Abstract:

Based on the risk assessment theory of red tide disaster and the conventional monitoring data of plankton and hydrology in the Haitan Strait, the index system of red tide disaster assessment in the Haitan Strait was constructed by using the method of Analytic Hierarchy Process (AHP), and the weight was assigned by entropy method and coefficient of variation method. A scientific and credible assessment model was established, and the thematic maps of ecological risk disaster of the Haitan Strait were obtained. The results are as follows. The medium-to-high risk areas were mainly distributed in the north of the strait in spring; the southern part of the strait was mainly at low risk. In summer, most of sea areas of the strait had low risk, while the south of the strait faced high risk. In autumn, the risk levels were mainly low and medium, and the medium risk areas were mainly distributed in the northwest and southeast of the strait. In winter, high-risk areas and highest-risk areas were concentrated in the northwest or northeast part of the strait. Because the eutrophication degree of the strait was high and the eutrophication index had a large weight, reducing nitrogen and phosphorus inputs into the strait can reduce the risk of red tide disasters. In addition, it displayed a good temporal and spatial correlation distribution between the red tide events for many years and disaster-causing factor level distribution.

Key words: Haitan Strait, Analytic Hierarchy Process (AHP), entropy method, coefficient of variation method, red tide disaster, potential ecological risk