基于镭同位素分布的黄海和东海垂直混合速率计算

在黄海和东海采样测定了水体中的镭同位素分布,用平流扩散模型描述镭同位素分布,最小二乘方法计算了垂直涡动扩散系数和上升流或下降流流速.结果给出北黄海中部、南黄海中部、浙江沿岸和台湾北部海域存在上升流,流速分别为0.46×10-3cm·s-1、0.17×10-3~1.39×10-3cm·s-1、2.02×10-3~3.04×10-3 cm·s-1和1.06×10-3~2.51×10-3 cm·s-1.北黄海中部和东海东北部存在下降流.流速分别为-2.30×10-3 cm·s-1和-0.61×10-3~-2.10×10-3 cm·s-1.计算同时给出的垂直涡动扩散系数为5.84~48.2 cm2·s-1,平均值为22.3 cm2·s-1.北黄海和浙江沿岸上升流流速与文献的结果一致;北黄海中部存在下降流与文献的结论一致.本研究结果与文献结果一致是对所建立的方法的肯定,也是对文献研究结果的支持.

Vertical mixing rate evaluation based on radium isotope distributions of Yellow Sea and East China Sea

Radium isotopes in the seawater of the Yellow Sea and the East China Sea (YSECS) were measured and their vertical distributions were described using an advection-diffusion model. Vertical eddy diffusion coefficients and advection velocities in the YSECS were calculated by fitting the distributions of radium isotopes in the seawater using least-square method. Results showed that upwellings occur in the middle of Northern and Southern Yellow Sea, coastal zone of Zhejiang, and Northeast of Taiwan. The current rates of upwellings are 0.46×10^-3 cm·s^-1, 0.17×10^-3~1.39×10^-3cm·s^-1, 2.02×10^-3~3.04×10^-3 cm·s^-1 and 1.06×10^-3~2.51×10^-3 cm·s^-1 for above four sea areas respectively. Downwellings are indicated in the middle of Northern Yellow Sea and Northeastern East China Sea and the current rates are -2.30×10^-3cm·s^-1 and -0.61×10^-3~-2.10×10^-3 cm·s^-1 respectively. The vertical eddy diffusion coefficients were obtained as 5.84~48.2 cm²·s^-1 with an average of 22.3 cm²·s^-1 from the same calculation. Upwelling velocity of Northern Yellow Sea and coastal zone of Zhejiang given by this study is in agreement with the results of literatures, and downwelling in Northern Yellow Sea is also supported by the literature. The agreement of the results obtained in this study with that of literatures not only confirms previous inference about upwelling distribution in the Yellow Sea and East China Sea, but also affirms the validity of our method.