Record-breaking heavy and persistent precipitation occurred over the Yangtze River Valley (YRV) in June-July (JJ) 2020. An observational data analysis has indicated that the strong and persistent rainfall arose from the confluence of southerly wind anomalies to the south associated with an extremely strong anomalous anticyclone over the western North Pacific (WNPAC) and northeasterly anomalies to the north associated with a high-pressure anomaly over Northeast Asia. A further observational and modeling study has shown that the extremely strong WNPAC was caused by both La Niña-like SST anomaly (SSTA) forcing in the equatorial Pacific and warm SSTA forcing in the tropical Indian Ocean (IO). Different from conventional central Pacific (CP) El Niños that decay slowly, a CP El Niño in early 2020 decayed quickly and became a La Niña by early summer. This quick transition had a critical impact on the WNPAC. Meanwhile, an unusually large area of SST warming occurred in the tropical IO because a moderate interannual SSTA over the IO associated with the CP El Niño was superposed by an interdecadal/long-term trend component. Numerical sensitivity experiments have demonstrated that both the heating anomaly in the IO and the heating anomaly in the tropical Pacific contributed to the formation and maintenance of the WNPAC. The persistent high-pressure anomaly in Northeast Asia was part of a stationary Rossby wave train in the midlatitudes, driven by combined heating anomalies over India, the tropical eastern Pacific, and the tropical Atlantic.
2020年6-7月, 长江流域出现了创纪录的持续性特大暴雨. 观测资料表明, 与西北太平洋异常反气旋 (WNPAC) 相关的南风异常和与东北亚异常高压相联系的东北风异常交汇, 从而导致该持续性暴雨的发生. 进一步的观测和模式研究表明, 超强的 WNPAC 由赤道太平洋的 La Niña 型海温异常和热带印度洋的暖海温异常共同强迫产生. 与传统的中太平洋型 (CP) El Niño 的缓慢衰减不同, 2020 年初 CP El Niño 快速衰减, 到初夏演变为 La Niña. ENSO 的快速位相转换对 WNPAC 的形成发挥着关键的作用. 同时, 与 CP El Niño 相关的印度洋年际尺度海温异常叠加了年代际分量, 导致热带印度洋海温出现极端增暖. 数值试验表明, 热带印度洋和太平洋的热源对 WNPAC 的形成和维持均有贡献. 持续的东北亚高压异常则是中纬度静止 Rossby 波列的一部分, 由印度、 热带东太平洋和热带大西洋的热源共同强迫产生.
Adler, R. F., G. J. Huffman, A. Chang, R. Ferraro, P. Xie, J. Janowiak, B. Rudolf, U. Schneider, S. Curtis, D. Bolvin, A. Gruber, J. Susskind, and P. Arkin, 2003: The Version 2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979-Present). J. Hydrometeor., 4, 1147–1167, https://doi.org/10.1175/1525-7541(2003)004<1147:TVGPCP>2.0.CO;2.
Alessandri, A., S. Gualdi, J. Polcher, and A. Navarra, 2007: Effects of land surface-vegetation on the boreal summer surface climate of a GCM. J. Clim., 20(2), 255–278, https://doi.org/10.1175/JCLI3983.1.
Alexander, M. A., I. Bladé, M. Newman, J. R. Lanzante, N. C. Lau, and J. D. Scott, 2002: The atmospheric bridge: The influence of ENSO teleconnections on air-sea interaction over the global ocean. J. Clim., 15(16), 2205–2231, https://doi.org/10.1175/1520-0442(2002)015<2205:TAB-TIO>2.0.CO;2.
Chang, C. P., Y. S. Zhang, and T. Li, 2000a: Interannual and inter-decadal variations of the East Asian summer monsoon and tropical Pacific SSTs. Part I: Roles of the subtropical ridge. J. Clim., 13, 4310–4325, https://doi.org/10.1175/1520-0442(2000)013<4310:IAIVOT>2.0.CO;2.
Chang, C. P., Y. S. Zhang, and T. Li, 2000b: Interannual and Inter-decadal Variations of the East Asian Summer Monsoon and Tropical Pacific SSTs. Part II: Meridional Structure of the Monsoon. J. Clim., 13, 4326–4340, https://doi.org/10.1175/1520-0442(2000)013<4326:IAIVOT>2.0.CO;2.
Chen, G., and R. Huang, 2012: Excitation mechanisms of the tele-connection patterns affecting the July precipitation in northwest China. J. Clim., 25, 7834–7851, https://doi.org/10.1175/JCLI-D-11-00684.1.
Chen, G., R. Huang, and L. Zhou, 2013: Baroclinic instability of the Silk Road pattern induced by thermal damping. J. Atmos. Sci., 70, 2875–2893, https://doi.org/10.1175/JAS-D-12-0326.1.
Chen, X. L., and T. J. Zhou, 2014: Relative role of tropical SST forcing in the 1990s periodicity change of the Pacific-Japan pattern interannual variability. J. Geophys. Res. Atmos., 119(13), 043–13, 066.
Chen, Y., and P. M. Zhai, 2016: Mechanisms for concurrent low-latitude circulation anomalies responsible for persistent extreme precipitation in the Yangtze River Valley. Clim. Dyn., 47, 989–1006, https://doi.org/10.1007/s00382-015-2885-6.
Chen, Z. S., Z. P. Wen, R. G. Wu, X. B. Lin, and J. B. Wang, 2016: Relative importance of tropical SST anomalies in maintaining the western North Pacific anomalous anticyclone during El Niño to La Niña transition years. Clim. Dyn., 46, 1027–1041, https://doi.org/10.1007/s00382-015-2630-1.
Chiang, J. C. H., and D. J. Vimont, 2004: Analogous Pacific and Atlantic meridional modes of tropical atmosphere-ocean variability. J. Clim., 17, 4143–4158, https://doi.org/10.1175/JCLI4953.1.
Ding, Q., and B. Wang, 2005: Circumglobal teleconnection in the Northern Hemisphere summer. J. Clim., 18(17), 3483–3505, https://doi.org/10.1175/JCLI3473.1.
Ding, Q. H., J. M. Wallace, and G. Branstator, 2011: Tropical-extratropical teleconnections in boreal summer: Observed interannual variability. J. Clim., 24, 1878–1896, https://doi.org/10.1175/2011JCLI3621.1.
Enomoto, T., 2004: Interannual variability of the Bonin high associated with the propagation of Rossby waves along the Asian jet. J. Meteor. Soc. Jpn., 82, 1019–1034, https://doi.org/10.2151/jmsj.2004.1019.
Enomoto, T., B. J. Hoskins, and Y. Matsuda, 2003: The formation mechanism of the Bonin high in August. Quart. J. Roy. Meteor. Soc., 129, 157–178, https://doi.org/10.1256/qj.01.211.
Fan, H., B. Huang, S. Yang, and W. Dong, 2020: Influence of Pacific Meridional Mode on ENSO evolution and predictability: Asymmetric modulation and ocean preconditioning. J. Clim., 34(5), 1881–1901.
Gill, A. E., 1980: Some simple solutions for heat-induced tropical circulation. Q. J. R. Meteorol. Soc, 106, 447–462, https://doi.org/10.1002/qj.49710644905.
Han, T. T., S. P. He, X. Hao, and H. J. Wang, 2018: Recent inter-decadal shift in the relationship between Northeast China’s winter precipitation and the North Atlantic and Indian Oceans. Clim. Dyn., 50(3–4), 1413–1424, https://doi.org/10.1007/s00382-017-3694-x.
He, S. P., Y. Q. Gao, F. Li, H. J. Wang, and Y. C. He, 2017: Impact of Arctic Oscillation on the East Asian climate: A review. Earth-Sci. Rev., 164, 48–62, https://doi.org/10.1016/j.earscirev.2016.10.014.
Hersbach, H., B. Bell, P. Berrisford, A. Horányi, J. M. Sabater, J. Nicolas, R. Radu, D. Schepers, A. Simmons, C. Soci, and D. Dee, 2019: Global reanalysis: goodbye ERA-Interim, hello ERA5. ECMWF Newsletter, 159, 17–24.
Hong, X. W., R. Y. Lu, and S. L. Li, 2018: Differences in the Silk Road pattern and its relationship to the North Atlantic Oscillation between early and late summers. J. Clim., 31, 9283–9292, https://doi.org/10.1175/JCLI-D-18-0283.1.
Huang, B., P. W. Thorne, V. F. Banzon, T. Boyer, G. Chepurin, J. H. Lawrimore, M. J. Menne, T. M. Smith, R. S. Vose, and H. M. Zhang, 2017: Extended Reconstructed Sea Surface Temperature version 5 (ERSSTv5), Upgrades, validations, and inter-scomparisons. J. Clim., 30(20), 8179–8205, https://doi.org/10.1175/JCLI-D-16-0836.1.
Huang, R. H., and W. J. Li, 1988: Influence and physical mechanism of heat source anomaly over the tropical western Pacific on the subtropical high over East Asia (in Chinese). Chin. J. Atmos. Sci., 12, 107–116.
Hsu P. C., T. Li, L. You, J. Gao, and H. L. Ren, 2015: A spatial-temporal projection method for 10–30-day forecast of heavy rainfall in Southern China. Clim. Dyn., 44, 1227–1244, https://doi.org/10.1007/s00382-014-2215-4.
Jiang, L., and T. Li, 2019: Relative roles of El Niño-induced extratropical and tropical forcing in generating Tropical North Atlantic (TNA) SST anomaly. Clim. Dyn., 53(7–8), 3791–3804, https://doi.org/10.1007/s00382-019-04748-7.
Johnson, N. C., and Y. Kosaka, 2016: The impact of eastern equatorial Pacific convection on the diversity of boreal winter El Niño teleconnection patterns. Clim. Dyn., 47, 3737–3765, https://doi.org/10.1007/s00382-016-3039-1.
Kosaka, Y., and H. Nakamura, 2006: Structure and dynamics of the summertime Pacific-Japan teleconnection pattern. Q. J. R. Meteorol. Soc., 132, 2009–2030, https://doi.org/10.1256/qj.05.204.
Kosaka, Y., H. Nakamura, M. Watanabe, and M. Kimoto, 2009: Analysis on the dynamics of a wave-like teleconnection pattern along the summertime Asian jet based on a reanalysis dataset and climate model simulations. J. Meteor. Soc. Jpn., 87, 561–580, https://doi.org/10.2151/jmsj.87.561.
Li, T., and B. Wang, 2005: A review on the western North Pacific monsoon: synoptic-to-interannual variabilities. Terr. Atmos. Ocean Sci., 16, 285–314, https://doi.org/10.3319/TAO.2005.16.2.285(A).
Li, T., B. Wang, B. Wu, T. J. Zhou, C. P. Chang, and R. H. Zhang, 2017: Theories on formation of an anomalous anticyclone in Western North Pacific during El Niño: a review. J. Meteorol. Res., 31(6), 987–1006, https://doi.org/10.1007/s13351-017-7147-6.
Lin, J. S., B. Wu, and T. J. Zhou, 2016: Is the interdecadal circumglobal teleconnection pattern excited by the Atlantic multi-decadal Oscillation? Atmos. Oceanic Sci. Lett., 9(6), 451–457, https://doi.org/10.1080/16742834.2016.1233800.
Liu, Y. Y., and Y. H. Ding, 2008: Teleconnection between the Indian summer monsoon onset and the Meiyu over the Yangtze River Valley. Sci. China Ser. D-Earth Sci., 51, 1021–1035, https://doi.org/10.1007/s11430-008-0073-9.
Lu, R. Y., J. H. Oh, and B. J. Kim, 2002: A teleconnection pattern in upper-level meridional wind over the North African and Eurasian continent in summer. Tellus, 54A, 44–55.
Lu, R., Z. W. Zhu, T. Li, and H. Y. Zhang, 2020: Interannual and interdecadal variabilities of spring rainfall over northeast China and their associated sea surface temperature anomaly forcings. J. Clim., 33(4), 1423–1435, https://doi.org/10.1175/JCLI-D-19-0302.1.
Nan, S. L., and J. P. Li., 2005: The relationship between the summer precipitation in the Yangtze River Valley and the boreal spring Southern Hemisphere annular mode. Geophys. Res. Lett., 30, 4–1-4-4.
Neelin, J. D., and I. M. Held, 1987: Modeling tropical convergence based on the moist static energy budget. Mon. Wea. Rev., 115, 3–12, https://doi.org/10.1175/1520-0493(1987)115<0003:MTCBOT>2.0.CO;2.
Nitta, T., 1987: Convective activities in the tropical western Pacific and their impact on the northern hemisphere summer circulation. J. Meteorol. Soc. Jpn., 65, 373–390, https://doi.org/10.2151/jmsj1965.65.3_373.
Piao, J., W. Chen, S. F. Chen, H. N. Gong, and B. Liu, 2020: The intensified impact of El Niño on late-summer precipitation over East Asia since the early 1990s. Clim. Dyn., 54, 4793–4809, https://doi.org/10.1007/s00382-020-05254-x.
Roeckner, E., E. Arpe, L. Bengtsson, M. Christoph, M. Claussen, L. Dümenil, M. Esch, M. Giorgetta, U. Schlese, and U. Schulzweida, 1996: The atmospheric general circulation model ECHAM4: Model description and simulation of present-day climate. Max-Planck-Institut für Meteorologie Report Series 218. Technical Report, Max-Planck-Institut für Meteorologie, 99pp.
Sato, N., and M. Takahashi, 2006: Dynamical processes related to the appearance of quasi-stationary waves on the subtropical jet in the midsummer Northern Hemisphere. J. Clim., 19, 1531–1544, https://doi.org/10.1175/JCLI3697.1.
Sun, J. Q., and H. J. Wang, 2012: Changes of the connection between the summer North Atlantic Oscillation and the East Asian summer rainfall. J. Geophys. Res. Atmos., 117(D8).
Wallace, J. M., and D. S. Gutzler, 1981: Teleconnections in the geopotential height fields during the Northern Hemisphere winter. Mon. Weather Rev., 109(4), 784–812, https://doi.org/10.1175/1520-0493(1981)109<0784:TIT-GHF>2.0.CO;2.
Wang, B., and Q. Zhang, 2002: Pacific-East Asian Teleconnection. Part II: How the Philippine sea anomalous anticyclone is established during El Niño development. J. Clim., 15(22), 3252–3265, https://doi.org/10.1175/1504-0442(2002)015<3252:PEATPI>2.0.CO;2.
Wang, B., B. Q. Xiang, and J. Y. Lee, 2013: Subtropical high predictability establishes a promising way for monsoon and tropical storm predictions. Proc. Natl. Acad. Sci. USA, 110, 2718–2722, https://doi.org/10.1073/pnas.1214626110.
Wang, B., J. Li, and Q. He, 2017a: Variable and robust East Asian monsoon rainfall response to El Niño over the past 60 years (1957–2016). Adv. Atmos. Sci., 34(10), 1235–1248, https://doi.org/10.1007/s00376-017-7016-3.
Wang, B., J. Liu, J. Yang, T. Zhou, and Z. Wu, 2009: Distinct principal modes of early and late summer rainfall anomalies in East Asia. J. Clim., 22, 3864–3875, https://doi.org/10.1175/2009JCLI2850.1.
Wang, B., R. G. Wu, and T. Li, 2003: Atmosphere-warm ocean interaction and its impacts on Asian-Australian monsoon variation. J. Clim., 16, 1195–1211, https://doi.org/10.1175/1520-0442(2003)16<1195:AOIAII>2.0.CO;2.
Wang, B., R. Wu, and X. Fu, 2000: Pacific-East Asian Teleconnection: How does ENSO affect East Asian climate? J. Clim., 13(9), 1517–1536, https://doi.org/10.1175/1520-0442(2000)013<1517:PEATHD>2.0.CO;2.
Wang, B., X. Luo, Y. M. Yang, W. Y. Sun, M. A. Cane, W. J. Cai, S. W. Yeh, and J. Liu, 2019: Historical change of El Niño properties sheds light on future changes of extreme El Niño. Proceedings of the National Academy of Sciences, 116(45), 22512–22517, https://doi.org/10.1073/pnas.1911130116.
Wang, L., T. Li, E. Maloney, and B. Wang, 2017b: Fundamental causes of propagating and non-propagating MJOs in MJOTF/GASS models. J. Clim., 30(10), 3743–3769, https://doi.org/10.1175/JCLI-D-16-0765.1.
Wang, X., 2018: The influence of SST in subtropical North Pacific on the warm-cold phase transition of ENSO. Climatic Environ. Res. (in Chinese), 23(4), 453–462.
Wei, W., R. Zhang, S. Yang, W. Li, and M. Wen, 2019: Quasi-biweekly oscillation of the South Asian High and its role in connecting the Indian and East Asian summer rainfalls. Geophys. Res. Lett., 46(24), 14742–14750, https://doi.org/10.1029/2019GL086180.
Wu, B., J. Lin, and T. Zhou, 2016: Interdecadal circumglobal tele-connection pattern during boreal summer. Atmos. Sci. Lett., 17(8), 446–452, https://doi.org/10.1002/asl.677.
Wu, B., T. Li, and T. Zhou, 2010: Relative Contributions of the Indian Ocean and local SST anomalies to the maintenance of the western North Pacific anomalous anticyclone during the El Niño decaying summer. J. Clim., 23(11), 2974–2986, https://doi.org/10.1175/2010JCLI3300.1.
Wu, R., 2002: A mid-latitude Asian circulation anomaly pattern in boreal summer and its connection with the Indian and East Asian summer monsoons. Int. J. Climatol., 22, 1879–1895, https://doi.org/10.1002/joc.845.
Xie, P., and P. A. Arkin, 1997: Global precipitation: A 17-year monthly analysis based on gauge observations, satellite estimates, and numerical model outputs. Bull. Amer. Meteor. Soc., 78, 2539–2558, https://doi.org/10.1175/1520-0477(1997)078<2539:GPAYMA>2.0.CO;2.
Xie, S. P., K. Hu, J. Hafner, H. Tokinaga, Y. Du, G. Huang, and T. Sampe, 2009: Indian Ocean capacitor effect on Indo-western Pacific climate during the summer following El Niño. J. Clim., 22(3), 730–747, https://doi.org/10.1175/2008JCLI2544.1.
Xing, W., B. Wang, and S. Y. Yim, 2016: Peak-summer East Asian rainfall predictability and prediction part I: Southeast Asia. Clim. Dyn., 47, 1–13, https://doi.org/10.1007/s00382-014-2385-0. doi: https://doi.org/10.1175/2008JCLI2544.1.
Xing, W., B. Wang, S. Y. Yim, and K. J. Ha, 2017: Predictable patterns of the May–June rainfall anomaly over East Asia. J. Geophys. Res. Atmos, 122, 2203–2217, https://doi.org/10.1002/2016JD025856.
Xu, Z. Q., K. Fan, and H. J. Wang, 2015: Decadal Variation of Summer Precipitation over China and Associated Atmospheric Circulation after the Late 1990s. J. Clim., 28, 4086–4106, https://doi.org/10.1175/JCLI-D-14-00464.1.
Yang, S. Y., and T. Li, 2016: Zonal shift of the South Asian High on the subseasonal time-scale and its relation to the summer rainfall anomaly in China. Q. J. R. Meteorol. Soc., 142, 2324–2335, https://doi.org/10.1002/qj.2826.
Yasui, S., and M. Watanabe, 2010: Forcing processes of the summertime circumglobal teleconnection pattern in a dry AGCM. J. Clim., 23, 2093–2114, https://doi.org/10.1175/2009JCLI3323.1.
Yuan, Y., and S. Yang, 2012: Impacts of different types of El Niño on the East Asian climate: Focus on ENSO cycles. J. Clim., 25, 7702–7722, https://doi.org/10.1175/JCLI-D-11-00576.1.
Zhang, R. H., Q. Y. Min, and J. Z. Su, 2017: Impact of El Niño on atmospheric circulations over East Asia and rainfall in China: Role of the anomalous western North Pacific anticyclone. Sci. China Earth Sci., 60, 1124–1132, https://doi.org/10.1007/s11430-016-9026-x.
Zhu, Z. W., 2018: Breakdown of the relationship between Australian summer rainfall and ENSO caused by tropical Indian Ocean SST warming. J. Clim., 31(6), 2321–2336, https://doi.org/10.1175/JCLI-D-17-0132.1.
Zhu, Z. W., and T. Li, 2016: A new paradigm for continental U.S. summer rainfall variability: Asia-North America teleconnection. J. Clim., 29(20), 7313–7327, https://doi.org/10.1175/JCLI-D-16-0137.1.
Zhu, Z. W., and T. Li, 2017: The record-breaking hot summer in 2015 over Hawaiian Islands and its physical causes. J. Clim., 30(11), 4253–4266, https://doi.org/10.1175/JCLI-D-16-0438.1.
Zhu, Z. W., T. Li, and J. H. He, 2014: Out-of-phase relationship between boreal spring and summer decadal rainfall changes in southern China. J. Clim., 27(3), 1083–1099, https://doi.org/10.1175/JCLI-D-13-00180.1.
Zhu, Z. W., T. Li, P. C. Hsu, and J. H. He, 2015: A spatial-temporal projection model for extended-range forecast in the tropics. Clim. Dyn., 45, 1085–1098, https://doi.org/10.1007/s00382-014-2353-8.
Zhu, Z. W., R. Lu, H. Yan, W. Li, T. Li, and J. H. He, 2020: The dynamic origin of the interannual variability of West China Autumn Rainfall. J. Clim., 33(22), 9643–9652, https://doi.org/10.1175/JCLI-D-20-0097.1.
This work was jointly supported by China National Key R&D Program 2018YFA0605604, NSFC Grant No. 42088101, NOAA NA18OAR4310298, and NSF AGS-2006553. This is SOEST contribution number 11354, IPRC contribution number 1524, and ESMC number 350.
• The Yangtze River Valley experienced record-breaking strong and persistent rainfall in June–July 2020 due to the confrontation of a strong anomalous anticyclone over the western North Pacific to the south and cold/dry advection induced by anomalous northeasterly to the north.
• The extremely strong anomalous anticyclone over the western North Pacific resulted from a combined effect of a quick El Niño to La Niña phase transition and strong Indian Ocean warming.
• The unusual Indian Ocean warming was a result of superposition of an interannual and an interdecadal/long-term trend component.
• The persistent northeasterly anomaly in Northeast Asia was part of a zonally oriented Rossby wave train, forced by heating anomalies over India, the eastern Pacific, and the Atlantic.
This paper is a contribution to the special issue on Summer 2020: Record Rainfall in Asia — Mechanisms, Predictability and Impacts.
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Pan, X., Li, T., Sun, Y. et al. Cause of Extreme Heavy and Persistent Rainfall over Yangtze River in Summer 2020. Adv. Atmos. Sci. 38, 1994–2009 (2021). https://doi.org/10.1007/s00376-021-0433-3
- Yangtze River floods
- anomalous anticyclone over the western North Pacific
- CP and EP El Niño
- Indian Ocean warming
- La Niña
- Rossby wave train