Dynamic change of water surface area in Baiyangdian by MNDWI

Baiyangdian is the largest lake in Hebei Province, its water area changes are not only an indicator of climate change in the North China Plain, but also a microcosm of the relationship between people and water in North China. Studying the changes in its water areas is of great significance to the ecological security of the North China Plain. This study uses TM image data, based on the MNDWI water body index method, combined with the IWZ threshold segmentation method, to extract the water distribution range of Baiyangdian from 1992 to 2018. On this basis, the characteristics of time and spatial change of Baiyangdian are analyzed, and the correlation between water area change and water fragmentation is analyzed, and the main conclusions are as follows:(1) From 1992 to 2018, the water area of Baiyangdian presents a trend of more in the beginning and end years and less in the middle years, and the overall curve fluctuates greatly. (2) The degree of fragmentation is inversely proportional to the water area. (3) The accumulated water storage space of Baiyangdian increased from the outside to the inside overall, and the core water storage area is dispersed and distributed.