Research On The Dynamic Evolution Trend Of Coastal Dunes In Changli,Hebei

Coastal dune is an important part of the coastal beach system.Under the combined action of nature and human beings,the sedimentation of the sediments in the dune-beach system leads to the loss of the sediments and the loss of the dunes.Dune as a living environment of herbs and birds,mammals,amphibians and reptiles diversity has been greatly damaged.Coastal dunes are closely related to coastal biodiversity.The degradation of coastal dune has destroyed the integrity and diversity of coastal ecosystems.Therefore,the protection of coastal dune resources is of great significance to the sustainable development of coastal ecological environment.It provides a natural laboratory for the study of marine geomorphology processes such as ocean power and land and sea changes.Based on the GPS-RTK technique,the monitoring data of coastal dunes in spring(May)and autumn(October)were obtained from the Changwei Gold Coast Nature Reserve.Year and interannual two dimensions of the dynamic evolution of the dunes to conduct a comprehensive analysis.SPSS22.0 statistical analysis software was used to analyze the dynamic factors such as sandstorm,synthetic wind and dune height.The dynamic evolution trend of coastal dune in Changli Gold Coast is analyzed by means of state space analysis,analytic hierarchy process and spearman rank correlation coefficient method.The results show that:(1)Since October 2004,the height of the dune dune has been reduced,the highest point of the ridge line has been reduced by 1.47 m,and the saddle has been reduced by 3.54 m.And the middle of the junction line at the ridge line,slope foot line to the sea migration trend;dune moving speed has accelerated,because the ridge line than the foot line movement speed,slow to the slope faster than the slope,The easing velocity to the slope is: 0.47 °/a,0.17 °/a.(2)Changli Daxu area in the main area of the main changes in the wind speed is stable,the change is obvious during the year,the rainfall is less spring is also the windseason is conducive to sand movement,under the action of sand,the main movement of the dune The movement of the dunes is more obvious than that of the winds,especially the winds of the dunes,and the change of the dunes is often lagging behind the change of the air condition.Therefore,the movement rate of the dunes in October and the following year is obviously higher than that in May and October,ridge line moving distance of about 1.7 m/a,slope foot line moving distance of about 0.4 m/a.(3)Based on the change of the location of the dune,the change of the vegetation coverage around the dune,the material supply of the dune and the morphological changes of the dune as the index of the dune degeneration,the evolution trend of the sand dune is evaluated as-0.38,The sand and sky evolved smoothly.(4)Degradation trend of coastal mobile dunes in Changli County,Hebei Province in the next 50 years is obvious.The total area of coastal dune has changed greatly,and the area of coastal dune has been reduced by 49.61 hm2.The continuous expansion of dune vegetation has led to the area of coastal dune area The recession.