Drought and Global Climate Change :: Environment, Climate Change

drouth is a multi-causal and complex environmental issue, and squeeze out have serious socioeconomic consequences. Recently, IPCC (the Intergovernmental Panel on Climate Change) in Fourth Assessment Report (AR4) concluded that South Asia and the Middle due east would experience sever, pro coherented droughts as a result of global mode changes, explicitly the development in greenhouse gases in the atmosphere (IPCC, 2007). drouth is a weather-related natural disaster whose effect is aggravated by clement activities. Sometime drought affects large regions and even several countries for a long period of time. Drought has a serious impact on aliment productivity of a land, and even on the life expectancy of inhabitants. The event of drought involves in socioeconomic, bionomic issues (WGA, 1996) (Jeyaseelan, 2005 Pongracza et al., 1996). Iran encompassing drylands has been periodically jeopardized by drought events, which have devastatingly affected society and environment (Shams ipour et al., 2008). Therefore, the ask of drought of necessity several sources of datasets. In other words, the design of a planning purport for a region for sustainable development, the acquisition of updated data is critical, particularly for countries with arid to semi-arid climates. The recent innovations in contrasted sensing methods have brought new solutions to study of environmental problems in geosciences. In the assessment of natural hazards like drought, remote sensing provides rapid, instant spatial data about the natural phenomena they ar useful in decision-makings as well as weather forecasts (Sunyurp et al., 2004). The supervise of drought via remote sensing depends on the factors that cause drought (Jeyaseelan, 2005). Drought indicators and variables, obtained through remotely sensed data, can carry some uncertainties, which is induces by the sensitivity of factors, or their dependency to weather and environment conditions. Additionally, some non-standard alg orithms capability lead to wrong estimation of drought intensity. More effective methods for increase accuracy of assessment and analysis of remotely sensed data atomic number 18 applying models which can combine in data layers. Geographic Information Systems (GIS) are used to combine the layers of data in the modeling of drought. Recently, space technologies, much(prenominal) RS and GIS, and the numerical modeling techniques have been developed as powerful tools for the ecological assessment of environment (Krivtsov, 2004 MacMillan et al., 2004 Store and Jokimki, 2003). Utilizing these technologies not only supply a platform to support multi-level and hierarchically integrated analysis on resourcefulness and environment, but also integrate the obtained information in a relative theoretical ecosystem analysis. Meanwhile, Plummer (2000) argued that perspectives of combining ecological models and remotely sensed data would stress on the estimation of accuracy, the issues of spat ial and temporal scale, and long-term comprehensive datasets.