Interdecadal modulation of the influence of La Niña events on mei-yu rainfall over the Yangtze River valley
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The aim of this study was to investigate changes in the relationship between mei-yu rainfall over East China and La Niña events in the late 1970s, a period concurrent with the Pacific climate shift, using meiyu rainfall data and the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis. This relationship was modulated by the climate shift: Before the 1977/1978 climate shift and after the 1992/1993 climate shift, mei-yu rainfall levels were above normal in most La Niña years, whereas during the period 1979–1991, mei-yu rainfall was usually below normal levels in La Niña years.
Both composite analyses and results from an atmospheric general circulation model show remarkable detail in terms of La Niña’s impacts on mei-yu rainfall in the late 1970s due to the change in the mean climatic state over the tropical Pacific. After the late 1970s, the tropical Pacific SSTs were warmer, and the mean state of low-level anticyclone circulation over the western North Pacific (WNP) weakened. Superimposed on La Niña-related cyclonic anomaly over the WNP, anticyclonic circulation weakened. Prior to the late 1970s, the mean state of low-level anticyclone circulation over the WNP was stronger and was less affected by La Niña-related anomalous cyclones. Anticyclone circulation may have brought moisture to the Yangtze River valley, leading to above-normal rainfall.
Key wordsmei-yu decadal modulation La Niña
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- Chan, J. C. L., and W. Zhou, 2005: PDO, ENSO and the summer monsoon rainfall over South China. Geophys. Res. Lett., 32, L08810.Google Scholar
- Gong, D.-Y., and C.-H. Ho, 2002: Shift in the summer rainfall over the Yangtze River valley in the late 1970s. Geophys. Res. Lett., 29, doi: 10.1029/2001GL014523.Google Scholar
- Ninomiya, K. 2000: Large- and meso-α-scale characteristics of Meiyu/Baiu front associated with intense rainfalls in 1–10 July 1991. J. Meteor. Soc. Japan, 78, 141–157.Google Scholar
- Nitta, T., 1987: Convective activities in the tropical western Pacific and their impact on the Northern Hemisphere summer circulation. J. Meteor. Soc. Japan, 65, 373–390.Google Scholar
- Nitta, T., and Z.-Z. Hu, 1996: Summer climate variability in China and its association with 500 hPa height and tropical convection. J. Meteor. Soc. Japan, 74, 425–445.Google Scholar
- Rayner, N. A., D. E. Parker, E. B. Horton, C. K. Folland, L. V. Alexander, D. P. Rowell, E. C. Kent, and A. Kaplan, 2003: Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J. Geophys. Res., 108, doi: 10.1029/2002JD002670.Google Scholar
- Shen, S., and K. M. Lau, 1995: Biennial oscillation associated with the East Asian monsoon and tropical sea surface temperatures. J. Meteor. Soc. Japan, 73, 105–124.Google Scholar
- Tanaka, M., 1997: Interannual and interdecadal variations of the western North Pacific monsoon and Baiu rainfall and their relationship to the ENSO cycle. J. Meteor. Soc. Japan, 75, 1109–1123.Google Scholar
- Wang, X., C. Wang, W. Zhou, D. Wang, and J. Song, 2010: Teleconnected influence of North Atlantic sea surface temperature on the El Niño onset. Climate Dyn., doi: 10.1007/s00382-010-0833-z. (in press)Google Scholar
- Wei, F., and Q. Song, 2005: Spatial distribution of the global sea surface temperature with interdecadal scale and their potential influence on meiyu in middle and lower reaches of Yangtze River. Acta Meteorologica Sinica, 63, 477–484. (in Chinese)Google Scholar
- Zhang, R. H., A. Sumi, and M. Kimoto, 1996: Impact of El Niño on the East Asian monsoon: A diagnostic study of the 86/87 and 91/92 events. J. Meteor. Soc. Japan, 74, 49–62.Google Scholar
- Zhuo, D., Y. Zhang, B. Wang, L. Li, and Y. Huang, 2010: Analysis on the 10-yr simulation of the meiyu precipitation and its associated circulation with the GAMIL model. Acta Meteorologi ca Sinica, 24, 328–339.Google Scholar