全生命周期浒苔信息提取的空间尺度效应——基于Landsat/HJ与MODIS影像的比较

Spatial Scale Effect on Enteromorpha Information Extraction in Life Cycle Based on the Comparison of Landsat/HJ and MODIS

2008年至今,我国已连续多年爆发浒苔灾害,对当地生态环境和经济都造成严重影响.多源卫星遥感影像是监测浒苔信息的主要数据源,但利用不同的遥感影像,浒苔信息提取结果存在较大差异.通常认为这是由空间尺度差异造成的.本文利用准同步的30 m空间分辨率的HJ数据、Landsat数据和250 m空间分辨率的MODIS数据对全生命周期浒苔信息提取能力进行尺度效应分析.结果表明:(1)独立浒苔斑块面积小于0.25 km^2时,MODIS影像无法提取浒苔信息,而随着独立浒苔斑块面积增大,MODIS影像提取的浒苔信息与Landsat和HJ遥感影像数据提取结果的差距也随之增大;(2)浒苔斑块聚合度越大,空间分辨率对浒苔信息提取的影响越小;(3)在浒苔灾害发生初期和末期,由于斑块小而疏松,MODIS数据很难监测到浒苔信息.又由于MODIS数据无法兼顾聚集的浒苔斑块和疏松的浒苔斑块,因此在浒苔发展和爆发期,MODIS提取的浒苔面积大于Landsat与HJ遥感影像数据提取的结果.研究结果在一定程度上为浒苔灾害的遥感监测方法提供了影像选择的空间尺度依据.

Since 2008,the Enteromorpha disaster has been striking China for many years,seriously impacting the local ecological environment and economy.Multi-source satellite remote sensing images are the main data sources for monitoring Enteromorpha prolifera information,but there are great differences in the results of extracting Enteromorpha prolifera information by different remote sensing images.It is generally believed that this is caused by spatial scale differences.In this paper,quasi-synchronous HJ data with 30 m spatial resolution,Landsat data and MODIS data with 250 m spatial resolution are used to analyze the scale effect of Enteromorpha prolifera information extraction capability in the whole life cycle.The results showed that:(1)When the area of the independent Enteromorpha prolifera patch was less than 0.25 km^2,the MODIS image could not extract Enteromorpha prolifera information.As the area of the independent Enteromorpha prolifera patch increases,the difference between the Enteromorpha prolifera information extracted by Landsat and HJ data and the Enteromorpha prolifera information extracted from MODIS image also increased.(2)The larger the aggregation degree of Enteromorpha prolifera patch,the smaller the influence of spatial resolution on Enteromorpha prolifera information extraction is.(3)In the early and late stages of Enteromorpha disaster,due to small and loose patches,it is very difficult to detect Enteromorpha information from MODIS data.In addition,because MODIS data cannot take into account the aggregated Enteromorpha prolifera patch and the loose Enteromorpha prolifera patch,the area of Enteromorpha prolifera extracted by MODIS is larger than the area of Enteromorpha prolifera extracted by Landsat and HJ data during the growth and outbreak of Enteromorpha prolifera.The research results provide a guidance of spatial scale for selecting images in the remote detection of Enteromorpha disaster.