基于被动微波遥感的植被指数对不同植被类型的动态监测能力分析

Dynamic Monitoring Ability of Passive Microwave-based Vegetation Index for Different Vegetation Types

全球植被的动态监测对于区域和全球的生态环境保护具有极其重要的意义。长期以来,光学植被指数都被作为植被监测的重要工具。微波具有良好的穿透能力,能够探测到植被的木质结构及含水量信息,可以作为重要的补充数据。针对12种植被类型,以光学植被指数NDVI、EVI作为基准,分析了基于被动微波遥感的植被指数MPDI、MVI_B和EDVI在近3 a间的月均值变化并计算了其它植被指数同NDVI的相关系数。研究结果表明:EDVI对植被的动态变化具有较强的监测能力,同NDVI相比EDVI对植被的生长和含水量的变化具有更高的灵敏度以及更大的数值分布范围,能够显示更多的细节。MPDI仅适用于生长周期明显的中、低等生物量的植被类型的监测。MVI_B对大多数植被的季节性变化不敏感,监测能力较差。

Global vegetation dynamic monitoring has great significance in regional and global ecological environ⁃ment protection.Optical vegetation indexes such as Normalized Difference Vegetation Index(NDVI)and En⁃hanced Vegetation Index(EVI)have been used as important tools for vegetation monitoring for a long time.While,microwave-based vegetation index,which can detect the woody parts of vegetation and be sensitive to vegetation water content,can provide a possible complementary dataset for monitoring global vegetation.With NDVI and EVI as the reference,the changes of MPDI,MVI_B and EDVI in the microwave band in the past three years were analyzed,and the correlation coefficients between other vegetation indexes and NDVI were cal⁃culated.The results show that EDVI has a strong ability to monitor the dynamic changes of vegetation.Com⁃pared with NDVI,EDVI has a higher sensitivity to vegetation growth and water content changes,contributing to a wider dynamic range and more details.MVI_B is insensitive to seasonal changes for most vegetation types,and MPDI is suitable for monitoring medium-and low-biomass vegetation with distinct growth cycles.