黄河下游宽滩区及其沿线植被覆盖度变化特征.

Vegetation coverage is an important indicator to reflect the ecological environment status of the lower Yellow River floodplain and its changes mirror natural evolution and the effect of human activities on the ecological environment. The county-level administrative area involved in the wide beach area of the lower Yellow River was used as the research area, and the seven periods of Landsat in 1987, 1994, 1998, 2003, 2008, 2013 and 2017 were used as the remote sensing data source. It used the pixel dichotomy method based on the NDVI index to obtain vegetation coverage and classification. It used the methods of univariate linear trend analysis, transfer matrix method, center of gravity transfer model and correlation analysis to analyze the spatial and temporal changes of vegetation coverage in the study area and the influencing factors. The results show that the overall vegetation coverage in the broad beach area of the lower Yellow River and along the area has shown an overall improvement trend in the past 30 years. The gap between the vegetation coverage in the beach area and the vegetation coverage in the coastal administrative areas are gradually decreased after 2003, and it achieves an overtake in 2017. The annual change of vegetation coverage presents an obvious “bimodal” characteristic. The channel contraction and the development of urbanization have an important impact on the inter-annual changes in vegetation coverage. [ABSTRACT FROM AUTHOR]