基于DSAS模型协同GEE长时序影像的巽他海峡东海岸岸线变迁时空分析及预测

Spatiotemporal Analysis and Prediction of Coastline Changes in the East Coast of the Sunda Strait Based on DSAS Model and GEE Long Time Series Images

海岸线变化作为海岸带变化的标志之一,通过海岸线监测,可以有效了解海岸带的变化情况。选用巽他海峡东海岸多年光学数据影像,通过GEE平台进行预处理后,利用MNDWI和二值化阈值分割操作反演了2005-2020年海岸线。而后运用DSAS对海岸线变化数据进行分析,其结果结合回归模型预测未来海岸线。结果表明,2005-2020年海岸线整体表现为向海域推进,增长岸线占比最大,平衡岸线占比其次,侵蚀岸线占比最少;2005-2010年,增长岸线比例为55.50%,平衡岸线比例为44.34%,侵蚀岸线为0.16%;2010-2015年,增长岸线比例发生突变,比例从55.50%增长至100%,无平衡岸线及侵蚀岸线;2015-2020年,增长岸线比例从100%降低至58.30%,平衡岸线比例为30.76%,侵蚀岸线比例为10.94%。活跃的地质活动以及沿岸泥沙淤积可能是导致海岸线向海域推进的主要原因。利用DSAS模型对未来海岸线的变化趋势进行预测,在2030年和2040年海岸线向海域推进平均距离分别为87.73、80.72 m。

Coastline change is one of the signs of coastal zone change.By monitoring it, the authors can effectively understand the change of coastal zone.In this study, the multi-year optical data images of the study area were selected, and after preprocessing through the GEE(Google Earth Engine) platform, the 2005-2020 coastline was inverted using the MNDWI(Modified Normalized Water Index) index and binarization threshold segmentation operations.Then the DSAS(Digital Shoreline Analysis System) component is used to analyze the coastline change data, and the results are combined with the regression model to predict the future coastline.The research results show that: from 2005 to 2020,the overall performance is to advance to the sea, with the growing coastline accounting for the largest proportion, followed by the balanced coastline, and the eroded coastline accounting for the least.In 2005-2010,the proportion of growth coastlines was 55.50%,the proportion of balanced coastlines was 44.34%,and the proportion of erosion coastlines was 0.16%.In 2010-2015,the proportion of growing coastlines changed abruptly, and the proportion of shorelines increased from 55.50% to 100%,with no balanced coastlines and eroded coastlines in 2015-2020,the proportion of growing coastlines decreased from 100% to 58.30%,followed by the proportion of balanced coastlines at 30.76% and eroded coastlines at 10.94%.Active geological activities and coastal sedimentation may be the main reasons for the advance of the coastline to the sea.Using the model to predict the future change trend of the coastline, the coastline of the study area will advance 87.73 m and 80.72 m to the sea in 2030 and 2040,respectively.