Vol.35, NO.1, 2024
Turn off MathJax
Article Contents
Article Navigation >  Journal of Applied Meteorological Science  > 2024  >  35(1): 1-16
Chen Xunlai, Xu Ting, Wang Rui, et al. Fine observation characteristics and causes of '9·7' extreme heavy rainstorm over Pearl River Delta, China. J Appl Meteor Sci, 2024, 35(1): 1-16. DOI:  10.11898/1001-7313.20240101.
Citation: Chen Xunlai, Xu Ting, Wang Rui, et al. Fine observation characteristics and causes of "9·7" extreme heavy rainstorm over Pearl River Delta, China. J Appl Meteor Sci, 2024, 35(1): 1-16. DOI:  10.11898/1001-7313.20240101.
shu

Fine Observation Characteristics and Causes of "9·7" Extreme Heavy Rainstorm over Pearl River Delta, China

DOI: 10.11898/1001-7313.20240101
  • 1.

    Shenzhen Meteorological Service, Shenzhen 518040

  • 2.

    Shenzhen Key Laboratory of Severe Weather in South China, Shenzhen 518040

  • 3.

    Shenzhen National Climate Observatory, Shenzhen 518040

  • Received Date: 2023-11-13
  • Rev Recd Date: 2023-12-19
  • Publish Date: 2024-01-31
    Abstract
  • On 7-8 September 2023, the Pearl River Delta experiences an extremely heavy rainstorm, known as "9·7" extreme rainstorm. Multi-source data are comprehensively utilized, including high-density automatic weather station data, sounding data, wind profiler data, Doppler radar data, high-resolution measurements from FY-4B satellite, and the fifth-generation European Centre for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalysis (ERA5), to analyze the fine precipitation characteristics and causes of this case. Results indicate that the extremely heavy rainstorm is characterized by area of coverage, wide coverage area, long duration, and substantial rainfall. The extremely heavy rainstorm is caused by the combined interaction of 200 hPa upper-level divergence, the middle-level weak guiding flow, the lower-level southwest monsoon, and the residual vortex of Typhoon Haikui (2311). It is generated by the long-term horizontal scale of about 100 km banded mesoscale convective complex, with significant train effect and warm cloud precipitation characteristics. The centroid of intense echoes with an intensity greater than 45 dBZ is located below 4 km during the most intense precipitation stage, while intense echoes with an intensity greater than 30 dBZ can last for up to 21 hours in Shenzhen. In terms of raindrop distribution characteristics extreme rainfall is mainly caused by a high density of small and medium-sized raindrops. When the rainfall intensity exceeds 20 mm·h-1, the size of raindrop particles increases, but the numerical concentration significantly decreases. Results in an increase in raindrop size but a decrease in the number of concentrations. The duration, intensity, and area of extreme rainstorms have a strong correlation with the fluctuation of the low-level jet in the boundary layer and the location of the core area of the jet. Heavy rainfall occurs within 1-2 hours after a rapid strengthening of the low-level jet index. After the low-level jet index decreases, the intensity of heavy precipitation diminishes. Variations in the low-level jet and low-level jet index have significant implications for heavy rainfall. The prolonged presence of Typhoon Haikui residual vortex in the Pearl River Delta is the synoptic-scale cause of this extremely heavy rainstorm. The residence time of the lingering vortex exceeds 16 hours. During that time, the deep boundary layer low-level jet continuously transfers warm water vapor to the lingering vortex. Simultaneously, the water vapor from the western Pacific, carried by the northeast airflow of Typhoon Yunyeung, and the southwest monsoon water vapor transfers through the Bay of Bengal, Indochina Peninsula, and the South China Sea, ultimately results in the formation of a stable mesoscale convergence line near the Pearl River Delta, causing an extremely heavy rainstorm.
    • FullText(HTML)
    References(40)

  • Fig. 1  Rainfall(unit:mm)(a) and maximum rainfall intensity(unit:mm·h-1)(b) from 1600 BT 7 Sep to 1600 BT 8 Sep in 2023

    DownLoad: Full-Size Img PowerPoint

    Fig. 2  Hourly rainfall of typical stations from 1700 BT 7 Sep to 1600 BT 8 Sep in 2023

    DownLoad: Full-Size Img PowerPoint

    Fig. 3  Wind(the barb), wind speed(the shaded) and geopotential height(the red contour, unit:dagpm)from 5 Sep to 8 Sep in 2023

    DownLoad: Full-Size Img PowerPoint

    Fig. 4  FY-4B TBB from 7 Sep to 8 Sep in 2023

    DownLoad: Full-Size Img PowerPoint

    Fig. 5  Radar combination reflectivity of Guangdong from 7 Sep to 8 Sep in 2023

    DownLoad: Full-Size Img PowerPoint

    Fig. 6  Time-height section of radar combination reflectivity(the shaded) and rainfall intensity(the black solid line)at Xiaowutong Station of Shenzhen from 1800 BT 7 Sep to 2000 BT 8 Sep in 2023

    DownLoad: Full-Size Img PowerPoint

    Fig. 7  Raindrop number concentration(the shaded), raindrop diameter(height of the shaded)and rainfall intensity(the black solid line) at Shiyan Station of Shenzhen from 1600 BT 7 Sep to 1600 BT 8 Sep in 2023

    DownLoad: Full-Size Img PowerPoint

    Fig. 8  Scatter plots of rainfall intensity with raindrop mass-weighted average diameter(a)and standardized number concentration(b) at Shiyan Station of Shenzhen from 1600 BT 7 Sep to 1600 BT 8 Sep in 2023

    DownLoad: Full-Size Img PowerPoint

    Fig. 9  Wind at 850 hPa(the red solid line denotes converging line) from 7 Sep to 8 Sep in 2023

    DownLoad: Full-Size Img PowerPoint

    Fig. 10  Wind profile of radar(the shaded denotes wind speed no less than 12 m·s-1) at Longgang Station of Shengzhen(a) and low jet index and hourly rainfall(b) from 7 Sep to 8 Sep in 2023

    DownLoad: Full-Size Img PowerPoint

    Fig. 11  Wind(the vector) and divergence(the shaded denotes less than -2×10-5 s-1)at 975 hPa from 7 Sep to 8 Sep in 2023

    DownLoad: Full-Size Img PowerPoint

    Fig. 12  Water vapor transport at 925 hPa(the vector, unit:g·cm-1·hPa·s-1)from 7 Sep to 8 Sep in 2023(the shaded denotes water vapor flux)

    DownLoad: Full-Size Img PowerPoint
  • [1]
    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
    [2]
    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
    [3]
    Wu H Y, Zou Y, Liu W. Quantitative assessment of regional heavy rainfall process in Guangdong and its climatological characteristics. J Appl Meteor Sci, 2019, 30(2): 233-244. doi:  10.11898/1001-7313.20190210
    [4]
    Wang Y J, Zhou B T, Qin D H, et al. Changes in mean and extreme temperature and precipitation over the arid region of northwestern China: Observation and projection. Adv Atmos Sci, 2017, 34(3): 289-305. doi:  10.1007/s00376-016-6160-5
    [5]
    Liu F F, Zheng Y G, Luo Q, et al. Comparison of characteristics of light precipitation and short-time heavy precipitation over Beijing, Tianjin, Hebei and neighbouring areas. J Appl Meteor Sci, 2023, 34(5): 619-629. doi:  10.11898/1001-7313.20230510
    [6]
    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.
    [7]
    Bao X H, Xia R D, Luo Y L, et al. Comparative analysis on meteorological and hydrological rain gauge observations of the extreme heavy rainfall event in Henan Province during July 2021. J Appl Meteor Sci, 2022, 33(6): 668-681. doi:  10.11898/1001-7313.20220603
    [8]
    Tian F Y, Zheng Y G, Zhang X L, et al. Structure, triggering and maintenance mechanism of convective systems during the Guangzhou extreme rainfall on 7 May 2017. Meteor Mon, 2018, 44(4): 469-484.
    [9]
    Chyi D, He L F, Wang X M, 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
    [10]
    Duan T, Chen Q L, Liao Y J. Analysis of "21. 7" extreme rainstorm formation process and disaster mechanism in Zhengzhou. J Meteor Sci, 2022, 42(2): 152-161.
    [11]
    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.
    [12]
    Sun J C, Guan Z Y, Li M G, et al. Anomalous circulation patterns in association with two types of regional daily precipitation extremes over South China from July to October. Acta Meteor Sinica, 2019, 77(1): 43-57.
    [13]
    Fu J L, Ma X K, Chen T, et al. Characteristics and synoptic mechanism of the July 2016 extreme precipitation event in North China. Meteor Mon, 2017, 43(5): 528-539.
    [14]
    Fang C, Mao D Y, 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.
    [15]
    Yang S N, Lu Y X, Zhang F H, et al. Analysis on causes of persistent heavy rainfall brought by tropical storm Ewiniar. Meteor Mon, 2021, 47(1): 106-116.
    [16]
    Lin L X, Liang Q Q, Huang Z. Analysis of circulation pattern of rapidly intensified offshore tropical cyclones of South China. Meteor Mon, 2006, 32(2): 14-18.
    [17]
    Chen L S, Ding Y H. Introduction to Typhoons in the Western Pacific. Beijing: Science Press, 1979.
    [18]
    Lin W, Lin C C, Li B L, et al. Rainfall intensity and raindrop spectrum for different parts in landing Typhoon Matmo. J Appl Meteor Sci, 2016, 27(2): 239-248. doi:  10.11898/1001-7313.20160212
    [19]
    Huang Y Y, Meng W G, Feng Y R, et al. Problems in asymmetry and sustainability of landfalling typhoon precipitation over South China. Meteor Mon, 2023, 49(4): 385-399.
    [20]
    Mao Z Y, Fu D H, Huang Y B, et al. Peripheral cloud system structure and precipitation characteristics of Typhoon Bebinca(1816). J Appl Meteor Sci, 2022, 33(5): 604-616. doi:  10.11898/1001-7313.20220508
    [21]
    Yan L, Zhou Y S, Wang Y Q. Analysis on different characteristics and causes of precipitation distribution during the landing of Typhoon "Soudelor"(1513) and Typhoon "Matmo" (1410) with similar tracks. Chinese J Atmos Sci, 2019, 43(2): 297-310.
    [22]
    Lu S, Wang L J, Guan Z Y, et al. Comparison of impacts of low-latitude monsoon surge on the enhanced rainstorm from landing typhoons Durian and Bilis. Trans Atmos Sci, 2012, 35(2): 175-185.
    [23]
    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
    [24]
    Qin H, Zheng F Q, Wu L Q. The interaction between intensity and rainfall of Typhoon Rammasun(1409). J Appl Meteor Sci, 2022, 33(4): 477-488. doi:  10.11898/1001-7313.20220408
    [25]
    Ye C Z, Li Y Y. A numerical study of the characteristics of strong moisture transport as a result of the interaction of tropical storm Bilis with the South China Sea monsoon. Acta Meteor Sinica, 2011, 69(3): 496-507.
    [26]
    Cheng Z Q, Lin L X, Yang G J, et al. Rapid intensification and associated large-scale circulation of super Typhoon Rammasun in 2014. J Appl Meteor Sci, 2017, 28(3): 318-326. doi:  10.11898/1001-7313.20170306
    [27]
    Liu S Y, Zheng Y G, Tao Z Y. The analysis of the relationship between pulse of LLJ and heavy rain using wind profiler data. J Trop Meteor, 2003, 19(3): 285-290.
    [28]
    McAnelly R L, Cotton W R. Meso-β-scale characteristics of an episode of meso-α-scale convective complexes. Mon Wea Rev, 1986, 114(9): 1740-1770. doi:  10.1175/1520-0493(1986)114<1740:MSCOAE>2.0.CO;2
    [29]
    Doswell C A III, Brooks H E, Maddox R A. Flash flood forecasting: An ingredients-based methodology. Wea Forecasting, 1996, 11(4): 560-581. doi:  10.1175/1520-0434(1996)011<0560:FFFAIB>2.0.CO;2
    [30]
    Yu X D, Zhou X G, Wang X M. The advances in the nowcasting techniques on thunderstorms and severe convection. Acta Meteor Sinica, 2012, 70(3): 311-337.
    [31]
    Zhu H F, Wang D Y, Yang Z X, et al. Analysis of raindrop spectrum characteristics for a heavy rain event caused by Typhoon Haikui(No. 1211) in Anhui. Torrential Rain Disasters, 2020, 39(2): 167-175.
    [32]
    Yu X D. Nowcasting thinking and method of flash heavy rain. Torrential Rain Disasters, 2013, 32(3): 202-209.
    [33]
    Zheng Y G, Zhou K H, Sheng J, et al. Advances in techniques of monitoring, forecasting and warning of severe convective weather. J Appl Meteor Sci, 2015, 26(6): 641-657. doi:  10.11898/1001-7313.20150601
    [34]
    Gao Y, Cai M, Cao Z Q, et al. Environmental conditions and cloud macro and micro features of "21·7" extreme heavy rainfall in Henan Province. J Appl Meteor Sci, 2022, 33(6): 682-695. doi:  10.11898/1001-7313.20220604
    [35]
    Chen G, Zhao K, Lu Y, et al. Variability of microphysical characteristics in the "21·7" Henan extremely heavy rainfall event. Sci China(Earth Sci), 2022, 65(10): 1861-1878.
    [36]
    Zhang Z, Qi Y C, Li D H, et al. Raindrop size distribution characteristics of the extreme rainstorm event in Zhengzhou 20 July, 2021 and its impacts on radar quantitative precipitation estimation. Chinese J Atmos Sci, 2022, 46(4): 1002-1016.
    [37]
    Bringi V N, Chandrasekar V. Polarimetric Doppler Weather Radar. Cambridge: Cambridge University Press, 2001.
    [38]
    Ma Y, Ni G H, Chandra C V, et al. Statistical characteristics of raindrop size distribution during rainy seasons in the Beijing urban area and implications for radar rainfall estimation. Hydrol Earth Syst Sci, 2019, 23(10): 4153-4170.
    [39]
    Gou A N, Wu C H, Wang Y J, et al. Meso and small-scale characteristics of heavy rain during Meiyu period in Hubei based on wind profile radar. J Arid Meteor, 2022, 40(1): 84-94.
    [40]
    Liao F, Deng H, Hou L. The effect assessment of wind field inversion based on WPR in precipitation. J Trop Meteor, 2016, 32(5): 588-595.
    • Relative Articles
    • Supplements(0)
    • Cited By
  • 加载中
  • -->

Catalog

    Figures(12)

    Get Citation
    PDF
    XML
    Article views (898) PDF downloads(313) Cited by()
    • Received : 2023-11-13
    • Accepted : 2023-12-19
    • Published : 2024-01-31
    Journal Online
    Contact

    © 2020 Journal of Applied Meteorological Science   京ICP备15006967号-1

    Supported by Beijing Renhe Information Technology Co. Ltd

    /

    DownLoad:  Full-Size Img  PowerPoint
    Return