Evidence of solar and tropical ocean forcing of hydroclimate variability in south-eastern Australia for the past 6500 years

McGowan, Hamish, Marx, Samuel, Soderholm, Joshua and Denholm, John (2010). Evidence of solar and tropical ocean forcing of hydroclimate variability in south-eastern Australia for the past 6500 years. In: Program and Abstracts: AQUA Meeting. AQUA2010: Australasian Quaternary Association Biennial Meeting, Dunwich, North Stradbroke Island, Qld., Australia, (18-19). 11-16 July 2010.

Author McGowan, Hamish
Marx, Samuel
Soderholm, Joshua
Denholm, John
Title of paper Evidence of solar and tropical ocean forcing of hydroclimate variability in south-eastern Australia for the past 6500 years
Conference name AQUA2010: Australasian Quaternary Association Biennial Meeting
Conference location Dunwich, North Stradbroke Island, Qld., Australia
Conference dates 11-16 July 2010
Proceedings title Program and Abstracts: AQUA Meeting
Publisher Australasian Quaternary Association
Publication Year 2010
Sub-type Published abstract
Start page 18
End page 19
Total pages 2
Language eng
Formatted Abstract/Summary
Evidence of solar and tropical ocean forcing of climate cycles has been found in numerous proxy palaeoclimate records. Numerical modelling studies show physical mechanisms by which direct and indirect solar forcing may affect temperature and precipitation, while there is mounting evidence of solar forcing of tropical ocean-atmosphere decadal oscillations such as the Pacific Decadal Oscillation (PDO). We present a 6500 yr record of dust deposition from the Snowy Mountains, Australia which we have shown to be a proxy for regional hydroclimate variability. Spectral analysis of the record provides evidence of statistically significant cycles in dust deposition of 35 to 43 yrs, 62 to 73 yrs, 161 yrs (> 95% C.I.) and 2200 yrs (>90% C.I.), which correlate with phases of the PDO and variability in solar irradiance associated with the Gleissberg, Suess and Hallstattzeit solar cycles. Analysis of the spectral content of the non-stationary dust deposition time series using Morlet wavelet analyses identified the 35 yr cycle was most pronounced during the past 300 years with a trend toward a slightly longer period of ≈ 43 yrs around 250 yrs BP. This cycle also appeared to be dominant around 550 and 850 yrs BP, while the ≈ 63 to ≈ 73 yr cycle was dominant around 550, 1000 and 1500 yrs BP, and then again between 4000 to 4500 yrs BP. The longer ≈ 160 yr cycle was most pronounced during the past 1000 yrs (centered on 500 yrs BP) encompassing the Maunder, Spörer and Wolf solar minima. The results confirm that solar and tropical ocean forcing of climate at multi-decadal to millennial time scales affects the hydroclimate of southeast Australia and must be considered in predictions of future climate variability.
Q-Index Code EX
Q-Index Status Provisional Code
Institutional Status UQ
Additional Notes Presented during Session 3: "Temperate Australia" as Paper #3.1. Prepress title: "Evidence of solar and tropical ocean forcing of hydroclimate variability in southeast Australia for the past 6500 years".

 
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Created: Mon, 28 Feb 2011, 14:58:56 EST by Associate Professor Hamish Mcgowan on behalf of School of Geography, Planning & Env Management