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本文利用南海海洋再分析产品REDOS(Reanalysis Dataset of the South China Sea)和风场资料CCMP(Cross-Calibrated,Multi-Platform),从能量学角度探讨了1992—2011年夏季(6—9月)越南离岸流区域涡-流相互作用特征,并通过能量收支方程诊断评估了风应力、压力梯度、正压不稳定以及平流的相对贡献。以越南离岸流的强度作为分类标准,对1992—2011年划分为正异常年、负异常年和正常年。结果表明,在正异常年,涡动能EKE(Eddy Kinetic Energy)和涡势能EPE(Eddy available Potential Energy)极大值主要分布在越南离岸流附近;在负异常年,EKE极大值向南北两侧分散,EPE极大值向北延伸;在正常年,EKE和EPE的极值空间分布介于正负异常之间。斜压不稳定是EPE年际变化的主要因素,越南离岸流影响周围海域的速度和密度分布,是斜压不稳定的主要原因。而影响EKE年际变化的因素较为复杂,压力做功是最主要的影响因素,风应力做功和平流做功次之,正压不稳定最小,其中正压不稳定依赖于流速大小和由风应力旋度扰动引起的上层水平流速剪切。
Based on the Reanalysis Dataset of the South China Sea (REDOS) and Cross-Calibrated (Multi-Platform) data from the South China Sea, this paper explored the summer (June-September) Vietnam from 1992 to 2011 And the eddy-flow interaction characteristics of the shoal flow are analyzed. The relative contributions of wind stress, pressure gradient, positive pressure instability and advection are evaluated by the energy budget equation. Taking the intensity of offshore flow in Vietnam as a classification criterion, the period from 1992 to 2011 is divided into positive anomalies, negative anomalies and normal years. The results show that the maximum values of Eddy Kinetic Energy (EKE) and Eddy available Potential Energy (EPE) are mainly distributed near the offshore stream in Vietnam. In negative anomalies, In the normal years, the extreme spatial distribution of EKE and EPE is between positive and negative anomalies. Baroclinic instability is the main factor in the interannual variation of EPE. The velocity and density distribution of offshore waters in Vietnam affect the off-shore pressure, which is the main reason for baroclinic instability. However, the factors that affect the interannual variation of EKE are more complicated. The most important factor is the pressure work, and the second is the work done by wind stress and advection. The instability of the positive pressure is the least. The instability of positive pressure depends on the flow velocity and wind stress curl Perturbation caused by the upper horizontal flow shear.