Changes of Extreme Temperature and Its Influencing Factors in Shiyang River Basin, Northwest China

• Published in: Atmosphere
• Main Authors: Junju Zhou, Jumei Huang, Xi Zhao, Li Lei, Wei Shi, Lanying Wang, Wei Wei, Chunfang Liu, Guofeng Zhu, Xuemei Yang
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2020
• Subjects: extreme temperatures; arid region; Shiyang River Basin; atmospheric circulation anomalies; Meteorology. Climatology; QC851-999; Arctic; Pacific; Kendall; Global warming; Ice; permafrost
• Online Access: https://doi.org/10.3390/atmos11111171; https://doaj.org/article/27e7944bd7cd4580bc255b8ccdacc1c0

The increase in the frequency and intensity of extreme weather events around the world has led to the frequent occurrence of global disasters, which have had serious impacts on the society, economic and ecological environment, especially fragile arid areas. Based on the daily maximum temperature and daily minimum temperature data of four meteorological stations in Shiyang River Basin (SRB) from 1960 to 2015, the spatio-temporal variation characteristics of extreme temperature indices were analyzed by means of univariate linear regression analysis, Mann–Kendall test and correlation analysis. The results showed that the extreme temperatures warming indices and the minimum of daily maximum temperature (TXn) and the minimum of daily minimum temperature (TNn) of cold indices showed an increasing trend from 1960 to 2016, especially since the 1990s, where the growth rate was fast and the response to global warming was sensitive. Except TXn and TNn, other cold indices showed a decreasing trend, especially Diurnal temperature (DTR) range, which decreased rapidly, indicating that the increasing speed of daily min-temperature were greater than of daily max-temperature in SRB. In space, the change tendency rate of the warm index basically showed an obvious altitude gradient effect that decreased with the altitude, which was consistent with Frost day (FD0) and Cool nights (TN10p) in the cold index, while Ice days (ID0) and Cool days (TX10p) are opposite. The mutation of the cold indices occurred earlier than the warm indices, illustrating that the cold indices in SRB were more sensitive to global warming. The change in extreme temperatures that would have a significant impact on the vegetation and glacier permafrost in the basin was the result of the combined function of different atmospheric circulation systems, which included the Arctic polar vortex, Western Pacific subtropical high and Qinghai-tibet Plateau circulation.