Estimation of vertical diffusion coefficient based on a onedimensional temperature diffusion equation with an inverse method

• Published in: 海洋学报：英文版 2014, Vol.33 (5), p.28-36
• Main Author: LIANG Hui ZHAO Wei DAI Dejun ZHANG Jun
• Format: Article
• Language: English
• Subjects: 一维; 估计; 垂直混合; 基础; 扩散方程; 扩散系数; 温度分布; 逆方法
• ISSN: 0253-505X; 1869-1099
• DOI: 10.1007/s13131-014-0472-z

Diapycnal mixing is important in oceanic circulation. An inverse method in which a semi-explicit scheme is applied to discretize the one-dimensional temperature diffusion equation is established to estimate the vertical temperature diffusion coefficient based on the observed temperature profiles. The sensitivity of the inverse model in the idealized and actual conditions is tested in detail. It can be found that this inverse model has high feasibility under multiple situations ensuring the stability of the inverse model, and can be considered as an efficient way to estimate the temperature diffusion coefficient in the weak current regions of the ocean. Here, the hydrographic profiles from Argo floats are used to estimate the temporal and spatial distribution of the vertical mixing in the north central Pacific based on this inverse method. It is further found that the vertical mixing in the upper ocean displays a distinct seasonal variation with the amplitude decreasing with depth, and the vertical mixing over rough topography is stronger than that over smooth topography It is suggested that the high-resolution profiles from Argo floats and a more reasonable design of the inverse scheme will serve to understand mixing processes.