The Arctic is currently experiencing unprecedented changes across all components of the climate system, primarily driven by global warming. As an important indicator of climate change in the Arctic, sea level reflects variations in both the atmosphere and ocean. This paper analyzes the sea level variation of the Arctic Ocean over the past four decades using ORAS5 data, which is the product of the latest reanalysis-analysis system produced by the European Centre for Medium-Range Weather Forecasts (ECMWF). ORAS5 accurately reproduces the main spatial features of the climatology and temporal evolution of sea surface height (SSH) in the Arctic Ocean, as observed by satellite altimeters, and reveals that seasonal variability is the most significant property of the sea level variation in this region. The seasonal cycle of SSH is closely linked to atmospheric circulation and sea ice formation. The first two dominant modes of the annual-mean SSH in the Arctic Ocean exhibit significant decadal variability. The first mode can be explained by the Ekman transport of wind related to the Arctic Oscillation (AO), which leads to antiphase changes in SSH on the continental shelves and in the deep basins. The second mode shows an antiphase oscillation of SSH between the Eurasian and Canadian Arctic Archipelago (CAA) sides and is driven by the wind anomaly associated with the Arctic dipole anomaly (DA). Due to the decadal variations associated with climate modes, particularly the AO, sea level in the Arctic Ocean has been continuously rising since the mid-1990s or early 2000s, with the most rapid sea level rise occurring in the Beaufort Sea.

中文翻译：

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基于ORAS5数据的1979年以来北冰洋海平面变化

北极目前正在经历气候系统所有组成部分的前所未有的变化，这主要是由全球变暖驱动的。作为北极气候变化的重要指标，海平面反映了大气和海洋的变化。本文利用欧洲中期天气预报中心（ECMWF）生产的最新再分析-分析系统ORAS5数据分析了过去四十年北冰洋的海平面变化。ORAS5 准确再现了卫星高度计观测到的北冰洋气候学和海面高度 (SSH) 时间演变的主要空间特征，揭示了季节变化是该地区海平面变化的最显着特性。SSH 的季节性循环与大气环流和海冰形成密切相关。北冰洋年平均 SSH 的前两个主要模式表现出显着的年代际变化。第一种模式可以用与北极涛动 (AO) 相关的埃克曼风传输来解释，这导致大陆架和深盆地 SSH 的反相变化。第二种模式显示欧亚和加拿大北极群岛 (CAA) 两侧之间的 SSH 反相振荡，并由与北极偶极子异常 (DA) 相关的风异常驱动。由于与气候模式相关的年代际变化，特别是 AO，北冰洋的海平面自 20 世纪 90 年代中期或 2000 年代初以来一直在持续上升，其中波弗特海的海平面上升最快。