北冰洋海平面变化的观测和研究现状

Status of observation and study on level variation of Arctic Dcean

回顾北冰洋海平面观测和研究现状,总结了北冰洋海平面变化特征和变化机制。北冰洋海平面季节变化受海冰生消、蒸发降水和陆地径流季节变化的影响,由比容变化主导;年际到年代际海平面变化受北极涛动影响显著,可用风场异常导致的淡水分布来解释。盐比容变化是深水洋盆海平面变化的主导因素,由之引起的质量变化控制陆架海域和北冰洋平均的海平面变化。近期波弗特环流区域海平面上升极快,与波弗特高压持续增强及淡水积聚有关。气候变暖会导致北冰洋海平面持续上升。海冰快速减退和格陵兰岛冰川融化对北冰洋海平面变化的影响有待深入研究。数据的短缺和观测的不确定性目前仍然制约北冰洋海平面变化的研究工作,高分辨率数值模拟有望成为未来研究的重要工具。

The present situation of observation and research on sea level variation in the Arctic Ocean were reviewed in this study,and the characteristics and mechanisms of the Arctic sea level variability based on the analysis of observation data and numerical simulation were summarized.It has been pointed out that the seasonal sea level variability is related to the seasonal variation of sea ice formation and melt,net precipitation minus evaporation and river runoff,and is dominated by halosteric effect.The inter-annual to decadal variability is closely related to the spatial distribution of freshwater caused by anomalous cyclonic and anticyclonic atmospheric circulation associated with the Arctic Oscillation.Halosteric change dominates the low-frequency sea level variability in the deep basin,and consequent ocean mass change dominates the sea level variation on the continental shelf and the average sea level change of the Arctic Ocean.The fast sea level rise in the Beaufort Gyre region recently can be explained by freshwater accumulation due to the enhancement of high and rapid sea ice decline in Beaufort Sea.The mean sea level of the Arctic Ocean will continue rising under the global warming.The influence of recent sea ice decline and the Greenland ice sheet melt on the Arctic sea level change needs further study.The shortage of data and uncertainty of observations still restrict the research on Arctic sea level variation and the high-resolution numerical simulation is expected to be an important tool for future research.