1979-2012年北极海冰运动特征及其对气旋活动的响应研究

发布时间：2018-01-12 11:28

本文关键词：1979-2012年北极海冰运动特征及其对气旋活动的响应研究　出处：《上海海洋大学》2016年硕士论文　论文类型：学位论文

【摘要】：北冰洋是全球淡水、热量和盐交换的重要区域。北极地区的海洋科学研究对全球气候变化、北极航道开辟等重要课题的开展都起到举足轻重的作用。过去的几十年,北冰洋发生了剧烈的变化,其显著特征是北极海冰的急剧减少。海冰是北冰洋与大气的隔离层,海冰的覆盖范围对海洋的反照率、温盐环流和大气-海洋间多种通量交换的调控发挥至关重要的作用。因此北极海冰变化及其影响因素的研究,为评估北极乃至全球气候变化提供理论依据,对了解北冰洋与中低纬度海洋的物质、能量交换具有积极意义。首先,本文利用美国冰雪数据中心发布的逐月海冰平均运动数据和范围数据,分析了1979—2012年北极整体区域和波弗特-楚科奇海域、弗拉姆海峡两个子区域的海冰运动学特征及其与海冰范围之间的关系。结果表明在过去34年里海冰平均运动速度呈增强的趋势,冬季海冰平均运动速度增加趋势明显强于夏季;北极整体区域以及波弗特-楚科奇海域、弗拉姆海峡的冬、夏季海冰平均运动速度的增长率分别为2.1%/年和1.7%/年、2.0%/年和1.6%/年以及4.9%/年和2.2%/年。1979-2012海冰运动速度与范围之间存在显著的负相关关系,相关系数为-0.77。其次,利用美国环境预报中心/国家大气研究中心的月平均风速再分析资料,分析了1979-2012年风场的长期变化趋势。北极冬季和夏季风场的长期变化趋势与海冰平均运动速度的变化趋势一致,冬、夏季也均呈现增长的趋势,冬季的增长率高于夏季。二者之间在冬季和夏季的相关系数分别为0.50和0.48。结合欧洲中期天气预报中心提供逐日气压场、风场、海冰密集度资料以及美国冰雪中心提供的逐日海冰运动数据,以2007年和2012年为例探讨了北极表面风场作用下海冰的运动特征以及辐散辐合。风场和气压场对海冰的运动、辐散和分布发挥着重要作用。2007年夏季第234-273天波弗特海域被高压系统控制,白令海峡和楚科奇海及其北部盛行南风。波弗特涡旋强盛,使得波弗特海域海冰聚集在北极中央区;顺时针的风场促使海冰向格陵兰岛和加拿大北极群岛以北聚合。2012年白令海峡和楚科奇海域处于低压和高压系统的交界处,盛行偏北风,导致海冰从北极东部往西部输运,加拿大海盆的多年海冰因离岸运动而辐散,产生薄冰,与喀拉海、拉普捷夫海域的海冰移向东西伯利亚海,并最终移入楚科奇海域,并在此区域受低纬暖水入流的影响而融化。再次,本文利用欧洲中心逐日4时次(6小时)的风场、海平面气压、海表面温度、500hPa温度等再分析资料,采用气旋自动识别和追踪方法,统计了1979-2012年北极气旋数量、空间分布、生命史、运行距离和速度等特征。结果发现,冬季和夏季北极气旋数量均呈波动形式变化,冬季数量多于夏季。冬季和夏季北极气旋的生命史分布基本一致,生命周期为5天以内的北极气旋占绝大多数。相对静止或纬向运动这一类气旋的运行距离约在60km内,累积频率约达到80%以上;其他三类北极气旋的变化趋势相对较为平缓,在100km附近的累积频率接近80%。北极气旋的平均运行速度为4.73m·s-1,在3~6m·s-1范围的气旋数量所占比例最大。气旋的生成区和消亡区均呈现出空间分布的不均匀性,主要集中在大西洋一侧的北极。楚科奇海域作为北冰洋与低纬度海洋联通的渠道,是气旋消亡的极值区。夏季海冰的变薄、面积的缩减和开阔水域的增加,导致北极海冰更容易受到气旋的影响。因此,本文最后探讨了夏季北极气旋个数与海冰范围之间的关系。结果发现1996-2012年夏季北极较强气旋发生的个数与海冰范围之间存在较为显著的负相关关系,相关系数为-0.5。这可以说明,1996-2012年较强气旋的个数与海冰变化之间关系较为紧密。另外通过北极气旋案例研究发现,海冰受气旋影响,运动模式趋向于气旋式,速度会发生突增,密集度会骤减。这为进一步研究北极气旋对海冰的影响提供了证据。
[Abstract]:The Arctic Ocean is an important area of global freshwater, salt and heat exchange. The global climate change on marine scientific research in the Arctic, Arctic waterways and other important open research have played a pivotal role. In the past few decades, has undergone dramatic changes in the Arctic Ocean, a significant feature is the drastic reduction of Arctic sea ice ice. The isolation layer and the atmosphere, sea ice coverage of the ocean albedo, thermohaline circulation and air sea flux exchange between the various regulation play a crucial role. Therefore the Arctic sea ice and its influencing factors, and provide a theoretical basis for the evaluation of the Arctic and global climate change, on the understanding of the Arctic Ocean and the low latitude ocean the material, has the positive significance of energy exchange. First of all, the monthly sea ice using National Snow and Ice Data Center released the average motion data and data analysis. 1979 - 2012 - Chukotka area and overall Arctic Beaufort Sea area, the relationship between sea ice kinematics characteristics of Flam Strait, two sub regions and sea ice extent. The results show that in the past 34 years the average velocity of sea ice is increasing, the average velocity of winter sea ice increasing trend was stronger in summer; the Arctic region and whole Beaufort - the Chukotka sea, the Strait of Flam winter, summer sea ice velocity average growth rates were 2.1%/ and 1.7%/, there was a significant negative correlation between 2.0%/ and 1.6%/, 4.9%/ and 2.2%/.1979-2012 ice movement speed and range, the correlation coefficient is -0.77. second, then according to the analysis data of National Centers for environmental prediction / the National Center for atmospheric research, the average monthly wind speed, analysis of long-term trends in 1979-2012 wind field. The Arctic winter and summer winds long The same trend, the average velocity of phase change trend and sea ice in winter, summer also showed a growth trend, the growth rate of winter than in summer. The correlation coefficient between the two in winter and summer were 0.50 and 0.48. with ECMWF provide daily pressure field, the wind field, the daily sea ice motion data the snow and sea ice concentration data center, in 2007 and 2012 as an example of the Arctic surface wind field under the sea ice motion characteristics and divergence movement. Wind and pressure field on the ice, divergence and distribution plays an important role in.2007 234-273, the sea is the summer sky wave high pressure system control, the Bering Strait and Chukotka sea and the northern prevailing southerly. Beaufort Sea Ice strong vortex, the Beaufort gathered in the central Arctic; clockwise wind field makes to the Greenland Sea Ice Orchid Island and Canadian Arctic islands to the North.2012 polymerization of the Bering Strait and Chukotka waters is at the junction of the low and high pressure systems, prevailing northerly winds, resulting in sea ice from the Arctic to the west east transport, multi-year sea ice in the Canada Basin due to offshore movement and divergence, produce ice, and the Kara Sea, Rapp Jeff sea ice motion to the east of the sea of Siberia, and eventually moved into the Chukotka sea, and the effect of this region by melting and low latitude warm water inflow. Again, the European center daily 4 times (6 hours) of the wind field, sea level pressure, sea surface temperature, 500hPa temperature reanalysis data, the automatic identification and tracking method of cyclone, statistics 1979-2012 Arctic cyclone number, spatial distribution, life history, running distance and speed characteristics. The results showed that the number of winter and summer Arctic cyclone were fluctuation change, more than the number of winter Summer is basically the same. The history of life distribution in winter and summer Arctic cyclone, life cycle within 5 days of the Arctic cyclone majority. Relative distance running static or latitudinal motion of this type of cyclone is about 60km, the cumulative frequency reached about 80% above trend; the other three types of Arctic cyclone is relatively flat. The average speed of the cumulative frequency near 100km 80%. near the Arctic cyclone was 4.73M - s-1, 3~6m - S-1 in the cyclone number range accounted for the largest proportion. Generating area and disappearance of cyclone show area uneven distribution, mainly concentrated in the the Atlantic side of the Arctic waters of Chukotka. As the Arctic Ocean and the low latitude marine Unicom channel, is the extreme area cyclone dies. The summer sea ice thinning, area reduction and open water increases, resulting in Arctic sea ice is more vulnerable to cyclone effect. Therefore, the most After discusses the relationship between summer Arctic cyclone number and sea ice extent. The results show that there is a significant negative correlation between the 1996-2012 summer Arctic cyclone strong with the number of the sea ice extent, the correlation coefficient is -0.5. which can show the relationship between the number of sea ice and the change of 1996-2012 years strong cyclone also through more closely. Arctic cyclone case study found that sea ice was affected by cyclone, cyclone movement patterns tend to occur, the speed of surge intensity will sharply. This provides evidence for the further research on the influence of sea ice in the Arctic cyclone.

【学位授予单位】：上海海洋大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P731.15;P732

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