Drought Assessment Based on Rainfall Anomaly Index (RAI) Across Erbil-Iraq

Abstract

The prolonged occurrence of anomalies in rainfall is a significant hydro-meteorological event that has the potential to impact the hydrological imbalance, contribute to climate change, and affect the production of agriculture, which is mainly dependent on rainfall. This study analyzes the rainfall data of 12 stations for 20 years from 2001 to 2020 to indicate drought occurrence across Erbil-Iraq. Previous research used different methods for studying and analyzing droughts in the region but not RAI; the current study aims to evaluate the meteorological Rainfall Anomaly Index (RAI) in Erbil to evaluate the dry and wet years in the rainfall pattern in the study area. Results showed multi-successive drought years in all stations with different extents; the 2007 drought year was common in most stations and persisted for a long period (six years in some stations), with RAI ranging from ¡2.2 to ¡6.2 among all stations, also 2010 with RAI ranging from ¡2.6 to ¡6.6. Rainfall anomalies for Qushtapa station lasted 11 years, ranging from ¡0.3 to ¡4.6, from 2007 to 2017, the longest in the region and a rare case, another rare case of “Extremely dry” condition was found in Sidakan in 2010 with RAI ¼ ¡6.6. Furthermore, RAI can assess wet events, and results also showed that 2018 and 2019 were the wettest in all stations in the study period of 20 years. Quastapa in particular, faced an “Extremely humid” year in 2018 with RAI ¼ 13.3. In conclusion, the RAI index can accurately and easily indicate dry and wet years.

Keywords

• rainfall anomaly index, drought, wet, kurdistan region-iraq (kri), erbil