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Biogeophysical impacts of land use on present-day climate: near-surface temperature change and radiative forcing
"Urban Meteorology And Air Quality" Meeting 21st March 2001, University of Birmingham
Despite the snow and disruption to the transport networks, a healthy audience of 55 witnessed an excellent meeting on a topical theme. The Royal Meteorological Society is actively seeking to hold more of their meetings outside London, to give their regional members an opportunity to save time and money. So far the response has been encouraging and it is to be hoped that even more regional members will support this initiative and attend the Second National Conference at UMIST in Manchester (12 - 14 September). Dr Burridge, the President of the Royal Meteorological Society, opened the meeting and welcomed those who had braved the weather. Dr Thornes (University of Birmingham), the meeting organiser, gave an overview of the NERC URGENT (Urban Regeneration and the Environment) research programme, which has funded more than 20 projects on the West Midlands (see http://www.urgent.nerc.ac.uk). The meeting would report results from several of the projects relating to weather, climate and air quality in the West Midlands and elsewhere. Dr Thornes then gave the first presentation entitled The Thermal Climatology of Urban Areas. A one-dimensional road surface energy balance model has been modified using a GIS (geographical information system) to account for the geographical variables of latitude, optical depth, sky-view factor, slope and slope orientation for the West Midlands. The physical variables of albedo, emissivity and surface roughness are also included. Using a satellite landcover classification, aided by a field analysis of urban canyon characteristics, it has been possible to estimate the spatial variety of surface variables across the West Midlands. Winter Solstice heat island intensity for calm clear nights in the West Midlands is calculated to be 4.7°C. A new method of Sky View Factor analysis has also been developed using GPS (global positioning system) to assess the variation in urban canyon geometry across cities. Dr Belcher (University of Reading) - The Dynamics of Urban Meteorology - gave a very understandable account of an urban canopy model which is being developed to describe the temporal and spatial variations of wind and air temperature over cities. The results from this urban modelling can then be used for local forecasting, parameterization of NWP (numerical weather prediction) and in studies of air pollution transport and mixing in cities. The urban canopy model has been developed to work at scales from street canyons to conurbations. The results are encouraging and show that wind direction is also important. Dr Cai (University of Birmingham) - Using RAMS/UAM to Model Air Quality - described clearly the development of a mesoscale model for the West Midlands using RAMS/UAM (Regional Atmospheric Modelling System/Urban Airshed Model). The output of the model ©2001 Royal Meteorological Society
has been tested against data collected by the PUMA (Pollution of Urban Midland Atmosphere) summer field campaign measuring meteorological conditions and atmospheric pollution. Retrospective results were presented for a photochemical pollution event and for days when there was a significant shift in wind direction and air temperature. Further developments and trials are taking place so that the model should be able to predict air pollution events, for a variety of pollutants, up to 24 hours ahead. Dr Gallagher (University of Manchester Institute of Science and Technology UMIST) Aerosol Fluxes - sources, sinks and methodologies for urban measurement - gave a fascinating summary of results from a study in Edinburgh measuring urban aerosols directly above Princess Street. The study attempted to provide addition information as to the sources of urban aerosols on a larger urban scale than hitherto undertaken. These measurements complement existing street level measurements that are now widely made in urban areas across the UK in order to identify likely sources. The study distinguishes between particle numbers, size of particles and their mass. This will enable methodologies to be developed to obtain net urban particle emissions for comparison with inventory and indirect techniques. Professor Harrison (University of Birmingham) - Urban Air Quality and the NERC Urgent Programme - gave an excellent overview of the atmospheric science research within the NERC URGENT programme and how it is geared to user needs. He then concentrated on the measurement and inventory of sources of fine (< 2.5 µm) and coarse particles. He concluded that whilst PM2.5 is largely accounted for by secondary particles and vehicle emissions, resuspended soil and dust in coarse particles require quantification. Also secondary organic particles are important in the summer months, and that sodium chloride (road salt or marine aerosol) makes an important contribution to coarse particle mass in the winter. Professor Julian Hunt (University College, London) - Modelling Air Flow Over Cities entertained the audience with a series of unique hand-drawn overheads that Picasso would have been proud of! He demonstrated graphically how the topography surrounding urban areas is very important (especially in cities like Phoenix, Arizona) as well as the climatic location. It was a perfect end to an enjoyable meeting and despite the weather not a soul left the meeting early.
Dr John Thornes University of Birmingham
Despite the snow and disruption to the transport networks, a healthy audience of 55 witnessed an excellent meeting on a topical theme. The Royal Meteorological Society is actively seeking to hold more of their meetings outside London, to give their regional members an opportunity to save time and money. So far the response has been encouraging and it is to be hoped that even more regional members will support this initiative and attend the Second National Conference at UMIST in Manchester (12 - 14 September). Dr Burridge, the President of the Royal Meteorological Society, opened the meeting and welcomed those who had braved the weather. Dr Thornes (University of Birmingham), the meeting organiser, gave an overview of the NERC URGENT (Urban Regeneration and the Environment) research programme, which has funded more than 20 projects on the West Midlands (see http://www.urgent.nerc.ac.uk). The meeting would report results from several of the projects relating to weather, climate and air quality in the West Midlands and elsewhere. Dr Thornes then gave the first presentation entitled The Thermal Climatology of Urban Areas. A one-dimensional road surface energy balance model has been modified using a GIS (geographical information system) to account for the geographical variables of latitude, optical depth, sky-view factor, slope and slope orientation for the West Midlands. The physical variables of albedo, emissivity and surface roughness are also included. Using a satellite landcover classification, aided by a field analysis of urban canyon characteristics, it has been possible to estimate the spatial variety of surface variables across the West Midlands. Winter Solstice heat island intensity for calm clear nights in the West Midlands is calculated to be 4.7°C. A new method of Sky View Factor analysis has also been developed using GPS (global positioning system) to assess the variation in urban canyon geometry across cities. Dr Belcher (University of Reading) - The Dynamics of Urban Meteorology - gave a very understandable account of an urban canopy model which is being developed to describe the temporal and spatial variations of wind and air temperature over cities. The results from this urban modelling can then be used for local forecasting, parameterization of NWP (numerical weather prediction) and in studies of air pollution transport and mixing in cities. The urban canopy model has been developed to work at scales from street canyons to conurbations. The results are encouraging and show that wind direction is also important. Dr Cai (University of Birmingham) - Using RAMS/UAM to Model Air Quality - described clearly the development of a mesoscale model for the West Midlands using RAMS/UAM (Regional Atmospheric Modelling System/Urban Airshed Model). The output of the model ©2001 Royal Meteorological Society
has been tested against data collected by the PUMA (Pollution of Urban Midland Atmosphere) summer field campaign measuring meteorological conditions and atmospheric pollution. Retrospective results were presented for a photochemical pollution event and for days when there was a significant shift in wind direction and air temperature. Further developments and trials are taking place so that the model should be able to predict air pollution events, for a variety of pollutants, up to 24 hours ahead. Dr Gallagher (University of Manchester Institute of Science and Technology UMIST) Aerosol Fluxes - sources, sinks and methodologies for urban measurement - gave a fascinating summary of results from a study in Edinburgh measuring urban aerosols directly above Princess Street. The study attempted to provide addition information as to the sources of urban aerosols on a larger urban scale than hitherto undertaken. These measurements complement existing street level measurements that are now widely made in urban areas across the UK in order to identify likely sources. The study distinguishes between particle numbers, size of particles and their mass. This will enable methodologies to be developed to obtain net urban particle emissions for comparison with inventory and indirect techniques. Professor Harrison (University of Birmingham) - Urban Air Quality and the NERC Urgent Programme - gave an excellent overview of the atmospheric science research within the NERC URGENT programme and how it is geared to user needs. He then concentrated on the measurement and inventory of sources of fine (< 2.5 µm) and coarse particles. He concluded that whilst PM2.5 is largely accounted for by secondary particles and vehicle emissions, resuspended soil and dust in coarse particles require quantification. Also secondary organic particles are important in the summer months, and that sodium chloride (road salt or marine aerosol) makes an important contribution to coarse particle mass in the winter. Professor Julian Hunt (University College, London) - Modelling Air Flow Over Cities entertained the audience with a series of unique hand-drawn overheads that Picasso would have been proud of! He demonstrated graphically how the topography surrounding urban areas is very important (especially in cities like Phoenix, Arizona) as well as the climatic location. It was a perfect end to an enjoyable meeting and despite the weather not a soul left the meeting early.
Dr John Thornes University of Birmingham