A remote sensing study of spatiotemporal variations in drought conditions in northern Asir, Saudi Arabia
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A remote sensing study of spatiotemporal variations in drought conditions in northern Asir, Saudi Arabia Wisam E. Mohammed
&
Saeed Algarni
Received: 13 July 2020 / Accepted: 19 November 2020 # Springer Nature Switzerland AG 2020
Abstract Changes in vegetation land cover are influenced by, and therefore an indicator of, climatic conditions. The aim of this study is to investigate the relationship between vegetation cover changes and drought events in a small-scale area. Six Landsat images during 1987–2019 were used to extract information about the vegetation land cover changes using the normalized difference vegetation index (NDVI) and the fractional vegetation cover (FVC) in Balqarn Governorate in the northern mountains of Asir, Saudi Arabia. Two climatic parameters, temperature and precipitation, were used as time series for the same period and were decomposed to investigate the seasonal and trend changes for each parameter. The two parameters were also used to calculate the standardized precipitation evapotranspiration index (SPEI) to conduct an in-depth analysis of the drought events influencing vegetation cover. The results showed that the state of the vegetation coverage of the
study area remained at a medium level with an average NDVI value, but the FVC values showed evidence of dynamic variability associated with drought and moisture events. The SPEI showed that the study area has been undergoing a long-duration drought event since 2004, ranging from light to severe drought, which was consistent with the time series decomposition results. This investigation has revealed that drought drives changes in vegetation cover and is expressed on small geographic scales as changes in the vegetation cover structure. The framework described here is simple and can be used to evaluate and manage drought risks.
W. E. Mohammed (*) Landscape Architecture Department, College of Architecture and Planning, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia e-mail: [email protected]
Studies on vegetation land cover have received much attention in recent years due to the importance of vegetation for sustaining terrestrial ecosystems. It is widely recognized that vegetation cover is experiencing degradation on a global scale (Higginbottom and Symeonakis 2014; Piao et al. 2011; Tutubalina and Rees 2001; Xu et al. 2017). Vegetation cover changes are nonlinear and nonstationary, and their patterns and parameters are time dependent (Guan 2014). In the recent past, interest in the driving factors of vegetation cover changes has increased, and many researchers have reported that climatic and anthropogenic factors are driving these changes (Wei et al. 2018; Xue et al. 2019), while several
e-mail: [email protected] S. Algarni Department of Geography, College of Sharia and Islamic Studies, Imam Mohammad Ibn Saud Islamic University, P.O. Box 1730, Al Hassa 11382, Saudi Arabia e-mail: [email protected] S. Algarni e-mail: [email protected]
Keywords Drought . Vegetation dynamics . NDVI
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