School of the Environment, University of Windsor, Windsor, Ontario N9C 2J9, Canada.
School of Geography and Environmental Science, Ulster University, Coleraine, UK; Geological Sciences, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Westville Campus, Durban, South Africa.
Sci Total Environ. 2021 Apr 1;763:144444. doi: 10.1016/j.scitotenv.2020.144444. Epub 2020 Dec 25.
Topographic steering has been observed around Gran Canaria, a high-profile circular island located in the Canary Island Archipelago, Spain, culminating in a complex lee-side wind regime at the Maspalomas dunefield. Maspalomas has experienced rapid environmental changes since the 1960s, coincident with a boom in the tourism industry in the region and requires further examination on the linkages between meso-scale airflow patterns and aeolian processes modifying the landscape. The aim of this work is to simulate mean and turbulent airflow conditions at Maspalomas due to incremental changes in the regional wind direction and to compare these results to the predicted and observed aeolian dynamics taken from meteorological records, a global wind retro-analysis model, and remote sensing data. A Smagorinsky Large Eddy Simulation (S-LES) model was used to identify meso-scale airflow perturbations and turbulence at different locations around the island. Variability in meteorological data was also identified, with sites recording accelerated or retarded velocities and directional distributions ranging between unimodal to bimodal. Using a global retro-analysis model, relatively consistent up-wind conditions were predicted over a period coinciding with three aerial LiDAR surveys (i.e., 2006, 2008, and 2011) at the Maspalomas dunefield. Despite the consistent predicted airflow conditions, dune migration rates dropped from 7.26 m y to 2.80 m y and 28% of dunes experienced crest reversal towards the east, or opposite of the primary westerly migration direction during the second time period. Our results indicate that meso-scale airflow steering alters local wind conditions that can modify sediment transport gradients at Maspalomas. Given the rapidity of environmental changes and anthropogenic impacts at Maspalomas, these findings improve our understanding on the aeolian dynamics at Maspalomas and can be used to inform future management strategies. Lastly, the approach used in this study could be applied to other high-profile island settings or similarly complex aeolian environments.
加那利群岛中的大加纳利岛是一座引人注目的圆形岛屿，位于西班牙的加那利群岛群岛中，在马斯帕洛马斯沙丘场形成了复杂的背风侧风况。自 20 世纪 60 年代以来，马斯帕洛马斯经历了快速的环境变化，与该地区旅游业的繁荣相吻合，需要进一步研究中尺度气流模式与改变景观的风沙过程之间的联系。这项工作的目的是模拟马斯帕洛马斯由于区域风向的增量变化导致的平均和湍流气流条件，并将这些结果与从气象记录、全球风反演模型和遥感数据中预测和观察到的风沙动力学进行比较。使用 Smagorinsky 大涡模拟 (S-LES) 模型来识别岛屿周围不同位置的中尺度气流扰动和湍流。还确定了气象数据的可变性，记录的站点的速度和方向分布存在加速或延迟，范围从单峰到双峰。使用全球反演模型，在与马斯帕洛马斯沙丘场的三次航空激光雷达调查（即 2006 年、2008 年和 2011 年）期间相对一致的上风向条件下进行预测。尽管预测的气流条件相对一致，但沙丘迁移率从 7.26 米/年下降到 2.80 米/年，并且 28%的沙丘经历了向东的脊反转，即与第二个时间段的主要西风迁移方向相反。我们的结果表明，中尺度气流转向改变了当地的风况，从而可以改变马斯帕洛马斯的泥沙输运梯度。鉴于马斯帕洛马斯的环境变化和人为影响的迅速性，这些发现提高了我们对马斯帕洛马斯风沙动力学的理解，并可用于为未来的管理策略提供信息。最后，本研究中使用的方法可应用于其他高知名度的岛屿环境或类似复杂的风沙环境。
