Comprehensive analysis of droughts over the Middle East using IMERG data over the past two decades (2001–2020)

Abstract

The Middle East is home to approximately 475 million people, most of whom face food insecurity due to severe and extreme droughts that have affected most regions over the past two decades. In this study, we analyzed the spatio-temporal characteristics of different drought intensities during the period 2001–2020 using the Integrated Multi-satellitE Retrievals for GPM (IMERG) precipitation and ERA5 temperature datasets. As a first step, we compared the consistency of the IMERG-based 1-month Standardized Precipitation Evapotranspiration Index (SPEI1) with the station-based SPEI1. The results showed good agreement between them with R2 ranging from 64% to 84%. The principal component analysis method is used to show the different modes of the monthly 3-month SPEI (SPEI3) and the associated circulation types in this region. Spatially, SPEI3 shows a homogeneous region in the first five leading modes and for SPEI3 below −0.84 there was high spatial variability and inhomogeneity within and between countries. The most significant SPEI3 trend is observed in June–August with up to −0.1 SPEI3/year in some countries. Nine circulation types (CTs) were identified for the eight most severe and extreme drought episodes. The first circulation type in the positive and negative phases could explain the drought variability up to 30.1% and are closely associated with the Arabian thermal low pressure and the Siberian high pressure systems, respectively. In a final step, the moisture transport in each episode is analyzed using the vertical integral moisture flux (VIMF) and its divergence.