太湖氮、磷自净能力的实验与模型模拟

于2011年9月对太湖竺山湖开展了1次湖区实验,根据质量平衡原理,通过进出竺山湖湖区河道以及竺山湖湾心、湾口水量、水质测量,弄清了竺山湖湖区营养物质进出以及消纳规律,从而为完善水量-水质模型参数提供依据,也为进一步研究太湖水体自净能力提供了基础资料.采用EcoTaihu模型模拟了太湖营养物质的循环以及自净能力,根据竺山湖湖区实测结果对模型进行了验证,实验得到竺山湖湖区总氮年自净能力为1 979 t,总磷年自净能力为119 t,通过EcoTaihu模型计算得到竺山湖总氮年自净能力为1 911 t,总磷年自净能力为116 t,实测数据和模型较为吻合.模型计算结果表明,2006、2008、2010年太湖氮元素自净能力分别为4.00、4.27、4.11万t.2006、2008、2010年太湖磷元素自净能力分别为1 566、1 798、1 712 t.

Experiment and Model Simulation of Self-Purification Capacity of Nitrogen and Phosphorus in Lake Taihu

A field experiment was carried out in Zhushanhu in September, 2011. On the basis of mass balance, nutrients flow in and out of Zhushanhu and their Digestion-absorption law was illustrated through water quantity-water quality observation of bay heart, bay mouth and rivers around Zhushanhu, which provides basic data for the further research on the self-purification capacity of Lake Taihu. The EcoTaihu model was adopted to simulate the nutrients flow and their self-purification capacity of Lake Taihu. The simulated annual self-purification capacity of total nitrogen and total phosphorus of Zhushanhu was 1911 t and 116 t, respectively, whereas the observed annual self-purification capacity of total nitrogen and total phosphorus of Zhushanhu was 1979 t and 119 t, respectively. The model was validated by the observation data. The simulated result showed that the self-purification capacity of total nitrogen of Lake Taihu in year 2006, 2008 and 2010 was 4.00×10⁴ t, 4.27×10⁴ t and 4.11×10⁴ t, respectively, whereas the self-purification capacity of total phosphorus of Lake Taihu in year 2006, 2008 and 2010 was 1.56×10³ t, 1.80×10³ t and 1.71×10³ t, respectively.