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CR prepress abstract   -  DOI: https://doi.org/10.3354/cr01634

Impact of automated statistical downscaling and Delta downscaling methods on projecting future climate change in northeast Tibetan Plateau

Aijiao Chen, Shiqiang Zhang*, Zhe Li

*Corresponding author:

ABSTRACT: The impact of different downscaling methods from general circulation models (GCMs) on projecting future precipitation and air temperature, which is important for future water resource management, in the Tibetan Plateau has rarely been addressed. The performance of automated statistical downscaling (ASD) and Delta downscaling methods on precipitation and air temperature was evaluated at 19 meteorological stations in the Qilian Mountains and Hexi Corridor (QM—HC) by comparing with insitu observed data from 2006 to 2015. Comparisons between observed and simulated precipitation and air temperature during 2006–2015, based on Representative Concentration Pathway 4.5 (RCP4.5), suggested that the difference in annual precipitation between the ASD model and Delta method is 17 mm. Testing of different weights of the two downscaling methods indicates that combining the two methods results of lower uncertainty. The downscaling of annual precipitation projected by weighting the results of the two methods suggested that precipitation will not increase significantly from 2021 to 2100 compared to the past (1961–2005), based on RCP4.5, and precipitation will fluctuate steadily in the coming decades. These projections are in contrast with previous projections of a significant increase. From 2021 to 2100, air temperature is projected to increase by approximately 0.2 °C/10 years, according to the weighted average of the ASD model and Delta method based on RCP4.5. This study indicates that management measures based on projected increased precipitation should be carefully considered in different regions.