Rainfall variability of decadal and longer time scales: signal or noise?

Meinke, Holger and deVoil, Peter and Hammer, Graeme L. and Power, Scott and Allan, Robert J. and Stone, Roger C. and Folland, Chris K. and Potgieter, Andries B. (2005) Rainfall variability of decadal and longer time scales: signal or noise? Journal of Climate, 18 (1). pp. 89-90. ISSN 0894-8755


Rainfall variability occurs over a wide range of temporal scales. Knowledge and understanding of such variability can lead to improved risk management practices in agricultural and other industries. Analyses of temporal patterns in 100 yr of observed monthly global sea surface temperature and sea level pressure data show that the single most important cause of explainable, terrestrial rainfall variability resides within the El Nino-Southern Oscillation (ENSO) frequency domain (2.5–8.0 yr), followed by a slightly weaker but highly significant decadal signal (9–13 yr), with some evidence of lesser but significant rainfall variability at interdecadal time scales (15–18 yr). Most of the rainfall variability significantly linked to frequencies lower than ENSO occurs in the Australasian region, with smaller effects in North and South America, central and southern Africa, and western Europe. While low-frequency (LF) signals at a decadal frequency are dominant, the variability evident was ENSO-like in all the frequency domains considered. The extent to which such LF variability is (i) predictable and (ii) either part of the overall ENSO variability or caused by independent processes remains an as yet unanswered question. Further progress can only he made through mechanistic studies using a variety of models.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Author's version not held.
Faculty / Department / School: Historic - Faculty of Sciences - No Department
Date Deposited: 02 Apr 2010 02:26
Last Modified: 31 Oct 2013 05:50
Uncontrolled Keywords: rainfall variability; El Nino; Southern Oscillation
Fields of Research : 04 Earth Sciences > 0401 Atmospheric Sciences > 040107 Meteorology
04 Earth Sciences > 0401 Atmospheric Sciences > 040105 Climatology (excl.Climate Change Processes)
07 Agricultural and Veterinary Sciences > 0799 Other Agricultural and Veterinary Sciences > 079901 Agricultural Hydrology (Drainage, Flooding, Irrigation, Quality, etc.)
Socio-Economic Objective: D Environment > 96 Environment > 9603 Climate and Climate Change > 960301 Climate Change Adaptation Measures
Identification Number or DOI: 10.1175/JCLI-3263.1
URI: http://eprints.usq.edu.au/id/eprint/7263

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