Chyi Dorina, He Lifu, Wang Xiuming, et al. Fine observation characteristics and thermodynamic mechanisms of extreme heavy rainfall in Henan on 20 July 2021. J Appl Meteor Sci, 2022, 33(1): 1-15. DOI:  10.11898/1001-7313.20220101.
Citation: Chyi Dorina, He Lifu, Wang Xiuming, et al. Fine observation characteristics and thermodynamic mechanisms of extreme heavy rainfall in Henan on 20 July 2021. J Appl Meteor Sci, 2022, 33(1): 1-15. DOI:  10.11898/1001-7313.20220101.

Fine Observation Characteristics and Thermodynamic Mechanisms of Extreme Heavy Rainfall in Henan on 20 July 2021

DOI: 10.11898/1001-7313.20220101
  • Received Date: 2021-10-09
  • Rev Recd Date: 2021-11-26
  • Publish Date: 2022-01-19
  • The typical circulation configuration, fine structure of mesoscale system and thermodynamic development mechanism of affecting system associated with the extreme heavy rainfall of Henan from 19 July to 21 July in 2021 are analyzed with data which contain minutely automatic weather station observations, FY-4A satellite high-resolution measurements, Doppler radar products and the fifth-generation European Center for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalysis (ERA5). Results show that the extreme heavy rainfall occurs under a weaken saddle field which is between the subtropical high and the continental high. The dominant systems are the weak low-pressure system at 500 hPa and easterly shear line at low level. A long-term maintained mesoscale convective cloud plays great roles in the extreme heavy rainfall of Henan, which features a nearly circular structure with a horizontal scale of about 300 km. The long-term maintenance of this cloud is related to the merging of its inside multiple β-mesoscale convective systems. Meanwhile, the confluence of three easterly flows in the east of warm zone in the southeast of the periphery keep triggering new convective cells which are constantly integrated into the mesoscale convective cloud. These two processes lead to the train effect, which is crucial to the extreme heavy rainfall in Henan. The rainfall intensity at Zhengzhou Station is 201.9 mm·h-1, and breaks the hourly rainfall record in inland regions. It is mainly caused by quasi-stationary β-mesoscale convective systems, which show bow echo in Doppler weather radar. The vertical structure of the convective system, which has the strong echo centroid below 5 km in Doppler weather radar, reflects the extremely efficient precipitation. During the extreme rainfall from 1600 BT to 1700 BT on 20 Jul 2021, the minutely continuous precipitation is stable at 3-4.7 mm, and the 5-minute rainfall maximum could reach 21 mm. The strong convection is triggered by the dynamic convergence of the boundary layer wind, leading to the pseudo equivalent temperature (θse) front above the heavy rainfall area maintaining in a neutral stratification of nearly barotropic structure for a long time. Meanwhile, the low-level convergence collocates with the high-level divergence, which benefits an intense ascend through the tropopause. The high-level divergent flow forms a sinking branch of the secondary circulation near the Northwest Pacific subtropical high. The significant positive vorticity advection near the cyclonic circulation at 500 hPa, the continuous warm advection transport by easterly flow at 925 hPa, the frontogenesis of low-level deformation field and the abnormally strong jet water vapor transport from the coast of East China are the thermodynamic mechanisms of the development and maintenance of the extreme heavy rainfall in Henan.
  • Fig. 1  Monitoring of heavy rainfall from 18 Jul to 22 Jul in 2021  (a)the accumulative rainfall from 0800 BT 18 Jul to 0800 BT 22 Jul, (b)the rainfall from 0800 BT 20 Jul to 0800 BT 21 Jul, (c)hourly rainfall of Zhengzhou Station from 0800 BT 19 Jul to 0800 BT 22 Jul, (d)minutely rainfall (the column) and accumulative rainfall in 5 minutes (the blue solid line) of Zhengzhou Station from 1500 BT to 1759 BT on 20 Jul

    Fig. 2  500 hPa geopotential height (the contour, unit: dagpm) with its standardized anomaly (the shaded) and 850 hPa wind (the barb) from 19 Jul to 21 Jul in 2021

    Fig. 3  TBB images of FY-4A from 0800 BT 20 Jul to 0500 BT 21 Jul in 2021

    Fig. 4  The evolution of radar combined reflectivity factor from 1600 BT to 1700 BT on 20 Jul 2021

    Fig. 5  Reflectivity factors of Luoyang radar with cross-section along AB at 1618 BT 20 Jul(a) and 1654 BT 20 Jul(b) in 2021

    Fig. 6  Cross-section of θse (the contour, unit: K), vertical velocity (the shaded) and the combination (the arrow) of zonal wind (unit: m·s-1) and vertical movement (unit: 10-2m·s-1) along Zhengzhou Station from 20 Jul to 21 Jul in 2021 (the black triangle is the longitude position of Zhengzhou Station, the blue dotted line refers to 0℃)

    Fig. 7  The height (the contour, unit: dagpm), wind (the arrow) and positive vorticity advection (the shaded) at 500 hPa from 19 Jul to 21 Jul in 2021

    Fig. 8  θse (the contour, unit: K), wind (the barb) and warm advection (the shaded) at 925 hPa from 19 Jul to 21 Jul in 2021

    Fig. 9  Time-pressure cross-section of divergence (the contour, unit: 10-5 s-1) and deformation frontogenesis of heavy rainfall area-averaged (33.5°-36°N, 112.5°-115°E) from 19 Jul to 22 Jul in 2021

    Fig. 10  Wind anomalies (the barb), moisture flux anomalies (the shaded) and moisture flux standardized anomalies (the contour, Ds≥3, the interval is 1) at 925 hPa from 20 Jul to 21 Jul in 2021 (the gray denotes the topography higher than 700 m)

  • [1]
    Li H M, Zhou T J, Yu R C. Analysis of July-August daily precipitation characteristics variation in eastern China during 1958-2000. Chinese J Atmos Sci, 2008, 32(2): 358-370. doi:  10.3878/j.issn.1006-9895.2008.02.14
    [2]
    Liu H W, Ding Y H. The interdecadal variability of summer precipitation over North China. J Appl Meteor Sci, 2011, 22(2): 129-137. doi:  10.3969/j.issn.1001-7313.2011.02.001
    [3]
    Zhai P M, Zhang X B, Wan H, et al. Trends in total precipitation and frequency of daily precipitation extremes over China. J Climate, 2005, 18(18): 1096-1108.
    [4]
    Zhu J T. Impact of climate change on extreme rainfall across the United States. J Hydrol Eng, 2013, 18(10): 1301-1305. doi:  10.1061/(ASCE)HE.1943-5584.0000725
    [5]
    Bao M. The statistical analysis of the persistent heavy rain in the last 50 years over China and their backgrounds on the large scale circulation. Chinese J Atmos Sci, 2007, 31(5): 779-792. doi:  10.3878/j.issn.1006-9895.2007.05.03
    [6]
    Min S, Qian Y F. Regionality and persistence of extreme precipitation events in China. Adv Water Sci, 2008, 19(6): 765-771. https://www.cnki.com.cn/Article/CJFDTOTAL-SKXJ200806002.htm
    [7]
    Niu R Y, Liu C H, Liu W Y, et al. Characteristics of temporal and spatial distribution of regional rainstorm processes to the east of 95°E in China during 1981-2015. Acta Meteor Sinica, 2018, 76(2): 182-195. https://www.cnki.com.cn/Article/CJFDTOTAL-QXXB201802002.htm
    [8]
    Zhou M S. The circulation analysis of regional heavy rainstorms in the north of China. Meteor Mon, 1993, 19(7): 14-18. https://www.cnki.com.cn/Article/CJFDTOTAL-QXXX199307003.htm
    [9]
    Sun J H, Zhang X L, Wei J, et al. A study on severe heavy rainfall in North China during the 1990s. Climatic Environ Res, 2005, 10(3): 492-506. https://www.cnki.com.cn/Article/CJFDTOTAL-QHYH200503019.htm
    [10]
    Zhou X, Sun J S, Zhang L N, et al. Classification characteristics of continuous extreme rainfall events in North China. Acta Meteor Sinica, 2020, 78(5): 761-777. https://www.cnki.com.cn/Article/CJFDTOTAL-QXXB202005004.htm
    [11]
    Zhao Y Y, Zhang Q H, Du Y, et al. Objective analysis of the extreme of circulation patterns during the 21 July 2012 torrential rain event in Beijing. Acta Meteor Sinica, 2013, 71(5): 817-824. https://www.cnki.com.cn/Article/CJFDTOTAL-QXXB201305002.htm
    [12]
    You J Y. The mesoscale systems in heavy rainfall zone. Acta Meteor Sinica, 1965, 35(3): 293-304. https://www.cnki.com.cn/Article/CJFDTOTAL-QXXB196503003.htm
    [13]
    Sun J H, Zhao S X, Fu S M, et al. Multi-scale characteristics of record heavy rainfall over Beijing Area on July 21, 2012. Chinese J Atmos Sci, 2013, 37(3): 705-718. https://www.cnki.com.cn/Article/CJFDTOTAL-DQXK201303014.htm
    [14]
    Lei L, Sun J S, He N, et al. A study on the mechanism for the vortex system evolution and development during the torrential rain event in North China on 20 July 2016. Acta Meteor Sinica, 2017, 75(5): 685-699. https://www.cnki.com.cn/Article/CJFDTOTAL-QXXB201705001.htm
    [15]
    He L F, Chen S, Guo Y Q. Observation characteristics and synoptic mechanisms of Typhoon Lekima extreme rainfall in 2019. J Appl Meteor Sci, 2020, 31(5): 513-526. doi:  10.11898/1001-7313.20200501
    [16]
    Yang S N, Duan Y H. Extremity analysis on the precipitation and environmental field of Typhoon Rumbia in 2018. J Appl Meteor Sci, 2020, 31(3): 290-302. doi:  10.11898/1001-7313.20200304
    [17]
    Wang J, Jiang J Y, Jiang J X. A Jinan heavy rainfall on 18 July 2007. J Appl Meteor Sci, 2009, 20(3): 295-302. doi:  10.3969/j.issn.1001-7313.2009.03.005
    [18]
    Hou J Z, Wang C, Lu Y P, et al. Activity of typhoons and extreme rainstorms in Shaanxi Province. J Trop Meteor, 2006, 22(2): 203-208. doi:  10.3969/j.issn.1004-4965.2006.02.014
    [19]
    Kang L, Niu J L, Xu L N, et al. Comparative analysis on the ambient field of torrential rains impacted by typhoon in Sichuan. Meteor Mon, 2013, 39(4): 427-435. https://www.cnki.com.cn/Article/CJFDTOTAL-QXXX201304005.htm
    [20]
    Zhang D E, Liang Y Y. Study of the heavy torrential rain over the Huang-Huai region in eastern China in 1730-An extreme climatic events in history. Adv Climate Change Res, 2016, 12(5): 407-412. https://www.cnki.com.cn/Article/CJFDTOTAL-QHBH201605010.htm
    [21]
    Lei Y S. The compositive analysis of the meridional type persistent severe rainstorms. Acta Meteor Sinica, 1981, 39(2): 168-181. https://www.cnki.com.cn/Article/CJFDTOTAL-QXXB198102004.htm
    [22]
    Sun J S, He N, Wang G R, et al. Preliminary analysis on synoptic configuration evolvement and mechanism of a torrential rain occurring in Beijing on 21 July 2012. Torrential Rain Disaster, 2012, 31(3): 218-225. https://www.cnki.com.cn/Article/CJFDTOTAL-HBQX201203003.htm
    [23]
    Sun J, Chen Y, Yang S N, et al. Analysis and thinking on the extremes of the 21 July 2012 torrential rain in Beijing Part Ⅱ: Preliminary causation analysis and thinking. Meteor Mon, 2012, 38(10): 1267-1277. doi:  10.7519/j.issn.1000-0526.2012.10.013
    [24]
    Liu Y J, Ding Y H, Zhang Y X, et al. Role of a warm and wet transport belt of Asian summer monsoon and cold air from north in the Beijing July 21 heavy rainstorm. J Trop Meteor, 2015, 31(6): 721-732. https://www.cnki.com.cn/Article/CJFDTOTAL-RDQX201506001.htm
    [25]
    Chen Y, Sun J, Xu J, et al. Analysis and thinking on the extremes of the 21 July 2012 torrential rain in Beijing Part Ⅰ: Observation and thinking. Meteor Mon, 2012, 38(10): 1255-1266. doi:  10.7519/j.issn.1000-0526.2012.10.012
    [26]
    Fang C, Mao Y D, Zhang X W, et al. Analysis on the mesoscale convective conditions and characteristics of an extreme torrential rain in Beijing on 21 July 2012. Meteor Mon, 2012, 38(10): 1278-1287. doi:  10.7519/j.issn.1000-0526.2012.10.014
    [27]
    Yu X D. Investigation of Beijing extreme flooding event on 21 July 2012. Meteor Mon, 2012, 38(11): 1313-1329. https://www.cnki.com.cn/Article/CJFDTOTAL-QXXX201211003.htm
    [28]
    Wang S L, Kang H W, Gu X Q, et al. Numerical simulation of mesoscale convective system in the warm sector of Beijing "7.21" severe rainstorm. Meteor Mon, 2015, 41(5): 544-553. doi:  10.3969/j.issn.1000-6362.2015.05.003
    [29]
    Meng Z Y, Tang X J, Yue J, et al. Impact of EnKF surface and rawinsonde data assimilation on the simulation of the extremely heavy rainfall in Beijing on July 21, 2012. Acta Sci Nat Univ Pekin, 2019, 55(2): 237-245. https://www.cnki.com.cn/Article/CJFDTOTAL-BJDZ201902005.htm
    [30]
    Sun S Q, Ji L R. The numerical experiment of latent heat condensation effect on large scale flow field. Chin Sci Bull, 1986, 31(14): 1090-1092. https://www.cnki.com.cn/Article/CJFDTOTAL-KXTB198614013.htm
    [31]
    Liang F, Tao S Y. Diagnosis of a heavy rain event caused by the intense development of Yellow River cyclone in July, 1998. J Appl Meteor Sci, 2007, 18(5): 577-585. doi:  10.3969/j.issn.1001-7313.2007.05.001
    [32]
    He L F, Chen T, Kong Q. A review of studies on prefrontal torrential rain in South China. J Appl Meteor Sci, 2016, 27(5): 559-569. doi:  10.11898/1001-7313.20160505
    [33]
    Li H, Wang X M, Zhang X, et al. Analysis on extremity and characteristics of the 19 July 2016 severe torrential rain in the north of Henan Province. Meteor Mon, 2018, 44(9): 1136-1147. https://www.cnki.com.cn/Article/CJFDTOTAL-QXXX201809002.htm
    [34]
    Ni Y Q, Zhou X J, Zhang R H, et al. Experiments and studies for heavy rainfall in southern China. J Appl Meteor Sci, 2006, 17(6): 690-704. doi:  10.3969/j.issn.1001-7313.2006.06.007
    [35]
    Sun S Q, Zheng J, Zhi S L, et al. Analysis of a Meiyu-front rainstorm caused by "train effect". Plateau Meteor, 2015, 34(1): 190-201. https://www.cnki.com.cn/Article/CJFDTOTAL-GYQX201501020.htm
    [36]
    Wu Q M, Liu Z, Wang G R, et al. The influence of boundary layer east wind on a North China rainstorm. J Appl Meteor Sci, 2015, 26(2): 160-172. doi:  10.11898/1001-7313.20150204
    [37]
    Li M H, Chen F L, Jiang S, et al. The analysis of train effect features of a record-breaking severe rainfall in eastern region of Guangdong in August 2018. Torrential Rain Disaster, 2019, 38(4): 329-337. doi:  10.3969/j.issn.1004-9045.2019.04.005
    [38]
    Chen F L, Jiang S, Li M H, et al. The role of boundary layer jet in two severe rainfalls over eastern region of Guangdong Province. Meteor Mon, 2021, 47(3): 290-302. https://www.cnki.com.cn/Article/CJFDTOTAL-QXXX202103003.htm
    [39]
    Ji X D, Qi L B. Evaluation and application of ECMWF model precipitation and extreme weather forecast index of precipitation on heavy rainfall forecast. Torrential Rain Disaster, 2018, 37(6): 566-573. doi:  10.3969/j.issn.1004-9045.2018.06.010
    [40]
    Zhai P M, Li L, Zhou B Q, et al. Progress on mechanism and prediction methods for persistent extreme precipitation in the Yangtze-Huai River Valley. J Appl Meteor Sci, 2016, 27(5): 631-640. doi:  10.11898/1001-7313.20160511
    [41]
    Luo L, Lou X F, Fu L, et al. Application of precipitation extreme forecast index from ECMWF in typhoon rainstorm in East China. Meteor Mon, 2019, 45(10): 1382-1391. doi:  10.7519/j.issn.1000-0526.2019.10.005
    [42]
    Hersbach H, Bell B, Berrisford P, et al. The ERA5 global reanalysis. Quart J Roy Meteor Soc, 2020, 146(730): 1999-2049. doi:  10.1002/qj.3803
    [43]
    Hart R, Grumm R. Using normalized climatological anomalies to rank synoptic-scale events objectively. Mon Wea Rev, 2001, 129(9): 2426. doi:  10.1175/1520-0493(2001)129<2426:UNCATR>2.0.CO;2
    [44]
    Zhu Q G, Lin J R, Shou S W, et al. The Principle and Method of Weather(3rd Ed). Beijing: China Meteorological Press, 2000.
    [45]
    Zeng Z L, Chen Y, Wang D H. Observation and mechanism analysis for a record-breaking heavy rainfall event over Southern China in August 2018. Chinese J Atmos Sci, 2020, 44(4): 695-715. https://www.cnki.com.cn/Article/CJFDTOTAL-DQXK202004002.htm
  • 加载中
  • -->

Catalog

    Figures(10)

    Article views (3233) PDF downloads(704) Cited by()
    • Received : 2021-10-09
    • Accepted : 2021-11-26
    • Published : 2022-01-19

    /

    DownLoad:  Full-Size Img  PowerPoint