模拟消落带水华暴发行为的数值沙堆模型

以长江最大支流汉江近年来水华污染的现场资料为例,通过氮磷浓度、水温、流速和光照等实测数据构建了消落带开放水域环境体系的数值沙堆模型,描述了藻类生长及水华暴发的动力学机制;利用数值沙堆系统崩塌行为反映出的频率-尺度幂律关系作为判断消落带水域是否暴发水华以及规模大小的依据,采用有限尺度标度分析从不同侧面验证了水华暴发系统的自组织临界性,并揭示出各种拟合参数与水华暴发规模之间的定量关系.研究表明,沙堆模型如果存在良好的幂律关系,相应的消落带水域将暴发水华,且幂律指数越大,水华污染程度越严重.

Numerical sandpile model for simulating algal bloom behaviors in fluctuating band along riversides of the Three-Gorges valley

According to the current decade local monitoring data such as total concentrations of nitrogen and phosphorus, water temperatures, flow velocities and light illuminations, a numerical sandpile model based on self-organized criticality theory was constructed to reveal inherent dynamic mechanism of algal blooms and describe complex evolution process of alga growth in an open environmental system of water fluctuating band along riversides of the Three-Gorges valley. With the frequency-scale power law relationship, the avalanche behavior of numerical sandpile has been charactered as a criterion to estimate algal bloom and predict the scales, the self-organized criticality of the algal bloom system also verified through finite size scaling analysis, and all results were consistent with the monitoring data very well. Simulating computation showed if there existed power law relationship in the sandpile model, the corresponding water fluctuating band system would appear algal bloom pollution, and absolute values of exponent of the power law were all directly proportional to scales of algal bloom.