Drought Severity and Frequency Analysis Aided by Spectral and Meteorological Indices in the Kurdistan Region of Iraq

Abstract

In the past two decades, severe drought has been a recurrent problem in Iraq due in part to climate change. Additionally, the catastrophic drop in the discharge of the Tigris and Euphrates rivers and their tributaries has aggravated the drought situation in Iraq, which was formerly one of the most water-rich nations in the Middle East. The Kurdistan Region of Iraq (KRI) also has catastrophic drought conditions. This study analyzed a Landsat time-series dataset from 1998 to 2021 to determine the drought severity status in the KRI. The Modified Soil-Adjusted Vegetation Index (MSAVI2) and Normalized Difference Water Index (NDWI) were used as spectral-based drought indices to evaluate the severity of the drought and study the changes in vegetative cover, water bodies, and precipitation. The Standardized Precipitation Index (SPI) and the Spatial Coefficient of Variation (CV) were used as meteorologically based drought indices. According to this study, the study area had precipitation deficits and severe droughts in 2000, 2008, 2012, and 2021. The MSAVI2 results indicated that the vegetative cover decreased by 36.4%, 39.8%, and 46.3% in 2000, 2008, and 2012, respectively. The SPI’s results indicated that the KRI experienced droughts in 1999, 2000, 2008, 2009, 2012, and 2021, while the southeastern part of the KRI was most affected by drought in 2008. In 2012, the KRI’s western and southern parts were also considerably affected by drought. Furthermore, Lake Dukan (LD), which lost 63.9% of its surface area in 1999, experienced the most remarkable shrinkage among water bodies. Analysis of the geographic distribution of the CV of annual precipitation indicated that the northeastern parts, which get much more precipitation, had less spatial rainfall variability and more uniform distribution throughout the year than other areas. Moreover, the southwest parts exhibited a higher fluctuation in annual spatial variation. There was a statistically significant positive correlation between MSAVI2, SPI, NDWI, and agricultural yield-based vegetation cover. The results also revealed that low precipitation rates are always associated with declining crop yields and LD shrinkage. These findings may be concluded to provide policymakers in the KRI with a scientific foundation for agricultural preservation and drought mitigation.

Exploring climatic variability and drought characteristics in Morocco’s Sais Plateau and Middle Atlas: A statistical and spectral analysis

“…This indicates a meaningful contribution of SPI12 in elucidating the observed fluctuations in NDWI, and reciprocally, NDWI provides valuable insights into the variations present in SPI12. This correlation has already been pointed out by other studies [32]. Consequently, the findings from the NDWI analysis harmonize with those derived from SPI, prompting the conclusion that both spectral and statistical indices synergistically reinforce one another.…”

Determining The Agricultural Drought and Desertification Intensity in Diyala Province / Iraq Using Sentinel-2 images

“…The MSAVI2 approach is less sensitive to bare soil than the SAVI [22]. MSAVI2 values range from -1 to + 1, with -1 and 0 denoting non-plant characteristics, including barren ground, a built-up region, and a water body, while the value of + 1 and larger indicating vegetation cover [23] [18], as shown in Eq. (1) [22].…”

Corrigendum to ''Integrate Terrain Variables and Rapid Eye Satellite in Vegetation Indices, for Identifying Forest Cover Area and Density: A Case Study in Mountainous Iraqi Kurdistan Region (IKR)'' [Volume 6, Issue 1, 107-114]

“…Topographic features, including aspect, elevation, slope, and site, considerably effect vegetation distribution and characteristics as they adapt to the local climate [4] . Because of the different solar radiation obtained [5] , the distinctive vegetation cover and associated with environments between slopes, aspects such as north or south aspects, and pole-facing slopes, which is a worldwide occurrence at the middle of the angular distance of a place north or south of the Earth's equator [6,7] . In general, south-facing slopes are described as dry and hot, with low soil nutrients and harsh eroded soil, and are inhabited by xeric vegetation [8] , whereas north-facing slopes are cold and wet, with rich organic matter soil, and are linked with mesic vegetation.…”