Arid Zone Research ›› 2021, Vol. 38 ›› Issue (2): 339-350.doi: 10.13866/j.azr.2021.02.05

• Weather and Climate • Previous Articles     Next Articles

Combined analysis of the spatiotemporal variations in snowmelt (ice) flood frequency in Xinjiang over 20 years and atmospheric circulation patterns

ZHANG Junlan1(),LUO Ji2,WANG Rongmei3   

  1. 1. Meteorological Observatory of Xinjiang Uygur Autonomous Region, Urumqi 830002, Xinjiang, China
    2. Aksu Regional Meteorological Bureau, Aksu 843000, Xinjiang, China
    3. Weather Modification Office of Xinjiang Uygur Autonomous Region, Urumqi 830002, Xinjiang, China
  • Received:2020-04-13 Revised:2020-06-10 Online:2021-03-15 Published:2021-04-25

Abstract:

Using 20 years of data (2000-2019) on snowmelt (ice) flood disasters in Xinjiang, the temporal and spatial distribution and difference characteristics of snowmelt (ice) flood frequency were analyzed over various time scales in northern and southern Xinjiang. Clear temporal and spatial distributions as well as regional differences in snowmelt (ice) flood frequency were observed in northern and southern Xinjiang, with the snowmelt flood frequency in northern Xinjiang (163 times) accounting for >75% of the total frequency. The main snowmelt flood season in northern Xinjiang was in spring (March), whereas that in southern Xinjiang was in summer (July); in Yili Prefecture, the main snowmelt flood season was in winter. In the past 20 years, the frequency of snowmelt flooding in spring has increased in northern and southern Xinjiang, with the frequency of snowmelt flooding in the last 10 years increasing by 30% compared with that in the first 10 years. The synoptic types of snowmelt (ice)-type floods in Xinjiang were revealed from the perspective of synoptic science. the eastward expansion of the Iran subtropical high, the westward extension of the West Pacific subtropical high, and the development of the Xinjiang ridge, are provided here. We conclude that the 100-700 hPa Xinjiang high ridge is a deep synoptic system, whereas the 100 hPa South Asia high is a haplotype. Before the occurrence of snowmelt flooding, the height of the 0 °C layer is obviously higher and the precipitation in mountainous areas is obviously increased. Northern Xinjiang should focus on the prevention of seasonal snowmelt floods in the middle and low mountain regions, such as in Ili Prefecture, in spring, whereas southern Xinjiang should closely monitor two types of snowmelt (ice) floods in summer, i.e., high mountain ice lake break types and snow and glacier melt types.

Key words: snowmelt (ice) flood, atmospheric circulation types, spatial-temporal distribution, Xinjiang