图们江下游圈河流域河岸沙丘动态变化

以图们江下游跨国界地区圈河流域河岸沙丘为研究对象,运用遥感与GIS技术,结合遥感影像、地形图等资料,分析该区1984~2015年河岸沙丘空间分布与格局演变,计算河岸沙丘分维值与稳定性指数。结果表明：该区河岸沙丘主要分布在弯曲型河道东岸,呈WNW-ESE向带状展布,面积15.71 km²。近31 a沙丘面积总体呈减少态势,净减少0.09 km²,其中,较少有人类活动的A区,沙丘面积呈减少趋势,减少幅度为8.21%;而受人类活动影响较大的B区,沙丘面积持续增加,尤其近5 a增幅达32%。河岸沙丘分维值虽总体高于内陆沙漠沙丘,但变化不显著,说明河岸沙丘处于相对稳定的发育演化过程中。该研究为图们江下游跨国界地区生态环境可续持发展提供科学依据。

Dynamic Change of Riparian Dune in the Quanhe River Basin of the Downstream Tumen River

This article takes the riparian dune of the Quanhe River Basin as the research object which is in trans-boundary area of Tumen River downstream. Based on remote sensing and GIS technology combined with data of remote sensing images and relief map in this area during 1984 to 2015, the spatial distribution and pattern change of riparian dune were analyzed, fractal dimension value and stability index of riparian dune calculated and the formation mechanism and development mode of riparian dune discussed. The results show that the riparian dune of study area is distributed in right coast of the river mainly. The main aeolian landform type include parabolic dunes, barchan dunes and longitudinal dunes, covering an area of about 15.71 km² and extending as a strip in WNW-ESE direction. On the whole, the aeolian sand landform area of A region is 7.06 km², and the landform type is mainly composed of fixed parabolic dune. The area of aeolian sand landform in B is 8.65 km², which is dominated by barchan chain. In resent 31 years, the area of sand dunes in the study area slightly decreased on the whole with a net decrease of 0.09 km². Besides, the A region that is far away from human activities continued to decrease with a range of 8.21% by now. There appears a trend of continuous reduction during the period of 1984 to 2010 with a decrease of 0.67 km² with the main performance being the fixed dunes because the vegetation was fixed with an increasing trend during the period of 2010 to 2015. The riparian dune of study area moves toward ESE-SE on the whole which is consistent with the main regional wind direction. The longitudinal section line of parabolic dune in A region extends as a strip in WNW-ESE direction; riparian dune appears as a forward migration in a way that spreads as the tongue shape at the leading edge, with an annual average moving rate of 1.8 m. The B region which is affected by human activities has a significant continuous increasing trend, and the increasing extent reached up to 32% in resent 5 years. It increased by 31% compared with the same period in A region, which also shows that the intensity of human activities greatly influence the development of sand dunes under the background of the same climatic change. The fractal dimension value of riparian dune is higher than that of desert dunes of inland area on the whole. However, there are no significant changes, which shows that riparian dune was in a relatively steady development and evolution process. The research provides scientific basis for sustainable development of ecological environment in trans-boundary area of Tumen River downstream.