Urban Meteorology S. E. Belcher Department of Meteorology, University of Reading A. Agusti-Panareda, J. F. Barlow, M. J. Best, O. Coceal, S. L. Gray, I. N. Harman,

04/03/03Urban Meteorology at Reading2 Snapshot of current UK science –Urban Meteorology –Dispersion in urban areas 10 presentations, 90 attendees

04/03/03Urban Meteorology at Reading3 UWERN Strategy Grand science challenge: To develop scientific understanding to –Forecast air quality up to 5 days ahead –Assimilates observations from the air quality network

04/03/03Urban Meteorology at Reading4 Representation in NWP Urban energy balance Friction drag Mixed layer ln(z) Logarithmic velocity profile Roughness sub-layer Surface layer Surface layer: –z 0 and d –L MO and H

04/03/03Urban Meteorology at Reading5 Street circulations Louka, Belcher & Harrison 2000 Hall Farm Salfex DAPPLE

04/03/03Urban Meteorology at Reading6 Ventilation from streets Lab technique Barlow & Belcher 2002; Barlow, Belcher & Harman; Harman, Barlow & Belcher

04/03/03Urban Meteorology at Reading7 h y x Urban canopy model Belcher, Jerram & Hunt; Coceal & Belcher Spatially averaged flow Neighbourhood scale

04/03/038 Ventilation of boundary layer by: Warm and cold conveyor belts in extratropical cyclones Stacked slantwise convective circulations Shear instability and turbulent mixing Mixing and transport by fronts From Bader et al. (1995) From Browning et al. (2001) Range (km) Height (km) Doppler velocity perpendicular to an approaching cold front

04/03/03Urban Meteorology at Reading9 Summary Street-scale –Controls ventilation of street –Controls urban energy balance Neighbourhood scale –Bridge between street and city scales –Efficient model based on spatial average –Potential for use in NWP Regional scale –Fronts ventilate boundary layer