Ba Rui, Song Weiguo, Lovallo Michele, Lo Siuming, Telesca Luciano
State Key Laboratory of Fire Science, University of Science and Technology of China, Jinzhai 96, Hefei 230026, China.
Department of Civil and Architectural Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
Entropy (Basel). 2020 Apr 7;22(4):415. doi: 10.3390/e22040415.
The analysis of vegetation dynamics affected by wildfires contributes to the understanding of ecological changes under disturbances. The use of the Normalized Difference Vegetation Index (NDVI) of satellite time series can effectively contribute to this investigation. In this paper, we employed the methods of multifractal detrended fluctuation analysis (MFDFA) and Fisher-Shannon (FS) analysis to investigate the NDVI series acquired from the Visible Infrared Imaging Radiometer Suite (VIIRS) of the Suomi National Polar-Orbiting Partnership (Suomi-NPP). Four study sites that were covered by two different types of vegetation were analyzed, among them two sites were affected by a wildfire (the Camp Fire, 2018). Our findings reveal that the wildfire increases the heterogeneity of the NDVI time series along with their organization structure. Furthermore, the fire-affected and fire-unaffected pixels are quite well separated through the range of the generalized Hurst exponents and the FS information plane. The analysis could provide deeper insights on the temporal dynamics of vegetation that are induced by wildfire.
对受野火影响的植被动态进行分析，有助于理解干扰下的生态变化。利用卫星时间序列的归一化植被指数（NDVI）能够有效地助力此项研究。在本文中，我们采用多重分形去趋势波动分析（MFDFA）和费舍尔-香农（FS）分析方法，对从苏梅国家极地轨道伙伴关系（Suomi-NPP）的可见红外成像辐射仪套件（VIIRS）获取的NDVI序列进行研究。分析了四个被两种不同植被覆盖的研究地点，其中两个地点受野火影响（2018年坎普大火）。我们的研究结果表明，野火增加了NDVI时间序列的异质性及其组织结构。此外，通过广义赫斯特指数范围和FS信息平面，受火灾影响和未受火灾影响的像素能够得到很好的区分。该分析可以为野火引发的植被时间动态提供更深入的见解。
