哈德逊湾海冰时空变化及其对气候元素变化的响应

发布时间：2019-03-26 11:55

【摘要】：作为海洋系统的主要组成,海冰在全球气候系统中的影响也不容小觑。它是海洋和大气之间的能量媒介,通过热量和动能使海洋和大气产生时空上的相互作用。哈德逊湾海冰存在明显的区域性、季节性、年际差异性变化。在1971-2011年间,哈德逊湾的海冰总面积及海冰密集度大幅下降,季节冰数量减少,多年冰不复存在。于此同时,在夏季海冰消融比率越来越高。海冰变化研究对于全球气候、生态系统以及人类活动意义重大。结合1971-2011年哈德逊湾海冰及气温数据,本文总体特征、海冰密集度变化、季节冰和多年冰、夏季海冰以及气温对冰情的影响五个方面展开了研究。结果显示：(1)从空间角度对哈德逊湾海冰进行分析,可得：哈德逊湾地区海冰分布情况不均,总体呈现从南向北海冰密集度变大的趋势。按地域标准将哈德逊湾分为不同区间,海冰年际变化率从大到小依次为：北部、东部、西北、中部。其中变化最小的中部海域变化值接近海域内的平均值。总体而言,以东北和西南为轴,把哈德逊湾分为两个研究区域,则东北区域变化远远大于西南区域。哈德逊湾冰情整体变化情况对分区海域的影响表现在：海冰总量的变化主要发生在东部和北部海域,西南海域的海冰变化趋势较弱。(2)从时间角度对哈德逊湾海冰进行分析,发现：各海域在四个季节中海冰密集度的排序从大到小依次为：冬季、春季、秋季、夏季。从海冰面积的角度而言,夏季海冰面积最小,而冬季海冰分布面积最大。在海域分区中,中部海域在四个季节中海冰变化最为明显。各密集度的海冰的变化趋势基本一致：冬季海冰密集度与分布范围都是最大的,显而易见夏季两者的值都最小。(3)哈德逊湾季节年冰和多年冰数量均呈逐年递减的趋势。在1981-2011年间多年冰密集度呈减小的趋势,其中又以北部海域的减小趋势最为明显。东部海域季节冰密集度平均值最小,中部海域的季节冰密集度最大,北部海域的季节冰密度值最接近平均值。从1981-2011年间的变化趋势而言,北部海域的减小速率最快,西北和中部海域的速率几乎持平。(4)哈德逊湾夏季海冰密集度整体为减小趋势,R值为0.18。夏季海冰变化趋势最大的为西北海域,最小的为东部海域。夏季每个月的海冰变化趋势大致相似,都符合整体的季节变化趋势范围。九月以后天气转凉,海冰面积由春夏季的减少变为增加趋势,海冰密集度也开始变大。(5)综合气温数据和海冰密集度变化分析发现：在1971-2011年间,平均每年解冻期、冰封期、无冰期变化的天数依次为0.50、0.46、0.91天。从空间范围来看,冰封期推迟的范围最大,占到了总体的83.8%。
[Abstract]:As a major component of the ocean system, the impact of sea ice on the global climate system should not be underestimated. It is an energy medium between the ocean and the atmosphere, which causes spatio-temporal interactions between the ocean and the atmosphere through heat and kinetic energy. There are obvious regional seasonal and interannual variations of sea ice in Hudson Bay. In 1971-2011, the total area and concentration of sea ice in Hudson Bay decreased significantly, seasonal ice volume decreased, and years of ice ceased to exist. At the same time, the rate of sea ice melting is getting higher and higher in summer. The study of sea ice change is of great significance to the global climate, ecosystem and human activities. Based on the data of sea ice and air temperature in Hudson Bay from 1971 to 2011, the general characteristics, the variation of sea ice concentration, seasonal ice and multi-year ice, summer sea ice and the effect of temperature on ice condition are studied. The results are as follows: (1) the sea ice in Hudson Bay is analyzed from the angle of space, and the distribution of sea ice in Hudson Bay is uneven, showing a trend of increasing ice density from south to north sea. According to the regional standard, Hudson Bay is divided into different zones, the interannual change rate of sea ice from large to small is: northern, eastern, northwest, central. The change value of the middle sea area which has the least variation is close to the average value of the sea area. In general, taking the northeast and southwest as the axis, the Hudson Bay is divided into two research areas, and the changes in the northeast are much larger than those in the southwest. The overall changes in the ice conditions in Hudson Bay have an impact on the regional sea areas: the total sea ice volume changes mainly occur in the eastern and northern waters. The trend of sea ice variation in southwest sea area is weak. (2) the sea ice in Hudson Bay is analyzed from the point of view of time. It is found that the order of sea ice density in four seasons is winter, spring, autumn and summer in the following order: winter, spring, autumn and summer. From the point of view of sea ice area, the sea ice area is the smallest in summer and the largest in winter. In the sea area division, the sea ice change in the middle sea area is most obvious in the four seasons. The variation trend of sea ice concentration is basically the same: the concentration and distribution range of sea ice in winter are both the largest and obviously the smallest in summer. (3) the number of annual ice and multi-year ice in Hudson Bay decreases year by year. In 1981-2011, the ice density decreased, especially in the northern sea area. The average value of seasonal ice density is the smallest in the eastern sea area, the largest in the central sea area, and the closest to the average value in the northern sea area. From the trend of change from 1981 to 2011, the decrease rate of the northern sea area is the fastest, and the rate of the northwest and central waters is almost the same. (4) the summer sea ice density of Hudson Bay decreases as a whole, the R value is 0.18. The largest trend of sea ice variation in summer is in the northwest sea area and the smallest in the eastern sea area. The monthly sea ice change trend in summer is similar, all accord with the whole seasonal variation trend range. After September, the weather turned colder, the sea ice area changed from spring and summer to an increasing trend, and the sea ice density also began to increase. (5) the analysis of combined air temperature data and sea ice density showed that during the period of 1971-2011, the average annual freezer period was. The change days of ice seal period and no ice period were 0.50,0.46 and 0.91 days respectively. In terms of spatial scope, the postponement of the ice seal was the largest, accounting for 83.8% of the total.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P731.15

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