Determination of Impacts of Climate Change on Temperature and Rainfall Variations in Some Southern Iraqi Governorate Using GIS

Abstract

The concept of temperature change is closely related to climate change. Global warming is one of its most prominent manifestations, and the effects of this will be significant on the climate. It will lead to an increase in the intensity of the air cycle, the encroachment of climatic regions towards the poles, an increase in the frequency of extreme weather phenomena, a change in the distribution of heat and rain in different cities of the world, and a rise in sea levels and the threat of most coastal areas. The research aims to determine the variation in temperature, the amount of rain, and its distribution system in the (Basra, Thi Qar, and Missan) during the period (1998 – 2020), and diagnosis of changes in temperature, rain amount, and their cause, as well as its distribution system by analyzing the trend of change in the annual averages of temperature and annual rainfall amounts for the same study period. The results of spatial analysis using GIS for monthly temperature average data for the same period indicated that the general trend of temperature distribution in all study stations is high, and the peaks during the months (June, July, August, and September), where we notice a large and clear increase, especially in recent years, if compared with rates in previous years. As for the rain data analysis in Iraq, the study found that it was limited to five months (Nov., Dec., Jan., March, April), and October month, which represents the beginning of the rainy season in most monitoring stations, and the month of March, which represents its end, did not record any amount of rain, and this means that the depressions which Iraq exposed to during these two months are unable to produce heavy amounts of the rain because of their shallowness, from the spatial distribution of the amount of rain in the study area that the rainfall rates are reduced to the highest level and its irregular distribution, and therefore reflected in the decrease in water resources in the areas under study. A large amount of daily precipitation in Iraq is due to the recurrence of three atmospheric depressions the (Mediterranean, combined, and Sudanese) depression. These responsible depressions are distinguished by their differences from one region to another, the short duration of their stay and recurrence, the weather conditions that dominate them, and the pressure patterns accompanying them in the upper atmosphere layers. Or some of these depressions reach dryness or are accompanied by non-rainy clouds. This makes Iraq’s rains few, leading to many repercussions on climate, the environment, humans, and various activities.