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为了探讨海岸盐沼在台风条件下的海岸防护机制,利用小型压力传感器、电磁式流速仪、Seapoint浊度计观测了互花米草盐沼、光滩在2006年“格美”台风登陆前后的水位、流速、流向、悬沙浓度等沉积动力参数.结果显示:互花米草盐沼内底层流速一般小于5cm·s-1,明显低于光滩(5～35cm·s-1);互花米草盐沼内底层流速大小对台风的响应不显著,但其流向随台风作用强度的不同而出现较大差异;台风过境对附近海域悬沙浓度的影响非常显著,悬沙浓度达到正常天气情况下的13～19倍,台风影响后期互花米草盐沼底层悬沙浓度高于光滩.计算结果表明,台风期间互花米草盐沼和光滩底层悬沙输运量是平常天气情况下的4倍左右;落潮期间,光滩底部切应力在大部分时间大于临界切应力,滩面发生侵蚀,台风登陆后的侵蚀通量为正常天气情况下的2～3倍不等,而互花米草盐沼底层切应力一般小于临界侵蚀切应力,符合悬沙沉降条件的时间段也比较长,整个滩面很少发生侵蚀,以沉降为主,台风显著影响期间的悬沙沉降通量是正常天气情况下的3～6倍,落潮期间的沉降通量是涨潮期间的1～2倍.根据台风期间互花米草盐沼和光滩的沉积动力过程的对比,前者有利于悬沙的堆积,而光滩的沉积动力过程则使滩面发生侵蚀。
In order to discuss the coast protection mechanism of coastal salt marsh under typhoon condition, Spartina alterniflora was observed with a small pressure sensor, a magnetic flowmeter and a Seapoint turbidimeter. In 2006, The sediment dynamic parameters of the Spartina alterniflora salt marsh were generally less than 5cm · s-1, which were significantly lower than that of the light beach (5 ~ 35cm · s-1) The response of typhoon to the velocity of the bottom layer of Spartina alterniflora was not significant, but its flow direction differed greatly with the intensity of typhoon. The typhoon transit had a significant effect on the concentration of suspended sediment in the nearby sea. The concentration of suspended sediment reached Under normal weather conditions, the suspended sediment concentration at the bottom of Spartina alterniflora salt marsh was higher than that of the light beach at the late stage of typhoon. The calculated results show that the suspended sediment transport of Spartina alterniflora and the bottom of the light beach during the typhoon is normal weather conditions , The shear stress at the bottom of the light beach is greater than the critical shear stress during most of the ebb tide, erosion occurs on the beach surface, and the erosion flux after the typhoon landed is 2 to 3 times higher than that under normal weather conditions Spartina grass salt cut at the bottom Generally less than the critical shear stress, suspended sedimentation conditions in line with the time period is relatively long, the erosion of the beach rarely occur, the main settlement, the significant impact of typhoon during the suspended sedimentation flux is normal weather conditions 3 ~ 6 times the sedimentation flux during ebb tidal period is 1 to 2 times during the tide.According to the sediment dynamic process during the typhoon Spartina alterniflora and light beach contrast, the former is conducive to the accumulation of suspended sediment, and light beach depositional dynamics The process is to erode the beach.