北极楚科奇海阿拉斯加沿岸冰间湖及相关的海洋过程分析

发布时间：2018-01-05 13:14

本文关键词：北极楚科奇海阿拉斯加沿岸冰间湖及相关的海洋过程分析　出处：《中国海洋大学》2014年硕士论文　论文类型：学位论文

【摘要】：利用2003年至2011年AMSR-E（Advanced Microwave Scanning Radiometer-Earth Observing System）日平均海冰密集度数据，对楚科奇海阿拉斯加沿岸冰间湖进行了分析。针对冰间湖的特点，在阈值法的基础上，通过统计无冰水域出现的频率，限定冰间湖的最大范围，区分各个冰间湖。通过计算阿拉斯加沿岸冰间湖的面积，结合NCEP（National Centers for Environmental Prediction）再分析风场数据和白令海峡潜标观测的温盐和海流数据，初步探讨冰间湖发生、发展的规律。为了排除海冰外缘区对判断冰间湖的影响，研究仅限于白令海峡完全冰封的1月至4月。阿拉斯加沿岸海域每年冬季都会出现5个冰间湖，，多数时间为固定于大陆边缘的沿岸冰间湖，北端在3月和4月会出现位于沿岸固定冰之外的裂缝冰间湖。冰间湖面积每天都发生变化，表现出天气尺度的变化特征，经历长达数日的发展和消失的过程，与风场的转换有密切关系。离岸风有利于沿岸冰间湖的扩展，但是该海域1-4月的盛行风为东北风和北风，对于多数冰间湖而言为沿岸风，不利于冰间湖的形成，因而冰间湖会出现长达数十日的消失。在偏北风的影响下，太平洋入流对北部的冰间湖几无作用，而对南部冰间湖的空间分布有着重要影响。利用NCEP再分析数据计算冰间湖海气界面的热通量和产盐量。阿拉斯加沿岸冰间湖冬季感热热通量主导着热平衡。冰间湖表面的热损失并不是直接取决于冰间开阔水域的面积，而是会受到冰间湖发生时间以及季节影响。冰间湖的每日产盐量呈现出天气尺度的变化特征，其变化率十分大。2003年-2011年各年的累计产盐量总值均为2.8x1012kg左右；但2004年的的总产盐量高达6.8x1012kg，为其它年份的2倍多。产盐量与冰间湖面积有密切关系。80%的累计产盐量都是在一月和二月形成的，这时候，开阔水域面积和每日产盐量都十分巨大。结合现场观测数据，冰间湖对加拿大海盆盐跃层结构的变化有着重要影响，这反映在冰间湖产盐量与加拿大海盆冬季太平洋水盐度之间的滞后相关性上，前者与后者的滞后时间为1年。进一步通过建立理论模型，计算冰间湖的盐跃层水产量，2003-2011年冬天阿拉斯加沿岸冰间湖的盐跃层水产量年平均为0.15±0.1Sv；而理论计算维持加拿大海盆盐跃层所需的高密度水量为0.2±0.1Sv，因此，阿拉斯加沿岸冰间湖对北极加拿大海盆盐跃层的形成和维持有着重要贡献，贡献率达到75%以上。
[Abstract]:Using AMSR-E from 2003 to 2011 (. Advanced Microwave Scanning Radiometer-Earth Observing system. Daily average sea ice intensity data. This paper analyzes the interglacial lake in Alaska coast of Chukchi Sea. According to the characteristics of the interglacial lake, based on the threshold method, the maximum range of the ice-free lake is limited by counting the frequency of the ice-free waters. The area of the interglacial lake along Alaska's coast is calculated. Combined with NCEP(National Centers for Environmental prediction). The wind field data and the temperature, salt and current data from the Bering Strait submersible survey are analyzed again. In order to exclude the influence of the outer edge of sea ice on judging the interglacial lake, the study is limited to the period from January to April when the Bering Strait is completely frozen. Five interglacial lakes occur every winter in the coastal waters of Alaska, most of the time in coastal interglacial lakes that are fixed on the continental margin. On March and April, there will be a fissure interglacial lake located outside the fixed ice along the coast. The area of the interglacial lake will change every day, showing the characteristics of synoptic scale change, and going through several days of development and disappearance. The offshore wind is favorable to the expansion of the interglacial lake, but the prevailing wind in January and April in this sea area is the northeast wind and the northern wind, and for most of the interglacial lakes, it is the coastal wind. It is not conducive to the formation of the interglacial lake, which will disappear for decades. Under the influence of the northerly wind, the Pacific inflow has little effect on the northern interglacial lake. But it has an important influence on the spatial distribution of the southern interglacial lake. Using the NCEP reanalysis data, the heat flux and salt production at the sea and air interface of the interglacial lake are calculated. The sensible heat flux of the interglacial lake in Alaska dominates the heat balance in winter. The heat loss on the surface of the interglacial lake is not directly dependent on the interglacial lake surface. The area of open water between ice. It will be affected by the time and season of the interglacial lake. The daily salt yield of the interglacial lake shows the characteristics of synoptic scale, and its rate of change is very large. The accumulative total salt yield of each year from 2003 to 2011 is about 2.8 x 1012kg; In 2004, the total salt production reached 6.8x1012kg. The total salt yield of 80% of the total salt production was formed in January and February. At this time, the area of open water and the daily salt production were very large. Combined with the field observation data, the interglacial lake has an important influence on the change of the salt cline structure of the Canadian basin, which is reflected in the lag correlation between the salt yield of the interglacial lake and the salinity of the Pacific Ocean in the Canadian basin in winter. The lag time of the former and the latter is one year. Further, through the establishment of theoretical model, the yield of salt cline water in the interglacial lake is calculated. In the winter of 2003-2011, the average annual water yield of salt cline in the interglacial lake of Alaska was 0.15 卤0.1 Sv. The theoretical calculation of the high density water required to maintain the salt cline in the Canadian basin is 0.2 卤0.1 Sv. Therefore, the interglacial lake along the Alaska coast has an important contribution to the formation and maintenance of the salt cline in the Arctic Canadian basin. The contribution rate is more than 75%.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P731.15

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