Tracing surface water change from 1990 to 2020 in China's Shandong Province using Landsat series images

Accurate and long-term series surface water extraction is of great significance for development of agro-ecosystem and sustainable management of water resources. Data and knowledge of the spatial–temporal dynamics of surface water are still very limited in Shandong Province, China. This study provides a rapid and robust method for open-surface water detecting based on the Google Earth Engine (GEE) platform. The 30-m annual maps of surface water frequency are generated to analyze the distribution and variation of surface water in Shandong Province during 1990–2020. In addition, the effects of climatic and anthropogenic drivers are investigated on the temporal and spatial dynamics of surface water. A previously published global surface water dataset is used to valid our results. The results show that the correlation coefficient (R) of permanent surface water area (SWA) is 0.95 from 1990 to 2020. And in this study, the surface water area is well extracted in 1994 which is underestimated by Joint Research Centre (JRC). Surface water is widely distributed in Shandong Province; however, the interannual variation of SWA is substantial. The permanent SWA presents an increasing trend in Shandong Province, especially from 1990 to 2004. Multitemporal monitoring results show that the permanent SWA of Dongping Lake, Xiashan Reservoir, and Chanzhi Reservoir fluctuate most in 1990–1994 and 2013–2018. Precipitation and water supply significantly affect the permanent SWA , with R of 0.38 and −0.70. The results will provide a critical guidance for implementing sustainable water resources management so as to avoid flood-hazards and drought disasters.