The UFAM (Universities Facility for Atmospheric Measurement) infrared Doppler lidar, owned by the University of Salford, has been utilised to make measurements within the urban environment enabling a range of boundary layer parameters including boundary layer depth to be derived.  An intercomparison with balloon-borne in situ turbulence instrumentation at a rural site in September 2002 has enabled the precision of the lidar to be determined, giving confidence in the reliability of the lidar data, an important step towards utilising the instrument in field campaigns.  The accuracy of the lidar system will be discussed along with measurements made during urban field campaigns over the conurbations of Salford, Greater Manchester and West London.  Emphasis will be placed on the spatial variation in boundary layer depth which may be associated with the heterogeneity of the urban surface under particular stability conditions. 

Lidar measurements have been made during several days in May 2002 and November 2003 over the urban conurbation of Salford, Greater Manchester.   The lidar system was situated approximately 3 km from Salford city centre which lies to the south west and 4 km from Manchester city centre situated to the south east.  The field of view to the south of the lidar location covered the River Irwell flood plane with two storey terraced housing to the east and west of the lidar location.  The lidar was positioned at a height of 20 m above the terrain to the south east through to the south west. 

An urban field campaign was undertaken in West London as part of the UK HM Treasury Invest to Save Budget (ISB52) funded project which explores the use of Doppler lidar for improving air quality studies.  The aim of the project is the improvement of air quality forecasting through the use of dual Doppler lidar data.  Two identical Doppler lidar systems (QinetiQ and UFAM) were operated simultaneously to provide measurements of the three-dimensional wind field and turbulence over an urban area centred on RAF Northolt which lies approximately 20 km west of central London.  The field campaign took place in July 2003 and the dual Doppler lidar data has been used to produce flow visualisations by the University of Essex, with the aim of improving the UK Met Office models of local air flow and thus providing a better prediction of pollution concentration and dispersal.  The area surrounding RAF Northolt consists of a more rural sector from the north east anticlockwise to the south east, whilst the north clockwise to the south is more urban consisting mainly of two storey residential buildings.  Observations of boundary layer depth made in West London showed differences of up to 800 m over a distance of 9 km along this urban/rural transition zone.