基于Landsat 8遥感数据的东洞庭湖湿地变化监测与分析

基于2013~2018年Landsat8-OLI 9个时相的遥感数据,采用湿地三类分级系统,以决策树分类法提取不同时间的湿地类型,结果表明:2013-2018年东洞庭湖湖泊草洲、泥滩地和水域面积呈现动态变化,其中草洲面积平均714km²、泥滩地面积平均81km²、水域面积平均502km²;湖区草洲和水体面积占比大,且此消彼长,草洲面积平均占比55.1%,水域面积平均占比38.7%,泥滩地面积最少平均占比仅6.2%;水位变化是湖区草洲出露面积的主控因素,随水位升高,草洲出露面积逐渐减小,且在典型高低水位下草洲空间分布差异明显,高水位下主要分布在南部柴下洲和北部藕池河一带地形较高区域,而低水位条件下湖区大部分草洲面积分布广泛,其面积占湖区总面积的74%。成果进一步验证了东洞庭湖不同水情下的湿地景观格局。

Monitoring and analysis of wetland change in East Dongting Lake based on Landsat8 remote sensing data

Based on the 2013–2018 Landsat8-oli,the results showed that:(1)from 2013 to 2018,the area of emergent herbaceous wetland,mudflat,and water area of Dongting Lake showed dynamic changes,among which the area of emergent herbaceous wetland was an average of 714 km².The area of the mudflat was an average of 81 km²,and the average water area was 502 km².(2)Overall,the area of emergent herbaceous wetland and water body accounted for a large proportion,and the area of mudflat was the least,with an average of 55.1%for the emergent herbaceous wetland area,6.2%for the mudflat area,and 38.7%for the water area.(3)The change in water level was the main controlling factor of emergent herbaceous wetland exposed areas in the lake area.There was a significant correlation between the emergent herbaceous wetland exposed area and the daily water level of the Yangtze River.With the increase in water level,the exposed area of the emergent herbaceous wetland decreased gradually.(3)Under typical high and low water levels,the distribution of emergent herbaceous wetlands was obviously different.The topography in the south and north lakes was relatively high,and the emergent herbaceous wetland was normally exposed.Most of the emergent herbaceous wetland areas in the lake area were widely distributed under low water level conditions,accounting for 74%of the total area of the lake area.The results further verified the wetland landscape pattern of Dongting Lake under different water regimes.