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Late Holocene changes in precipitation in northwest Tasmania and their potential links to shifts in the Southern Hemisphere westerly winds


Saunders, KM and Kamenik, C and Hodgson, DA and Hunziker, S and Siffert, L and Fischer, D and Fujak, M and Gibson, JAE and Grosjean, M, Late Holocene changes in precipitation in northwest Tasmania and their potential links to shifts in the Southern Hemisphere westerly winds, Global and Planetary Change, 92-93 pp. 82-91. ISSN 0921-8181 (2012) [Refereed Article]

Copyright Statement

Copyright 2012 Elsevier B.V.

DOI: doi:10.1016/j.gloplacha.2012.04.005


Accurate projections of future climate changes in regions susceptible to drought depend on a good understanding of past climate changes and the processes driving them. In the absence of longer term instrumental data, paleoclimate data are needed. In this study we develop a precipitation reconstruction for Rebecca Lagoon (41°11′S, 144°41′E), northwest Tasmania. First, the relationship between scanning reflectance spectroscopy measurements of sediment cores in the visible spectrum (380–730 nm) and instrumental precipitation record (1912–2009) was used to develop a model to reconstruct precipitation back in time. Results showed that the ratio of reflectance between 660 and 670 nm (i.e., reflectance at 660 nm/reflectance at 670 nm; a measure of pigment diagenesis) was significantly related to annual precipitation. A calibration model was developed (R = − 0.56, pauto < 0.001, RMSEP = 43.0 mm yr− 1, 5 year triangular filtered data, calibration period 1912–2009). Second, this calibration-in-time model was used to reconstruct late Holocene precipitation changes over the last ~ 3000 years. This showed relatively dry conditions from ca. 3100–2800 cal yr BP, wet conditions from ca. 2800–2400 cal yr BP, dry conditions from ca. 2400–2000 calyr BP, and variable conditions after this. Relatively wet conditions occurred from ca. 500 cal yr BP to the late AD 1800 s (ca. 50 cal. yr BP). The precipitation reconstruction indicates that conditions were relatively dry for the 20th century compared to the last ~ 3000 years. In particular, the dry period measured in recent decades is one of the most intense in at least the last 500 years. As precipitation in this region is primarily driven by the Southern Hemisphere westerly winds, these changes are discussed in terms of shifts in westerly wind strength and/or position.

Item Details

Item Type:Refereed Article
Keywords:lake sediments, climate change, Australia, reflectance spectroscopy, westerly winds
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Palaeoecology
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Effects of climate change on Australia (excl. social impacts)
UTAS Author:Saunders, KM (Dr Krystyna Saunders)
UTAS Author:Gibson, JAE (Dr John Gibson)
ID Code:83438
Year Published:2012
Web of Science® Times Cited:23
Deposited By:IMAS Research and Education Centre
Deposited On:2013-03-13
Last Modified:2015-08-13
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