北极海冰范围时空变化及其与海温气温间的数值分析

本文利用美国国家冰雪中心提供的1989-2014年海冰范围资料,分析了北极海冰范围的年际变化和季节变化规律。分析发现,北极海冰范围呈减少趋势,每年减小\begin{array}{c}5.91\times {10}^4\mathit{k}{m}^2\end{array},夏季减少趋势显著,冬季减少趋势弱。北极海冰范围显现相对稳定的季节变化规律,海冰的结冰和融化主要发生在各个边缘海,夏季期间的海冰具有融化快、冻结快的特征。结合海温、气温数据,进行北极海冰范围与海温、气温间的数值分析,结果表明北极海冰范围变化通过影响北极海温变化进而影响北极气温变化。海冰范围的季节变化滞后于海温和气温的季节变化。基于北极考察走航海温气温数据,进行楚科奇海海冰范围线与海温气温间的数值分析,发现楚科奇海海冰范围线所在区域的海温、气温与纬度高低、离陆地远近有关。

Spatio-Temporal Variability of Arctic Sea Ice Extent and Its Numerical Analysis with Sea Surface Temperature and Air Temperature

The annual and seasonal variability of Arctic sea ice extent was analyzed using of the sea ice extent data from 1989 to 2014, which was offered by the America National Snow and Ice Data Center. According to the data, it can be found that the Arctic sea ice extent decreases with an amplitude about 59 100 km² annually. Moreover, the fastest decline occurs in summer, while the slowest decrease appears in winter. In addition, the Arctic sea ice extent shows a relatively stable seasonal variation, which exhibit the same thawing and freezing period. Arctic sea ice extent reaches its maximum value in March, undergoing the ice thawing period from April to September. It has the minimum value in September. Subsequently, it is the ice freezing period from October to March. During the summer, the sea ice reveals some featured characteristics, such as the fast thawing and sudden freezing. The Arctic sea ice thaws quickly in July and August, and freezes fast in October and November. The freezing and thawing process maps of the Arctic sea ice were made by ArcGIS software. Then, the freezing and thawing processes of the sea ice were discussed in detail. The results show that the Arctic sea ice mainly freezes and thaws in various marginal seas, including the Bering sea, Okhotsk, Beaufort Sea, Chukchi Sea, East Siberian Sea, Laptev Sea, Kara Sea, Barents Sea, Hudson B. and Baffin Bay. Finally, according to the sea surface temperature and air temperature data, the relationships among Arctic sea ice extent, sea surface temperature and air temperature were preliminarily discussed here. The results show that a change of the Arctic sea ice which affects the sea surface temperature may cause a variation of the air temperature. However, the seasonal changes of sea ice extent occur later than the seasonal changes of sea surface temperature and air temperature. The relationships among Arctic sea ice extent, sea surface temperature and air temperature in Chukotskoye More were analyzed using the sea surface temperature data and air temperature data derived from the ship-based observations. The data show that when the sea ice extent gets closer to the North Pole, the sea surface temperature and air temperature will be lower. When the sea ice extent gets closer to the land, the sea surface temperature and air temperature will be higher.