Potential Impacts of Offshore Wind Farms on North Sea Stratification.
Potential Impacts of Offshore Wind Farms on North Sea Stratification.
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DOI：
10.1371/journal.pone.0160830
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Baschek B
中科院分区：
文献类型：
--
作者：
Carpenter JR;Merckelbach L;Callies U;Clark S;Gaslikova L;Baschek B
近海风力发电场(OWF)技术的进步最近导致了它们在沿海水域的建设，这些水域的深度足以按季节分层。当潮流通过OWF基础结构时，它们会产生一个湍流尾迹，这将有助于分层水柱的混合。在这项研究中，我们表明，以这种方式产生的混合可能会对北海德意志海湾地区的大尺度层结产生重大影响。这一区域被选为本研究的重点，因为OWF的规划特别广泛。结合理想化模拟和现场测量，我们提供了两个重要时间尺度的数量级估计，这两个时间尺度对于理解OWF的影响至关重要：(I)混合时间尺度，描述层结的完全混合需要多长时间；(Ii)平流时间尺度，量化一个水块预计将经历多长时间的增强风电场混合。结果对阻力系数和地基结构的类型以及增强混合条件下的跃层演化都特别敏感--这两者都不是很清楚。考虑到这些限制，结果表明，OWF可能会影响大范围的层结，但只有当它们占据广泛的陆架区域时。预计在北海目前的能力下，它们对大规模分层的影响很小，但在未来的大规模开发情景中，影响可能会很大。
Advances in offshore wind farm (OWF) technology have recently led to their construction in coastal waters that are deep enough to be seasonally stratified. As tidal currents move past the OWF foundation structures they generate a turbulent wake that will contribute to a mixing of the stratified water column. In this study we show that the mixing generated in this way may have a significant impact on the large-scale stratification of the German Bight region of the North Sea. This region is chosen as the focus of this study since the planning of OWFs is particularly widespread. Using a combination of idealised modelling and in situ measurements, we provide order-of-magnitude estimates of two important time scales that are key to understanding the impacts of OWFs: (i) a mixing time scale, describing how long a complete mixing of the stratification takes, and (ii) an advective time scale, quantifying for how long a water parcel is expected to undergo enhanced wind farm mixing. The results are especially sensitive to both the drag coefficient and type of foundation structure, as well as the evolution of the pycnocline under enhanced mixing conditions—both of which are not well known. With these limitations in mind, the results show that OWFs could impact the large-scale stratification, but only when they occupy extensive shelf regions. They are expected to have very little impact on large-scale stratification at the current capacity in the North Sea, but the impact could be significant in future large-scale development scenarios.