| 2022 年初冬伊犁河谷一次极端暴雪过程诊断分析 |
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| 引用本文： | 祝小梅,范宏云,Qiaolipan?Bieken.2022 年初冬伊犁河谷一次极端暴雪过程诊断分析[J].新疆气象,2023,17(4):1-6. |
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| 作者姓名： | 祝小梅 范宏云 Qiaolipan?Bieken |
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| 作者单位： | 新疆人工影响天气办公室 |
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| 摘 要： | 为了更全面地伊犁河谷极端暴雪发生发展的机制,利用常规探空和地面观测资料、FY-2H长波辐射资料(Outgoing Long-wave Radiation,OLR)和NCEP/NCAR１°×１°再分析资料,采用天气动力学分析方法对2022年11月22日-24日出现在伊犁河谷极端暴雪过程的成因和动力结构演变特征进行分析,结果表明:(1)此次降雪为强锋区降雪,锋区内不断有短波东移,是暴雪发生的大尺度环流背景；300hPa极锋急流、500hPa强锋区、700hPa强偏西急流的流场配置起至关重要作用。(2)低层冷空气入侵,迫使暖湿空气抬升、气温下降,形成了下冷上暖的强逆温层结,而导致降水相态转变。降雪持续时间长,导致强降雪发生。(3)低层偏西急流把水汽输送到暴雪区,并在暴雪区上方产生强的水汽辐合中心,为本次暴雪提供了有利的水汽条件。散度场对大暴雪的发生有较好的先兆意义,双辐合-辐散结构的散度场特征可以作为预报降雪加大的指标。(4)暴雪过程发生时大气处于对流稳定状态,但存在对称不稳定能量的释放。(5)OLR特征分析表明OLR３ｈ平均值与３ｈ降雪量存在明显的负相关关系。
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| 关 键 词： | 极端事件 暴雪 低空急流 湿位涡 OLR |
| 收稿时间： | 2023/1/11 0:00:00 |
| 修稿时间： | 2023/2/20 0:00:00 |
Diagnostic Analysis of an Extreme Blizzard Process Over Yili River Valley in the Early Winter of 2022 |
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| ZHU Xiaomei,Fan Hongyun,Qiaolipan?Bieken.Diagnostic Analysis of an Extreme Blizzard Process Over Yili River Valley in the Early Winter of 2022[J].Bimonthly of Xinjiang Meteorology,2023,17(4):1-6. |
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| Authors: | ZHU Xiaomei Fan Hongyun Qiaolipan?Bieken |
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| Institution: | China Meteorological Administration Transportation Meteorology Key Laboratory,Ili MeteorologIcal Bureau |
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| Abstract: | In order to comprehensively understand the occurrence and development mechanism of extreme snowfall in Yili Valley, the Outgoing Long-wave Radiation (OLR) data of FY-2H and the NCEP/NCAR1°×1° reanalysis data were used. The causes and dynamic structure evolution characteristics of the extreme snowfall in Yili Valley from November 22 to 24, 2022 were analyzed by using the weather dynamics analysis method. The results showed that: (1) the snowfall was in the strong front area, and the short wave moved eastward continuously in the front area, which was the large-scale circulation background of the snowfall. The flow field configuration of 300hPa polar front jet, 500hPa strong front zone and 700hPa strong westerly jet plays a crucial role. (2) The invasion of cold air at low level forced the warm and wet air to rise and the temperature to fall, forming a strong inversion stratification of cold below and warm above, which led to the transition of precipitation phase state. The snowfall lasted for a long time, resulting in heavy snowfall. (3) The westerly jet at lower level transported water vapor to the blizzard area and generated a strong water vapor convergence center over the blizzard area, which provided favorable water vapor conditions for the blizzard. The divergence field has a good precursor significance to the occurrence of heavy snowfall, and the divergence field characteristics of the double-convergence-divergence structure can be used as an indicator to forecast the increase of snowfall. (4) The atmosphere is in a convective stable state when the blizzard process occurs, but there is the release of symmetric unstable energy. (5) The analysis of OLR characteristics showed that there was an obvious negative correlation between OLR3h average and 3h snowfall. |
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| Keywords: | Extreme event Snowstorm Low-level Jet Moist potential vorticity OL |
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