Abascal Ana J, Castanedo Sonia, Medina Raul, Losada Inigo J, Alvarez-Fanjul Enrique
Environmental Hydraulics Institute, Universidad de Cantabria, Avda. de los Castros s/n. 39005, Santander, Spain.
Mar Pollut Bull. 2009 Feb;58(2):238-48. doi: 10.1016/j.marpolbul.2008.09.020. Epub 2008 Nov 8.
In this work, the benefits of high-frequency (HF) radar currents for oil spill modeling and trajectory analysis of floating objects are analyzed. The HF radar performance is evaluated by means of comparison between a drifter buoy trajectory and the one simulated using a Lagrangian trajectory model. A methodology to optimize the transport model performance and to calculate the search area of the predicted positions is proposed. This method is applied to data collected during the Galicia HF Radar Experience. This experiment was carried out to explore the capabilities of this technology for operational monitoring along the Spanish coast. Two long-range HF radar stations were installed and operated between November 2005 and February 2006 on the Galician coast. In addition, a drifter buoy was released inside the coverage area of the radar. The HF radar currents, as well as numerical wind data were used to simulate the buoy trajectory using the TESEO oil spill transport model. In order to evaluate the contribution of HF radar currents to trajectory analysis, two simulation alternatives were carried out. In the first one, wind data were used to simulate the motion of the buoy. In the second alternative, surface currents from the HF radar were also taken into account. For each alternative, the model was calibrated by means of the global optimization algorithm SCEM-UA (Shuffled Complex Evolution Metropolis) in order to obtain the probability density function of the model parameters. The buoy trajectory was computed for 24h intervals using a Monte Carlo approach based on the results provided in the calibration process. A bivariate kernel estimator was applied to determine the 95% confidence areas. The analysis performed showed that simulated trajectories integrating HF radar currents are more accurate than those obtained considering only wind numerical data. After a 24h period, the error in the final simulated position improves using HF radar currents. Averaging the information from all the simulated daily periods, the mean search and rescue area calculated using HF radar currents, is reduced by approximately a 62% in comparison with the search area calculated without these data. These results show the positive contribution of HF radar currents for trajectory analysis, and demonstrate that these data combined with atmospheric forecast models, are of value for trajectory analysis of oil spills or floating objects.
在这项工作中，分析了高频（HF）雷达海流在溢油建模和漂浮物轨迹分析方面的优势。通过将漂流浮标轨迹与使用拉格朗日轨迹模型模拟的轨迹进行比较，对高频雷达性能进行了评估。提出了一种优化输运模型性能并计算预测位置搜索区域的方法。该方法应用于加利西亚高频雷达试验期间收集的数据。进行该实验是为了探索这项技术用于西班牙沿海业务监测的能力。2005年11月至2006年2月期间，在加利西亚海岸安装并运行了两个远程高频雷达站。此外，在雷达覆盖区域内释放了一个漂流浮标。利用高频雷达海流以及数值风数据，使用TESEO溢油输运模型模拟浮标轨迹。为了评估高频雷达海流对轨迹分析的贡献，进行了两种模拟方案。在第一种方案中，使用风数据模拟浮标的运动。在第二种方案中，还考虑了高频雷达的表层海流。对于每种方案，通过全局优化算法SCEM-UA（洗牌复合进化 metropolis）对模型进行校准，以获得模型参数的概率密度函数。基于校准过程中提供的结果，采用蒙特卡罗方法以24小时为间隔计算浮标轨迹。应用双变量核估计器确定95%置信区域。所进行的分析表明，整合了高频雷达海流的模拟轨迹比仅考虑风数值数据获得的轨迹更准确。经过24小时后，使用高频雷达海流可改善最终模拟位置的误差。对所有模拟日时段的信息进行平均，与不使用这些数据计算的搜索区域相比，使用高频雷达海流计算的平均搜索和救援区域减少了约62%。这些结果表明高频雷达海流对轨迹分析有积极贡献，并证明这些数据与大气预报模型相结合，对于溢油或漂浮物的轨迹分析具有价值。
