气力人工上升流环境效应监测与评估的初步研究

发布时间：2018-05-28 18:37

本文选题：人工上升流 + 温度　；参考：《浙江大学》2014年硕士论文

【摘要】：在我国东海表层海域中,营养盐在近岸海域分布极高,但仅限于靠岸的狭长海域,在50m以深的陆架区,营养盐含量低,无法满足浮游生物的需求。深层海水温度低且含有丰富的营养盐,上升流可将其提升至表层,这样可以改变周围海域水体温度和营养盐等的分布,从而改善海洋生态环境,提高海洋初级生产力。目前人工上升流技术是国内外海洋科学研究的热点与前沿,但是国内外文献少,各方面研究相对独立,关于环境效应的研究以及如何监测和进行评价比较少见。本文针对气力人工上升流,围绕环境效应的监测和评估,从以下几个方面展开：前期为了验证“浅层注气理论”的提升效果和上升流过程对环境效应的影响,课题组成员在千岛湖地区进行了两次湖试监测研究,试验过程中采用单点和立体监测相结合的方法,成功测得了在不同喷嘴形状、注气量和管径条件下的温度、溶解氧、叶绿素a和pH等参数随时间的变化。温度和营养盐是水体最好的“指示剂”,也是重要的环境参数。在湖试监测的基础上,运用计算流体力学对上升流系统周围水体温度和营养盐进行了仿真模拟研究。仿真时水体分为湖水和海水两种情况。在湖水中,运用fluent中的VOF模型分析上升流过程中温度的变化,温度仿真结果与湖试监测结果基本吻合,仿真模型能够很好地预测周围水体的温度；在海水中,运用组分传输模型分析温度和营养盐的变化,通过改变上升流速度和洋流速度等,可以控制混合层温度和营养盐的变化。叶绿素a是评估人工上升流作用海域初级生产力的重要参数。为了对初级生产力进行评估,运用了多种模型对叶绿素a进行建模分析,研究了叶绿素a、溶解氧、深度、温度、盐度和pH值之间的关系,建立了模型,并比较了人工上升流系统中不同叶绿素a预测模型的预测精度,并确定了最佳预测模型。建模结果将有助于进行人工上升流系统环境效应的评估。本文提出的气力人工上升流环境效应的监测和评估技术已经进行了湖试监测、仿真和建模研究。湖试监测结果充分验证了气力人工上升流技术的提升效果和对环境效应的影响,仿真模型通过湖试结果进行验证并用于以后的海试工作和上升流环境效应的评估提供一定的参考。
[Abstract]:In the surface waters of the East China Sea, the nutrient distribution in the coastal waters is very high, but it is limited to the long and narrow coastal areas. In the 50 m deep continental shelf area, the nutrient content is low and can not meet the demand of plankton. The deep seawater has low temperature and abundant nutrients, which can be raised to the surface by upwelling, which can change the distribution of water temperature and nutrient salt in the surrounding sea area, thus improve the marine ecological environment and increase the marine primary productivity. At present, artificial upwelling technology is the hot spot and frontier of marine science research at home and abroad, but there are few literatures at home and abroad, and the research on environmental effect and how to monitor and evaluate are relatively rare. This paper focuses on the monitoring and evaluation of the environmental effects in the light of the artificial upwelling of the pneumatic force from the following aspects: In order to verify the effect of "shallow gas injection theory" and the effect of upwelling process on environmental effect, the members of the research group carried out two lake test monitoring studies in Qiandao Lake area. The temperature, dissolved oxygen, chlorophyll a and pH of the nozzle with different nozzle shape, gas injection and pipe diameter were measured by the method of single point and stereoscopic monitoring. Temperature and nutrient are the best indicator and important environmental parameters. On the basis of lake test monitoring, the temperature and nutrients around the upwelling system were simulated by computational fluid dynamics (CFD). The simulation results show that the water can be divided into lake water and sea water. In the lake water, the VOF model in fluent is used to analyze the temperature change during the upwelling process. The temperature simulation results are in good agreement with the monitoring results of the lake test. The simulation model can well predict the temperature of the surrounding water body, and in the seawater, the temperature of the surrounding water body can be predicted by the simulation model. The variation of temperature and nutrient salt in the mixed layer can be controlled by changing the upwelling velocity and ocean current velocity by using the component transport model to analyze the variation of temperature and nutrient salt. Chlorophyll a is an important parameter for evaluating the primary productivity of the sea area affected by artificial upwelling. In order to evaluate primary productivity, several models were used to model and analyze chlorophyll a. The relationships between chlorophyll a, dissolved oxygen, depth, temperature, salinity and pH were studied. The prediction accuracy of different chlorophyll a prediction models in artificial upwelling system was compared and the optimal prediction model was determined. The modeling results will be helpful for the assessment of the environmental effects of the artificial upwelling system. The technique of monitoring and evaluating the environmental effects of artificial upwelling in this paper has been studied by lake test monitoring, simulation and modeling. The results of lake test monitoring fully verify the lifting effect of pneumatic artificial upwelling technology and its influence on environmental effects. The simulation model is verified by the results of lake test and can be used for future sea trial and assessment of upwelling environmental effects.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：X834;P73

【参考文献】