| 天山两麓一次极端暴雪天气多尺度配置特征及机制分析 |
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| 引用本文： | 于碧馨,洪月,张云惠,吐莉尼沙,许婷婷,李娜,阿不力米提·阿布力克木.天山两麓一次极端暴雪天气多尺度配置特征及机制分析[J].新疆气象,2020,14(5):11-18. |
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| 作者姓名： | 于碧馨 洪月 张云惠 吐莉尼沙 许婷婷 李娜 阿不力米提·阿布力克木 |
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| 作者单位： | 新疆维吾尔自治区气象台,新疆维吾尔自治区气象台,新疆维吾尔自治区气象台,新疆维吾尔自治区气象台,新疆维吾尔自治区气象台,新疆维吾尔自治区气象台,新疆维吾尔自治区气象台 |
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| 基金项目： | 国家自然科学基金（41965002）；中亚大气科学研究基金项目（CAAS202005）；中国气象局预报员专项（CMAYBY2018-088） |
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| 摘 要： | 利用自动站小时监测资料、常规与加密观测资料、NCEP/NCAR再分析资料（0.25°×0.25°）、FY-2G卫星相当黑体亮温（TBB）资料，分析2017年2月19日至20日天山两麓的极端暴雪天气过程。结果表明: （1）此次过程发生在500 hPa南欧脊衰退、乌拉尔低槽与中亚偏南低槽先结合、后分段东移进入的环流背景下，天山北麓暴雪高低空系统呈典型后倾结构，天山南麓暴雪形势为典型“东西夹攻”型。（2）影响天山北麓暴雪的低空西北急流和影响天山南麓暴雪的低空偏东急流均为冷湿气流，西北急流风速的增大比雪强的增强提早12h左右，偏东急流比降雪提前6h出现。（3）主要水汽通道在850～400 hPa，水汽通量进入新疆后，850～700 hPa偏西水汽输送强于600～400 hPa西南水汽输送，水汽辐合主要在850～700 hPa。（4）乌鲁木齐降雪前位势不稳定性加强，沙雅降雪前有明显对流不稳定，两暴雪中心均有地形强迫强化产生并维持的中尺度垂直上升支和次级环流圈，而沙雅系统性动力作用小于乌鲁木齐的。（6）中尺度云团是造成天山两麓暴雪产生的最直接的影响系统。
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| 关 键 词： | 极端暴雪 多尺度配置 低空急流 天山地形 |
| 收稿时间： | 2020/1/11 0:00:00 |
| 修稿时间： | 2020/4/9 0:00:00 |
Multiscale Configuration Characteristic and Mechanism Analysis of An Extreme Snowstorm Astride Mount Tianshan |
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| yubixin,Hong Yue,Zhang Yunhui,Tuli Nish,Xu Tingting,Li Na and Ablimitjan Ablikim.Multiscale Configuration Characteristic and Mechanism Analysis of An Extreme Snowstorm Astride Mount Tianshan[J].Bimonthly of Xinjiang Meteorology,2020,14(5):11-18. |
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| Authors: | yubixin Hong Yue Zhang Yunhui Tuli Nish Xu Tingting Li Na and Ablimitjan Ablikim |
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| Institution: | Xinjiang Meteorological Observatory,Xinjiang Meteorological Observatory,Xinjiang Meteorological Observatory,Xinjiang Meteorological Observatory,Xinjiang Meteorological Observatory,Xinjiang Meteorological Observatory,Xinjiang Meteorological Observatory |
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| Abstract: | Using hourly observational data, the conventional and intensive detecting data, the NCEP reanalysis data (0.25°×0.25°) and the FY-2G Satellite Bold Bright Temperature data, an extreme snowstorm astride Mount Tianshan from February 19th to 20th in 2017 was analyzed. Results suggested as follows. The event occurred under the background that as the high-pressure ridge over the south of Europe has retreated, the low-pressure trough, north and south in combination from Ural and Central Asia firstly and then divided into two above the Balkhash Lake, moves to east into Xinjiang at 500 hPa. The effect systems at high and low level of the extreme snowstorm on the north slope of Tianshan Mountain presents a backward-tilting structure. The snowstorm on the sorth slope of Tianshan Mountain is caused by the typical atmospheric circulation of the combined action between the southwestern warm air eastwards and the easterly cold air westwards. The low-level northwest and easterly jet, respectively effecting the snowstorm on the northern slope and southern slope of Mount Tianshan, are both cold and wet. The northwest jet speed has increased about 12 hours earlier than that the snow intensity enhances. The easterly jet shows up 6 hours earlier than the snowfall. In this event, the major water vapor channel is at 850-500 hPa. When the water vapor flux has entered Xinjiang, the westerly water vapor transport at 850-700 hPa is stronger than the southwest one at 600-400 hPa. The water vapor convergence is mainly at 850-700 hPa. Before the snowfall, the potential instability of the atmosphere over Urumqi has intensified, but the atmosphere over Shaya is convective unstable. There exists mesoscale vertical ascending branch and secondary circulation over both the two snowstorm centers, produced and maintained by the intensification of topographic forcing. However, the systematic dynamic action of Shaya snowstorm is weaker than that of Urumqi snowstorm. The most direct effect systems are mesoscale clouds in this event. |
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| Keywords: | extreme snowstorm multiscale configuration low-level jet Mount Tianshan topographic |
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