Remote Sensing Monitoring Research On The Spatial And Temporal Evolution Of Surface Water In The Huaihe River Basin In The Past 30 Years

Land surface water bodies play a crucial role in industrial and agricultural production,climate regulation,and ecosystem maintenance.The spatiotemporal pattern of land surface water bodies is sensitive to climate change and anthropogenic activities.Thus,rapid and accurate spatio-temporal change monitoring is of great significance to water resources management and protection and prediction of future climate change.Previous studies of the dynamic changes of land surface water bodies was based on a single time of year.The high acquisition cost and huge data volume of remote sensing data restricted the drawing of long-term series of land surface water bodies.The surface areas of water bodies have significant inter-annual and intra-annual variations.Therefore,there are a lot of uncertainties using a single image to map water surface areas.Due to the rapid development of the Internet and computer technology,cloud storage and cloud computing technology have developed rapidly in the past few years.Advances in technology have made it possible to store and process massive high-resolution images to obtain land surface water maps.This article used programming to obtain Landsat5 TM,Landsat7 ETM + and Landsat8 OLI images for nearly 30 years on the Google Earth Engine(GEE),and uses the water surface judgment method combining the water body index,vegetation index and water body index to obtain Hongze Lake and Huai River in the past 30 years The spatial and temporal pattern of land surface water bodies in the basin,and explore the relationship between the dynamic changes of land surface water bodies,climate change and human activities.The major results include:(1)Based on Google Earth Engine using all Landsat data during the study period,different water surface recognition algorithms can be constructed for the Huaihe River Basin and Hongze Lake respectively,which can quickly and accurately monitor the water spatiotemporal pattern.(2)The maximum water area,Seasonal change water area and water storage data based on gravity satellites of the Huaihe River Basin from 1989 to 2017 all showed a downward trend,while the minimum water area showed a slight upward trend.Changes in water area are positively correlated with precipitation(including snow)and negatively correlated with temperature.(3)Small water bodies in the Huaihe River Basin are the leading factors for surface water quantity changes.Water bodies with smaller areas are more likely to disappear under arid climatic conditions and are more vulnerable under the background of climate warming;large water bodies are the leading factors of the water area changes,among which 216 large and medium-sized reservoirs(including large lakes such as Hongze Lake and Linhuaigang)have played an important role in maintaining the relative stability of the surface water in the Huaihe River Basin.(4)The maximum,minimum and seasonal change water area of ??Hongze Lake from 1987 to 2018 all showed a downward trend.The change in water area was positively correlated with precipitation,negatively correlated with temperature,and positively correlated with water storage data.(5)The minimum value of the minimum and maximum water area of ??Hongze Lake appears from July to September,while the maximum value of the seasonal change water body area appears from July to September.