A 600 years warm-season temperature record from varved sediments of Lago Plomo, Northern Patagonia, Chile (47°S)

Elbert, Julie; Jacques-Coper, Martín; Van Daele, Maarten; Urrutia, Roberto; Grosjean, Martin (2015). A 600 years warm-season temperature record from varved sediments of Lago Plomo, Northern Patagonia, Chile (47°S). Quaternary International, 377, pp. 28-37. Pergamon Press 10.1016/j.quaint.2015.01.004

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High-resolution records of calibrated proxy data for the past millennium are fundamental to place current changes into the context of pre-industrial natural forced and unforced variability. Although the need for regional spatially-explicit comprehensive reconstructions is widely recognized, the proxy data sources are still scarce, particularly for the Southern Hemisphere and especially for South America. We present a 600-year long warm season temperature record from varved sediments of Lago Plomo, a proglacial lake of the Northern Patagonian Ice field in Southern Chile (46°59′S, 72°52′W, 203 m a.s.l.). The thickness of the bright summer sediment layer relative to the dark winter layer (measured as total brightness; % reflectance 400–730 nm) is calibrated against warm season SONDJF temperature (1900–2009; r = 0.58, p(aut) = 0.056, RE = 0.52; CE = 0.15, RMSEP = 0.28 °C; five-year triangular filtered data). In Lago Plomo, warm summer temperatures lead to enhanced glacier melt and suspended sediment transport, which results in thicker light summer layers and to brighter sediments. Although Patagonia shows pronounced regional differences in decadal temperature trends and variability, the 600 years temperature reconstruction from Lago Plomo compares favourably with other regional/continental temperature records, but also emphasizes significant regional differences for which no data and information existed so far. These regional differences seem to be real as they are also reflected in modern climate data sets (1900–2010). The reconstruction shows pronounced subdecadal – multidecadal variability with cold phases during parts of the Little Ice Age (16th and 18th centuries) and in the beginning of the 20th century. The most prominent warm phase is the 19th century which is as warm as the second half of the 20th century. The exceptional summer warmth AD 1780–1810 is also found in other archives of Northern Patagonia and Central Chile. Our record shows the delayed 20th century warming in the Southern Hemisphere. The comparison between winter precipitation and summer temperature (inter-seasonal coupling) from Lago Plomo reveals alternating phases with parallel and contrasting decadal trends of winter precipitation and summer temperature (positive and negative running correlations Rwinter PP; summer TT). This observation from the sediment proxy data is also confirmed by two sets of reanalysis data for the 20th century. Reanalysis data show that phases with negative correlations between winter precipitation and summer temperature (e.g., dry winters and warm summers) at Lago Plomo are characteristic for periods when circumpolar Westerly flow is displaced southward and enhanced around 60°S.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geography > Physical Geography > Unit Paleolimnology
10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Institute of Geography

Graduate School:

Graduate School of Climate Sciences

UniBE Contributor:

Elbert, Julie; Jacques, Martin and Grosjean, Martin

Subjects:

500 Science > 550 Earth sciences & geology
900 History > 910 Geography & travel

ISSN:

1040-6182

Publisher:

Pergamon Press

Language:

English

Submitter:

Monika Wälti-Stampfli

Date Deposited:

21 Sep 2015 13:09

Last Modified:

02 Mar 2016 16:27

Publisher DOI:

10.1016/j.quaint.2015.01.004

BORIS DOI:

10.7892/boris.71842

URI:

https://boris.unibe.ch/id/eprint/71842

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