多源时序影像洞庭湖流域水体时空演变特征分析

Analysis of spatio-temporal evolution characteristics of water bodies in Dongting Lake Basin based on multi-source time series images

湖泊作为重要的国土资源,研究湖泊水域的动态变化有利于区域水资源开发利用,以及为生态平衡稳定提供重要保障。本文基于Google Earth Engine平台,以1989—2022年多源遥感数据为数据源,在归一化差分水体指数(NDWI)、改进的归一化差分水体指数(MNDWI)、自动水提取指数(AWEI_(sh))及基于线性判别分析的水体指数(WI_(2015))4种目前常用的水体指数中,选取最优水体指数进行洞庭湖流域水体提取;结合流域内降水气温、人口密度及土地利用等多种数据,探究洞庭湖流域水体演变特征并进行驱动力分析。结果表明,1989—2022年,洞庭湖区丰、枯水期水体面积总体呈下降趋势,3大湖区均有不同程度的缩减,平均减少93.27和140.15 km^(2)。流域内湖泊面积是自然气候变化和人类活动共同影响作用的结果。其中,降水和气温是影响湖面积的重要自然因素,人口增加、围湖造田引起的土地利用类型转移是导致湖面积减少的人为因素。

Lakes are important land resources,and the study of the dynamic changes of lake waters is conducive to providing an important guarantee for the development and utilization of regional water resources and the stability of ecological balance.Based on Google Earth Engine,using multi-source remote sensing data from 1989 to 2022 as the data source,in normalized difference water index(NDWI),modified normalized difference water index(MNDWI),automatic water extraction index(AWEI_(sh)) and the water index(WI_(2015)) selects the optimal water body index from the four commonly used water body indexes to extract the water body of Dongting Lake Basin.Combined with various data such as precipitation,temperature,population density and land use in the basin to explore the Dongting Lake analysis of water body evolution characteristics and driving forces in the lake basin.The results show that,from 1989 to 2022,the water body area in the Dongting lake area showed an overall downward trend in the wet and dry seasons,and the three major lake areas all had different degrees of reduction,with an average reduction of 93.27 km^(2)and 140.15 km^(2).The area of lakes in the basin is the result of the combined effects of natural climate change and human activities.Precipitation and temperature are important natural factors affecting the area of lakes.The increase in population and the transfer of land use types caused by reclamation of lakes are the human factors for the reduction of lake area.