热带气旋对琼东上升流区温盐特征的影响及机制分析
发布时间：2018-10-13 11:45
【摘要】：位于海南岛东部的琼东上升流是南海北部陆架上升流系统的强中心之一,其温盐特征的变化对局地生态、渔业、气候等有直接影响。南海和西太平洋生成的热带气旋在移动过程中常与琼东上升流区不期而遇。探究热带气旋对琼东上升流的影响规律和机制,具有重要的科学意义和应用价值。本文利用近30年的卫星遥感资料和2013年现场观测资料,对过境琼东上升流区的热带气旋引起的海表温度(SST)和温盐结构变化进行分析。结果显示,与开阔大洋显著不同,琼东上升流区SST变化存在降温、基本不变和降温三种类型。1982-2011年过境琼东上升流区的36例热带气旋中,有为17例引起降温、16例SST基本不变,3例引起升温。平均升温2.1oC大于平均降温-1.5oC。SST变化与热带气旋要素的统计关系显示,与气旋过境时长相比,热带气旋强度和入射角度对SST变化幅度影响更大。2013年8月热带气旋“飞燕”过境琼东上升流区,上升流区SST上升,尤其是气旋路径右侧上升流中心升温幅度最大为1oC。气旋前后现场观测断面的对比分析显示,琼东上升流区整个水层的温盐特性和层结结构发生显著变化。等温线和等密线的向岸爬升和跃层深度向岸变浅在热带气旋过境后消失。近岸区表层增温且混合层和跃层显著加深(平均15 m),近岸浅层整层升温。离岸区表层温度降低,混合层和跃层深度基本不变。整个断面,跃层基本水平分布于20 30 m水层,并出现30 40 km的次中尺度波动信号。对琼东上升流区温度变化机制的分析发现,热带气旋在外海引起的非线性海面孤立波向近岸的热输送是SST升温的主要机制,观测的SST升温与热带气旋入射角度的关系与理论结果吻合。热带气旋过境琼东上升流区引起的温度变化特征取决于热带气旋引起的局地垂向对流和混合过程的热损失、局地风场驱动的近岸Ekman输送和外海非线性孤立波向岸热输的相对大小。
[Abstract]:The Qiongdong upwelling in the eastern part of Hainan Island is one of the strong centers of the upwelling system in the northern shelf of the South China Sea. The variation of its temperature and salt characteristics has a direct influence on the local ecology, fishery and climate. The tropical cyclones formed in the South China Sea and the Western Pacific are often encountered in the eastward upwelling zone. It is of great scientific significance and practical value to study the influence of tropical cyclones on the upwelling of eastern Qiongdong. Based on the satellite remote sensing data of nearly 30 years and the field observation data in 2013, the changes of sea surface temperature (SST) and temperature and salt structure caused by tropical cyclones in the upwelling area of eastern Hainan are analyzed in this paper. The results show that, in contrast to the open ocean, there are three types of SST variation in the East Hainan upwelling zone: cooling, basically unchanged and cooling. From 1982 to 2011, 36 cases of tropical cyclones in the East Hainan upwelling zone were transited. There were 17 cases of hypothermia, 16 cases of SST remained unchanged, 3 cases of temperature. The statistical relationship between mean warming 2.1oC and tropical cyclone elements is greater than that of average cooling 1.5oC.SST, which is compared with the cyclones transit time. The intensity and incidence angle of tropical cyclone have more influence on the range of SST. In August 2013, tropical cyclone "Feiyan" transited the upwelling area of Qiongdong, and the upwelling area SST increased, especially the upwelling center on the right side of the cyclone path was the largest one. The comparative analysis of the observed sections before and after the cyclone shows that the characteristics of temperature and salt and the stratification structure of the whole water layer in the upwelling area of east Qiongdong have changed significantly. The isotherm and isodilinear climbing along the shore and the depth of the cline shallowing disappear after the transit of the tropical cyclone. The surface layer of the inshore area is heated and the mixing layer and cline layer are obviously deepened (average 15 m), the whole shallow layer of the nearshore layer is warming up.) The surface temperature of the offshore zone decreases and the mixing and cline depths remain unchanged. In the whole section, the basic horizontal distribution of the cline is in the water layer of 20 ~ 30 m, and the sub-mesoscale wave signal of 30 ~ 40 km appears. Based on the analysis of the temperature variation mechanism in the upwelling zone of eastern Hainan, it is found that the thermal transport of nonlinear sea solitary waves to the shore caused by tropical cyclones in the open sea is the main mechanism of SST warming. The relationship between the observed SST temperature and the incidence angle of tropical cyclone is in agreement with the theoretical results. The characteristics of temperature variation caused by tropical cyclones passing through the upwelling zone of eastern Hainan depend on the local heat loss of vertical convection and mixing process caused by tropical cyclones. The relative magnitude of the near-shore Ekman transport driven by local wind field and the offshore nonlinear solitary wave to shore heat transport.
【学位授予单位】：广东海洋大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P732.6
本文编号：2268498
[Abstract]:The Qiongdong upwelling in the eastern part of Hainan Island is one of the strong centers of the upwelling system in the northern shelf of the South China Sea. The variation of its temperature and salt characteristics has a direct influence on the local ecology, fishery and climate. The tropical cyclones formed in the South China Sea and the Western Pacific are often encountered in the eastward upwelling zone. It is of great scientific significance and practical value to study the influence of tropical cyclones on the upwelling of eastern Qiongdong. Based on the satellite remote sensing data of nearly 30 years and the field observation data in 2013, the changes of sea surface temperature (SST) and temperature and salt structure caused by tropical cyclones in the upwelling area of eastern Hainan are analyzed in this paper. The results show that, in contrast to the open ocean, there are three types of SST variation in the East Hainan upwelling zone: cooling, basically unchanged and cooling. From 1982 to 2011, 36 cases of tropical cyclones in the East Hainan upwelling zone were transited. There were 17 cases of hypothermia, 16 cases of SST remained unchanged, 3 cases of temperature. The statistical relationship between mean warming 2.1oC and tropical cyclone elements is greater than that of average cooling 1.5oC.SST, which is compared with the cyclones transit time. The intensity and incidence angle of tropical cyclone have more influence on the range of SST. In August 2013, tropical cyclone "Feiyan" transited the upwelling area of Qiongdong, and the upwelling area SST increased, especially the upwelling center on the right side of the cyclone path was the largest one. The comparative analysis of the observed sections before and after the cyclone shows that the characteristics of temperature and salt and the stratification structure of the whole water layer in the upwelling area of east Qiongdong have changed significantly. The isotherm and isodilinear climbing along the shore and the depth of the cline shallowing disappear after the transit of the tropical cyclone. The surface layer of the inshore area is heated and the mixing layer and cline layer are obviously deepened (average 15 m), the whole shallow layer of the nearshore layer is warming up.) The surface temperature of the offshore zone decreases and the mixing and cline depths remain unchanged. In the whole section, the basic horizontal distribution of the cline is in the water layer of 20 ~ 30 m, and the sub-mesoscale wave signal of 30 ~ 40 km appears. Based on the analysis of the temperature variation mechanism in the upwelling zone of eastern Hainan, it is found that the thermal transport of nonlinear sea solitary waves to the shore caused by tropical cyclones in the open sea is the main mechanism of SST warming. The relationship between the observed SST temperature and the incidence angle of tropical cyclone is in agreement with the theoretical results. The characteristics of temperature variation caused by tropical cyclones passing through the upwelling zone of eastern Hainan depend on the local heat loss of vertical convection and mixing process caused by tropical cyclones. The relative magnitude of the near-shore Ekman transport driven by local wind field and the offshore nonlinear solitary wave to shore heat transport.
【学位授予单位】：广东海洋大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P732.6
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相关期刊论文 前3条
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3 吴日升,李立;南海上升流研究概述[J];台湾海峡;2003年02期
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