Improving the numerical stability of the MAGIC model

Article type: Research Article

Authors: Deng, Yi-xiang | Chen, Ji-ning | Hu, Xue-tao

Affiliations: Department of Environment Sciences and Engineering,Tsinghua University, Beijing 100084, China. E-mail:dyx99g@mails.tsinghua.edu.cn

Abstract: MAGIC is one of the most widely used models for forecasting long-term acidification. The model's code, however, has been experiencing numerical instability, though this might not be widely known to the public users. The major instability comes from the analytical solution to two cubic equations for calculating SO_4²^-concentration and the exchangeable fraction of Al on the soils. The mathematical algorithm for calculating the concentration of SO_4²^- from a quadratic equation is also found instable. This paper is aimed at improving the instability above through proved numericalalgorithms.

Keywords: numerical instability, MAGIC model

Journal: Journal of Environmental Sciences, vol. 13, no. 2, pp. 189-191, 2001