Kuraklık tehlike haritalarının SPI indisi ve CBS kullanılarak oluşturulması Pilot çalışma: Fars vilayeti, İran

Drought is one of the main natural hazards affecting the economy and the environment of large areas .Semi-arid and arid regions worldwide regularly confront drought. Some of the potentially significant and far reaching consequences of drought include impacts on: poverty rates, health, ecosystem services, land sustainability, and economic development. Unfortunately, recent climate change models predict that over the next 40 years, semi-arid and arid regions worldwide will experience an increase in the severity and intensity of drought as these regions encounter more aridity and less precipitation. Most populated regions, especially in arid and semi-arid environments, are experiencing substantial conflicts over freshwater resources as governments try to meet agricultural and urban water demands and leave flows for the environment. And while the global supply of freshwater resources has been nearly constant for the last 2,000 years recent predictions from climate change models suggest less precipitation and hence further reductions in freshwater supplies in many of the already water-stressed semi-arid and arid regions worldwide, including parts of the Europe, Africa, Australia, and western United States. Important efforts for developing methodologies to quantify different aspects related to droughts have been made, such as the spatial differences in the drought hazard, the prediction of droughts by means of the use of atmospheric circulation indices and the mitigation of drought effects. However, more efforts have been made to develop drought indices, which allow an earlier identification of droughts, their intensity and surface extent. During the twentieth century, several drought indices were developed, based on different variables and parameters. Drought indices are very important for monitoring droughts continuously in time and space , and drought early warning systems are based primarily on the information that drought indices provideThe majority of drought indices have a fixed time scale. Some of them have many problems related to calibration and spatial comparability. To solve these problems, scientists developed other indices like the Standardized Precipitation Index (SPI),which can be calculated at different time scales to monitor droughts in the different usable water resources.in recent years, Geographic information system (GIS) has played a key role in studying different types of hazards either natural or man-made. As well as, Iran is a dry land with very low atmospheric precipitation such that rainfall in Iran is less than one third of the average rainfall throughout the world. Meanwhile, the precipitation time and its place do not conform to an agricultural need which is the main consumer of water in the country. Fars province has had remarkable record in crop production especially wheat yield in the country. On the other hand, comprehensive management and decision making in the field of water resources requires reliable prediction of drought area, duration and severity. To study drought and mapping this thesis Standardized Precipitation Index (SPI) and spatial interpolation in GIS is used. It is practical and simple method. The base of this index is precipitation. To study the drought, Records from10 stations within the same period of 13 years (1994-2006) and 17 stations within the same period of (2007-2011) in scale of annual. For better results three spatial interpolation is compared and Inverse Distance Weighted (IDW) interpolation is more practical for this study area. The result of analysis, is showed that the least SPI and drought magnitude has happened in Sadedorodzan station , in the north of Fars province for 17 stations between 1994-2011 and 10 stations between 2007-2011. For 10 stations during 1994-2006 ,the least SPI is related to the Lamerd station. Figures that produced by interpolation method between 1994-2011 illustrated that drought was generated in the south and it was rapidly extended to north and northeast and northwest. This prediction is used in Fars province to manage the drought .It is the first attempt of its kind in this region and studying such researches by taking into consideration of climate changes may prove to be useful for regional planners, and policy makers for agricultural and environmental strategies, not only in Southern Iran but also in other countries facing similar problem.