Spatiotemporal Modelling of Nitrate and Phosphorus in River Catchments for England and Wales

Claire Miller1, Ana-Maria Magdalina1, Adrian Bowman1, Marian Scott1, Duncan Lee1, Robert Willows2, Chris Burgess2 and Linda

Pope2

1Statistics, University of Glasgow2Environment Agency of England & Wales

Data – England and Wales (E&W)

Objective:To investigate the overall pattern of nutrient concentrations in E&W river surface waters over the past 20-30 years.

Response: Total Oxidised Nitrogen

(log transformed and non-detects

imputed)

River catchment: Large Hydrological Areas (59 units)

LHA 22 Coquet-Wansbeck Blyth

Additive Model

Additive model to investigate temporal and spatial trends and

seasonality and incorporating space-time interactions:

).,,().,(

)().(),()log(

54

3210

dayyearNorthingEastingmdayyeardoym

doymdayyearmNorthingEastingmTON

TON for Coquet, Wansbeck, Blyth LHA in the NE (1994 - 2009)

The plot highlights the adjustments that should be added to the main effect for season at particular time points.

trend seasonality

Interaction between day and year

time and space interaction

The movie highlights the spatial adjustments that should be added to the main effect for space at particular time points.

Easting

Nor

thin

g

Spatial Trend

Interaction between space and time

TON for Coquet, Wansbeck, Blyth LHA in the NE (1994 - 2009)