Mapping observations using AUV and numerical simulations of leaked CO2 diffusion in sub-seabed CO2 release experiment at Ardmucknish Bay
Mapping observations using AUV and numerical simulations of leaked CO2 diffusion in sub-seabed CO2 release experiment at Ardmucknish Bay
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DOI：
10.1016/j.ijggc.2015.01.017
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发表时间：
2015-07
影响因子：
3.9
通讯作者：
Y. Maeda;K. Shitashima;A. Sakamoto
中科院分区：
文献类型：
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作者：
Y. Maeda;K. Shitashima;A. Sakamoto
2012年在苏格兰Ardmucknish湾进行了受控海底CO2释放实验（QICS：量化和监测地质碳储存的潜在影响），以量化泄漏的CO2对海洋环境的影响。在这项实验中，将二氧化碳注入海底下方，并在二氧化碳泄漏到上覆水体中时进行密切监测。我们进行了测绘观测，使用自主水下航行器（AUV）配备传感器，以监测附近的CO2泄漏的物理和化学条件。AUV测绘观测结果表明，Ardmucknish湾水体的物理化学特征对潮汐变化较为敏感（低潮或高潮），泄漏CO2气泡的上升速度和泄漏区附近pH值的下降主要受潮汐相位的控制在海湾。利用安装在AUV上的声学多普勒流速剖面仪（ADCP）的观测结果表明，海湾中的水流在高潮时向西流动，在低潮时向东流动。模拟的潮流与ADCP观测的潮流吻合较好。数值模拟结果表明，CO2泄漏引起的pH值下降仅限于CO2泄漏区附近，且随潮汐变化而波动较大。在涨潮期间，低pH海水从湾口侵入海湾，泄漏的CO2引起的低pH羽流的扩散几乎检测不到。
A controlled sub-seabed CO2release experiment (QICS: quantifying and monitoring potential impacts of geological carbon storage) was conducted in Ardmucknish Bay, Scotland, in 2012, to quantify the effect of leaked CO2on marine environments. In this experiment, CO2was injected beneath the seafloor, and closely monitored as the CO2was allowed to leak into the overlying water column. We performed mapping observations using an autonomous underwater vehicle (AUV) equipped with sensors to monitor physical and chemical conditions in the vicinity of the CO2leakage. We also numerically simulated the behavior of the low-pH plume caused by the CO2leakage, within the calculated tidal current in the bay.The results of AUV mapping observations showed that physical and chemical characteristics of the water mass in Ardmucknish bay are sensitive to tidal variations (low or high tide), and the ascent speed of the leaked CO2bubble and the pH decrease in the vicinity of the CO2leakage area are predominantly controlled by the tidal phase in the bay. The observations using an acoustic Doppler current profiler (ADCP) installed in the AUV indicated that the current in the bay flows westwards at high tide and eastwards at low tide. The simulated tidal current agreed well with the tidal current observed by ADCP. Numerical simulation suggested that the pH decrease due to the leaked CO2is restricted to the vicinity of the CO2leakage area, and fluctuates greatly with tidal variations. In flood tide periods, diffusion of the low-pH plume caused by the leaked CO2is barely detectable because low-pH seawater intrudes into the bay from the bay mouth.