چکیده:
This study aims to evaluate effects of two downscaling methods; change-factor and statistical downscaling on the runoff of the Azam-Harat River located at Yazd province (with an arid climate) of Iran, under the A2 emission scenario for the period of 2010-2039. For this purpose, CGCM3-AR4 model; a rainfall-runoff conceptual model, IHACRES; two downscaling models, Change Factor and LARS-WG were applied. Results show 30% difference in runoff simulated by two downscaling methods. Also, according to the fact that Change Factor ignores climate fluctuations over the course of future period relative to base period, simulated runoff from the outputs of this downscaling method does not contain enough confidence and cannot represent the actual runoff of the basin in the future. Despite, fluctuations are modeled in the LARS-WG well. On the other hand, if the estimated runoff increase from the LARS-WG is more than the capacity of the Azam-Harat River and Basin, the risk of flood and damage could figure in the future.
خلاصه ماشینی:
"Talebia a Department of Watershed Management, Collage of Natural Resources, University of Yazd, Yazd, Iran b Department of Irrigation and Drainage Engineering, Collage of Abouraihan, University of Tehran, Pakdasht, Iran c Faculty of Natural Resources and Environment, Ferdowsi University Of Mashhad (FUM), Mashhad, Iran Received: 3 November 2013; Received in revised form: 1 July 2014; Accepted: 29 September 2014 Abstract This study aims to evaluate effects of two downscaling methods; change-factor and statistical downscaling on the runoff of the Azam-Harat River located at Yazd province (with an arid climate) of Iran, under the A2 emission scenario for the period of 2010-2039.
, 2004; Robera, 2005; Leander, 2007; Liu and Cui, 2011; Falloon and Betts, 2011; Andrew Day, 2013).
For constructing the climate change scenario of each GCM, the ‘difference’ and ‘ratio’ for the temperature and precipitation (equations 1 and 2), respectively, are calculated based on the long-term monthly average of the future period (here, 2010-2039 period) and baseline period (here, 1982-2008) simulated by the same GCM model in each cell of computational grid (IPCC, TGCIA, 2007).
3. Runoff projection Time series runoff of the Azam-Herat River Basin was projected by introducing precipitation and temperature time series downscaled by the CF method and two scenarios of LARS-WG to the calibrated with the IHACRES model for the period 2010-2039.
Conclusion In this study, the impact of climate change on runoff of the Azam-Herat River Basin located in Yazd province for the period of 2010-2039 under the uncertainty of downscaling methods was studied."