赤潮发生关键控制要素识别研究——以渤海为例

The Method to Identity the Key Control Factor of Red Tide:A Case Study of Bohai Sea

本文以渤海为例,建立了赤潮发生关键控制因子的识别方法,主要包括文献因子检索汇总、备选因子筛选、备选因子关联性分析、影响因子独立性、变动性分析、关键控制因子的识别等环节。通过对1990—2009年20年间与渤海赤潮发生相关要素进行关联性分析,熵值法和变异系数法分析要素的波动性,通过灵敏度分析,将主成分分析和层次分析结合起来确定关键控制要素。结果显示,有14个要素累计贡献率达到了90%,命名为备选因素。基于横向和纵向关联性分析,保证了有9个可以量化的要素,通过变异性系数和熵值法计算要素的权重,表明N/P、DIN、DIP、COD和降水具有较强的信息分辨能力。基于主成分分析和层次分析的结果,渤海赤潮发生的关键控制要素主要是DIN、DIP和N/P。它表明在渤海海域赤潮频发的主要原因可能与养分的输入,尤其是过量的氮养分输入所造成的营养结构失衡有关。因此,一些措施例如增加控制污染,减少陆源养分输入和减轻水体富营养化程度为渤海赤潮的治理和预测提供了依据。

Red tide has caused great economic loses because of the increasing occurrence frequency,geographic scope and the damage degree in the Bohai Sea.In this case,it is urgently to take measures to prevent and control the occurrence of red tide,the key of which is to determine the key control factors.However,there is no specific factors screening method in current study,or the screening methods are too single.Meanwhile,the key control factors of red tide may have differences in different sea areas.Therefore,based on red tide in the Bohai Sea,we establish an identification method of key control factors which includes the literature factor retrieval summary,alternative factor screening,alternative factor association analysis,the impact factor independence analysis,fluctuation analysis,and key control factor identification etc.Factors fluctuationis analyzed through entropy value method and variance coefficient method by analyzing statistical data associated with red tide occurrence from 1990 to 2009 in the Bohai Sea.And finally,the key control factors are identified with the theory of sensitivity analysis method by combing the principal component analysis and analytic hierarchyprocess（AHP）.Results show that there are 14 factors with cumulative frequency reaching 90%,named alternative factors.Independences of 9 quantifiable factors are assured based on the framework of horizontal and vertical association.And then,weight of factors are calculated by both variance coefficient method and entropy method.Result shows that N/P,DIN,DIP,COD and rainfall reflect stronger information resolution ability.Based on the results of principal component analysis and analytic hierarchy process,the key control factors of red tide primarily are DIN,DIP and N/P in Bohai Sea,indicating that the frequent occurrence of red tide in the Bohai Sea may be connected with the nutrient inputs,especially the imbalance of nutrient structure caused by the excessive input of nitrogenous nutrients.Therefore,some measures such as increasing control of pollution,reducing input of terrestrial nutrients and mitigating degree of eutrophication can provide the basis for the prediction and the governance of red tide in the Bohai Sea.