南海北部跨陆坡运动的模式诊断分析

发布时间：2018-08-24 08:26

【摘要】：基于POM诊断模型,用GDEM气候态温盐资料,对南海环流进行诊断计算.结果表明,南海北部普遍存在跨陆坡运动且具有明显空间分布特征.从水平和垂直断面分布可知,较强的跨陆坡运动发生于浅水陆坡和海底地形急剧变化的海区.跨陆坡运动引起近岸陆架与外洋之间的水交换,其输运量估算为:沿200,500和1000 m等深线断面的跨陆坡体积输运年平均值分别为9.4,15.8,-2.1 Sv,热含量输运的年平均值分别为0.78,0.84,-0.22 PW,盐含量输运的年平均值分别为342.5,575.0,-76.0 Gg s~(-1).这3处断面之间水体产生辐聚或辐散,造成显著的跨陆坡输运.跨陆坡运动同时伴随着热盐输运,即有大量的热量和盐分向陆架海区输送,而少量向外洋输送,且沿200和500 m等深线断面的跨陆坡输运存在冬强夏弱的季节差异.200~500 m等深线之间的海区主要为向陆架方向的跨陆坡输运,而500~2000 m等深线之间的海区主要为向外洋方向的输运.陆坡流中跨陆坡运动成分不可忽视,占15%~20%.正压涡度平衡方程逐项分析发现,地形与斜压联合效应项、位势涡度平流项、对流和扩散项对跨陆坡运动起主要贡献.地形与斜压的相互作用是跨陆坡运动产生的主要因素,且在118°E以东区域对跨陆坡运动起显著的增强作用.
[Abstract]:Based on the POM diagnostic model, the circulation in the South China Sea is diagnosed and calculated by using the GDEM climatic temperature and salt data. The results show that the transcontinental slope movement is common in the northern part of the South China Sea and has obvious spatial distribution characteristics. From the distribution of horizontal and vertical sections, it can be seen that the strong transcontinental movement occurs in the shallow continental slope and the sea area where the seabed topography changes dramatically. The transcontinental movement results in the exchange of water between the nearshore shelf and the ocean, It is estimated that the annual mean value of volume transport across the continental slope along the 200500 and 1000 m isobath sections is 9.4U 15.8U -2.1 Sv, respectively. The annual mean value of the thermal content transport of 0.78 PW, is 0.84kg-0.22 PW, respectively. The annual average value of the volume transport across the continental slope is 342.5575.0- 76.0 Gg s-1, and the annual average value of the volume transport along the 200500 and 1000 m isobaric sections is 342.5575.0- 76.0 Gg s-1, respectively. The convergence or divergence of water between these three sections resulted in significant transcontinental transport. The transcontinental movement is accompanied by both hot and salt transport, that is, a large amount of heat and salt is transported to the continental shelf and a small amount to the ocean. Moreover, there are seasonal differences between winter intensity and summer weakness in the cross-slope transport along the isobath section of 200 and 500m. The sea area between the 500m isobath and the 500m isobath is mainly transcontinental to the continental shelf, while the sea area between the 500m and 500m isobars is mainly transoceanic. The component of transcontinental movement in slope flow can not be ignored, accounting for 15 / 20. The analysis of barotropic vorticity equilibrium equation shows that the combined effects of topography and baroclinic potential vorticity advection convection and diffusion play a major role in the transcontinental slope motion. The interaction between topography and baroclinic is the main factor of the transcontinental slope movement, and the area east of 118 掳E plays a significant role in enhancing the cross-slope movement.
【作者单位】：中国科学院南海海洋研究所热带海洋环境国家重点实验室;中国科学院大学;
【基金】：国家自然科学基金(41376026,41176027,41349907,41406038) 广东省自然科学基金重点项目(2016A030311042) 中国科学院战略性先导科技专项(A类)(XDA11030302)资助
【分类号】：P731.2

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