The decadal variability and its cause of the extreme drought in China

This paper investigates the probability of extreme drought in four regions of China during the 1470-2000 A. D., and analyzes the delta O-18 record in Guliya ice core. By wavelet analysis, we find that the probability of drought in the four regions has the quasi-cycle of 350 a, like the delta O-18 record in Guliya ice core. When the delta O-18 record is high, the temperature of Qinghai-Xizang Plateau is high too, and the probability of drought is low, and vice versa. This paper also analyzes the Pacific decadal oscillation and finds the quasi-cycle of 80 a is weakening but the quasi-cycle of 50a is enhancing. When either of them is strong, the probability of drought is high, and the probability is low when the two quasi-cycles are alternating.