Projections of precipitation and temperature in Southern Iraq using a LARS-WG Stochastic weather generator

Abstract

Iraq is located in the Middle East, a climatic region distinguished by arid and semi-arid environments and which is expected being more susceptible to possible effects of global warming and climate change. In current research, a stochastic weather generator, LARS-WG 6.0, was utilized to simulate historical and projected future daily climatic data and the appropriateness of the model to project daily temperature and daily precipitation. Considering the enormous uncertainties associated with future climate projections, five general circulation models (GCMs), MIROC5, CanESM2, HadGEM2-ES, NorESM1-M, and CSIRO-Mk3.6.0, which represent the most suitable models for the region according to previous studies, were utilized to project the future climate depending on two important scenarios of emissions, RCP4.5 and RCP8.5, across the current century by three periods. The climate data from six meteorological stations located in Southern Iraq were used to validate the model, which was based on historical data spanning thirty years (1980–2010). According to the findings, the yearly maximum temperature will rise based on the generated predictions at the end of the twenty-first century by 1.32–3.94 °C under RCP4.5 and 1.50–5.92 °C under RCP8.5 for all stations studied. For precipitation, the model projections show that there are various trends over all the GCMs used. This denotes the high level of uncertainty of the precipitation prediction if applied to one model only, as some models, e.g., CanESM2, predict an increase in precipitation while other models, e.g., MIROC5, refer to a decreasing trend or no change in precipitation in the future. Changes in rainfall and temperature will have a big effect on how much water is available in the south of Iraq, especially in the marsh and agricultural areas, which will face desertification, water shortages, and other environmental problems.