Offshore Pollution Source Localization in Static Water Using Wireless Sensor Networks

In water environments such as water reservoirs and lakes, the diffusion of pollutants is affected by boundaries.Firstly, the offshore plume source diffusion in static water is analysed and a piecewise concentration model is proposed.The localization of the pollution source near an impervious boundary is studied. It is shown that unknown parameters include not only the source position but also the mass flow rate and the initial diffusion time. To estimate the unknown parameters, we provide three algorithms, which are respectively based on a general model, an approximation function and the unscented Kalman filter(UKF). The first two algorithms employ the original concentration model and piecewise concentration model respectively, and estimate the parameters by solving the constrained nonlinear least squares problem.By using the general model based algorithm, source parameters can be acquired promptly. The algorithm based on the approximation function is more robust compared with that on the general model, although it can only be executed for sufficient samples. Considering the diffusion process, the algorithm based on UKF achieves a good tradeoff between the computation complexity and the estimation accuracy. The simulation data are generated by MODFLOW, which is a standard software for the hydrological simulation of source diffusion. Three proposed algorithms are tested by simulation data, and the results demonstrate their advantages and disadvantages.