In order to predict environmental impacts it is therefore important to understand the geographic distribution of deposition. The group has worked in this area for a number of years. Field observations have been used to verify the accuracy of computer simulations of the physical processes that enhance deposition to upland regions. The major results concerning orographic enhancement and raindrop drift have been incorporated into national mapping procedures for wet deposition used by the Department of the Environment, Transport and the Regions . Additional research involves the investigation of the deposition of trace gases such as ozone to natural surfaces including forests using micrometeorological eddy correlation techniques.
Ozone can be injurious to vegetation at high concentrations.
This work also includes detailed modelling of turbulent transport of photochemically reacting species including oxides of nitrogen to and within forest canopies and emissions from forest soils which are an important natural source of background concentrations of nitrogen species in the atmosphere. This work also extends to measurements of greenhouse gas emissions at regional scales using the MRF's long range instrumental aircraft. The group is now heavily involved in work on atmospheric pollution in the urban environment. As an example we are currently undertaking a unique project to determine emissions of particles on cityscape scales using direct flux measurement techniques, the first attempt ever in the UK or Europe. To do this requires a combination of optical laser spectrometers for counting and sizing individual aerosol particles and high frequency turbulence measurements.