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Arid Land Geography ›› 2022, Vol. 45 ›› Issue (3): 725-733.doi: 10.12118/j.issn.1000-6060.2021.368

• Climate Change • Previous Articles     Next Articles

Hourly snowfall characteristics and influence system of heavy snowstorm in northern Xinjiang

YANG Tao1,2(),YANG Lianmei1(),ZHOU Hongkui3,YU Xingjie2,LI Yuanpeng2   

  1. 1. Institute of Desert Meteorology, CMA, Urumqi 830002, Xinjiang, China
    2. Xinjiang Climate Centre, Urumqi 830002, Xinjiang, China
    3. Xinjiang Meteorological Information Centre, Urumqi 830002, Xinjiang, China
  • Received:2021-08-16 Revised:2021-12-02 Online:2022-05-25 Published:2022-05-31
  • Contact: Lianmei YANG E-mail:yd_yang@sina.com;yanglm@idm.cn

Abstract:

Northern Xinjiang has been identified as one of China’s snowiest regions. Snowfall has significantly increased as a result of global warming, having a substantial impact on the climate in Xinjiang. Due to the limitation of observation data, no research on hourly snowfall has been conducted in this area, affecting the improvement of snowfall fine forecasting and service ability. The hourly snowfall characteristics in the cold season (November to February next year) are analyzed using data from 50 national meteorological stations in the Tianshan Mountains area of Xinjiang and its north (northern Xinjiang) from November 2012 to February 2021. Thirty heavy snowstorm processes are selected according to their snowfall amount and the daily snowfall amount for analysis of their hourly snowfall characteristics, impact systems, and typical circulation configuration. The results show the following: (1) Northern Altay Prefecture, the Tacheng Basin, and the Ili River Valley have a high snowfall hourly number (SHN), which can exceed 200 h·a-1. Tianshan Mountains’ high-frequency area is the middle mountain belt, with an altitude of 1800-2000 m, and the SHN is 127.3 h·a-1. There is little snow above 2000 m. (2) In northern Xinjiang and the Tianshan Mountains, the proportion of SHN in the order of R≤1.0 mm·h-1 is 91.7% and 91.9%, respectively, and its contribution to snowfall is 70.7% and 68.9% respectively. R>1.0 mm·h-1 is an hourly extreme snowfall event, yet it contributes 29.3% and 31.1% of the snowfall in the northern Xinjiang and Tianshan Mountains, respectively. (3) The average SHN and snowfall of the heavy snowfall process are 25.5 h and 30.7 mm, respectively, with a snowfall intensity of 1.2 mm·h-1. Heavy snowfall processes are caused by prolonged snowfall, and snowfall duration is key for heavy snowfall process research, forecasting, and service. Among the Central Asia trough systems, the Central Asia vortex, the Ural Mountain trough, and the West Siberian vortex (trough) system account for 30.0%, 6.7%, 13.3%, and 50.0%, respectively, while the middle latitude long wave trough (vortex) and West Siberian vortex (trough) systems account for 50.0%.

Key words: hourly snowfall, spatial-temporal distribution, heavy snowstorm, influence system, northern Xinjiang