Agricultural Drought Risk Area Identification Using Ndvi and Land Surface Temperature: a Case Study of East Arssi Zone, Ethiopia
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Date
2019-05-05
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Addis Ababa University
Abstract
Agriculture in the East Arssi Zone is the most vulnerable and sensitive sector that is seriously affected by the impact of climate variability and change, which is usually manifested through rainfall variability and recurrent drought.. Thus, in order to adapt and/or mitigate the impact of agricultural drought, agricultural drought risk area has to form one dimension of research to be done whereas the use of remote sensing and GIS techniques provides wide scope in drought risk area detection and mapping. Consequently, this study was conducted in East Arssi zone with the objective of assessing agricultural drought risk area identification and preparing agricultural drought risk area map using satellite data. To assess and examine spatiotemporal variation of seasonal agricultural drought patterns and severity, three drought indices namely, land surface temperature (LST), Standard precipitation index (SPI) and NDVI anomaly are applied. A time series MODIS NDVI AND LST satellite data for the years 2001- 2016 were utilized as input data for the indices while Meteorological data was used to validate the strength of indices in explaining the impact of agricultural drought. The result derived from indices for the study period has shown that the edge of rift valley and low land of Arssi continues mountain have been affected by severe drought, with observed spatial difference in severity level within East Arssi zone. However, the severity level was higher in 2009 and 2016 cropping seasons whereas 2015 being the most severe of all. In order to evaluate the strength of the indices for expressing the existence of agricultural drought, simple regression analysis of indices results with rain fall and NDVI, LST and SPI and NDVI and LST have been computed and can be a good indicator for occurrence of agricultural drought. Agricultural risk map of East Arssi zone was produced by integrating the three drought indices. The result indicates that East Arssi zone is classified into slight, severe and no drought agricultural drought risk area covering 22, 41.5 and 63.50 percent of the total geographical area respectively.
Thus, this agricultural drought risk mapping can be useful to guide decision-making process in drought monitoring and to reduce the risk of drought on agricultural production and productivity.
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Agricultural Drought, East Arssi, GIS, NDVI, Remote Sensing, SPI, LST