Ye Chen, Wang Jianjie, Zhang Wenlong. Formation mechanism of the snowstorm over Beijing in early winter of 2009. J Appl Meteor Sci, 2011, 22(4): 398-410.
Citation: Ye Chen, Wang Jianjie, Zhang Wenlong. Formation mechanism of the snowstorm over Beijing in early winter of 2009. J Appl Meteor Sci, 2011, 22(4): 398-410.

Formation Mechanism of the Snowstorm over Beijing in Early Winter of 2009

  • Received Date: 2010-12-29
  • Rev Recd Date: 2011-04-20
  • Publish Date: 2011-08-31
  • Using a variety of high spatial and temporal resolution observation data, an in-depth observation analysis is carried out on the formation and development mechanism of a snowstorm case happened on 1 Nov 2009 over Beijing and notable by its nature of the most early winter snowstorm in the past 60 years in Beijing. It shows that the snowstorm occurs under the favorable large scale atmospheric conditions. The enhanced 500 hPa trough over East Asian region together with the low level occluded front in Taihang and Yan mountain areas of North China provided strong forcing for the snowstorm. The occluded front is a terrain-driven cold-style occluded front system due to the encounter of the low level (below 1500 m) northwest to southeast cold air with the Taihang and Yan mountains. The low level cold air turns its original moving direction into west, and results in the moisture feeding to the occluded front zone from two different directions (the Bohai Sea and the edge of the water vapor-rich region in southern China).It shows that the snowstorm is the result of the low level occluded front, and precipitation distribution of 1101 process in 2009 is decided by the eastward-tilting structure of the occluded front, and Beijing is just located in the favorable front zone (the east side to the top of surface occluded front). Because vertical structure (below 1500 m) of the occluded front is shallower than the classic occluded front developed from the typical frontal cyclone, the vertical motion of the snowstorm case is not very strong. Therefore, its precipitation distributes evenly with time but lasts about 15 hours (rain first then it turns into snow) with large amount of the accumulated precipitation. The observation analysis based on wind profile suggests that the occluded front weakens from its bottom to top, which is caused by the cold air invading to the mature occluded front zone starting from layers below 500—800 m and then extending upward.Furthermore, the diagnosis shows that the precipitation transits from rain to snow because the surface air temperature decreases to near freezing point rapidly. The mechanisms for the temperature drop are not the same in different stages of precipitation. Evaporative cooling of the rainfall is the main contributor to the temperature drop before snowfall (from 00:00 to 08:00 on 1 November), while the low-level cold air advection plays the key role for maintaining lower air temperature during the whole snowfall period from 08:00 to 14:00 on 1 November in 2009.
  • Fig. 1  The precipitation distribution of 1101 process

    (a) the precipitation from 08:00 to 14:00 on 1 Nov 2009 in Beijing, (b) time series of precipitation, surface temperature on 1 Nov 2009 at Shijingshan Station

    Fig. 2  The precipitation distribution over the central and east of China from 20:00 31 Oct to 20:00 1 Nov in 2009(unit:mm)

    Fig. 3  The circulation characteristics of 1101 process (a)500 hPa geopotential height (solid line, unit:dagpm) and temperature (dashed line, unit:℃) at 20:00 31 Oct 2009, (b)850 hPa geopotential height (solid line, unit:dagpm), temperature (dashed line, unit:℃), specific humidity (shaded) and wind at 20:00 31 Oct 2009, (c) the surface observation plots and front evolution at 08:00 1 Nov 2009 (solid line: sea level pressure, unit:hPa; black circle: the concentrated area of snow)

    Fig. 4  Time evolution of sea level pressure isoline of 1030 hPa and Mongolia high from 31 Oct to 1 Nov in 2009

    (black line is for the topographic contour; within the green line is snowfall area; within the brown dashed line is the area with relatively high topography)

    Fig. 5  The water vapor distribution of 1101 process in 2009

    (a) specific humidity (shaded) and thermal advection (solid line, unit:10-5℃·s-1) of 925 hPa at 02:00 1 Nov 2009, (b) composite vector (arrow), modulus (contour, unit:g·hPa-1·cm-1·s-1) and divergence (shaded) of 925 hPa moisture flux at 02:00 1 Nov 2009, (c) cross section of horizontal wind through the time-height plane at 37°N, 114.5°E (south of Beijing)

    Fig. 6  Vertical sections along the brown line in Fig. 4 at 02:00 1 Nov 2009

    (a) thermal advection (contour, unit: 10-5 ℃·s-1) and vertical velocity (shaded), (b) potential temperature (contour, unit:K) and the projection of horizontal wind combined with vertical wind (vector)

    Fig. 7  Radar reflectivity at 1.5° elevation (a) and vertical sections along the black line (b) at 02:00 1 Nov 2009 of Beijing Weather Observatory

    Fig. 8  The wind field characteristics of stations (a) wind profile at Haidian Station, (b) radar PPI velocity of 1.5° at 10:00 1 Nov 2009 of Beijing Weather Observatory

    Fig. 9  The contribution of every item in formula 1 to 6 h temperature fluctuation in 975 hPa and 950 hPa

    (solid line is ∂T/∂t; dotted-dashad line is-V·∇hT-ω·∂T/∂P; dashed line is dT/dt)

    Fig. 10  Time series of surface half-hour temperature variation at Haidian Station

    (broken line is for the period of 1101 process from 15:00 31 Oct to 15:00 1 Nov in 2009; solid line is for the comparision period of no precipitation which is the average of 15:00 27 Oct to 15:00 28 Oct in 2009 and from 15:00 28 Oct to 15:00 29 Oct in 2009; box Ⅰ and box Ⅱ denote the periods of rainfall and snowfall, respectively)

    Fig. 11  Time series of precipitation, relative humidity of AWS and the time series of the 0℃ level height, temperature at different height of microwave radiometer observations in Beijing Weather Observatory

    Fig. 12  Cross section of thermal advection through the time-height plane at 40°N, 116°E

    (unit:10-5℃·s-1)

  • [1]
    Bennetts D A, Hoskins B J. Conditional symmetric instability—A possible explaination for frontal rainbands. Quart J Roy Meteo Soc, 1979, 105: 945-962. doi:  10.1002/(ISSN)1477-870X
    [2]
    Emanuel K A. Inetial instability and mesoscale convective system. Part Ⅰ: Linear theory of inertial instability in rotating viscous fluids. J Atmos Sci, 1979, 36: 2425-2499. doi:  10.1175/1520-0469(1979)036<2425:IIAMCS>2.0.CO;2
    [3]
    Sanders F, Bosart L F. Mesoscale structure in the megalopolitan snowstorm of 11-12 February 1983.Part Ⅰ: Frontogenetical forcing and symmetric instability.J Atmos Sci, 1985, 42:1050-1061. doi:  10.1175/1520-0469(1985)042<1050:MSITMS>2.0.CO;2
    [4]
    仪清菊, 刘延英, 许晨海.北京1980~1994年降雪的天气气候分析.应用气象学报, 1999, 10(2):249-254. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=19990253&flag=1
    [5]
    陶祖钰, 郑永光, 张小玲.2008年初冰雪灾害和华南准静止锋.气象学报, 2008, 66(5):850-854. doi:  10.11676/qxxb2008.077
    [6]
    王宝书, 高锋.初春一次罕见暴雪天气过程的诊断分析.吉林气象, 2009(3):9-12. http://www.cnki.com.cn/Article/CJFDTOTAL-JLQX200902004.htm
    [7]
    张腾飞, 鲁亚斌, 张杰, 等. 2000年以来云南4次强降雪过程的对比分析.应用气象学报, 2007, 18(1):64-72. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20070112&flag=1
    [8]
    梁凤霞, 胡长雷, 杨俊玲.吉林省2007年一次特大暴雪天气过程分析.安徽农业科学, 2009, 37(4):6527-6529. http://www.cnki.com.cn/Article/CJFDTOTAL-AHNY200914088.htm
    [9]
    王文, 程麟生."96.1"高原暴雪过程横波型不稳定的数值研究.应用气象学报, 2000, 11(4):392-399. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20000459&flag=1
    [10]
    王建中, 丁一汇.一次华北强降雪过程的湿对称不稳定性研究.气象学报, 1995, 53(4):451-460. doi:  10.11676/qxxb1995.051
    [11]
    周淑玲, 丛美环, 吴增茂, 等.2005年12月3—21日山东半岛持续性暴雪特征及维持机制.应用气象学报, 2008, 19(4):444-453. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20080408&flag=1
    [12]
    赵思雄, 孙建华, 陈红, 等.北京"12.7"降雪过程的分析研究.气候与环境研究, 2002, 7(1):7-21. http://www.cnki.com.cn/Article/CJFDTOTAL-QHYH200201001.htm
    [13]
    牛凤权, 许磊.罕见暴雪天气过程个例分析.气象水文海洋仪器, 2009(2):140-141. http://www.cnki.com.cn/Article/CJFDTOTAL-QXSW200902045.htm
    [14]
    单宝臣, 张成, 李建华, 等.威海地区2005年初冬首次暴雪诊断分析.山东气象, 2006(4):17-18. http://cpfd.cnki.com.cn/Article/CPFDTOTAL-ZGQX200610013242.htm
    [15]
    王迎春, 钱婷婷, 郑永光.北京连续降雪过程分析.应用气象学报, 2004, 15(1):58-65. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20040108&flag=1
    [16]
    Birkhimer S, Agee E M, Sorbjan Z.Convection structure in a cold air outbreak over lake Michigan during Lake ICE. J Atmo Sci, 2005, 62 (7):2414-2432. doi:  10.1175/JAS3494.1
    [17]
    Lavoie R L. A mesoscale numerical model of lake effect storms. J Atmos Sci, 1972, 29:1025-1040. doi:  10.1175/1520-0469(1972)029<1025:AMNMOL>2.0.CO;2
    [18]
    Ellenton G E, Danard M B. Inclusion of sensible heating in convective parameterization applied to lake effect snow. Mon Wea Rev, 1979, 107:551-565. doi:  10.1175/1520-0493(1979)107<0551:IOSHIC>2.0.CO;2
    [19]
    孙晶, 楼小凤, 胡志晋.祁连山冬季降雪个例模拟分析 (Ⅰ):降雪过程和地形影响.高原气象, 2009, 28(3):485-495. http://www.cnki.com.cn/Article/CJFDTOTAL-GYQX200903002.htm
    [20]
    邓远平, 程麟生, 张小玲.三相云显式降水方案和高原东部"96. 1"暴雪成因的中尺度数值模拟.高原气象, 2000, 19(4):401-414. http://www.cnki.com.cn/Article/CJFDTOTAL-GYQX200004000.htm
    [21]
    Srivastava R C, Matejka T J, Lorello T J.Doppler radar study of the trailing anvil region associated with a squall line. Atmos Sci, 1986, 43:336-377. doi:  10.1175/1520-0469%281986%29043<0356%3ADRSOTT>2.0.CO%3B2
    [22]
    Thomas M, Srivastava R C. An improved version of the extended velocity-azimuth display analysis of single-Doppler radar data. J Atmos Ocean Technol, 1991, 8 (4): 453-456. doi:  10.1175/1520-0426(1991)008<0453:AIVOTE>2.0.CO;2
    [23]
    林曲凤, 吴增茂, 梁玉海, 等.山东半岛一次强冷流降雪过程的中尺度特征分析.中国海洋大学学报, 2006, 36(6):908-914. http://www.cnki.com.cn/Article/CJFDTOTAL-QDHY200606011.htm
    [24]
    徐达生.1956年2月25日的华北锢囚结构和降水.天气月刊, 1957(5):5-10. http://cdmd.cnki.com.cn/Article/CDMD-85101-1011117365.htm
    [25]
    肖庆农.地形影响下冷锋的变形及锢囚.气象学报, 1994, 52(4):414-423. doi:  10.11676/qxxb1994.051
    [26]
    苗爱梅, 张红雨, 郝建萍.河套锢囚与山西暴雪.山西气象, 2003(1):11-14. http://www.cnki.com.cn/Article/CJFDTOTAL-SXQX200301003.htm
    [27]
    高智松, 魏柏温.南方大到暴雪的一种预报方法.气象, 1994, 20(4):41-43. doi:  10.7519/j.issn.1000-0526.1994.04.010
    [28]
    张迎新, 张守保.华北平原回流天气的结构特征.南京气象学院学报, 2006, 19(1):107-113. http://www.cnki.com.cn/Article/CJFDTOTAL-NJQX200601015.htm
    [29]
    周雪松, 谈哲敏.华北回流暴雪发展机理个例研究.气象, 2008, 34(1):18-26. doi:  10.7519/j.issn.1000-0526.2008.01.003
    [30]
    边志强, 王建捷, 谈哲敏.对华北锢囚锋个例的数值模拟分析.气象, 1999, 25(10):8-14. doi:  10.7519/j.issn.1000-0526.1999.10.002
    [31]
    Xiao Qingnong. Distortion and occlusion of cold fronts under the influence of orography. Acta Meteorologica Sinica, 1994, 8(4):440-449. http://www.cqvip.com/QK/88418X/199404/4001377013.html
    [32]
    杨成芳. 山东半岛冷流暴雪的多普雷雷达特征分析//新一代天气雷达业务应用论文集. 北京: 气象出版社, 2008: 301-307.
    [33]
    朱乾根, 林瑞祥, 寿绍文, 等.天气学原理和方法.北京:气象出版社, 2000:10-11.
  • 加载中
  • -->

Catalog

    Figures(12)

    Article views (4380) PDF downloads(2046) Cited by()
    • Received : 2010-12-29
    • Accepted : 2011-04-20
    • Published : 2011-08-31

    /

    DownLoad:  Full-Size Img  PowerPoint