白令海冷水团特征及其影响因素分析

发布时间：2019-01-01 11:13

【摘要】：北极的快速变化对周边陆地和海域,甚至全球的气候系统等都产生了重要的影响,因此对于北极海域水文特征和水体结构的研究已经成为极地物理海洋学的热点问题。白令海作为连接北冰洋与中低纬度海洋的重要海区,是近年来我国北极科学考察的重点调查海域。目前我国已经进行了七次北极科学考察,在白令海获得了大量珍贵的实测数据。本文在我国第1~6次北极科考的CTD温度、盐度和溶解氧数据的基础上,结合国际共享资料,系统分析了白令海水文要素的分布特征、水团的结构特性及海盆区水团的季节性变化特征,并讨论了西白令海冷水团的夏季变化特征及影响因素。主要研究结论如下:1.白令海海盆区和陆架区水文要素的分布特征分析结果表明:白令海海盆30m以浅的上层海洋具有高温低盐的特征。在40m附近存在显著的温跃层,跃层以下是低温冷水层;盐度随深度的增加而逐渐升高,中层海水的盐度表现出南高北低的特征,并在北部近陆坡区形成高温低盐下降水舌;断面上溶解氧含量可分为三层,200m以浅含量最高,200~1500m水层含量最低,1500m以深含量随深度增加逐渐上升。圣劳伦斯岛以北陆架区东部表层水体具有高温、低盐、低溶解氧的性质,西部水体具有低温、高盐的特征。圣劳伦斯岛以南陆架区温跃层出现在20m层附近,该部分海区中的溶解氧分布与温度、盐度均表现出了一定的相关性。2.夏季白令海海盆区的水团可以分为三类:高温、低盐的白令海上层水(4.2°CT11.0°C,31.5S33.3),分布于表层40m以浅;低温的白令海中层水(0.5°CT4.2°C,32.3S33.8),大致位于40~300m水层;高盐的白令海深层水(1.2°CT4.2°C,33.8S34.7)。圣劳伦斯岛以北陆架区东部为阿拉斯加沿岸水,西部为阿纳德尔水,中部为白令海陆架水。圣劳伦斯岛以南陆架区的水团可以分为四类:白令海陆架水、白令海陆坡水、混合变性水及阿拉斯加沿岸水。3.白令海海盆区中层冷水的厚度自南向北逐渐加深,可延伸至水下379m,中层冷水最低温度可达0.54°C(1999年),温度最高为1.99°C(2014年);白令海西部陆架区冷水团最低温度低于-2°C(1999年),冷核最高温度为-1.33°C(2003年)。1999年、2008年及2012年冷水团的分布范围较大,冷核温度在各调查年份中较低,冷水团具有明显的“冷年”特征。2003年、2005年、2014年冷核的最低温较高,冷水团分布范围及平均厚度值均比较小,具有“暖年”的特点。4.在白令海西部陆架区,2000~2005年及2014年1~3月的海表面平均气温相对其他年份较高,冷核中心的温度也相对较高,两者之间的变化有较高的一致性。白令海和鄂霍次克海的偶极子型海冰异常EOF第一时间模态结果显示,陆架区冷水团为冷年的年份偶极子型海冰变化处于明显的负位相,而冷水团为暖年时偶极子型海冰变化为正位相。
[Abstract]:The rapid changes of the Arctic have an important impact on the surrounding land and sea area, even the global climate system. Therefore, the study of the hydrological characteristics and water structure of the Arctic has become a hot topic in polar physical oceanography. The Bering Sea, as an important sea area connecting the Arctic Ocean and the middle and low latitudes, is the focus of the Arctic scientific investigation in China in recent years. At present, seven Arctic scientific surveys have been conducted in China, and a large number of precious measured data have been obtained in the Bering Sea. On the basis of the CTD temperature, salinity and dissolved oxygen data of the 6th Arctic scientific survey in China, the distribution characteristics of hydrological elements in Bering Sea are analyzed systematically based on the internationally shared data. The structure characteristics of water masses and the seasonal variation characteristics of water masses in the basin area are discussed. The summer variation characteristics and influencing factors of the water masses in the West Bering Sea are discussed. The main conclusions are as follows: 1. The distribution characteristics of hydrological elements in the Bering Sea basin and the continental shelf area are analyzed. The results show that the Bering Sea basin has the characteristics of high temperature and low salt in the shallow upper ocean. There is a significant thermocline in the vicinity of 40m, below which there is a low temperature cold water layer, the salinity increases gradually with the increase of depth, the salinity of the middle sea water shows the characteristics of south high and north low, and the high temperature and low salt drop water tongue is formed in the north near continental slope. The dissolved oxygen content on the section can be divided into three layers: the shallow content is the highest at 200m, the water layer is the lowest at 200m, and the depth content increases gradually with the depth increasing. The surface water in the eastern part of the continental shelf north of St. Lawrence Island has the characteristics of high temperature, low salt and low dissolved oxygen, and the western water body is characterized by low temperature and high salt. The thermocline in the continental shelf to the south of St. Lawrence Island appears near the 20m layer. The distribution of dissolved oxygen in this part of the sea area is correlated with temperature and salinity to a certain extent. 2. The water masses in the Bering Sea basin in summer can be divided into three types: high temperature, low salt water in the upper Bering Sea (4.2 掳CT11.0 掳C ~ (1) 31.5 S _ (33.3), distributed in the surface layer of 40 m shallow; The low temperature Bering Sea middle water (0.5 掳CT4.2 掳Cn32.3S33.8) is approximately located in the 40,300m water layer, and the high-salt Bering sea deep water (1.2 掳CT4.2 掳C _ (33.8) S _ (34.7). To the north of St. Lawrence Island, the coast of Alaska is to the east, Anadell to the west, and the Bering Sea shelf to the central part. Water masses in the continental shelf south of St. Lawrence Island can be classified into four categories: Bering Sea shelf water, Bering Sea slope water, mixed denatured water and Alaska coastal water. The thickness of the middle cold water in the Bering Sea basin gradually deepens from south to north, and can be extended to 379m underwater. The lowest temperature of the intermediate cold water can reach 0.54 掳C (1999), and the highest temperature is 1.99 掳C (2014). The minimum temperature of cold water mass in western Bering Sea is lower than -2 掳C (1999), and the highest temperature of cold nucleus is -1.33 掳C (2003). The distribution of cold water mass in 1999, 2008 and 2012 is large, and the cold core temperature is lower in each year of investigation. The cold water mass has the characteristic of "cold year". In 2003, 2005 and 2014, the lowest temperature of the cold core is higher, the distribution range and average thickness of the cold water mass are smaller, and the cold water mass has the characteristic of "warm year". 4. In the western Bering Sea continental shelf area, the mean sea surface temperature and the cold core center temperature are higher in the January to March of 2000 ~ 2005 and 2014 than in other years, respectively. The EOF first time mode results of dipole sea ice anomaly in Bering Sea and Okhotsk Sea show that the dipole sea ice changes in cold years in continental shelf are obviously negative phase. The cold water mass is a positive phase of dipole sea ice during warm years.
【学位授予单位】：国家海洋局第一海洋研究所
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P731.16

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