Climate Change Impact on Extreme Rainfalls in Arid Region of Iran

One of the major impacts on climate changes is change in extreme precipitation regime in the future, which have to be predicted to counteract the harmful effects of climate change. In this paper, climate change impact is assessed on extreme rainfalls in arid regions of Iran.

Future scenarios are downscaled using the NSRP model. Long-term daily rainfall series are generated for current climate and future scenarios. By comparing the distribution of extreme daily rainfalls for current and future conditions, the impacts of climate change on extreme rainfalls are assessed. In downscaling method, a wide range of statistics of large-scale scenarios has been transferred to downscaled scenarios. The understudying stations are in Bam, Zahedan, Tehran and Yazd synoptic stations as representatives of the arid regions of Iran.

Validation results indicate that the performance of this method in simulating daily rainfall series and distribution of extreme rainfall is acceptable. Results for most of stations and scenarios show that intensity of extreme daily rainfalls will increase in the future while average rainfall will decrease. As instance, in Yazd, extreme rainfall of 50 years return period would increase between 14 to 58 percent, while the average precipitation will change between +3 to -20 percent.

These results indicate that the precipitation situation in arid areas of Iran will worsen in the future. Therefore, more extensive investments and taking preventive activities to adapt to climate change is essential.