due to uncertainties in satellite-derived land surface temperatures (LST), logistical challenges to obtain high-resolution air temperatures, and limited understanding of spatial and temporal variability of rH and associated variables (e.g. thermal roughness length). This work uses an extensive LST dataset covering six years (2011-2016) in central London and a long-term in situ observation network to analyse variability of LST and rH variables. Results show that LST is spatially correlated with building and vegetation land cover with coherent thermal structures at length scales less than 500-1000 m. Additionally, satellite-observed LST varies with average building height (up to 10% cooler in areas with tall buildings). The rH term and associated variables are observed to vary on daily and seasonal cycles and findings are used to model QH using five variations of an ARM-based approach on a 100 m pixel basis. Modelled QH is compared to observations from three scintillometer paths and an eddy covariance flux tower. We find generally good agreement between observations and models, though there is uncertainty in all methods (mean absolute error ranges from 58.1-129.3 W m-2) due to challenges in determining high-resolution meteorological and surface inputs, particularly LST and friction velocity (u*). Additional complexity in evaluating modelled QH arises from anthropogenic heat sources: long-term towerbased observations show that TA and radiometer-derived T0 are warmer during working weekdays than non-working days (up to 0.7C) and that there is an observed lag (2-3 hours) between energy consumption and observed warming and QH.
International Journal of Climatology, 2007
Urban Air Quality — Recent Advances, 2002
Recent advances in understanding of the surface energy balance of urban areas, based on both expe... more Recent advances in understanding of the surface energy balance of urban areas, based on both experimental investigations and numerical models, are reviewed. Particular attention is directed to the outcome of a COST-715 Expert Meeting held in April 2000, as well as experiments initiated by that action. In addition, recent complete parameterisations of urban effects in meso-scale models are reviewed. Given that neither the surface energy balance, nor its components, normally are directly measured at meteorological stations, nor are there guidelines for the setup of representative meteorological stations in urban areas, this paper also provides recommendations to close these gaps.
Understanding Urban Metabolism addresses the gap between the bio-physical sciences and urban plan... more Understanding Urban Metabolism addresses the gap between the bio-physical sciences and urban planning and illustrates the advantages of accounting for urban metabolism issues in urban design decisions. Urban metabolism considers a city as a system, and distinguishes between energy and material flows as its components. Based on research from the BRIDGE project, this book deals with how the urban surface exchanges and transforms energy, water, carbon and pollutants in cities. This book also introduces a new method for evaluating how planning alternatives can modify the physical flows of urban metabolism components and how environmental and socioeconomic components interact. The inclusion of sustainability principles into urban planning provides an opportunity to place the new knowledge provided by bio-physical sciences at the centre of the planning process, but there is a strong need to bridge knowledge and practice, as well as for a better dissemination of research results and exchan...
Theoretical and Applied Climatology, 2011
Abstract The solar and longwave environmental irradiance geometry (SOLWEIG) model simulates spati... more Abstract The solar and longwave environmental irradiance geometry (SOLWEIG) model simulates spatial variations of 3-D radiation fluxes and mean radiant temperature (T mrt) as well as shadow patterns in complex urban settings. In this paper, a new vegetation scheme is included in SOLWEIG and evaluated. The new shadow casting algorithm for complex vegetation structures makes it possible to obtain continuous images of shadow patterns and sky view factors taking both buildings and vegetation into account. For the calculation of 3- ...
Quarterly Journal of the Royal Meteorological Society, 2010
† The contribution of Martin Best was written during the course of his employment at the Met Offi... more † The contribution of Martin Best was written during the course of his employment at the Met Office, UK and is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland For an increasing number of applications, mesoscale modelling systems now aim to better represent urban areas. The complexity of processes resolved by urban parametrization schemes varies with the application. The concept of fitness-forpurpose is therefore critical for both the choice of parametrizations and the way in which the scheme should be evaluated. A systematic and objective model response analysis procedure (Multiobjective Shuffled Complex Evolution Metropolis (MOSCEM) algorithm) is used to assess the fitness of the single-layer urban canopy parametrization implemented in the Weather Research and Forecasting (WRF) model. The scheme is evaluated regarding its ability to simulate observed surface energy fluxes and the sensitivity to input parameters. Recent amendments are described, focussing on features which improve its applicability to numerical weather prediction, such as a reduced and physically more meaningful list of input parameters. The study shows a high sensitivity of the scheme to parameters characterizing roof properties in contrast to a low response to road-related ones. Problems in partitioning of energy between turbulent sensible and latent heat fluxes are also emphasized. Some initial guidelines to prioritize efforts to obtain urban land-cover class characteristics in WRF are provided.
Journal of Applied Meteorology and Climatology, 2011
Recent developments to the Local-scale Urban Meteorological Parameterization Scheme (LUMPS), a si... more Recent developments to the Local-scale Urban Meteorological Parameterization Scheme (LUMPS), a simple model able to simulate the urban energy balance, are presented. The major development is the coupling of LUMPS to the Net All-Wave Radiation Parameterization (NARP). Other enhancements include that the model now accounts for the changing availability of water at the surface, seasonal variations of active vegetation, and the anthropogenic heat flux, while maintaining the need for only commonly available meteorological observations and basic surface characteristics. The incoming component of the longwave radiation (L↓) in NARP is improved through a simple relation derived using cloud cover observations from a ceilometer collected in central London, England. The new L↓ formulation is evaluated with two independent multiyear datasets (Łódź, Poland, and Baltimore, Maryland) and compared with alternatives that include the original NARP and a simpler one using the National Climatic Data Ce...
Journal of Applied Meteorology and Climatology, 2010
A large number of urban surface energy balance models now exist with different assumptions about ... more A large number of urban surface energy balance models now exist with different assumptions about the important features of the surface and exchange processes that need to be incorporated. To date, no comparison of these models has been conducted; in contrast, models for natural surfaces have been compared extensively as part of the Project for Intercomparison of Land-surface Parameterization Schemes. Here, the methods and first results from an extensive international comparison of 33 models are presented. The aim of the comparison overall is to understand the complexity required to model energy and water exchanges in urban areas. The degree of complexity included in the models is outlined and impacts on model performance are discussed. During the comparison there have been significant developments in the models with resulting improvements in performance (root-mean-square error falling by up to two-thirds). Evaluation is based on a dataset containing net all-wave radiation, sensible ...
International Journal of Climatology, 2011
To bridge the gaps between traditional mesoscale modelling and microscale modelling, the National... more To bridge the gaps between traditional mesoscale modelling and microscale modelling, the National Center for Atmospheric Research, in collaboration with other agencies and research groups, has developed an integrated urban modelling system coupled to the weather research and forecasting (WRF) model as a community tool to address urban environmental issues. The core of this WRF/urban modelling system consists of the following: (1) three methods with different degrees of freedom to parameterize urban surface processes, ranging from a simple bulk parameterization to a sophisticated multi-layer urban canopy model with an indoor-outdoor exchange sub-model that directly interacts with the atmospheric boundary layer, (2) coupling to fine-scale computational fluid dynamic Reynolds-averaged Navier-Stokes and Large-Eddy simulation models for transport and dispersion (T&D) applications, (3) procedures to incorporate highresolution urban land use, building morphology, and anthropogenic heating data using the National Urban Database and Access Portal Tool (NUDAPT), and (4) an urbanized high-resolution land data assimilation system. This paper provides an overview of this modelling system; addresses the daunting challenges of initializing the coupled WRF/urban model and of specifying the potentially vast number of parameters required to execute the WRF/urban model; explores the model sensitivity to these urban parameters; and evaluates the ability of WRF/urban to capture urban heat islands, complex boundary-layer structures aloft, and urban plume T&D for several major metropolitan regions. Recent applications of this modelling system illustrate its promising utility, as a regional climate-modelling tool, to investigate impacts of future urbanization on regional meteorological conditions and on air quality under future climate change scenarios.
International Journal of Climatology, 2013
Where a licence is displayed above, please note the terms and conditions of the licence govern yo... more Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.
Urban Ecosystems, 1997
This paper is a review of research in Chicago that linked analyses of vegetation structure with f... more This paper is a review of research in Chicago that linked analyses of vegetation structure with forest functions and values. During 1991, the regions trees removed an estimated 5575 metric tons of air pollutants, providing air cleansing worth 9.2 million. Each year they sequester an estimated 315 800 metric tons of carbon. Increasing tree cover 10% or planting about three
Global Change Biology, 2002
Bulletin of the American Meteorological Society, 2013
Atmospheric Chemistry and Physics, 2011
Quarterly Journal of the Royal Meteorological Society
Sensible heat flux (QH) is a critical driver of surface and boundary layer meteorological process... more Sensible heat flux (QH) is a critical driver of surface and boundary layer meteorological processes, especially in urban areas. Aerodynamic resistance methods (ARM) to model QH are promising because, in principle, all that is needed is surface temperature (T0), air temperature (TA) and an aerodynamic resistance term (rH). There are significant challenges in urban areas however, due to uncertainties in satellite-derived land surface temperatures (LST), logistical challenges to obtain high-resolution air temperatures, and limited understanding of spatial and temporal variability of rH and associated variables (e.g. thermal roughness length). This work uses an extensive LST dataset covering six years (2011-2016) in central London and a long-term in situ observation network to analyse variability of LST and rH variables. Results show that LST is spatially correlated with building and vegetation land cover with coherent thermal structures at length scales less than 500-1000 m. Additionally, satellite-observed LST varies with average building height (up to 10% cooler in areas with tall buildings). The rH term and associated variables are observed to vary on daily and seasonal cycles and findings are used to model QH using five variations of an ARM-based approach on a 100 m pixel basis. Modelled QH is compared to observations from three scintillometer paths and an eddy covariance flux tower. We find generally good agreement between observations and models, though there is uncertainty in all methods (mean absolute error ranges from 58.1-129.3 W m-2) due to challenges in determining high-resolution meteorological and surface inputs, particularly LST and friction velocity (u*). Additional complexity in evaluating modelled QH arises from anthropogenic heat sources: long-term towerbased observations show that TA and radiometer-derived T0 are warmer during working weekdays than non-working days (up to 0.7C) and that there is an observed lag (2-3 hours) between energy consumption and observed warming and QH.