In this paper, the index of polar vortex position is introduced. This index can preferably describe the variability of mid-high latitude circulation anomaly.

本文给出的极涡位置指数能较好地描述中高纬度环流异常的变率。

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Before middle age of 1970s, area and intensity index of northern polar vortex trend to rise, with small fluctuating, and after that, with clear undulating, it trend to minish.

上世纪70年代中期之前极涡面积、强度基本为上升阶段，之后为下降阶段。

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