北极海冰漂移对多年冰分布的影响研究

The Influence of Sea Ice Drift on the Distribution of Multiyear Ice

本文基于美国冰雪数据中心(NSIDC)提供的海冰漂移和冰龄数据,分析了1985-2014年北极海冰漂移场的主要模态和多年冰的分布特征,初步评估了海冰漂移对多年冰分布的影响。多年冰面积序列的小波变换结果显示多年冰面积的显著周期为1年和5年,其中5年周期在2007年之后变得显著。海冰漂移速度的经验正交分解的冬季第一模态向穿极流模态的转化,穿极流模态在30年间方差贡献率的逐步上升,穿极流态流轴位置的偏移与多年冰的分布在三个年代相吻合,揭示了二者的密切关系。波弗特海域在三个10年间速度趋势的上升,对于多年冰的输运起到了重要的作用。从三个时间段冬夏两季速度的变化来看,冬季是海冰漂移速度增加的主要时期,与该海域内多年冰面积的下降形成了正反馈关系。

Based on the sea ice drift and sea ice age data provided by the National Snow and Ice Data Center(NSIDC), this paper analyzes the main modes of ice drift in Arctic sea ice from 1985 to 2014 and the distribution characteristics of multi-year ice. The results of the wavelet transform of the multi-year ice area show that the significant period of the multi-year ice area is 1 year and 5 years, and the 5 years period becomes significant after 2007. The empirically orthogonal decomposition of the sea-ice drift indicates that the first mode in winter transfers to the transpolar drift mode. The contribution of the variance of the transpolar drift mode increases gradually in the 30 year. The position of the axis in the transpolar drift mode is shifted, which is consistent with the distribution of multi-year ice in the three decades, indicating the close relationship between the two. The increased trend of the drifting speed in the Beaufort Sea area over three decades played an important role in the transport of multi-year ice. The changes in the speeds in winter and summer seasons show that winter is the main period for the increase in sea ice drift, which forms a positive feedback relationship with the decline of the multi-year ice area in the three decades.