北极海冰变化对北半球气候影响研究

发布时间：2018-04-11 06:11

本文选题：CAM3.1模式 + 北极海冰　；参考：《中国海洋大学》2014年博士论文

【摘要】：自1979年有卫星观测记录以来,北极海冰面积特别是秋季海冰面积处于明显的下降趋势。2012年9月达到有观测记录以来的最低值为3.41百万平方公里,其次是2007年9月的4.13百万平方公里,而2013年9月比2012年同期增加了60%。本文研究了2007、2012年北极海冰达到极小值时,海冰融化区域不同的原因,以及2013年比2012年增加60%的原因。数据分析显示,北极秋季海冰融化区域不同,与底层大气环流和上层海洋异常场的分布密切相关,冰-温(表面气温和海表面温度)和冰-汽三个正反馈机制等,5个条件共同作用,导致海冰融化。近几年冬季,北半球大陆地区极端天气事件频繁发生,冻雨、冷冬、暴雪等造成人类社会巨大的经济损失。结合北极秋季海冰减少,本文运用数据分析和数值试验方法,研究其对北半球中纬度地区气候变化的影响。得出,受北极秋季海冰减少的影响,东亚、北极地区冬季气温呈跷跷板结构。冬季极区冷空气更容易入侵东亚,造成严寒等极端天气,而极区气温则出现气候变化的“北极放大效应”；另外受北极秋季海冰减少的影响,夏季趋向变热而冬季趋向变冷,冬、夏季温差变大,夏季易出现酷暑,冬季易出现严寒等极端天气事件；春、秋季升温明显,故夏季变长,春季提前进入夏季,秋季则滞后出现。海冰卫星数据显示,不同阶段北极海冰下降速度差异巨大,1996-2012年海冰平均下降速度比1979-1995年加快了近4倍。据此两阶段,本文分析了北极秋季海冰减少与北半球冬季大气环流的关系。数据分析和数值试验表明,海冰下降速率不同,所对应的大气环流模态截然不同：海冰下降慢时,西风急流加强,中纬度大陆地区出现暖冬：海冰下降快时,中纬度位势高度降低、西风急流和经向风减弱,使极区冷空气更加容易入侵中纬度地区,从而东亚、北美等地更易出现冷冬。模式结果表明,北极秋季海冰减少的影响在秋季对极区最大,减少慢时极区升温比减少快时要强烈,减少快时较高纬度变冷；冬季,海冰减少的最大影响扩展到中纬度地区,减少慢时易造成暖冬,而快时易出现冷冬；春季,这种影响减弱,且已移动到更低纬度；夏季,新一轮海冰开始融化,极区大气环流又发生变化,周而复始。若按目前北极秋季海冰下降速度推演,将来不久北极会面临海冰全部融化的风险。气候模型估计北极夏季将在2030年左右无冰。基于此本文设计了北极9月无冰试验,研究无冰对北半球大气环流的影响。实验结果显示,北极无冰使秋季极区气温明显降低：冬季,中纬度地区气温升高;直到夏季,无冰对大气环流的影响传输到热带等更低纬度。北极海冰继续快速融化直至无冰,北半球中纬度地区不仅在春、夏、秋三季变暖,冬季的冷冬也会消失,而转为暖冬。卫星数据显示,2013年秋季北极海冰没像往年一样继续下降,反而比2012年同期增加了60%,而2013年冬季北美遭受了几十年不遇的严寒和暴雪袭击。通过数据分析和数值试验探讨得知,2013年北美冷冬基本上是由于在北极秋季海冰快速下降的大背景下,2013年秋季海冰突然比2012年同期增加60%所致。北极秋季海冰变化,使北美2013年冬季位势高度场降低、经向风减弱、极地寒流入侵,造成了北美冷冬极端天气事件。若只是与气候态相比,2013年海冰下降的情况,不会造成2013年北美冬季极端严寒天气。北极秋季海冰在2007年和2012年分别达到次小值和最小值,而这两年北半球冬季降雪明显增多,但增多的区域不同。2007年主要在亚洲大陆和北美中部,2012年主要在欧洲中部和东亚渤海沿岸。数据分析结果表明,这两个特殊年份由于满足降雪的大气环流的动力、水汽、温度等条件的分布不同,而导致降雪增多的区域不同。
[Abstract]:Since 1979, satellite observation record, the Arctic sea ice area in autumn in the sea ice area significantly decreased.2012 in September reached the lowest since the observed record of 3 million 410 thousand square kilometers, followed by 4 million 130 thousand square kilometers in September 2007, and in September 2013 compared to the same period in 2012 increased by 60%. in this paper 20072012 years reaches the minimum value when the Arctic sea ice the reason, the melting of sea ice to different areas, and in 2013 than in 2012 increased by 60%. The data analysis shows that the Arctic sea ice area in autumn, and is closely related to the distribution of atmospheric circulation and ocean bottom layer anomaly, ice - temperature (surface temperature and sea surface temperature) and ice - steam three positive feedback mechanism. 5 conditions, interaction, resulting in melting of sea ice. Winter in recent years, extreme weather events in the northern hemisphere area occurred frequently, freezing rain, cold winter, snow and other man-made The social class of the huge economic loss. With the fall Arctic sea ice reduction, this paper uses data analysis and numerical experiment method, to study its effect on climate change in the northern hemisphere latitudes. The influence of Arctic sea ice to reduce the fall of East Asia, the Arctic winter temperatures in winter. The polar cold air seesaw structure more easily invaded East Asia. The cold caused by extreme weather, and polar temperatures in the emergence of climate change "Arctic amplification effect"; also affected by the reduced Arctic sea ice in summer autumn and winter, tend to become hot trend of cold, winter, summer temperature becomes large, prone to summer heat, winter prone to extreme weather events such as the spring and autumn cold; warming significantly, so the summer long, ahead of the spring into the summer, autumn is delayed. Sea ice satellite data show that the different stages of the Arctic sea ice decline speed difference is huge, 1996-2012 year sea ice The average rate of decline was up nearly 4 times more than 1979-1995 years. According to the two stage, this paper analyzes the Arctic sea ice in winter and autumn reduced the relationship between atmospheric circulation in the northern hemisphere. It shows that the data analysis and numerical experiment, sea ice decline rate is different, corresponding to the different atmospheric circulation mode: sea ice declined slowly, the westerly jet strengthened in warm winter latitude mainland: sea ice decline fast, mid latitude reduction of geopotential height, westerly jet and meridional wind weakened, the polar cold air intrusion more easily in the mid latitudes, and East Asia, North America and other places prone to cold winter. The results show that the effect of reducing the Arctic sea ice in the autumn fall on the polar maximum, reduce slow when the temperature rises quickly to reduce the region strongly, reduce fast higher latitude cold winter; maximum impact reduction in sea ice is extended to the mid latitude region to reduce easilycausing warm winter slow, and fast Easy to appear when the cold winter; spring, this effect is weakened, and has moved to lower latitudes; in summer, a new round of ice melting, polar atmospheric circulation change again, again and again. If the Arctic sea ice fall down speed deduction, the near future will face the risk of all the Arctic climate model to estimate the melting of sea ice. The Arctic summer around 2030. Based on this ice free Arctic ice free in September this paper designs test, no influence on the atmospheric circulation of the northern hemisphere ice research. Experimental results show that the Arctic ice free region in the autumn temperature decreased significantly: in winter, the temperature rise in mid latitudes; until summer, ice has no effect on the atmospheric circulation transmission to tropical etc. lower latitude. The rapid melting of Arctic sea ice continues until no ice, not only in the latitudes of the northern hemisphere in spring, summer, autumn three season warming, cold winter will disappear, and turn into warm winter. Satellite data show In the autumn of 2013, Arctic sea ice did not like in previous years continued to decline, but compared to the same period in 2012 increased by 60%, while in the winter of 2013, North America suffered in decades of cold and snow. Through data analysis and numerical tests on that cold winter in North America in 2013 basically is the large background on the sea ice in the Arctic in the rapid decline of the the autumn of 2013, the sea ice suddenly over the same period in 2012 increased by 60% due. Arctic sea ice changes in autumn, the North America in the winter of 2013, geopotential height decreased, meridional wind weakened, polar cold invasion, resulting in the north cold winter of extreme weather events. If it is compared with the climatology, 2013 sea ice decline, will not cause the 2013 North American winter the extreme cold weather. The Arctic sea ice in autumn respectively small value and the minimum value in 2007 and 2012, and this year the northern hemisphere winter snowfall increased significantly, but increased in different regions. In 2007, mainly in Asia and central North America in 2012, mainly in Central Europe and the east coast of Bohai. The results of data analysis showed that the two year as a result of special power, the atmospheric circulation of snow to meet the water vapor, temperature distribution of the different conditions caused by more snow in different regions.

【学位授予单位】：中国海洋大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P731.15;P461.2

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