Method for quickly delineating Merzbacher Lake extent based on Environment and Disaster Monitoring small satellite images

Abstract

The Merzbacher Glacial Lake located in the Sary Jaz-Kumarik River Basin has severe impacts on the environment and human well-being in downstream of the AKSU River in China. The Merzbacker Lake has flooded with increased frequency in recent years with the climate warming. It is vital to strengthen observation and monitoring of the Merzbacker Lake, especially by remote sensing data. Large portion by floating ice is the key issues of monitoring the lake. Based on the high temporal and spatial resolution Environment and Disaster Monitoring Satellite images, an improved method focused on threshold and mask technique were presented. Parts of the lake which is clear of ice was extracted mainly by Normalized Difference Water Index method. Parts of the lake covered by floating ice were relatively accurately extracted by using the Band B image of the HSV images. The area change information of Merzbacher Lake then were extracted by the post-processing of the areas in different periods. As an example, the changing areas series of Merbacher Lake in 2009 were analyzed. The results suggests that the date of the Merbacher Lake flood was around 30th July, and the flood lasted for no more than a week. The application indicates that the method can provide quick and relatively accurate monitoring of the lake flood, which is very import to construct forecasting and warning systems of Merzbacher Lake.