Air pollution meteorology
Several areas in New Zealand experience significant levels of air pollution largely due to localised factors, such as local weather and climate, topography and emission characteristics. Operational models used to predict levels of air pollution at this scale are frequently inadequate as they are unable to handle the complex nature of the terrain and the influence of varying surface characteristics. This is of particular concern to those involved with environmental management. Complicating factors include complexity in the thermal structure of the lower atmosphere, as well as related local wind circulations that can inhibit dispersion of pollutants.
A major aim of our research in air pollution meteorology is therefore to improve knowledge of the relevant processes that operate at and immediately above the ground, and their influence on atmospheric dispersion in complex local wind environments. However, the research also allows us to evaluate modelling as a tool for the management and amelioration of air quality problems.
The research conducted in the Geography Department has included in-depth investigation of boundary layer influences on urban air pollution in the Christchurch area. The management of this environmental problem relies on a clear understanding of the factors that contribute to the spatial and temporal variability of surface exchange of heat and air pollutants, and local to regional scale atmospheric dispersion processes. The research builds on our parallel programme of research in the area of local and regional wind systems and is of current international interest.
Specific aspects of our research programme have included:
- field investigation of the evolution of wind and temperature structures over Christchurch and other local cities (such as Timaru) during high air pollution events.
- field investigation of vertical profiles of particulate pollution and the factors that contribute to layering of pollutants in an environment affected by complex interaction of local wind systems.
- analysis of spatial patterns of air pollutants (particularly particulate material) measured at multiple surface sites, to identify the main factors affecting dispersion.
- the application of a range of different mesoscale atmospheric models (e.g. WRF, MM5, TAPM) to the dispersion of air pollutants over the city and the evaluation of their effectiveness.
- the use of modelling techniques to address air quality management and environmental problems.