溢油事故发生后, 油膜的漂移扩散会对周围水域和环境敏感目标造成污染。研究溢油事故后油膜漂移扩散, 可为溢油事故的处理提供理论指导。本文应用河口海岸三维水动力模式ECOM-si(semi-implicit estuarine, costal and ocean model), 耦合溢油漂移扩散模块, 模拟和分析长江口宝钢码头发生溢油事故后油膜的漂移扩散, 以及对环境敏感保护目标的影响。基于长江口崇明东滩气象站实测风速风向资料, 给出影响溢油漂移的主导风和不利风向。在冬季多年平均1月径流量11700m³·s^-1、主导风、3个不利风和潮汐作用下, 数值模拟并详细给出了宝钢码头溢油事故发生后油膜的平面分布、油膜到达和离开4个水库取水口和饮用水水源保护区以及其他环境敏感保护区的时间、持续影响时间和最大油膜厚度。长江口宝钢码头溢油事故发生后, 油膜随涨落潮流作上下游来回振荡, 径流使油膜向海输运, 风使油膜朝风向方向漂移。在主导风北风5.6m³·s^-1风速下, 油膜沿长江口南岸向下游漂移扩散, 小部分进入北槽南侧。在不利风向东南风4.0m³·s^-1风速下, 油膜西北方向漂移, 聚集于南支北岸, 受径流作用沿南支和北港的中北侧向下游输运。在不利风向西北风4.8m³·s^-1风速下, 西北风减轻了溢油事故点上游和北港、崇明东滩外侧敏感目标的影响, 加重了南港和南槽的环境敏感保护目标的影响。在不利风向西南风3.2m³·s^-1风速下, 大部分油膜在北港中北侧向下游漂移扩散, 小部分油膜聚集在北槽的中北侧。西南风减轻了溢油事故点上游和下游南港、南槽环境敏感目标受到的影响, 加重了对北港和崇明东滩外侧敏感目标的影响。不同风向作用下油膜的分布和对环境敏感保护目标影响显著不同, 风在油膜漂移扩散中起着十分重要的作用。

The drift and diffusion of oil film after the oil spill accident will pollute the surrounding waters, and environmental sensitive protection targets. The study of oil film drift and diffusion after oil spill accident can provide theoretical guidance for the treatment of oil spill accident. Coupling the oil spill drift and diffusion module, the estuarine and coastal three-dimensional hydrodynamic model ECOM-si (semi-implicit estuarine, costal and ocean Model) was used to simulate and analyzed the drift and diffusion of oil film after the oil spill accident at the Baosteel wharf in the Changjiang Estuary, and its impact on the environmental sensitive protection targets in this paper. Based on the measured wind speed and direction data at weather station on the Chongming eastern shola in the Changjiang Estuary, the prevailing wind and unfavorable wind affecting the oil spill drift are given. Forced by the monthly mean river discharge of 11700 m³·s^-1, prevailing wind, three unfavorable winds and tide in January, the horizontal distribution of oil film, time of the oil film reaching and leaving the water intakes of four reservoirs and drinking water source protection areas, and other environmental sensitive protection targets, duration and maximum oil film thickness of oil film after the oil spill accident at the Baosteel wharf was numerically simulated and analyzed in detail. After the oil spill accident, the oil film oscillates upstream and downstream with the flood and ebb current, meanwhile the runoff transports the oil film to the sea, and the wind makes the oil film drift towards the wind direction. Under the action of the prevailing wind, northerly wind of 5.6 m³·s^-1, the oil film drifts and diffuses downstream along the south coast of the Changjiang Estuary, and a small part enters the south side of the North Passage. Under the unfavorable wind, southeasterly wind of 4.0 m³·s^-1, the oil film drifts in the northwest and accumulates on the north coast of the South Branch. Forced by the runoff, it is transported downstream on the middle and north side of the South Branch and the North Channel. Under the unfavorable wind, northwesterly wind of 4.8 m³·s^-1, it weakens the impact on the sensitive targets upstream of the oil spill accident site and the ones in the North Channel, outside Chongming eastern shoal, and aggravates the impact on the environmental sensitive protection targets in the North Channel and South Passage. Under the unfavorable wind, southwesterly wind of 3.2 m³·s^-1, most of the oil film drifts and diffuses downstream on the middle and north side of the North Channel, and a small part of the oil film is on the middle and north side of the North Passage. It weakens the impact on environmental sensitive targets upstream of the oil spill accident site and the downstream ones in the South Channel and South Passage, and aggravates the impact on the sensitive targets in the North Channel and outside Chongming eastern shoal. The distribution of oil film and its impact on the environmental sensitive protection targets are significantly different under the force of different wind directions, indicating that wind plays a very important role in oil film drift and diffusion.