潮汐作用下的风沙运动过程研究进展

Progress of Research on Aeolian Sediment Transport Influenced by Tide

潮汐作用下的滩面干湿交替是影响风沙运动的重要过程之一。从潮汐作用干湿交替影响下的海滩表层湿度时空变化及其对滩面风沙运动的影响、潮汐作用干湿交替影响下的海滩风区长度变化及其对滩面风沙运动的影响等方面,较为系统地概括和总结了关于潮汐作用下海滩风沙运动过程的研究进展和主要成果。主要结论为:(1)表层湿度与潮汐水位变化之间的关系是非线性的,存在地下水和毛细作用双重的滞后效应;(2)海滩临界起沙风速随表层湿度的变化关系在低于临界表层湿度时正相关,超过临界表层湿度则滩面风沙活动近乎停滞;(3)海滩风沙输送量随风区长度的变化关系按达到平衡状态前、中、后,可分为正相关、不相关和负相关3个不同的阶段。最后,针对当前国内外潮汐-海滩风沙作用模式的研究现状,提出中国未来急需加强的研究方向。

Alternate wetting and drying beachface induced by tide is one of the most important process influencing beach aeolian sediment transport.From the aspects of temporal and spatial variabilities of surface moisture content and cyclical variation of wind fetch length,as well as their own effect on beach aeolian sediment transport in the environment of alternate wetting and drying induced by tide,this paper summarizes the main progress and achievements of beach aeolian sediment transport influenced by tide.The main conclusions of this review are shown as：（1）The relationship between surface moisture variabilities and tidal oscillation is nonlinear,which is separated by a double hysteresis effect induced by watertable and capillary fringe;（2）A positive correlation between aeolian sediment transport threshold and surface moisture has been found in the case of surface moisture less than critical moisture threshold and the beach aeolian transport system will nearly shut down once surface moisture greater than critical moisture threshold;（3）The correlation between aeolian mass flux and fetch length can be divided into three stages according to the equilibrium state of sediment transport：positive before equilibrium state,negative after equilibrium state and irrelevant during equilibrium state.Finally,some necessary future research directions in China are put forward,according to the present research situation of beach aeolian sediment transport influenced by tide.