Modeling of the Climate Chan ges and Growing Season Period Due to its Effects on Water Resources: A Case Study of Gonabad Synoptic Station

Nowadays، climate change، as one of the most important threats ahead of life on the earth، has resulted in increasing of tempreture and changes of precipitation type، temporat and spatial pattern of precipitation distribution and amount. Changing in precipitation pattern and dcreasing its amount as well as lengthening the growing season period has resulted in a lower diversity and density of palnts. Therefore، the study of climate change and its consequences are very essential. Studies indicated that recent climatic changes caused a longer growing season period in much areas of the earth. According to this، the purpose of this study is simulating of the climatic changes for next two decades and its comparing with past data. In this regard، Gonabad synopthic station data was used along with LARS-WG software، Had CM3 model and A1B، A2، and B2 senarios. The results suggested that annual average temperature has been increasing 1℃ since 1990 to 2030. Also growing season period has been increasing 6-18 days. Obviously، increasing the temperature and prolonging the growth period will decrease available water resources and increase crop water requirement.