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Quantifying uncertainty in the MEASURES framework - ES0107

Description
The MEASURES (Multiple Environmental from Agricultural Systems) project (WA0801) has produced a framework to calculate multiple environmental burdens produced by different agricultural systems that are modelled on a whole farm basis. It allows profitably to be calculated and can optimise the balance of animals and crops to predict the best economic performance of a farm. This can be weighted according to environmental or other constraints. The outputs of the model, and most of the environmental relationships used in it, currently do not have any estimate of uncertainty associated with them. The apparent benefits of alternative systems cannot consequently be judged to be significantly different.

Research is proposed that will identify and quantify the different sorts of uncertainty in the MEASURES framework. These may arise from: experimental measurement variation; errors in the simulation of processes; errors in estimates of the parameters of the models (simulations, inventories and MEASURES equations) and uncertainty from the effects of year to year variation caused by weather.

The different forms of uncertainty will be identified and quantified by suitable methods. A sensitivity analysis will be used to rank the main variables. The suitable methods may be analytical (if various assumptions are valid) or, more likely, by Monte Carlo simulations. Monte Carlo simulations allow complex models to be examined (especially when assumptions about Gaussian distributions are not valid). The method is computationally intensive and has been used successfully before at SRI in a Life Cycle Assessment model.

The MEASURES framework will be reprogrammed so that uncertainties are produced along with the conventional outputs of the means of environmental burdens etc. These will allow the probability of alternative systems delivering significantly different outcomes to be quantified.

A workshop will be held towards the end of the project for stakeholders. This will address aspects of multiple environmental interactions. The improved model will be featured in it.

Objective
The main objective is to quantify the uncertainty in the MEASURES framework and present it.

The individual objectives follow.

1. To identify the different forms of uncertainty in the MEASURES framework.
2. To quantify the different forms of uncertainty in the MEASURES framework.
3. To program the MEASURES framework so that the uncertainty is produced along with predicted mean values.
4. To use this knowledge to highlight areas of particular concern where scientific results used to inform DEFRA policy decisions may be misleading because of the absence of quantified uncertainty.
5. To suggest areas of work need to resolve such matters.
6. To hold a workshop on multiple environmental interactions in which the model with uncertainty will be demonstrated.

Project Documents
• Final Report : Quantifying uncertainty in the MEASURES framework   (842k)
• Final Report - Annex : Quantifying uncertainty in the MEASURES framework   (1021k)
• Final Report - Annex : Quantifying uncertainty in the MEASURES framework   (89k)
• Final Report - Annex : Quantifying uncertainty in the MEASURES framework   (77k)
Time-Scale and Cost
From: 2002

To: 2004

Cost: £49,707
Contractor / Funded Organisations
Silsoe Research Institute (BBSRC)
Keywords
Air Pollution              
Ammonia              
Arable              
Environmental Protection              
Livestock              
Modelling              
Nitrate              
Nitrates              
Phosphorus              
Pollution              
Soil              
Sustainable Production