Assessing the impact of drought stress on grasslands using multi-temporal SAR data of Sentinel-1: a case study in Eastern Cape, South Africa
Assessing the impact of drought stress on grasslands using multi-temporal SAR data of Sentinel-1: a case study in Eastern Cape, South Africa
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DOI：
10.1080/22797254.2020.1762514
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发表时间：
2020-05-16
影响因子：
4
通讯作者：
Greve, Klaus
中科院分区：
文献类型：
--
作者：
Abdel-Hamid, Ayman;Dubovyk, Olena;Greve, Klaus
草原是南非自然植被的主要组成部分，几乎覆盖了该国陆地表面的三分之一。目前的研究重点是利用 Sentinel-1 SAR 数据的多时相分析来评估干旱胁迫对东开普省公共和商业草地的影响。数据分析包括使用 Sentinel-1 SAR 后向散射系数检索草原的生物物理参数。对 SAR 数据和来自 Landsat-8 光学数据的 NDVI 值进行相关分析。进行了线性混合效应回归分析，以检测干旱和非干旱生长季节期间干旱对公共和商业草地的影响。我们的结果表明，研究区草地植被动态对气候波动高度敏感。对于公共草地和商业草地，Sentinel-1 SAR 数据（VH 和 VV）的后向散射系数与 NDVI 之间存在显着相关性（R-2 = 0.89）。结果还表明，公共草地比商业草地更容易受到干旱的影响。在商业草原中，管理活动可以改善草原的生长条件，减少干旱的影响，从而提高该生态系统的恢复力和生产力。
Grasslands are a major component of the natural vegetation in South Africa, it covers almost one-third of the country's land surface. The current study focuses on assessing the impact of drought stress on communal and commercial grasslands in Eastern Cape Province using multi-temporal analysis of Sentinel-1 SAR data. Data analysis included retrieval of biophysical parameters of grasslands using Sentinel-1 SAR backscattering coefficients. Correlation analysis was performed between SAR data and NDVI values derived from Landsat-8 optical data. A linear mixed-effects regression analysis was performed for detecting the impact of drought on communal and commercial grasslands during a drought and non-drought growing seasons. Our results indicate that vegetation dynamics in grasslands in the study area are highly responsive to the climatic fluctuations. A significant correlation between backscattering coefficients of Sentinel-1 SAR data (VH and VV) and NDVI was observed for both communal and commercial grasslands (R-2 = 0.89). Results also demonstrated that communal grasslands are more affected by drought impact than commercial grasslands. In commercial grasslands, management activities can improve the growing conditions of grasslands, reduce the impact of drought, and subsequently increase the resilience and productivity of this ecosystem.