Research on Spatial-Temporal Variations of Fractional Vegetation Covers Based on Remote Sensing

By taking the Landsat-7/ETM+ remote sensing images at two different time phases in Liaoyang, Liaoning, as the basic data, this paper proposes a method of describing FVCs from three aspects of space, time, and characteristic variations, to obtain the spatial and temporal variation scales of the FVCs in the research region through the remote sensing-based PCA and NDVI-based pixel dichotomy, and summarize the variation characteristics of the FVC diagrams at two phases. Results reveal that: (1) spatially, the FVCs decline in Liaoyang, among which, the most significant variation lies in the southeastern part, where the FVCs in a large area drop from high to medium-high; (2) temporally, the FVCs decline slightly from 53.142% at Phase I to 50.318% at Phase II, but those in local areas increase from 46.846% at Phase I to 49.669% at Phase II; and (3) the vegetation covers decrease by 318km2 for five years from approximately 31,312km2 at Phase I to 31,630km2 at Phase II. This research provides support for the decision making on ecological conservation and sustainable development in Liaoyang, with a vital practical significance.