Analysis of agricultural drought using remote sensing indices (Case study: Marivan city)

The effects of drought can be represented as water resources declinations, vegetation and consequently, reducing agricultural production. To study and monitor drought, it is necessary to quantify its effects using drought indices.  The purpose of this study was to analyze drought in Marivan city using Landsat images from 2000 to 2017. After preprocessing the images, vegetation drought index (VDI) and vegetation health index (VHI) were extracted. Assessment of the indices showed that agricultural drought in VDI index was not observed in any year, and the values of this index were close to 100 that it indicates normal and optimal conditions. So, from 2000 to 2004 the normal conditions and from 2008 to 2017 have been optimal conditions in the dominant region. The results of VHI also show the Conditions without drought in the region. According to this index, extreme drought, severe drought and moderate drought in the studied years did not occur. The largest area of mild drought in the eastern and southeastern parts of the region in 2000, 2001, 2003, and 2005 was 38.23, 38.28, 12.29 and 35.74 km2, respectively. In general, According to the main emphasis of this study, based on VDI and VHI indices, from 2000 to 2017 (with the exception of  2012), the results indicate the absence of agricultural drought in the Marivan city. Considering the benefits of satellite images such as broader coverage, higher temporal resolution, and lower cost, it is recommended to use the knowledge of remote sensing for drought study.