Meteorology and Atmospheric Physics

, Volume 65, Issue 3–4, pp 197–205 | Cite as

Recent trends in Australian region tropical cyclone activity

  • N. Nicholls
  • C. Landsea
  • J. Gill
Article

Summary

The number of tropical cyclones observed in the Australian region (south of equator; 105–160° E) has apparently declined since the start of reliable (satellite) observations in the 1969/70 season. However, the number of more intense cyclones (with minimum pressures dropping to 970 hPa or lower) has increased slightly. The numbers of weak (minimum pressures not dropping below 990 hPa) and moderate systems (minimum pressures between 970 and 990 hPa) have declined. Possible reasons for these different trends are discussed. The decline in the number of weaker cyclones may at least partly reflect improved understanding of the nature of some weak systems. The decline in the number of cyclones more intense than 990 hPa primarily reflects the downward trend in the Southern Oscillation Index (SOI). Previous work has demonstrated that the number of tropical cyclones observed in the Australian region each cyclone season is related to the value of the SOI prior to the start of the cyclone season. This relationship is clearest with the number of moderate cyclones. The SOI is only weakly related to the number of intense or weak cyclones. The increase in the number of intense cyclones is not attributable to the trend in the SOI. Nor is there clear reason, at present, to suspect that it is artificial (i.e., due to changes in observing or analysis techniques).

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Basher, R. E., Zheng, X., 1995: Tropical cyclones in the Southwest Pacific: Spatial patterns and relationships to the Southern Oscillation and sea surface temperature.J. Climate,8, 1249–1260.Google Scholar
  2. Chan, J. C. L., Shi, J., 1996: Long-term trends in interannual variability in tropical cyclone activity over the western North Pacific.Geophys. Res. Letts.,23, 2765–2767.Google Scholar
  3. Dong, K., 1988: El Niño and tropical cyclone frequency in the Australian region and the northwest Pacific.Aust. Met. Mag.,36, 219–225.Google Scholar
  4. Evans, J. L., Allan, R. J., 1992: El Niño/Southern oscillation modification to the structure of the monsoon and tropical cyclone activity in the Australasian region.Int. J. Climatol.,12, 611–623.Google Scholar
  5. Hastings, P. A., 1990: Southern Oscillation influences on tropical cyclone activity in the Australian/Southwest Pacific region.Int. J. Climatol.,10, 291–298.Google Scholar
  6. Holland, G. J., 1981: On the quality of the Australian tropical cyclone data base.Aust. Meteorol. Mag.,29, 169–181.Google Scholar
  7. Landsea, C. W., Nicholls, N., Gray, W. M., Avila, L. A., 1996: Downward trend in the frequency of intense Atlantic hurricanes during the past five decades.Geophys. Res. Letts.,23, 1697–1700.Google Scholar
  8. Nicholls, N., 1979: A possible method for predicting seasonal tropical cyclone activity in the Australian region.Mon. Wea. Rev.,107, 1221–1224.Google Scholar
  9. Nicholls, N., 1984: The Southern Oscillation, sea-surface temperature, and interannual fluctuations in Australian tropical cyclone activity.J. Climatol.,4, 661–670.Google Scholar
  10. Nicholls, N., 1985: Predictability of interannual variations of Australian seasonal tropical cyclone activity.Mon. Wea. Rev.,113, 1144–1149.Google Scholar
  11. Nicholls, N., 1992: Recent performance of a method for forecasting Australian seasonal tropical cyclone activity.Aust. Meteor. Mag.,40, 105–110.Google Scholar
  12. Revell, C. G., Goulter, S. W., 1986a: South Pacific tropical cyclones and the Southern Oscillation.Mon. Wea. Rev.,114, 1138–1145.Google Scholar
  13. Revell, C. G., Goulter, S. W., 1986b: Lagged relationships between the Southern Oscillation and numbers of tropical cyclones in the south Pacific region.Mon. Wea. Rev.,114, 2669–2670.Google Scholar
  14. Solow, A., Nicholls, N., 1990: The relationship between the Southern Oscillation and tropical cyclone frequency in the Australian region.J. Climate,3, 1097–1101.Google Scholar
  15. Torok, S. J., Nicholls, N., 1996: A historical annual temperature data set for Australia.Aust. Met. Mag.,45, 251–260.Google Scholar
  16. Trenberth, K. E., Hoar, T. J., 1996: The 1990–1995 El Niño-Southern Oscillation event: Longest on record.Geophys. Res. Letts.,23, 57–60.Google Scholar

Copyright information

© Springer-Verlag 1998

Authors and Affiliations

  • N. Nicholls
    • 1
  • C. Landsea
    • 2
  • J. Gill
    • 3
  1. 1.Bureau of Meteorology Research CentreMelbourneAustralia
  2. 2.Hurricane Research DivisionNOAA/AOMLMiamiU.S.A.
  3. 3.Bureau of MeteorologyMelbourneAustralia

Personalised recommendations