Determining the influence of waves on the physical behaviour of the sea ice with mechanically generated waves

The interaction of the ocean wave field with the sea ice was investigated by creating a wave generating machine to generate waves which have clearly defined parameters such as amplitude and frequency. A block of ice was cut from the ice sheet and attached to a computer controlled hydraulic activator suspended from a steel frame. The movement of the block in and out of the water generates a cyclical force on the ice through the frame which generates the waves that then propagate out in a cylindrical fashion. The waves are detected by tilt meters placed at distances up to 5km from the source. By relating the phase and amplitude of the detected waves with the phase and amplitude of the source the influence of waves on the physical behaviour of the sea ice was determined. This was tested over two seasons and the source was positioned in an area of known cracks and an array of tilt meters were radiating out from the source and spanning the crack for measurements. The relative locations on the source and detectors as well as the cracks were mapped by GPS. The results should enable the construction of a model of wave propagation in the presence of imperfections and consequently further enhance the understanding of the break up processes occurring in the marginal ice zone.本研究通过搭建振幅、频率等参数可精准调控的造波系统生成海浪，以此开展海浪场与海冰相互作用的实验探究。实验中从冰盖切割获取一块海冰试样，将其固定于由钢支架悬挂的计算机控制液压激振装置上。该海冰试样随液压激振装置往复运动时，会通过钢支架对海冰施加周期性作用力，进而生成海浪并以圆柱状向外扩散传播。在距造波源最远5公里的位置布设倾斜仪采集海浪数据，通过比对实测海浪与造波源的相位、振幅参数，即可明确海浪对海冰物理特性的影响规律。本实验分两个实验季开展：造波源布设至已知存在海冰裂缝的区域，同时以造波源为中心向外布设倾斜仪阵列，该阵列横跨裂缝以完成测量。通过全球定位系统(GPS)对造波源、倾斜仪探测器以及海冰裂缝的相对位置进行精准测绘。本研究所得结果将支持构建考虑海冰缺陷（如裂缝）的海浪传播模型，进而深化对冰缘区海冰破碎过程的科学认知。