The Response Characteristic To Typhoon "Aere" By Beach Topography And Morphology And Sediment In Fujian Coast

Beach is sensitive zone by the interaction of ocean and land, it is in the ceaseless homeostasis adjusting by the influence ocean dynamical environment. But with the effect of the change of natural condition or artificial factor, beach resource is destroyed badly, especially in typhoon process, strong wave energy and storm tide heights caused enormous effect to beach morphology and sediment. So studying the influence that typhoon worked to beach has important practical significance.Typhoon "Aere" effects Fujian coast on 8/25/2004, it landfalls first in Fuqin city Gaoshan town, later moves along coast towards southwest, and four landfall, three entering gulf, this is the characteristic of typhoon "Aere". With using disposal and measure of beach profiles, field sampling and granularity experiment analysis indoor of beach sediment before typhoon "Aere" and after typhoon "Aere", to contrast the change of beach morphology and sediment granularity characteristic, and study the change rules of beach morphology eroding or silting in different morphology types and direct significance of the change in sediment granularity characteristic.By typhoon attacking, beach morphology responds to typhoon, among middle tide belt is most acute, low tide belt more, high tide belt and backshore are relatively small. There are different response characteristic that beach profiles of different morphology types respond to typhoon: (1) in straight shore, backshore and high tide zone of beach profile are eroded, shoreline is eroded backwards, the change of beach eroding and silting goes to balance; (2) in shore between capes, beach profiles are effected by capes and the open direction of gulfs, foreshore beach face eroding is the dominating characteristic; (3) in bar-lagoon shore, eroding and silting change of beach profiles are complicated, they have the characteristic of straight shore beach and shore between capes, also have self character, middle tide belt is formed small bar. Beach of different location has different storm effect in same shore type. In granularity characteristic of sediment, after typhoon attacking, beach sediment incline to coarse,gravel content added, but part beach sediment show fine, sediment sorting becomes worse, skewness value minished, skewness changes to negative skewness direction, kurtosis value increased, the curves of sediment frequency distributing display double apices. Spring-movement transition is the dominate transition aggradation of sediment, after typhoon, the percent content of each grain size in spring-movement transition show changes, more coarse grain size has high percent content in eroding beach, and more fine grain size has high percent content in silting beach. These indicate that beach sediment is disturbed and moved in the process of storm wave, much grain size sediment are mixed, recombined and the trend of redistributing.There may has definite universal significance to study storm effects of different district and different morphological types beach by researching the effect characteristic about beach to typhoon "Aere" in Fujian coast, in order to understand the influence rule and characteristic and offer reference to beach tour resource protecting.