The model estimation and sensitivity analysis of greenhouse gas on water-air interface in Pengxi River, Three Gorges Reservoir

Abstract

模型估算法是水-气界面温室气体通量监测的主要方法，所得成果也不胜枚举.然而监测过程中诸多环境因素会对最终结果产生不确定的影响.结合三峡库区澎溪河背景条件，利用模型估算法进行水-气界面温室气体通量（以CO₂为例）估算，并且采用修正Morris筛选法尝试分析模型估算法中各个参数对温室气体扩散通量（以CO₂为例）的局部敏感性.研究结果表明：利用模型估算法计算三峡澎溪河流域水-气界面温室气体通量具有较高的可行性和可靠性；风速、水温以及pH值会对监测结果产生影响，且风速越强、水温越高、pH值越小，CO₂扩散通量就越大；pH值是高灵敏参数，风速和水温是灵敏参数.在三峡库区澎溪河监测过程中更应注意pH值的精确性，每次采样前需校正仪器.;Model estimation is one of the main method in greenhouse gas flux monitoring of water-air interface, which has made many achievements. However, many environmental factors will be uncertain influence on the final result in the process of monitoring. In Pengxi River of Three Gorges Reservoir, the water-gas interface greenhouse gas flux (CO₂, for example) was estimated with the model estimation, and the local sensitivity analysis fixed Morris screening method was carried out for all the parameters in model estimation on greenhouse gas diffusion flux. The research shows that the model estimation is used to calculate greenhouse gas flux on water-air interface in Pengxi River, Three Gorges Reservoir has high feasibility and reliability; wind velocity, water temperature and pH value will affect the monitoring results. And the stronger the wind speed, the higher the water temperature, the smaller the pH value, the greater the CO₂ diffusion flux; The pH value is a highly sensitive parameter, while wind speed and water temperature are sensitive parameters. In the monitoring process in Pengxi River of Three Gorges Reservoir, the instrument should be corrected in order to ensure the accuracy of pH value before sampling.