风暴期间Beaufort-Mackenzie海域海冰对海浪强度的影响

Influence of sea ice on wave intensity during an arctic storm in Beaufort-Mackenzie Sea area

为了研究风暴过程中海冰剧烈运动情形下Beaufort-Mackenzie海域各区位的海浪变化特性,基于该海域2008年开冰期西北向北极风暴(2008年10月5-8日)的风、浪及逐日海冰数据,分析了风暴期间海冰的密集度、发展阶段和尺寸的变化,并采用SWAN模型模拟了风暴过程中剧烈变化的风速、风向和海冰对海浪强度的影响,同时对比分析了2种海冰模式(采用实际海冰信息(密集度、发展阶段和尺寸信息)的海冰模式、不同海冰密集度为固定边界)的海浪数值模拟结果。结果表明:2种海冰模式均在离海冰较远海岸水域得到合理模拟结果;风暴期间以涵盖实际海冰信息的海冰模式能模拟得到更精细的海浪强度;以实际海冰信息的海冰模式进行模拟,发现风暴期间风速、风向和海冰的剧烈变化导致Beaufort-Mackenzie海域海浪强度、分布发生剧烈变化,最大海浪发生在风速最大时刻。

To clarify the wave properties at different locations in the Beaufort-Mackenzie Sea area when sea ice varied significantly under violent storm condition,based on the observed winds,waves and daily sea ice data of one of northwest arctic storm(Oct.5-8,2008)during open water season in the Beaufort-Mackenzie Sea area,changes of sea ice concentration,developing stage and sea ice size are studied.Waves are simulated with SWAN model under dramatic variations of wind velocity,wind direction and sea ice during the storm,and comparison study is also carried out between model simulations with sea ice mode covering realistic sea ice information(sea ice concentration,development stage and size information)and different sea ice concentrations as model boundary.The results show that reasonable simulation results are obtained in areas off sea ice cover region by using the two sea ice modes;sea ice mode covering realistic sea ice information gives more precise waves simulation results during storm.Simulation with sea ice mode covering realistic sea ice information indicates that dramatic changes of wind velocity,wind direction and sea ice induce severe variations of wave strength and distribution in Beaufort-Mackenzie region,the most violent waves occur at the biggest wind time.