乌鲁木齐东南风时空分布及层结稳定度特征分析  

Spatial and Temporal Distribution and Stratification Stability Characteristics of Southeast Wind in Urumqi

作　　者：汤浩 周雅蔓 李晨 蒋慧敏 TANG Hao;ZHOU Yaman;LI Chen;JIANG Huimin(Xinjiang Meteorological Observatory,Urumqi 830002,China;Dabancheng National Special Test Field for Comprehensive Meteorological Observation,Urumqi 830002,China;Xinjiang Climate Service Center,Urumqi 830002,China;Urumqi Meteorological Bureau,Urumqi 830002,China)

机构地区：[1]新疆维吾尔自治区气象台,新疆乌鲁木齐830002 [2]达坂城国家综合气象观测专项试验外场基地,新疆乌鲁木齐830002 [3]新疆维吾尔自治区气象服务中心,新疆乌鲁木齐830002 [4]乌鲁木齐市气象局,新疆乌鲁木齐830002

出　　处：《沙漠与绿洲气象》2025年第1期1-12,共12页Desert and Oasis Meteorology

基　　金：国家自然科学基金项目(42165002);新疆维吾尔自治区重点基金项目(2024D01D33)。

摘　　要：分析蒲氏3、6两级风力阈值下东南风时空分布、代表站气候变化、大风过程中层结稳定度特征,东南风季节变化的大气环流背景归因,结果表明:天山峡谷是乌鲁木齐东南风的主气流通道,峡谷北端向西北、东北延伸出两支大值区。两级阈值总体表现为冬季最强,春、秋季次之,夏季最弱;峡谷南北两端存在大值中心,大阈值全年及小阈值除冬季外北端强于南端。天山峡谷内冬季高发,夏季最低,峡谷出口、主城区、东北支为春、秋季高发,西北支春、秋、冬季高发。西北、东北两支上午高发,其他区域午后高发。乌鲁木齐、达坂城近50a积风均呈现下降趋势,其中达坂城的下降速率比乌鲁木齐快。乌鲁木齐2000年之前快速下降,2000年后下降速率变缓;达坂城的变化特征恰好相反。乌鲁木齐存在12a、5~7a的周期,其中12a周期最明显,达坂城在2000年前存在到6~8a周期。强风过程中迎风坡1900m高度存在稳定层结带,背风坡稳定层结带在500m高度。大风过程结束时,迎风坡稳定层结高度下降,背风坡稳定层结高度抬升、强度减弱。主城区、峡谷出口处东南风频率不高,但风速高于其他风向的风速;天山峡谷内、乌鲁木齐低空东南风秋、冬季频率及风速均强于其他季节。春季中纬度锋区活跃,易形成天山两侧气压场南高北低的形势且气压差较大,导致城区东南大风高发,秋、冬季蒙古国及我国内蒙古地区高压引起的回流和中低空反气旋环流造成天山峡谷及乌鲁木齐低空东南风常态化。This study analyzes the spatio-temporal distribution of southeast winds under Beaufort scale 3 and 6 wind thresholds,climate change at representative stations,and the stability characteristics of the atmospheric stratification during strong wind events.It also explores the atmospheric circulation responsible for the seasonal variation of southeast winds.The results show that:(1)The Tianshan Grand Canyon is the primary airflow channel for the southeast wind in Urumqi.Two areas with large values extend from the northern end of the Canyon to the northwest and northeast.The wind thresholds are strongest in winter,followed by spring and autumn,and weakest in summer.Large value centers are found at both the north and south ends of the Canyon,with the larger threshold consistently stronger at the north end than the south end throughout the year,except in winter.(2)The inter-monthly distribution characteristics show the highest frequency of southeast winds in winter and the lowest in summer within the Tianshan Grand Canyon.Wind frequency peaks in spring and autumn at the Canyon exit,the main urban area,and the northeast branch,while the highest frequency in the northwest branch occurs in spring,autumn,and winter.The diurnal variation shows a higher incidence in the morning along the northwest and northeast branches,while other areas experience peak occurrences in the afternoon.(3)The inter-annual variation characteristics at representative stations indicate that the annual accumulated wind in Urumqi and Dabancheng has decreased over the past 50 years,with the decline rate in Dabancheng being faster than in Urumqi.From 2000 onward,Urumqi experienced a rapid decline before 2000,followed by a slower decline after 2000,whereas Dabancheng showed the opposite trend.The variation cycles are as follows:Urumqi exhibits 12-year and 5-7 year cycles,with the 12-year cycle being the most prominent,while Dabancheng shows a 6-8 year cycle before 2000.(4)During strong wind events,a stable stratification zone is observed at a height of 1

关 键 词：乌鲁木齐 东南风 时空分布 层结稳定度 环流归因 

分 类 号：P468.024[天文地球—大气科学及气象学]