An Assessment of the potential impact of the Gothenburg Protocol on surface water chemistry using the dynamic MAGIC model at acid sensitive sites in the UK

摘要

The MAGIC model has been systematicallycalibrated to 12 sites in the UK, which form part of the UK Acid WatersMonitoring Network, using best available data. The modelsuccessfully simulates observed changes in major ions and acid neutralisingcapacity over the period 1988 to 2000. Predictions for thefuture are made assuming no further emission reductions from present day(constant deposition at current level) compared to reducedsulphur and nitrogen emission agreed under the Gothenburg Protocol (reducedsulphur dioxide emission by c.80%, nitrogen oxides byc.45% and ammonia by 20% by 2010). In addition, uncertainty in our understandingof future nitrogen dynamics is assessed using "best"and "worst" cases of nitrogen leaching in the model. The results clearlyindicate the need to achieve further emission reductionsin sulphur and nitrogen beyond present day levels to prevent continued surfacewater acidification. The predictions further indicate thatif the emission reductions agreed under the Gothenburg Protocol are achieved by2010 this will promote a recovery in acid neutralising capacityby 2020 at all sites. Differences between "best" and "worst" casenitrate leaching are relatively small, emphasising the need to achievethe sulphur reductions in the shorter term. In the longer term, beyond 2020,increased nitrogen leaching under the "worst case" leadingto further acidification is likely indicating a need for further reduction ofnitrogen emissions. style="line-height: 20px;">Keywords: acidification, recovery, model, Gothenburg Protocol, nitrogen