黄东海海域涡旋结构特征及其能量输送研究
发布时间：2019-06-11 05:50
【摘要】：首先,由于黑潮附近涡旋非常活跃,本文利用1993～2010年的卫星海表高度异常资料,运用一种基于流场几何特征的自动涡旋探测方法,对黄东海中尺度涡旋的数量、大小、生命史、相对涡度等统计特征及其生成机制进行研究。共捕捉到7716个瞬时涡旋(生命期大于或等于4周),其中3790个气旋型涡旋和3926个反气旋型涡旋。涡旋平均生命期为7周,平均半径为55千米,平均相对涡度为±0.1,且气旋型涡旋与反气旋型涡旋的上述特征并无明显差别。涡动动能较大值出现在黑潮以东,而黑潮以西涡动动能较小。气旋型涡旋多生成于黑潮以西而反气旋型涡旋多生成于黑潮以东,关于黑潮主轴对称分布。黑潮是附近海域涡旋的主要生成机制之一,且气旋型涡旋与其流量时间序列十分吻合,而由于地形作用和外海传入的干扰,使得反气旋型涡旋同时受制于其他因素。为了深入研究涡旋的三维结构和能量输送,进行更精细化的时空分析,重点对黄海海域海温与海流的季节性特征以及典型涡旋个例进行诊断和数值模拟。通过探讨气旋型与反气旋型两类涡旋个例的热动力和能量输送特征,得出结论：在黄海海域,气旋型涡旋和反气旋型涡旋的冷、暖中心并非存在于海洋表面,均呈现于25米左右深度。且气旋型涡旋的能量在水平方向上辐散,在垂直方向上呈现不对称性,流速强的部分能量下传更深更迅速。反气旋型涡旋的能量在水平方向上呈现辐合,在垂直方向上比较均匀,整体能量传输小于气旋型涡旋。FVCOM数值模拟对黄海海域涡旋进行的精细化时空结构与非对称能量输送时间演变的模拟与诊断显示：所模拟的气旋型涡旋较反气旋型涡旋从范围、强度、深度等方面均更大。它们的动量能量的传输深度、传输速度、传输持续时段都更深厚、更强、更长。对于气旋型涡旋,其中心部分较环状侧面部位能量传输更强更快更深。并且其环流的非对称性显著,也导致动量能量传输的非对称结构。对与反气旋式涡旋,由于强度弱,层次浅,动量能量传输的非对称性不显著,此外地形及水深对海流涡旋深度的影响也很显著。
[Abstract]:First of all, because the vortex near the Kuroshio is very active, this paper uses the satellite sea surface height anomaly data from 1993 to 2010, and uses an automatic vortex detection method based on the geometric characteristics of the flow field to determine the number and size of the meso-scale vortex in the Yellow and East China Sea. The statistical characteristics such as life history, relative vorticity and their generation mechanism are studied. A total of 7716 instantaneous vortexes (lifetime greater than or equal to 4 weeks) were captured, including 3790 cyclonic vortices and 3926 anticyclonic vortices. The average life period of vortex is 7 weeks, the average radius is 55 km, and the average relative vorticity is 卤0.1. There is no significant difference between cyclonic vortex and anticyclonic vortex. The larger value of vortex kinetic energy appears to the east of Kuroshio, while the westward vortex kinetic energy of Kuroshio is smaller. The cyclonic vortex is mostly formed to the west of the Kuroshio and the anticyclonic vortex is mostly to the east of the Kuroshio, which is about the symmetrical distribution of the Kuroshio principal axis. The Kuroshio is one of the main generating mechanisms of the vortex in the nearby sea area, and the cyclonic vortex is in good agreement with its flow time series. However, due to the topographic action and the incoming interference of the outer sea, the anticyclonic vortex is restricted by other factors at the same time. In order to deeply study the three-dimensional structure and energy transport of vortex, a more refined temporal and spatial analysis is carried out, with emphasis on the seasonal characteristics of sea surface temperature and current in Huang Hai sea area, as well as the diagnosis and numerical simulation of typical vortex cases. By discussing the thermal power and energy transport characteristics of cyclonic vortex and anticyclonic vortex, it is concluded that the cold and warm center of cyclonic vortex and anticyclonic vortex does not exist on the ocean surface in Huang Hai sea area. They all appear at a depth of about 25 meters. The energy of the cyclonic vortex diverges horizontally and asymmetrically in the vertical direction, and the partial energy with strong velocity propagates deeper and faster. The energy of the anticyclonic vortex converges horizontally and evenly in the vertical direction. The whole energy transfer is smaller than that of cyclonic vortex. The simulation and diagnosis of fine space-time structure and asymmetric energy transport time evolution of vortex in Huang Hai sea area by FVCOM numerical simulation show that the simulated cyclonic vortex follows the range of anti-cyclonic vortex. Strength, depth and other aspects are greater. Their momentum energy transmission depth, transmission speed, transmission duration are deeper, stronger, longer. For cyclonic vortices, the energy transfer in the central part of the vortex is stronger, faster and deeper than that in the annular side. Moreover, the asymmetry of the circulation is significant, which also leads to the asymmetric structure of momentum energy transmission. For the anticyclonic vortex, because of its weak intensity and shallow level, the asymmetry of momentum energy transfer is not significant. In addition, the influence of topography and water depth on the current vortex depth is also very significant.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P732
，
本文编号：2497058
[Abstract]:First of all, because the vortex near the Kuroshio is very active, this paper uses the satellite sea surface height anomaly data from 1993 to 2010, and uses an automatic vortex detection method based on the geometric characteristics of the flow field to determine the number and size of the meso-scale vortex in the Yellow and East China Sea. The statistical characteristics such as life history, relative vorticity and their generation mechanism are studied. A total of 7716 instantaneous vortexes (lifetime greater than or equal to 4 weeks) were captured, including 3790 cyclonic vortices and 3926 anticyclonic vortices. The average life period of vortex is 7 weeks, the average radius is 55 km, and the average relative vorticity is 卤0.1. There is no significant difference between cyclonic vortex and anticyclonic vortex. The larger value of vortex kinetic energy appears to the east of Kuroshio, while the westward vortex kinetic energy of Kuroshio is smaller. The cyclonic vortex is mostly formed to the west of the Kuroshio and the anticyclonic vortex is mostly to the east of the Kuroshio, which is about the symmetrical distribution of the Kuroshio principal axis. The Kuroshio is one of the main generating mechanisms of the vortex in the nearby sea area, and the cyclonic vortex is in good agreement with its flow time series. However, due to the topographic action and the incoming interference of the outer sea, the anticyclonic vortex is restricted by other factors at the same time. In order to deeply study the three-dimensional structure and energy transport of vortex, a more refined temporal and spatial analysis is carried out, with emphasis on the seasonal characteristics of sea surface temperature and current in Huang Hai sea area, as well as the diagnosis and numerical simulation of typical vortex cases. By discussing the thermal power and energy transport characteristics of cyclonic vortex and anticyclonic vortex, it is concluded that the cold and warm center of cyclonic vortex and anticyclonic vortex does not exist on the ocean surface in Huang Hai sea area. They all appear at a depth of about 25 meters. The energy of the cyclonic vortex diverges horizontally and asymmetrically in the vertical direction, and the partial energy with strong velocity propagates deeper and faster. The energy of the anticyclonic vortex converges horizontally and evenly in the vertical direction. The whole energy transfer is smaller than that of cyclonic vortex. The simulation and diagnosis of fine space-time structure and asymmetric energy transport time evolution of vortex in Huang Hai sea area by FVCOM numerical simulation show that the simulated cyclonic vortex follows the range of anti-cyclonic vortex. Strength, depth and other aspects are greater. Their momentum energy transmission depth, transmission speed, transmission duration are deeper, stronger, longer. For cyclonic vortices, the energy transfer in the central part of the vortex is stronger, faster and deeper than that in the annular side. Moreover, the asymmetry of the circulation is significant, which also leads to the asymmetric structure of momentum energy transmission. For the anticyclonic vortex, because of its weak intensity and shallow level, the asymmetry of momentum energy transfer is not significant. In addition, the influence of topography and water depth on the current vortex depth is also very significant.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P732
，
本文编号：2497058
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