USING RDI TO PREDICT DRY AREAS FOR THE PERIOD (2000-2025) AND FORECAST DROUGHT UNDER CLIMATE CHANGES CONDITIONS FOR THE PERIOD (2025-2044), NAJAF CITY, IRAQ

Drought is defined as a period of unusually dry weather, caused by low precipitation and high temperatures. It is also defined in terms of its impact on agriculture, when crops fail due to a lack of soil moisture, which leads to food shortages and serious humanitarian impacts, such as famine in severe cases.

This paper aims to study the historical time series of Al-Najaf Al-Ashraf Governorate for the period from 2000 to August 31, 2025. The average precipitation amounts which were obtained from the NASA POWER DATA website, were studied throughout this period and represented on a precipitation distribution map across the governorate using GIS 10.3 software. The results showed that the period from 2000 to 2017 had less average precipitation than the period from 2018 to August 31, 2025, the average amount of precipitation was concentrated in the northern and northeastern regions of the governorate, the lowest average precipitation amounts was 26 mm in the year 2001 and the highest average precipitation amounts reached 171.6 mm in the year 2023.The Reconnaissance Drought Index (RDI) was computed by DrinC software based on the governorate's average maximum and minimum temperatures, evapo transpiration, and average precipitation. The results showed that the RDI value for the first period, from 2000 to 2017, ranged between moderate wet and mild drought, while for the second period, from 2018 to 2024, all RDI values were near normal. Near normal values were also distributed across the southern and southeastern regions and parts of the northern regions; the rest of the governorate areas were experiencing mild drought. For the future period extending from 2025 to 2044, the climate model from the NSF National Center for Atmospheric Research website (NCAR) was used, and the results showed a decrease in rainfall amounts by 30.8%, and that the period extending from where the lowest average rainfall amounts was 48.5 mm in the year 2026 and the highest average rainfall amounts reached 118.9 mm in the year 2030.The RDI index was also calculated for the future period based on the average of future maximum and minimum temperatures and the calculation of evapo transpiration as well as the average precipitation amounts. The results showed that the period extending from 2025 to 2035 had an index value ranging between near normal and mild drought, while the second period extending from 2036 to 2044 had all mild drought except for the year 2043, which was near normal.