基于Landsat数据的黄河三角洲湿地提取及近30年动态研究

为深入了解黄河三角洲湿地近30a时空分布和动态变化特征,以山东省东营市为研究区,利用1986、1992、1998、2004、2010、2016年六个时期的Landsat遥感影像为数据源,综合利用光谱指数(MNDWI、NDVI)、目视解译、主成分分析(PCA)等方法,构建层次分类判别方法,提取研究区土地覆盖和湿地分类信息,分析研究区域近30a来的土地覆盖和湿地动态变化。结果表明:1)采用提出的层次分类判别方法提高了分类精度,6个时期的土地覆盖和湿地分类总体精度均高于85%;2)1986-2016的近30a间东营地区土地覆盖和湿地分布及面积发生了较大的改变,自然湿地退化现象严重,其中滩涂面积减少872.06 km^2,包括237.06 km^2转化为养殖池塘,114.79 km^2转化为盐田;沼泽湿地面积减少297.10 km^2,其中221.66 km^2转化为农田,河流面积基本变化不大。同时,盐田、养殖池塘、水库坑塘三类人工湿地面积分别增加了225.11 km^2、402.71 km^2,423.51km^2,呈现显著增加态势。自然与人工湿地总面积变化不大。

Mapping the wetland in Yellow River Delta and its dynamics in recent 30 years based on Landsat data

Landsat satellite data in 1986,1992,1998,2004,2010 and 2016 were selected to analyze the spatial and temporal distribution and dynamic changes of the Yellow River Delta wetland between 1986 and 2016.Such methods as spectral indices Modified Normalized Difference Water Index(MNDWI)and Normalized Difference Vegetation Index(NDVI),decision tree classification,visual interpretation,texture analysis and principal component analysis(PCA)were combined to build the hierarchical classification approach to extract the land cover and wetland classification information,which was used to further study the dynamic changes of land cover and wetland in the study area during the last 30 years.The results showed that:1)Using the hierarchical classification method,the overall accuracy of land cover and wetland classification in the six periods is higher than 85%.2)In the study area,between 1986 and 2016,the distribution of land cover and wetland had changed greatly,and serious degradation occurred for natural wetland.The area of mud flat decreased by 872.06 km^2,of which 237.06 km^2 was converted into aquaculture and 114.79 km^2 into salt pan.The area of swamp wetland reduced by 297.10 km^2,of which 221.66 km^2 was converted to farmland.The area of river has not changed much.Meanwhile,the area of artificial wetlands,such as salt pans,aquaculture and reservoir increased by 225.11 km^2,402.71 km^2 and 423.51 km^2,respectively,showing a significant increase trend.The total area of natural and artificial wetlands does not change much.