الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Climate change is a global common problem and affects many sectors of life on earth. Global warming phenomena induced by emissions of greenhouse gases which increasing as result the human activities. Climate change and global warming are imposing additional pressures, with negative effects on the quantity and quality of water resources and the capability to ensure food security, protect human health and preserve ecosystems. Iraq confronts the climate changes in all aspects of life particularly water sector. The greater area of Iraq’s land depends on the Tigris River and its tributaries for its living. The Greater Zab River (GZR) is largest Tigris tributary of water yield,
its headwaters from Ararat Mountains of south-eastern Turkey then passes
through the north of Iraq. Risky weather events like droughts, floods and variability in river discharge probably occur caused by climate change. The current study focuses on investigate the impacts of climate change on air temperatures and precipitation over the greater zab river basin at EskiKalak gauging station (20435 km2 ) during the observed period (1979-2005),
mid-21st century (2047-2073) and end-21st century (2074-2100) forecasted
periods under both emission scenarios the medium (RCP4.5) and the high
(RCP8.5). Employing Rossby Center Regional Atmospheric model (RCA4)
which derivative from ICHEC-EC-EARTH as a General Circulation Model
to acquire the future average air temperatures and precipitation over entire the basin. Lumped hydrological model established to simulate the surface runoff in the basin due to precipitation and forecast the stream flow of study area induced climate changes in order to best management of water resources systems. The HEC-HMS program version 4.2 was employed for these aims. The results from RCA4 regional climate model demonstrated an increasing in average air temperatures during the prediction periods compared the observed period owing to global warming. For both medium and high
emission scenarios, decreasing the average annually of number of cold days while, increasing the hot days relative to observed period (1979-2005). The increasing in average annually temperature under medium scenario (RCP4.5) would reach to 1.92 and 2.35 °C relative to the observed period whereas, at scenario RCP8.5 will be approximately 2.84 and 4.64 °C during mid-21st century and end-21st century periods, respectively. Rising air temperatures over all the basin owing to climate change have adverse
impacts on the many aspects of life including the quantity and quality of
water resources and the capability to protect human health and preserve
ecosystems. Model projections indicate that an increasing in rainy days
compared to the observed period. The increasing of average annually of total
precipitation as a ratio to the observed period were 23% and 28% under
medium scenario whereas, under high scenario were 25% and 23% for mid
and end 21st century periods, respectively. Probability density function (pdf) demonstrated increasing an intensity of daily precipitation for mid-21st century and end-21st century periods. These forecasts would be assist the decision makers to water resource management and in planning and design the hydraulic projects within the basin in future. Applying Integrated Water
Resource Management is the optimum manner to adaptive and cope climate
changes. HEC-HMS model may be employed with acceptable approximations on greater zab basin. If surface runoff for each sub-basin within study area was recorded and become available, it is recommended to utilize a distributed or semidistributed hydrological model of the basin.