Morphological changes and its dynamic mechanism of trough blowout in artificial foredune:A case study in Pingtan Island
Blowouts are the main subject of aeolian geomorphology study,and the morphological-dynamics process is the important issue of studying blowouts.Recently,after the artificial foredunes on the coast was generated due to artificial interference,it is urgent to carry out corresponding research along with the emer-gence of a large number of blowouts,but there is a lack of relevant research on the blowouts developed on the artificial foredunes so far.Pingtan Island,which has a typical development of wind blowouts on the artificial foredune,was selected as the study area,Here we study the feedback mechanism between aerodynamics and morphodynamics processes on artificial blowouts through surveying topography by high-resolution RTK-GPS,and monitoring aerodynamics process by 2 dimensional ultra-sound anemometers.The preliminary results show that:1)The trough blowout was developed in artificial foredunes controlled by artificial filled clay struc-tures.It displayed a different development path(a cycle)from previous observation,which started with the sed-iment-transport channel,to a fully developed blowout until died out,lastly went back a new sediment-transport channel.2)The morphology of trough blowout controlled how wind flow moved within blowout,which pro-moted deflation basin of blowout increasing due to positive feedback.3)The two-way feedback between blo-wout topography changes and aeolian process,which aerodynamic process lead to the morphology changes and morphology affect the operation mode of the process.As the angle between wind direction and long axis of trough blowout increases(48°～99°),flow deflection in the blowout was clearly visible and the helicoidal flow usually appeared.
trough blowoutmorphological changesurface airflowform-flow feedbackPingtan Island
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