Xiuping YAO1,Yifei HUANG1,2,Xiaohong BAO1,2,3,Ruoying LI1,2,Yaxuan ZHOU1,2,Jiali MA4
Abstract
Characteristics and water vapor condition of the extreme rainstorm in North China from 29 July to 1 August in 2023 are investigated based on surface meteorological observations of precipitation and the ERA5 reanalysis data. It is found that the “23·7” extreme rainstorm in North China has the characteristics of long precipitation period and large cumulative amount, exhibiting a significant extremity. The precipitation was mainly located in front of the Taihang mountain and the Yanshan mountain. The maximum precipitation center was basically consistent with the orientation of the mountains, showing a banded pattern. There were significant circulation anomalies during the extreme rainstorm. The northward shifted upper-level subtropical jet stream and the abnormally northerly western Pacific subtropical high pressure were the key circulation factors that affected the extreme rainstorm, while the remnant circulation of northward-moving typhoon Doksuri, typhoon Khanun and the low-level jet stream were the major weather systems affecting the extreme rainstorm. The water vapor condition of the extreme rainstorm showed obvious phase features. From 08:00 BT 29 to 08:00 BT 31 July, low-level convergence, high-level divergence and upward motion were strong in the main precipitation area, and the low-level cyclonic wind further deepened. Water vapor was transported by the remnant circulation of typhoon Doksuri over a short range and continued by typhoon Khanun, with the former being the main source. The entire layer of water vapor in Beijing-Tianjin-Hebei region was in a net inflow state, with the maximum net inflow reaching 1.5×108 kg/s. From 08:00 BT 31 July to 08:00 BT 1 August, the ascending motion, the lower-level convergence and upper-level divergence significantly weakened, the thickness of low-level cyclonic wind field shrank, and water vapor was transported only by typhoon Khanun over long distances. The entire layer of water vapor in Beijing-Tianjin-Hebei region was in a state of net outflow, with the maximum net outflow reaching 5×107 kg/s. The blocking effect of the Taihang mountain and Yanshan mountain caused the water vapor convergence center to remain for a long time, and their frictional effect may be favorable for the amplification of the ascent motions in front of the mountain. These effects provided favorable conditions for this extreme heavy rainfall.
References
Bian Q H, Ding Z Y, Wu M Y, et al. 2005. Statistical analysis of Typhoon heavy rainfall in north China. Meteor Mon, 31（3）: 61-65 （in Chinese）
Che S J, Li X, Ding T, et al. 2021. Typical summer rainstorm occurred in mid-autumn: Analysis of a disastrous continuous rainstorm and its extreme water vapor transport in northern China in early October 2021. Trans Atmos Sci, 44（6）: 825-834 （in Chinese）
Chen B Y, Min J Z. 2020. A study on the evolution of vortex system and multi-scale interaction mechanism during the "7·19" rainstorm in north China. J Trop Meteor, 36（1）: 85-96 （in Chinese）
Chen J, Zheng Y G, Zhang X L, et al. 2013. Analysis of the climatological distribution and diurnal variations of the short-duration heavy rain and its relation with diurnal variations of the MCSs over China during the warm season. Acta Meteor Sinica, 71（3）: 367-382 （in Chinese）
Chen S, Wang Y C, Zhang W L, et al. 2011. Intensifying mechanism of the convective storm moving from the mountain to the plain over Beijing area. Meteor Mon, 37（7）: 802-813 （in Chinese）
Ding Y H, Li J S, Sun S Q, et al. 1980. The analysis on mesoscale systems producing heavy rainfall in North China∥Papers of Institute of Atmospheric Physics, Chinese Academy Sciences （No. 9）: The Researches on Heavy Rainfall and Severe Convective Weather. Beijing: Science Press, 1-13 （in Chinese）
Ding Y H, Hu G Q. 2003. A study on water vapor budget over China during the 1998 severe flood periods. Acta Meteor Sinica, 61（2）: 129-145 （in Chinese）
Dong G H, He Q Y, Liu Y W, et al. 2011. The role of sea breeze front in local storm of Bohai coast. Meteor Mon, 37（9）: 110-1107 （in Chinese）
Fu J L, Ma X K, Chen T, et al. 2017. Characteristics and synoptic mechanism of the July 2016 extreme precipitation event in North China. Meteor Mon, 43（5）: 528-539 （in Chinese）
Han X L, Wang Y Q, Ji X P, et al. 2021. Diagnostic analysis on a heavy rainfall associated with the atmospheric river in North China. J Meteor Sci, 41（2）: 200-208 （in Chinese）
He Q Y, Xie Y Y, Dong G H, et al. 2011. The role of sea-land breeze circulation in local convective torrential rain happening in Tianjin on 26 September 2009. Meteor Mon, 37（3）: 291-297 （in Chinese）
Huang R, Wang Y C, Zhang W L. 2012. Initiating and intensifying mechanism of a local thunderstorm over complex terrain of Beijing. Torrential Rain Disaster, 31（3）: 232-241 （in Chinese）
Jiang J X, Xiang X K. 1997. A primary study of the extreme rainfall event in early August 1996 over Hebei province. Meteor Mon, 23（7）: 19-23 （in Chinese）
Lei L, Sun J S, He N, et al. 2017. 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, 75（5）: 685-69 （in Chinese）
Lin H M, Min J Z, Zhu L J, et al. 2023. The role of Taihang Mountain topography in "7·19" persistent low vortex rainstorm in North China. J Meteor Sci, 43（1）: 46-58 （in Chinese）
Lin X, Zhao L, Li D Q, et al. 2020. Multi-scale characteristics of the "7.20" heavy rainstorm event in North China. J Meteor Environ, 36（3）: 1-9 （in Chinese）
Liu A R, Guo D M, Xin B H, et al. 1979. The moisture of the "75.7" heavy rain in North China. Acta Meteor Sinica, 37（2）: 79-82 （in Chinese）
Liu H Z, Wang W G, Shao M X, et al. 2007. A case study of the influence of the western pacific subtropical high on the torrential rainfall in Beijing area. Chinese J Atmos Sci, 31（4）: 727-734 （in Chinese）
Chyi D, He L F, Wang X M, et al. 2022. Fine observation characteristics and thermodynamic mechanisms of extreme heavy rainfall in Henan on 20 July 2021. J Appl Meteor Sci, 33（1）: 1-15 （in Chinese）
Sheng C Y, Gao S T, Shi Y G. 2012. Numerical simulation of the dynamic effect of the orography on a Mentougou severe torrential rain event. Acta Meteor Sinica, 70（1）: 65-77 （in Chinese）
Sun J H, Zhang X L, Wei J, et al. 2005. A study on severe heavy rainfall in North China during the 1990s. Climatic Environ Res, 10（3）: 492-506 （in Chinese）
Sun J H, Zhao S X, Fu S M, et al. 2013. Multi-scale characteristics of record heavy rainfall over Beijing Area on July 21, 2012. Chinese J Atmos Sci, 37（3）: 705-718 （in Chinese）
Sun J H, Zhao S X. 2000. Diagnoses and simulations of typhoon （Tim） landing and producing heavy rainfall in China. Chinese J Atmos Sci, 24（2）: 223-237 （in Chinese）
Sun J S. 2005. The effects of vertical Distribution of the lower level flow on precipitation location. Plateau Meteor, 24（1）: 62-69 （in Chinese）
Sun J S, Wang H, Wang L, et al. 2006. The role of urban boundary layer in local convective torrential rain happening in Beijing on 10 July 2004. Chinese J Atmos Sci, 30（2）: 221-234 （in Chinese）
Sun J S, Yang B. 2008. Meso-β scale torrential rain affected by topography and the urban circulation. Chinese J Atmos Sci, 32（6）: 1352-1364 （in Chinese）
Sun J S, He N, Wang G R, et al. 2012. Preliminary analysis on synoptic configuration evolvement and mechanism of a torrential rain occurring in Beijing on 21 July 2012. Torrential Rain Disaster, 31（3）: 218-225 （in Chinese）
Sun M N, Wang X M, Hu L, et al. 2018. Study on initiation and propagation mechanism of a warm sector torrential rain in North China. Meteor Mon, 44（10）: 1255-1266 （in Chinese）
Tao S Y. 1980. The Torrential Rain in China. Beijing: Science Press, 225pp （in Chinese）
Tao S Y, Ding Y H, Zhou X P. 1979. The present status of the research on rainstorm and severe convective weathers in China. Chinese J Atmos Sci, 3（3）: 227-238 （in Chinese）
Tao Z Y. 1980. The structure and formation of the moist jet stream. Acta Meteor Sinica, 38（4）: 331-340 （in Chinese）
Tian H, Guo P W, Lu W S. 2004. Characteristics of vapor inflow corridors related to summer rainfall in China and impact factors. J Trop Meteor, 20（4）: 401-408 （in Chinese）
Wang L P, Shen T L, Cui X D, et al. 2006. Mesoscale convective cloud cluster analysis and numerical simulation of a cold-vortex heavy rain event. Meteor Sci Technol, 34（1）: 22-28 （in Chinese）
Xu H X, Xu X D, Zhang S J, et al. 2014. Long-range moisture alteration of a typhoon and its impact on Beijing extreme rainfall. Chinese J. Atmos Sci, 38（3）: 537-550 （in Chinese）
Yao X P, Yu Y B. 1998. Interactions of different scale systems in the "96.8" torrential rain event. J Nanjing Inst Meteor, 21（3）: 137-144 （in Chinese）
Yu Y B, Yao X P. 1999. Divergent and rotational wind kinetic energy budget and conversion during a torrential rain process caused by typhoon low pressure trough. Acta Meteor Sinica, 57（4）: 439-449 （in Chinese）
Zhang J, Zhou Y S, Shen X Y, et al. 2019. Evolution of dynamic and thermal structure and instability condition analysis of the extreme precipitation system in Beijing-Tianjin-Hebei on July 19 2016. Chinese J Atmos Sci, 43（4）: 930-942 （in Chinese）
Zhang W L, Cui X P. 2012. Main progress of torrential rain researches in North China during the past 50 years. Torrential Rain Disaster, 31（4）: 384-391 （in Chinese）
Zhang Y. 1983. The effect of terrain on precipitation. Meteor Mon, 9（2）: 9-13 （in Chinese）
Zhang Y. 1990. Blocking effect of high pressure system on the formation of extra-intense heavy rain. Acta Meteor Sinica, 48（4）: 469-479 （in Chinese）
Zhao Y, Cui X P, Gao S T. 2011. A study of structure of mesoscale systems producing a heavy rainfall event in North China. Chinese J Atmos Sci, 35（5）: 945-962 （in Chinese）
Zhou M S. 1993. The circulation analysis of regional heavy rainstorms in the North of China. Meteor Mon, 19（7）: 14-18 （in Chinese）
Zhou X, Sun J S, Zhang L N, et al. 2020. Classification characteristics of continuous extreme rainfall events in North China. Acta Meteor Sinica, 78（5）: 761-777 （in Chinese）
Zhou Y S, Gao S T, Deng G. 2005. A diagnostic study of water vapor transport and budget during heavy precipitation over the Changjiang river and the Huaihe river basins in 2003. Chinese J Atmos Sci, 29（2）: 195-204 （in Chinese）
Zhu Q G. 1975. The low-level jet and heavy rainfall. Meteor Sci Technol, （8）, 12-18 （in Chinese）
Cong J,Wu Z L,Ma Y X,et al. 2021. Improving numerical forecast of the rainstorms induced by Mongolia cold vortex in North China with the frequency matching method. Atmos Res,262:105791
Endlich R M. 1967. An iterative method for altering the kinematic properties of wind fields. 2.0.CO;2">J Appl Meteor,6(5):837-844
Hersbach H,Bell B,Berrisford P,et al. 2020. The ERA5 global reanalysis. Quart J Roy Meteor Soc,146(730):1999-2049
Jiang X Y,Liu W D. 2007. Numerical simulations of impacts of urbanization on heavy rainfall in Beijing using different land-use data. Acta Meteor Sinica,21(2):245-255
Li Z,Yan Z W,Tu K,et al. 2015. Changes of precipitation and extremes and the possible effect of urbanization in the Beijing metropolitan region during 1960—2012 based on homogenized observations. Adv Atmos Sci,32(9):1173-1185
Luo Y L,Wu M W,Ren F M,et al. 2016. Synoptic situations of extreme hourly precipitation over China. J Climate,29(24):8703-8719
Simmonds I,Bi D H,Hope P. 1999. Atmospheric water vapor flux and its association with rainfall over China in summer. 2.0.CO;2">J Climate,12(5):1353-1367
Sun B,Zhu Y L,Wang H J. 2011. The recent interdecadal and interannual variation of water vapor transport over Eastern China. Adv Atmos Sci,28(5):1039-1048
Xia R D,Zhang D L. 2019. An observational analysis of three extreme rainfall episodes of 19—20 July 2016 along the Taihang mountains in North China. Mon Wea Rev,147(11):4199-4220
Yin S Q,Li W J,Chen D L,et al. 2011. Diurnal variations of summer precipitation in the Beijing area and the possible effect of topography and urbanization. Adv Atmos Sci,28(4):725-734
Zhang H,Zhai P M. 2011. Temporal and spatial characteristics of extreme hourly precipitation over eastern China in the warm season. Adv Atmos Sci,28(5):1177-1183
