Evaliuation Change in Nayshabour Bar River flow Under Differents Climate Change Scenarios

This study the effects of climate change on temperature، precipitation and runoff in Bar watershed nyshabour by using outputs of Hadcm3 model under three scenarios A1B، A2 and B1 for the 2030-2010، 2065-2046 and 2099-2080 were analyzed. After the Calibration of LARS-WG model for down-scale of precipitation and temperature variable، monthy change of this for three period 2030-2011، 2065-2046 and 2099-2080 compared to the base period 2010-1971 were studied. All three scenarios almost a similar results based on decrease precipitation and increased solar radiation، minimum temperature and maximum temperature in future periods was showed. For exampel the result of A2 scenario showed annual average maximum and minimum almost 1. 1، 3. 2 and 4. 6 OC، Increase in solar radition 0. 07، 0. 3 and 0/33 mlj. m2. day and decrese in precipitiation 16. 4، 17. 6 and 31. 9 percent respectively for 2011-2030، 2046-2065 and 2080-2099 period into base period (1971-2010). Then generated variables was usege for input of rainfall – runoff IHACRES. Thus، the river flows for future periods under different scenarios was predict. For instace the result of A2 scenario showed that river flow 9، 44 and 66 percent respectively in 2011-2030، 2046-2065 and 2080-2099 periods will decrease compared to base period. In general، and according to the results of the model used in this study were observed Temperature and Precipitation in during 21 century Increase and decrease respectively that this changes، could be many negative impacts are on Nayshabour Bar river flows.