新疆巴州平原北部降水时空分布特征及其主要环流形势分析

Temporal and Spatial Distribution Characteristics of Precipitation and the Analysis of Its Main Circulation Situation in the Northern Bazhou Plain, Xinjiang

摘要: 本文利用新疆巴音郭楞蒙古自治州(以下简称“巴州”)平原北部共计9个国家气象观测站1981~2020年月降水量资料，运用数据统计法、线性趋势、Morlet小波分析等方法对新疆巴州平原北部降水量时空的分布特征及多时间尺度下的演变趋势进行了研究分析；并利用NCEP/NCAR 1˚ × 1˚再分析资料，总结分析了新疆巴州平原北部大范围降水天气过程的主要影响系统和环流形势。结果表明：1) 新疆巴州平原北部年降水量最多出现在焉耆盆地的和硕，最少出现在库尉轮地区的尉犁。2) 20世纪80年至90年代，新疆巴州平原北部整体处于相对较湿润的年代，其中焉耆盆地在90年代具有区域性增湿的显著特征。21世纪00年代至10年代，巴州平原北部整体增湿趋势放缓，但仍有区域性增湿的特征。近40年，库尉轮地区增湿的趋势则相对较弱。3) 在近40年来的年降水量序列研究时段内，新疆巴州平原北部的焉耆盆地存在4a、8a、22a振荡周期，库尉轮地区存在8a、12a振荡周期；其中8a尺度周期是新疆巴州平原北部全区域性的。该区域降水序列在时间上具有多尺度特征，空间分布差异显著，时间域与频率域的联合分布具有较强的局部特征。4) 造成新疆巴州平原北部大范围降水天气过程的环流形势主要为：西西伯利亚低槽(涡)型、中亚低槽(涡)型、西西伯利亚低槽和中亚低槽形成的南北结合型。

Abstract: This paper uses the monthly precipitation data from 1981 to 2020 from nine national meteorological observation stations in the northern plains of Bayingoleng Mongolian Autonomous Prefecture (hereinafter referred to as “Bazhou”) in Xinjiang. The spatial and temporal distribution characteristics of precipitation in the northern Bazhou Plain of Xinjiang and the evolution trend under multiple time scales are studied and analyzed by means of data statistics method, linear trend and Morlet wavelet analysis. Using the NCEP/NCAR 1˚ × 1˚ reanalysis data, the main influencing systems and circulation situation of the large-scale precipitation weather process in the northern Bazhou Plain of Xinjiang are summarized and analyzed. The results show that: 1) The annual precipitation in the northern Bazhou Plain of Xinjiang is the largest in Heshuo in the Yanqi Basin, and the least in Yuli in the Kuyulun area. 2) From the 1980s to the 1990s, the northern Bazhou Plain in Xinjiang was relatively humid as a whole, and the Yanqi Basin was characterized by regional humidification in the 1990s. From the 2000s to the 2010s, the overall growth trend in the northern Bazhou Plain slowed down, but it still had the characteristics of regional humidification. In the past 40 years, the trend of humidification in the Kuweilun area was relatively weak. 3) During the research period of the annual precipitation series in the past 40 years, the Yanqi Basin in the northern Bazhou Plain of Xinjiang has oscillation periods of 4a, 8a, and 22a, and the Kuweilun area has oscillation periods of 8a and 12a; among them, the 8a scale period is the Bazhou Basin in Xinjiang. North of the state plains are all regional. The precipitation sequence in this region has multi-scale characteristics in time, and the spatial distribution is significantly different. The joint distribution of time domain and frequency domain has strong local characteristics. 4) The circulation patterns that cause the large-scale precipitation weather process in the northern Bazhou Plain of Xinjiang are mainly: the West Siberian low trough (vortex) type, the Central Asian low trough (vortex) type, and the north-south combination formed by the West Siberian low trough and the Central Asian low trough type.