Journal of Meteorological Research

, Volume 33, Issue 4, pp 609–626 | Cite as

Extremely Active Tropical Cyclone Activities over the Western North Pacific and South China Sea in Summer 2018: Joint Effects of Decaying La Niña and Intraseasonal Oscillation

  • Lijuan ChenEmail author
  • Zhensong Gong
  • Jie Wu
  • Weijing Li
Forecasting Forum


In summer 2018, a total of 18 tropical cyclones (TCs) formed in the western North Pacific (WNP) and South China Sea (SCS), among which 8 TCs landed in China, ranking respectively the second and the first highest since 1951. Most of these TCs travelled northwest to northward, bringing in heavy rainfall and strong winds in eastern China and Japan. The present study investigates the impacts of decaying La Niña and intraseasonal oscillation (ISO) on the extremely active TCs over the WNP and SCS in summer 2018 by use of correlation and composite analyses. It is found that the La Niña episode from October 2017 to March 2018 led to above-normal sea surface temperature (SST) over central-western Pacific, lower sea level pressure and 500-hPa geopotential height over WNP, and abnormally strong convective activities over the western Pacific in summer 2018. These preceding oceanic thermal conditions and their effects on circulation anomalies are favorable to TC genesis in summer. Detailed examination reveals that the monsoon trough was located further north and east, inducing more TCs in northern and eastern WNP; and the more east-ward WNP subtropical high as well as the significant wave train with a “ − + − +” height anomaly pattern over the midlatitude Eurasia-North Pacific region facilitated the northwest to northward TC tracks. Further analyses reveal that two successively active periods of Madden-Julian Oscillation (MJO) occurred in summer 2018 and the boreal summer intraseasonal oscillation (BSISO) was also active over WNP, propagating northward significantly, corresponding to the more northward TC tracks. The MJO was stagnant over the Maritime Continent to western Pacific, leading to notably enhanced convection in the lower troposphere and divergence in the upper troposphere, conducive to TC occurrences. In a word, the extremely active TC activities over the WNP and SCS in summer 2018 are closely linked with the decaying La Niña, and the MJO and BSISO; their joint effects result in increased TC occurrences and the TC tracks being shifted more northwest to northward than normal.

Key words

western North Pacific (WNP) tropical cyclone (TC) La Nina event Madden-Julian Oscillation (MJO) boreal summer intraseasonal oscillation (BSISO) 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.



We thank the anonymous reviewers for their constructive comments that led to improvements to this paper.

Supplementary material

13351_2019_9009_MOESM1_ESM.pdf (4.1 mb)
Extremely Active Tropical Cyclone Activities over the Western North Pacific and South China Sea in Summer 2018: Joint Effects of Decaying La Niña and Intraseasonal Oscillation


  1. Chan, J. C. L., 1985: Tropical cyclone activity in the northwest Pacific in relation to the El Nino/Southern Oscillation phenomenon. Mon. Wea. Rev., 113, 599–606, doi:<0599:TCAITN>2.0.CO;2.CrossRefGoogle Scholar
  2. Chan, J. C. L., 2000: Tropical cyclone activity over the western North Pacific associated with El Niño and La Niña events. J. Climate, 13, 2960–2972, doi:<2960:TCAOTW>2.0.CO;2.CrossRefGoogle Scholar
  3. Chan, J. C. L., 2005: Interannual and interdecadal variations of tropical cyclone activity over the western North Pacific. Meteor. Atmos. Phys., 89, 143–152, doi: Scholar
  4. Chen, G. H., and R. H. Huang, 2009: Dynamical effects of low frequency oscillation on tropical cyclogenesis over the western North Pacific and the physical mechanisms. Chinese J. Atmos. Sci., 33, 205–214, doi: (in Chinese)Google Scholar
  5. Chen, L. J., W. Gu and W. J. Li, 2019: Why is the East Asian summer monsoon extremely strong in 2018? — Collaborative effects of SST and snow cover anomalies J. Meteor. Res., 33, 593–608, doi: Scholar
  6. Chen, L. S., 1965: The relationship of middle-high latitude circulation pattern over Asia and typhoon track over western Pacific in late summer. Acta Meteor. Sinica, 35, 476–185, doi: (in Chinese)Google Scholar
  7. Chen, L. S., and Y. H. Ding, 1979: Introduction to Typhoons over West Pacific. Science Press, Beijing, 491 pp. (in Chinese)Google Scholar
  8. Chen, T. C., S. P. Weng, N. Yamazaki, et al., 1998: Interannual variation in the tropical cyclone formation over the western North Pacific. Mon. Wea. Rev., 126, 1080–1090, doi:<1080:IVITTC>2.0.CO;2.CrossRefGoogle Scholar
  9. Chen, T. C., S. Y. Wang, and M. C. Yen, 2006: Interannual variation of the tropical cyclone activity over the western North Pacific. J. Climate, 19, 5709–5720, doi: Scholar
  10. Ding, Y. H., and E. R. Reiter, 1981a: Some conditions Influencing the variability of typhoon formation over the West Pacific ocean. Arch. Meteor. Geophys. Bioclim. Ser. A, 30, 327–342, doi: Scholar
  11. Ding, Y. H., and E. R. Reiter, 1981b: Large-scale circulation conditions affecting the variability in the frequency of tropical cyclones over the North Atlantic and the West Pacific. Environmental Research Paper No. 33, Colorado State University, Fort Collins, 25 pp.Google Scholar
  12. Emanuel, K., 2005: Increasing destructiveness of tropical cyclones over the past 30 years. Nature, 436, 686–688, doi: Scholar
  13. Fan, K., 2007: North Pacific sea ice cover, a predictor for the western North Pacific typhoon frequency? Sci. China Ser. D Earth Sci., 37, 851–856. (in Chinese)Google Scholar
  14. Gong, Z. S., and L. J. Chen, 2013: Analysis of anomalous tropical cyclone activities over the western North Pacific and South China Sea in 2010. Climatic Environ. Res., 88, 342–352, doi: (in Chinese)Google Scholar
  15. He, M., W. L. Song, and X. F. Chen, 1999: Typhoon activity in Northwest Pacific in relation with El Niño and La Niña events. J. Trop. Meteor., 5, 153–162.Google Scholar
  16. Hu, C. M., Y. H. Duan, H. Yu, et al., 2005: The diagnostic analysis of the rapid change in tropical cyclones intensity before landfall in South China. J. Trop. Meteor., 21, 377–382, doi: (in Chinese)Google Scholar
  17. Hu, J., and Y. Q. Wang, 1992: Atmosphere and ocean low-frequency oscillation and their effects on tropical cyclone tracks over the northwestern Pacific. Acta Meteor. Sinica, 50, 420–428, doi: (in Chinese)Google Scholar
  18. Huang, B. Y., P. W. Thorne, V. F. Banzon, et. al., 2017: Extended reconstructed sea surface temperature, version 5 (ERSSTv5): Upgrades, validations, and intercomparisons. J. Climate, 30, 8179–8205, doi: Scholar
  19. Huang, P., C. Chou, and R. H. Huang, 2011: Seasonal modulation of tropical intraseasonal oscillations on tropical cyclone geneses in the western North Pacific. J. Climate, 24, 6339–6352, doi: Scholar
  20. Huang, R. H., 1992: The East Asia/Pacific pattern teleconnection of summer circulation and climate anomaly in East Asia. Acta Meteor. Sinica, 6, 25–37.Google Scholar
  21. Huang, R. H., and W. J. Li, 1987: Influence of the heat source anomaly over the tropical western Pacific on the subtropical high over East Asia. Proceedings of International Conference on the General Circulation of East Asia, Chengdu, 10–15 April, 40–51.Google Scholar
  22. Huang, R. H., and G. H. Chen, 2007: Research on interannual variations of tracks of tropical cyclones over Northwest Pacific and their physical mechanism. Acta Meteor. Sinica, 65, 683–694, doi: (in Chinese)Google Scholar
  23. Kalnay, E., M. Kanamitsu, R. Kistler, et al., 1996: The NCEP/NCAR 40-year reanalysis project. Bull. Amer. Meteor. Soc., 77, 437–171, doi:<0437:TNYRP>2.0.CO;2.CrossRefGoogle Scholar
  24. Kim, H.-M., P. J. Webster, and J. A. Curry, 2011: Modulation of North Pacific tropical cyclone activity by three phases of ENSO. J. Climate, 24, 1839–1849, doi: Scholar
  25. Kim, J. H., C. H. Ho, H. S. Kim, et al., 2008: Systematic variation of summertime tropical cyclone activity in the western North Pacific in relation to the Madden-Jullian oscillation. J. Climate, 21, 1171–1191, doi: Scholar
  26. Kistler, R., E. Kalnay, W. Collins, et al., 2001: The NCEP-NCAR 50-year reanalysis: Monthly mean CD-ROM and documentation. Bull. Amer. Meteor. Soc., 882, 247–268, doi:<0247:TNNYRM>2.3.CO;2.CrossRefGoogle Scholar
  27. Lander, M. A., 1994: An exploratory analysis of the relationship between tropical storm formation in the western North Pacific and ENSO. Mon. Wea. Rev., 122, 636–651, doi:<0636:AEAOTR>2.0.CO;2.CrossRefGoogle Scholar
  28. Lee, J. Y., B. Wang, M. C. Wheeler, et al., 2013: Real-time multivariate indices for the boreal summer intraseasonal oscillation over the Asian summer monsoon region. Climate Dyn., 40, 493–509, doi: Scholar
  29. Li, C. Y., 1987: A study on the influence of El Niño upon typhoon action over the western Pacific. Acta Meteor. Sinica, 45, 229–236, doi: (in Chinese)Google Scholar
  30. Li, C. Y., J. Pan, H. Tian, et al., 2012: Typhoon activities over the western North Pacific and atmospheric intraseasonal oscillation. Meteor. Mon., 38, 1–16. (in Chinese)Google Scholar
  31. Li, R. C. Y. and W. Zhou, 2012: Changes in western Pacific tropical cyclones associated with the El Niño-Southern Oscillation cycle. J. Climate, 25, 5864–5878, doi: Scholar
  32. Li, R. C. Y., and W. Zhou, 2013a: Modulation of western North Pacific tropical cyclone activity by the ISO. Part I: Genesis and intensity. J. Climate, 26, 2904–2918, doi: Scholar
  33. Li, R. C. Y., and W. Zhou, 2013b: Modulation of western North Pacific tropical cyclone activity by the ISO. Part II: Tracks and landfalls. J. Climate, 26, 2919–2930, doi: Scholar
  34. Li, T., 2012: Synoptic and climatic aspects of tropical cyclogenesis in western North Pacific. Chap. 3, Cyclones: Formation, Triggers and Control, K. Oouchi, and H. Fudeyasu, Eds., Nova Science Publishers, Inc., Hauppauge, 61–94.Google Scholar
  35. Li, W. J., R. N. Zhang, C. H. Sun, et al., 2016: Recent research advances on the interannual-interdecadal variations of drought/flood in South China and associated causes. J. Appl. Meteor. Sci., 27, 577–591. (in Chinese)Google Scholar
  36. Liu, G., Q. Y. Zhang, and S. Q. Sun, 2007: A preliminary study on activities of tropical cyclones over the western North Pacific during the summer of 2006. Climatic Environ. Res., 12, 738–750, doi: (in Chinese)Google Scholar
  37. Liu, G., S. Q. Sun, Q. Y. Zhang, et al., 2009: Characteristics of the intraseasonal oscillation of intertropical convergence zone and its influence on the periodical tropical cyclogenesis. Chinese J. Atmos. Sci., 33, 879–889, doi: (in Chinese)Google Scholar
  38. Liu, Q., T. Li, and W. C. Zhou, 2018: Impact of 10–60-day low-frequency steering flows on straight northward-moving typhoon tracks over the western North Pacific. J. Meteor. Res., 32, 394–109, doi: Scholar
  39. Madden, R. A., and P. R. Julian, 1971: Detection of a 40–50 day oscillation in the zonal wind in the tropical Pacific. J. Atmos. Sci., 28, 702–708, doi:<0702:DOADOI>2.0.CO;2.CrossRefGoogle Scholar
  40. Nitta, T., 1987: Convective activities in the tropical western Pacific and their impact on the Northern Hemisphere summer circulation. J. Meteor. Soc. Japan, 65, 373–432, doi: Scholar
  41. Pan, J., C. Y. Li, and J. Song, 2010: The modulation of Madden-Julian Oscillation on typhoons in the northwestern Pacific Ocean. Chinese J. Atmos. Sci., 34, 1059–1070, doi: (in Chinese)Google Scholar
  42. Ren, H.-L., B. Lu, J. H. Wan, et al., 2018: Identification standard for ENSO events and its application to climate monitoring and prediction in China. J. Meteor. Res., 32, 923–936, doi: Scholar
  43. Reynolds, R. W., N. A. Rayner, T. M. Smith, et al., 2002: An improved in situ and satellite SST analysis for climate. J. Climate, 15, 1609–1625, doi:<1609:AIISAS>2.0.CO;2.CrossRefGoogle Scholar
  44. Sadler, J. C., 1978: Mid-season typhoon development and intensity changes and the tropical upper tropospheric trough. Mon. Wea. Rev., 106, 1137–1152, doi:<1137:MSTDAI>2.0.CO;2.CrossRefGoogle Scholar
  45. Sobel, A. H., and D. E. Maloney, 2000: Effect of ENSO and the MJO on western North Pacific tropical cyclones. Geophys. Res. Lett., 27, 1739–1742, doi: Scholar
  46. Sun, Z., J. Y. Mao, and G. X. Wu, 2009: Influences of intraseasonal oscillations on the clustering of tropical cyclone activities over the western North Pacific during boreal summer. Chinese J. Atmos. Sci., 33, 950–958, doi: (in Chinese)Google Scholar
  47. Tian, H., C. Y. Li, and H. Yang, 2010a: Modulation of typhoon genesis over the western North Pacific by intraseasonal oscillation. J. Trop. Meteor., 26, 283–292, doi: (in Chinese)Google Scholar
  48. Tian, H., C. Y. Li, and H. Yang, 2010b: Modulation of typhoon tracks over the western North Pacific by the intraseasonal oscillation. Chinese J. Atmos. Sci., 34, 559–579, doi: (in Chinese)Google Scholar
  49. Wang, B., and J. C. L. Chan, 2002: How strong ENSO events affect tropical storm activity over the western North Pacific. J. Climate, 15, 1643–1658, doi:<1643:HSEEAT>2.0.CO;2.CrossRefGoogle Scholar
  50. Wang, H., Y. H. Ding, and J. H. He, 2006: Influence of western North Pacific summer monsoon changes on typhoon genesis. Acta Meteor. Sinica, 64, 345–356, doi: (in Chinese)Google Scholar
  51. Wang, H. J., and K. Fan, 2006: Relationship between the Antarctic Oscillation and typhoon frequency in the western North Pacific. Chinese Sci. Bull., 51, 2910–2914, doi: (in Chinese)CrossRefGoogle Scholar
  52. Wang, H. J., J. Q. Sun, and K. Fan, 2007: Relationships between the North Pacific Oscillation and the typhoon/hurricane frequencies. Sci. China Ser. D Earth Sci., 50, 1409–1416. (in Chinese)CrossRefGoogle Scholar
  53. Wang, Z.-L., 1981: The infuence of the westerly belt long wave trough over Asia on the western Pacific typhoon tracks. Scientia Atmos. Sinica, 5, 198–206. (in Chinese)Google Scholar
  54. Wang, Z. Y., Y. J. Liu, T. Ding, et al., 2018: Features and possible causes for the climate anomalies in spring 2018. Meteor. Mon., 44, 1360–1369. (in Chinese)Google Scholar
  55. Webster, P. J., G. H. Holland, I. A. Curry, et al., 2005: Changes in tropical cyclone number, duration, and intensity in a warming environment. Science, 309, 1844–1846, doi: Scholar
  56. Wheeler, M., and G. N. Kiladis, 1999: Convectively coupled equatorial waves: Analysis of clouds and temperature in the wave-number-frequency domain. J. Atmos. Sci., 56, 374–399, doi:<0374:CCEWAO>2.0.CO;2.CrossRefGoogle Scholar
  57. Wheeler, M. C., and H. H. Hendon, 2004: An all-season real-time multivariate MJO index: Development of an index for monitoring and prediction. Mon. Wea. Rev., 132, 1917–1932, doi:<1917:AARMMI>2.0.CO;2.CrossRefGoogle Scholar
  58. Wu, G. X., and N.-C. Lau, 1992: A GCM simulation of the relationship between tropical storm formation and ENSO. Mon. Wea. Rev., 120, 958–977, doi:<0958:AGSOTR>2.0.CO;2.CrossRefGoogle Scholar
  59. Wu, J., H.-L. Ren, C. B. Zhao, et al., 2016: Research and application of operational MJO monitoring and prediction products in Beijing Climate Center. J. Appl. Meteor. Sci., 27, 641–653, doi: (in Chinese)Google Scholar
  60. Xie, P. Y., L. Tao, J. H. Li, et al., 2018: Variation of tropical cyclone track in the western North Pacific during ENSO developing and decaying years. Chinese J. Atmos. Sci., 42, 987–999, doi: (in Chinese)Google Scholar
  61. Ying, M., W. Zhang, H. Yu, et al., 2014: An overview of the China Meteorological Administration tropical cyclone database. J. Atmos. Oceanic Technol., 31, 287–301, doi: Scholar
  62. Yoshida, R., Y. Kajikawa, and H. Ishikawa, 2014: Impact of boreal summer intraseasonal oscillation on environment of tropical cyclone genesis over the western North Pacific. SOLA, 10, 15–18, doi: Scholar
  63. You, L. J., J. Y. Gao, H. Lin, et al., 2019: Impact of the intra-seasonal oscillation on tropical cyclone genesis over the western North Pacific. Int. J. Climatol., 39, 1969–1984, doi: Scholar
  64. Yu, J. H., T. Li, Z. M. Tan, et al., 2016a: Effects of tropical North Atlantic SST on tropical cyclone genesis in the western North Pacific. Climate Dyn., 46, 865–877, doi: Scholar
  65. Yu, J. H., C. Chen, T. Li, et al., 2016b: Contribution of major SSTA modes to the climate variability of tropical cyclone genesis frequency over the western North Pacific. Quart. J. Roy. Meteor. Soc., 142, 1171–1181, doi: Scholar
  66. Zhan, R. F., Y. Q. Wang, and X. T. Lei, 2011: Contributions of ENSO and east Indian Ocean SSTA to the interannual variability of Northwest Pacific tropical cyclone frequency. J. Climate, 24, 509–521, doi: Scholar
  67. Zhan, R. F., Y. H. Ding, L. G. Wu, et al., 2016: Role of ENSO in the interannual relationship between Tibetan Plateau winter snow cover and Northwest Pacific tropical cyclone genesis frequency. Sci. China Earth Sci., 59, 2009–2021, doi: (in Chinese)CrossRefGoogle Scholar
  68. Zhao, C., and T. Li, 2019: Basin dependence of the MJO modulating tropical cyclone genesis. Climate Dyn., 52, 6081–6096, doi: Scholar
  69. Zhu, C. W., T. Nakazawa, and J. P. Li, 2004: Modulation of tropical depression/cyclone over the Indian-western Pacific oceans by Madden-Julian oscillation. Acta Meteor. Sinica, 62, 42–51, doi: (in Chinese)Google Scholar

Copyright information

© The Chinese Meteorological Society and Springer-Verlag Berlin Heidelberg 2019

Authors and Affiliations

  • Lijuan Chen
    • 1
    • 2
    Email author
  • Zhensong Gong
    • 1
  • Jie Wu
    • 1
  • Weijing Li
    • 1
    • 2
  1. 1.Laboratory for Climate Studies National Climate CenterChina Meteorological AdministrationBeijingChina
  2. 2.Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science & TechnologyNanjingChina

Personalised recommendations