Title: Spatial representativeness evaluation of air quality monitoring sites by point-centred variography
Authors: Oliver Kracht; Michel Gerboles
Addresses: European Commission – Joint Research Centre, Directorate C – Energy, Transport and Climate, Air and Climate Unit, Via E. Fermi 2749, I-21027, Ispra, Italy; International Atomic Energy Agency – Vienna International Centre, P.O. Box 100, 1400 Vienna, Austria ' European Commission – Joint Research Centre, Directorate C – Energy, Transport and Climate, Air and Climate Unit, Via E. Fermi 2749, I-21027, Ispra, Italy
Abstract: We propose a geostatistical technique based on point-centred semi-variograms that can be used to derive valuable information about the spatial representativeness of air quality monitoring sites. Whereas classical geostatistics describes the spatial correlation structure of a concentration field in terms of the variogram, point-centred variography is based on the average of squared concentration differences observed in pairs formed from a particular central point and the set of all other points in the domain. It thereby places a monitoring station in the context of the local or regional air quality pattern. We demonstrate how a mathematical inversion of the point-centred variogram can provide estimates of the extent of the representativeness area of a monitoring site. The application of this approach is tested on a set of modelling data from the city of Antwerp, which was used for the FAIRMODE/AQUILA intercomparison exercise of methods for the assessment of spatial representativeness.
Keywords: point-centred variography; spatial representativeness; geostatistics; air pollution; air quality monitoring; measurements; modelling.
International Journal of Environment and Pollution, 2019 Vol.65 No.1/2/3, pp.229 - 245
Received: 20 Jan 2018
Accepted: 07 Jan 2019
Published online: 22 Aug 2019 *