基于无人机倾斜摄影测量技术的潮滩形态演变研究

Study on tidal flat morphology evolution based on UAV oblique photogrammetry technology

全球气候变化导致我国海平面高度发生变化,严重危害沿海潮滩覆盖面积及环境。为了解近年来我国沿海潮滩基本形态变化情况,以某近海潮滩为研究对象,通过引入无人机高光谱成像系统,基于无人机倾斜摄影测量技术对1年间该潮滩基本高程及潮沟形态演化规律展开了系统研究。研究结果表明:①我国近海潮滩受气候影响明显,海平面呈季节性波动,潮滩高程呈先增大后减小的变化趋势,但在1年内,潮滩的高程整体呈增大趋势;②潮沟由近海区域逐渐向内陆发育,且表现出明显的溯源侵蚀特征。1年内潮沟宽度先逐渐增大,但在当年12月消亡;③潮滩主潮沟的长度持续增大,且逐渐发育出若干个树枝状分支结构,潮沟密度亦不断增大。④在当年3—5月期间,主潮沟的曲率变化较小。但随着潮沟的发育和生长,新生的潮沟分支延伸进入互花米草滩,互花米草对潮滩土体有较强的防流失破坏作用,改变了潮沟的发育走向,导致潮沟的整体曲率变大。

Global climate change leads to the gradual rise of sea level in China,which seriously damages the coastal tidal flat coverage and environment.In order to understand the basic morphological change of coastal tidal flat in recent years,a tidal flat near the sea is taken as the research object.By introducing UAV hyperspectral imaging system and based on UAV oblique photogrammetry technology,the basic elevation of the tidal flat and the evolution regularity of the tidal channel morphology in one year are systematically studied.The research result is shown as follows.(1)The coastal tidal flat in China is obviously affected by the climate,the sea level fluctuates seasonally,and the tidal flat elevation first increases and then decreases.However,within one year,the tidal flat elevation shows an overall increasing trend.The tidal channels gradually develop from the coastal area to the inland,and show the obvious characteristics of retrogressive erosion.The width of the tidal channel increases gradually in one year,but it disappears in December of that year.(3)The length of the main tidal channel of the tidal flat continues to increase,and several branch structures gradually develop,and the density of the tidal channel also increases.(4)From March to May of the current year,the curvature of the main tidal channel changes little.However,with the development and growth of the tidal channel,the new branch of the tidal channel extends into the Spartina alterniflora beach.Spartina alterniflora has a strong anti-erosion and anti-damage effect on the soil of the tidal beach,which changes the development trend of the tidal channel and leads to the increase of the overall curvature of the tidal channel.