Evaluation of remotely sensed precipitation sources for drought assessment in Semi-Arid Iraq

Despite high impacts of recurrent droughts, studies related to drought characterization and risk assessment is very limited in Iraq due to unavailability of sufficient and reliable climate data. This paper attempts to assess the possibility of using Remotely Sensed Precipitation Data (RSPD) for monitoring droughts in Iraq. Two monthly RSPD namely, TRMM for the period 1998-2017 and PERSIANN for the period 1983-2016 were used for the estimation of Standardized Precipitation Index (SPI) of different climatic zones of the country for three timescales (SPI-3, SPI-6, and SPI-12). Obtained results were validated using sparsely distributed meteorological Ground Stations (GS) data. The results showed the potential of RSPD in monitoring droughts in Iraq. The RSPD was found capable of capturing the spatial distribution of precipitation estimated using GS data. The correlation coefficients of observed and TRMM SPI-3, SPI-6 and SPI-12 time series were found 0.8, 0.75, and 0.745, respectively, while those for PERSIANN were found 0.74, 0.69, and 0.7, respectively. Moreover, good consistency in SPI time series estimated using RSPD and GS data was observed. The TRMM was also found to estimate the dry periods and the Temporal Coincidence (TC) of droughts more accurately. The results indicated the suitability TRMM precipitation in monitoring droughts in different climatic zones of Iraq.