Electromagnetic(EM) measurement of sea ice is an efficient, fast and high-precision method. In the present paper, we used shipborne data in the fourth Chinese National Arctic Research Expedition, which was acquired by EM31 -ICE electromagnetic induction device, laser range finderas well assonar. Through pre-processing the preliminary data of sea ice thickness, and then combined with calibration information from ice core samples in the long-term ice stations, we obtained the correction parameters of EM31 -ICE. Results through the analysis of anomalous data together with wavelet denoising and statistical processing, demonstrate that: ice thickness mainly varies between 0.5 m and 2.5 m in the way to arctic, whereasin the back way from arctic, it becomes thinner, ranging from 0.5 m to 2.0 m. The thickness of sea ice in high-latitude regions is significantly greater than those in low-latitude regions. Moreover, in high-latitude regions, two peaks appear in the histogramsof sea ice thickness, while in the low-latitude regions only one peak appears. Throughout the whole go and return process, ice with the thickness over 4 m is less than 1 %.%利用EM31-ICE电磁感应仪与激光测距仪、声纳等设备在中国第四次北极科学考察过程对海冰厚度进行走航观测,通过对数据预处理获得了海冰厚度数据,结合长期冰站上采集的多组冰厚样本,获得EM31-ICE的各项校正参数.同时通过对异常数据的分析以及小波去噪、统计处理等方法,得出最终的解释结果:在去程时海冰厚度主要分布在0.5-2.5 m之间,而返程时的海冰厚度有明显变薄的倾向,主要分布在0.5-2.0m之间.在高纬度地区海冰厚度明显大于低纬度地区,并且在高纬度地区海冰厚度统计图中常出现两个波峰,而低纬度地区常是一个波峰.在整个去程与返程过程中,超过4m厚的海冰不到1％.
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