海洋环境沉积物输运研究进展

RECENT PROGRESS IN SEDIMENT TRANSPORT RESEARCH FOR MARINE ENVIRONMENTS

海洋环境中沉积物的输运涉及复杂的过程和机制。20世纪后半叶发展起来的悬沙输运数学模型已经成为海洋沉积动力学的一个有力的研究工具。悬沙输运数学模型的有效运行需要正确的数值解法和模型中所含参数的确定,包括悬沙沉降速度、扩散系数、底床糙度和切应力,以及底边界上的沉降—再悬浮通量。由于复杂的水动力条件、屏蔽效应以及海底生物扰动等因素的作用,海洋环境推移质输运的经验、半经验公式具有一定的局限性。因此,充分考虑以上各种因素是正确预测海洋环境中推移质输运的关键。海洋环境沉积物输运理论的进一步发展需要着重进行各种过程和机制的研究,而这项工作依赖于高精度、高分辨率现场观测仪器的发展和更先进的颗粒态物质运动理论的建立。

Sediment transport in marine environments is associated with complex process. The development of mathematical modeling for suspended sediment transport in the late 20th century has provided a powerful tool for marine sediment dynamics. Effective running of the models requires appropriate algorithm and correct input parameters including the settling velocity of suspended matter, diffusion/dispersion coefficients for sediment, seabed roughness length, nearbed shear stress and the vertical (settling/resuspension) fluxes at the seabed boundary. For bedload transport, empirical and semiempirical formulae have been adopted, but these need further improvement, taking into account the factors of hydrodynamic setting, bed armoring, intensive activities of benthos, etc. Investigations into the physical processes and mechanisms for transport in the marine environment are needed to determine those parameters in suspended sediment transport models and to establish a more advanced theory for the physics of granular materials, which will be benefited by advancement in measurement technologies using instruments with high accuracy and resolution. 