Arid Zone Research ›› 2025, Vol. 42 ›› Issue (4): 577-588.doi: 10.13866/j.azr.2025.04.01

• Weather and Climate • Previous Articles     Next Articles

Interdecadal variations and influencing factors in the leading modes of summer precipitation in Xinjiang

LIU Jing1,2(), ZHENG Yulin3, LIU Yan2(), LI Hanwei4   

  1. 1. Institute of Desert Meteorology, China Meteorological Administration, Urumqi 830002, Xinjiang, China
    2. Xinjiang Climate Center, Urumqi 830002, Xinjiang, China
    3. Xinjiang Meteorological Observatory, Urumqi 830002, Xinjiang, China
    4. Xinjiang Branch China Meteorological Administration Training Centre, Urumqi 830013, Xinjiang, China
  • Received:2024-08-27 Revised:2024-12-31 Online:2025-04-15 Published:2025-04-10
  • Contact: LIU Yan E-mail:1107092572@qq.com;1127780551@qq.com

Abstract:

To investigate the formation mechanisms and potential external forcing impacts of the dominant summer precipitation patterns in Xinjiang, this study analyzed precipitation data from 89 stations spanning 1979 to 2023 using the sliding Empirical Orthogonal Function method. The evolutionary traits of these patterns were explored through a comparative analysis of precipitation patterns, circulation configurations, and correlated variations in sea surface temperature (SST) and snow cover. The results show that the main mode of summer precipitation in Xinjiang shifted around 2005 from a region-wide consistent pattern to a western-southern Xinjiang pattern. The distribution of regionally consistent high (low) precipitation was closely related to the strong (weakened) Ural blocking highs, active (attenuated) Central Asian vortex, strong (weak) Bay of Bengal anticyclone, and the positive (negative) phase of the East Asia-Pacific Remote Correlation (EAP). The abnormal circulation patterns at high, middle, and low latitudes led to the strengthening (weakening) of four key water vapor conveyor belts originating from the Arctic Ocean, the Northwest Pacific Ocean, the Bay of Bengal, and the Aral Sea. The SST anomalies in the equatorial Middle Eastern Pacific Ocean, the tropical Indian Ocean Basin-Wide, and the North Atlantic Triple influenced the circulation anomalies. The high (low) precipitation of the western-southern Xinjiang pattern was mainly influenced by the anticyclone-cyclone (cyclone-anticyclone) radial dipole wave train from the Caspian Sea to Lake Baikal as well as the strengthening (weakening) of the Tashkent low vortex. The pattern correlated significantly with the dipole anomaly of more east than west (less east than west) of the previous winter’s snow cover in Eastern Europe and Western Siberia. The snow cover anomalies in key areas can be induced by the “snow cover, soil moisture, and atmosphere feedback” process forming a zonal dipole wave train from West Siberia to Lake Baikal and a meridional triple wave train from Eastern Europe to the Iranian Plateau. These wave trains adjusted the east-west wind convergence and divergence anomalies in northern Xinjiang and altered the intensity change in the Tashkent low vortex, establishing a physical mechanism that affected the distribution of precipitation in western-southern Xinjiang.

Key words: summer, dominant modes, decadal changes, atmospheric circulation, Xinjiang