Spatio-temporal variations of precipitation extremes in Xinjiang, China

This study aims to study joint probabilities and changing characteristics of precipitation extremes, as well as the implications of these changes in Xinjiang. Daily rainfall data from 53 stations across Xinjiang, China, covering a period of 1957–2009 were collected. Using eight precipitation indices, probabilistic characteristics of precipitation extremes were analyzed based on Copulas. The K–S method was employed to select appropriate marginal probability distributions for determining quantiles, and the Akaike Information Criterion (AIC) was used to select copulas. Results indicate the following: (1) North Xinjiang is wetter than south Xinjiang; (2) More concurrent strong and weak precipitation extremes are observed in the areas along Tianshan Mountains, and in eastern parts of the Xinjiang than those in western parts of the Xinjiang; (3) After 1980, the Xinjiang region is exhibiting a wetting tendency, and the heavy precipitation extremes tend to occur more severely and frequently; and also the possibilities of concurrent strong and weak precipitation extremes altered in a distinct pattern; (4) Tianshan Mountains can be taken as the demarcation for the occurrences of floods and droughts and the risk of droughts and floods across the Xinjiang region is expected to increase.