Uncertainty of annual maximum daily rainfall under greenhouse gases emission scenarios in 2040: Khorasan-Razavi province

Nowadays, increasing of greenhouse gases emissionscussed by human activities is the main factor of climate change. Global warming has also changed the frequency of extreme rainfall events in many areas. This research presents an analysis of how the change in the frequency of maximum daily rainfall under three emission scenarios in 2021-2040 periods in the Khorasan-Razavi province. The maximum daily rainfall series areprojected for the future periods in the 23 weather stations by developing a nonparametric downscaling model for arid and semi-arid regions. The uncertainty of climate change scenarios is quantified using a simple parametric uncertainty estimator in the three risk levels (25%, 50% and 75%) for each of emission scenarios. The frequency analysis of maximum series showsthat the daily rainfall intensitiesin therisk level 2 will be changed between -22.9% to .3% than baseline (1993-2012), that a wider range of these changes is related to thelonger return periods. Generally, central and southern regions will be received slight increase than northern regions. The rainfall intensities in more areas decrease with theincreasein greenhouse gases emissions that this decreasewill be more for the rainfalls with lower return periods. Flooding in the high rainfall regions will be also occurred withseverity while the low rainfall regions get a more decrease. Maximum daily rainfall will be increased in the future periods by reducing the level of risk; it can be warning to design hydraulic infrastructures with high emphasis.