TRENDS ANALYSIS-METHODS FOR ENVIRONMENTAL DATA

Recently, the heightened interest in the assessment of the current state of enviromnental conditions and the detection of change in environmental conditions has led to a corresponding interest in statistical trend assessment methods. In the present paper, the analysis for trend is considered as part of the larger task of characterizing the variability of an environmental quality indicator when data are available from a monitoring programme. The features of several parametric and non-parametric methods are discussed with respect to methods of accounting for seasonality, inherent models for trend, the ability to handle changes of different forms, the inclusion of concomitant variables in the analysis and the assumptions of the method. Examples of the analysis of water quality data using these methods axe given.