北半球海冰变化及其与气候要素的关系

发布时间：2018-01-11 17:25

本文关键词：北半球海冰变化及其与气候要素的关系　出处：《南京大学》2014年硕士论文　论文类型：学位论文

【摘要】：在过去几十年,北极地区的海冰大量减少,海冰覆盖面积的年平均下降速度不断加快,夏季9月最小海冰外缘线面积在2007和2012年先后创下有卫星数据记录以来的最小值。北极海冰密集度总体下降,夏季极点附近出现大面积海冰融池。北极海冰的冰龄也在逐渐减小,多年冰覆盖面积下降,季节性海冰覆盖范围增加,海冰的季节性变化加剧。海冰是北极海洋系统的重要组成部分,同时在全球气候系统中也扮演着极其重要的角色,它影响着太阳辐射以及热量和动能在海洋和大气之间的交换,在不同的时间和空间尺度上对海洋和大气产生相互作用。北极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。本文采用美国雪冰数据中心1979-2013年的SMMR、SSMI和SSMIS逐日海冰密集度产品,NCEP/NCAR再分析资料中的气温数据以及美国气象预报中心提供的AO、NAO和ENSO指数,分析月平均、多年月平均、季节平均和年平均时间尺度上,北半球地区海冰密集度、海冰外缘线面积以及海冰面积的变化情况,讨论35年间北半球多年冰和季节冰的变化趋势。同时,初步探讨了北半球海冰变化特征与各气候要素的关系。首先,35年来北半球地区海冰密集度整体不断下降。特别是2007至2012年间,海冰密集度变化尤为明显,高值区面积大大缩小,海冰密集度低值区延伸到极点附近。北半球海冰密集度在3月达到最大值,9月出现最小值,海冰密集度在低纬和高纬之间表现出周期性的时空差异。海冰有规律的生长和消融过程,在季节平均和多年月平均尺度上表现明显。其次,整个北半球的海冰外缘线面积和海冰面积也在减小,年平均下降速度分别为-55.5×106km2.a-1和-53.0×106km2.a-1,二者在不同时间尺度上的变化趋势基本一致,只是海冰面积相对海冰外缘线面积总体偏小。北半球多年冰主要分布在北冰洋核心区,35年来覆盖范围不断缩小,2007年至今的变化最为明显。随着多年冰面积的减少,季节性海冰的覆盖面积逐渐占领北冰洋核心区大部分海域。再次,整个北半球地区以及9个分海区海冰外缘线面积、海冰面积、多年冰和季节冰的变化特征各不相同。此外,各海区的海冰面积与对应海冰外缘线面积的变化趋势也有一定差异。通过比较发现,对整个北半球海冰的变化贡献率最大的海域主要有北冰洋核心区、喀拉海和巴伦支海,它们的海冰变化情况直接影响到整个北半球地区海冰的总体变化特征。最后,北半球年平均海冰外缘线面积和海冰面积与北半球年平均气温的相关系数R都高达-0.94，二者与气温有很强的负相关关系。再将海冰外缘线面积和海冰面积与冬季标准化AO和NAO指数做相关分析,相关性显著的海域包括圣劳伦斯湾、巴芬湾／拉布拉多海和哈德孙湾。年平均海冰外缘线面积和海冰面积与冬季标准化AO指数的相关系数通过95%的置信检验,与NAO指数的相关系数通过99%的置信检验。ENSO与年平均海冰外缘线面积之间的相关性分析得出,总体上ENSO的El Nino(暖事件)年期间,海冰外缘线面积增加；而在ENSO的La Nina(冷事件)年,则出现海冰外缘线面积减少的现象。
[Abstract]:In the past few decades, a substantial reduction in Arctic sea ice, sea ice cover the average annual rate of decline is accelerating, the September summer minimum sea ice edge area in 2007 and 2012 has hit a minimum value of the satellite data record. Arctic sea ice concentration decreased and the large area of sea ice melting occurs near the pole. The Arctic summer ice ice age is gradually reduced, decreased years of ice cover, seasonal sea ice coverage increased, increasing the seasonal variation of sea ice, sea ice is an important part of the Arctic Ocean system, at the same time in the global climate system also plays a very important role, it affects the solar radiation and heat and energy exchange in between the ocean and the atmosphere, in different time and space scale interaction of Oceanic and atmospheric research. Arctic sea ice changes to the global climate and ecosystem And human activities are of great significance.
The National Snow and Ice Data Center 1979-2013 years of SMMR, SSMI and SSMIS daily sea ice concentration, NCEP/NCAR reanalysis data and temperature data provided the weather forecast center of AO, NAO and ENSO index, based on the monthly mean, mean monthly, seasonal and annual average time scale, the northern hemisphere sea ice of the sea ice edge area and the change of sea ice area, discuss the change trend of 35 years of the northern hemisphere ice and ice season. At the same time, discussed the relationship characteristics of sea ice changes in the northern hemisphere and climatic factors.
First of all, in 35 years the northern hemisphere sea ice concentration overall declining. Especially in the 2007 to 2012 years, sea ice concentration change is obvious, the high value area greatly reduced sea ice concentration low value area extends to near the pole. The northern hemisphere sea ice concentration in March reached the maximum value, the minimum value of sea ice in September. Dispersion between low and high latitude areas showed spatial differences. Regular periodic sea ice growth and melting process, the seasonal and monthly mean scale performance significantly.
Secondly, the sea ice edge area and sea ice area in the northern hemisphere are reduced, average annual rate of decline was -55.5 * 106km2.a-1 and -53.0 * 106km2.a-1, the changes at different time scales. The trend of the two are basically the same, only the sea ice area relative to the sea ice edge area is too small. The northern hemisphere is mainly distributed in the Arctic ice for many years the core area of 35 years of coverage is shrinking, the most obvious change since 2007. With the decrease of multiyear ice area, covering an area of seasonal sea ice gradually occupied the core area of the Arctic Ocean most waters.
Again, the entire northern hemisphere and 9 sub sea ice edge area, sea ice, ice ice and seasonal variation characteristics for each. In addition, the change trend of the sea ice area and the corresponding sea ice edge area also have certain differences. By comparison, the change of the northern hemisphere sea ice contribution the maximum rate of the main core area of the Arctic Ocean sea, Kara Sea and Barents Sea ice conditions, which directly affects the overall features of the sea areas of the northern hemisphere.
Finally, the northern hemisphere average sea ice edge area and the northern hemisphere sea ice area and the average annual temperature and the correlation coefficient R is as high as two -0.94, there is a strong negative correlation with temperature. The correlation analysis of the sea ice edge area and sea ice area in winter and standardized AO and NAO index, significant correlation including the waters of the Gulf of St. Lawrence, Baffin Bay and the Labrador Sea and Hudson Bay. The correlation coefficient of the annual average sea ice edge area and sea ice area in winter and standardization of AO index by 95% confidence test, correlation coefficient and NAO index by confidence seized 99% experimental correlation between.ENSO and the annual average sea ice edge area analysis in general, ENSO El Nino (warm events) during the period, the sea ice edge area increased; and in the ENSO La Nina (cold event), appeared in the sea ice edge area to reduce the phenomenon.

【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P731.15;P732

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