2014年夏季北极东北航道冰情分析

ANALYSIS OF SEA ICE CONDITIONS IN THE ARCTIC NORTHEAST PASSAGE IN SUMMER 2014

使用2003—2014年6—9月份的AMSR-E和AMSR-2海冰密集度数据计算了北极海冰范围,并获得海冰空间分布图。通过分析得出,2014年北极夏季海冰范围在数值上与2003—2013年的多年平均值很接近,在空间分布上与多年中值范围相比主要表现为两个方面的不同:(1)2014年夏季拉普捷夫海及其以北海域海冰明显少于多年中值范围,9月份冰区最北边界超过了85°N;(2)巴伦支海北部斯瓦尔巴群岛至法兰士约瑟夫地群岛区域海冰范围明显多于多年中值范围,而且海冰范围在8月份不减反增,冰区边界较7月份往南扩张了约0.8个纬度。2014年夏季在拉普捷夫海以南风为主,而在巴伦支海以北风为主。南风将俄罗斯大陆上温暖的空气吹向高纬地区,造成高纬地区温度偏高,促进拉普捷夫海海冰融化,并使海冰往北退缩。北风将北冰洋上的冷空气吹向低纬地区,造成巴伦支海的气温偏低,不利于海冰的融化,同时北风使海冰往南漂移扩散,造成巴伦支海北部海冰范围在2014年偏多。2014年北地群岛航线开通时间范围大约在8月上旬到10月上旬,时长约两个月。新西伯利亚群岛及附近海域的开通时间稍早于北地群岛,但关闭时间比北地群岛晚,所以2014年东北航道全线开通的时间主要受制于北地群岛附近海冰变化。

Data obtained from AMSR-E and AMSR-2 were used to calculate the extent of Arctic sea ice and to determine sea ice distributions during June—September from 2003 to 2014. Little difference was found between the extent of sea ice in 2014 and the mean 2003—2013 distribution. However,two apparent differences were found between the spatial distribution of sea ice in 2014 and the median 2003—2013 extent.（ 1） Sea ice in the Laptev Sea was obviously less than the median extent,and the sea ice boundary was higher than 85°N in September.（ 2） Sea ice extent in the northern Barents Sea was greater than the median extent,and the sea ice boundary expanded during summer 2014. The air pressure field in summer 2014 caused southerly winds over the Laptev Sea and northerly winds over the Barents Sea. The southerly winds brought warmer air,which promoted sea ice melting and forced the sea ice boundary to retreat northward. The northerly winds brought colder air,which reduced sea ice melting and forced the sea ice to drift southward. This resulted in a greater amount of sea ice in the northern Barents Sea. The Northeast Passage is generally navigable from early August to early October in Severnaya Zemlya. The time of opening of the Northeast Passage in the New Siberian Islands and adjacent sea regions is earlier than in Severnaya Zemlya and it closes later. Therefore,the navigability of the entire Northeast Passage depends on sea ice conditions around Severnaya Zemlya.