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2012年南海西北陆架冬季水文特征的观测分析 总被引：1，自引：0，他引：1
本文基于2012年12月南海西北部陆架海区的温盐和流速实测资料，分析了粤西和琼东陆架海区冬季三维温、盐结构和流场特征，给出沿陆架和跨陆架方向的水体和热盐通量。结果表明：（1）在50m以浅，粤西和琼东海区温度均由近岸向外海递增，深层则相反；冬季近岸海区混合层较深，外海密度跃层位于60—120m深度且层结较强，浮力频率大于10–2/s；（2）海流大致沿等深线向西南流动，30m以深流速大小在0.03—0.40m/s之间，且随着深度增加而略有减小；琼东海区100m等深线附近在60m以浅水层观测到水体辐聚并有明显温度锋面存在；（3）沿陆架方向的水体和热盐输送均大于跨陆架方向，其中粤西单位面积沿/跨陆架水体通量平均值为0.13×10–6/0.03×10–6Sv/m2，低于琼东海区的0.91×10–6/0.56×10–6Sv/m2。 相似文献
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2012年夏季海南岛东岸上升流区的混合观测 总被引：1，自引：0，他引：1
The turbulent mixing in the upwelling region east of Hainan Island in the South China Sea is analyzed based on in situ microstructure observations made in July 2012. During the observation, strong upwelling appears in the coastal waters, which are 3℃ cooler than the offshore waters and have a salinity 1.0 greater than that of the offshore waters. The magnitude of the dissipation rate of turbulent kinetic energy ε in the upwelling region is O(10–9 W/kg), which is comparable to the general oceanic dissipation. The inferred eddy diffusivity K_ρ is O(10–6 m~2/s), which is one order of magnitude lower than that in the open ocean. The values are elevated to K_ρ≈O(10–4 m~2/s) near the boundaries. Weak mixing in the upwelling region is consistent with weak instability as a result of moderate shears versus strong stratifications by the joint influence of surface heating and upwelling of cold water.The validity of two fine-scale structure mixing parameterization models are tested by comparison with the observed dissipation rates. The results indicate that the model developed by Mac Kinnon and Gregg in 2003 provides relatively better estimates with magnitudes close to the observations. Mixing parameterization models need to be further improved in the coastal upwelling region. 相似文献
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全球变暖背景下沿岸上升流的年际变化是近年来的研究热点。本文基于1982—2012年的海表面温度和风场资料,分析了琼东上升流的强度和中心位置的年际变化规律以及沿岸风应力及其旋度的作用。结果显示,近30年来,琼东上升流强度总体减弱,相比于沿岸风应力,其变化与减弱的局地风应力旋度相关性更高;琼东上升流强中心位置最大概率发生在19.2°—19.3°N,与最大风应力旋度位置接近,且存在北移趋势。琼东上升流强度和位置的年际变化还存在周期约3年、5年和10年的本征模态,以3年周期变化为主。局地风应力旋度在琼东上升流的年际变化中发挥了重要作用。 相似文献
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