Satellite remote sensing of lake area in Wuhan from 1973 to 2015

In recent years, the Wuhan city has suffered flood disasters frequently, and the decrease of lake area is thought to be an important factor. Up to now, there is no consistent data of Wuhan lakes area. In order to analyze spatial and temporal variation of the Wuhan lakes in recent decades, this study used multi-source satellite data, to retrieve the lake images with a combined algorithm of normalized difference water index (NDWI) and object-oriented segmentation from 1973 to 2015. The influence factors of this change were also analyzed in combination with meteorological data and Wuhan Statistical Yearbooks. The results are as follows: (1) in 1973, the area of lakes in Wuhan was 1170.84 km2, and was 856.27 km2 in 2015. The decrease was 314.57 km2 during the period, and the severe decrease period occurred in 1973-2005, after 2005, it basically stabilized. (2) In 1973, the area of lakes in central districts of Wuhan was 148.90 km2, and the area was basically stable from 1973 to 1996. After 1996, the area of lakes in central districts of Wuhan began to decrease drastically, and tends to be stable after 2010. In 2015, the area of lakes in Wuhan central districts was 99.94 km2, a decrease of 48.96 km2 compared to 1973. (3) From 1973 to 2015, the annual precipitation in Wuhan showed a slight increase trend, while the average annual air temperature showed a significant increase trend. After 1990, the population growth, urban development and real estate development in Wuhan led to a large number of lakes were encroached. Climate change combined with human activities led to the changes of lake area in Wuhan, in which human activity may be the main factor. © 2017, China Water Power Press. All right reserved.