Spatiotemporal assessment of meteorological drought using satellite-based precipitation data over Iraq

Abstract

Iraq is a semi-arid country, which suffers the impact of recurrent droughts. However, studies related to the characterization of drought and risk evaluation in Iraq are scarce due to the lack of accurate climatic datasets. The present work seeks to examine the feasibility of utilizing Precipitation Data based on Remotely Sensed information from satellites (PDRS) in Iraq to monitor droughts. Two monthly PDRS are collected, namely CHIRPS for the period 1983-2016, and TRMM for the period 1998-2017 were used to calculate the Standardized Precipitation Index (SPI) for various timescales (SPI-3, SPI-6, and SPI-12) of different climate zones in the region. The findings obtained have been checked using data from sparsely scattered ground meteorological stations (GS). Although the PDRS was found to be capable of capturing estimated precipitation by GS data at different climatic zone, the two PDRS products demonstrated different responses to GS data. While the TRMM revealed a strong correlation for the droughts estimated with GS data, the CHIRPS data showed a milder correlation with the GS data. Besides, good consistency was observed in the time series of SPIs calculated with GS and PDRS data. Overall, the TRMM was found to measure the dry classes more accurately while CHIRPS was found to be better at various dry and wet classes in Temporal Coincidence (TC) terms. In addition, the TRMM – SPI data showed a better correlation in detecting the drought characteristics for Z-I and Z-II, however, the CHIRPS revealed a stronger correlation for Z-III. The findings suggested the suitability of TRMM precipitation for drought analysis and monitoring in Iraq Zones I and II, and the use of CHIRPS precipitation data for Z-III.