Project

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Scanning in-situ reflectance spectroscopy as a novel tool for high-resolution climate reconstructions from lake sediments, southern Chile

Applicant Grosjean Martin
Number 121869
Funding scheme Project funding (Div. I-III)
Research institution Oeschger-Zentrum für Klimaforschung Universität Bern
Institution of higher education University of Berne - BE
Main discipline Other disciplines of Environmental Sciences
Start/End 01.12.2008 - 30.11.2011
Approved amount 209'410.00
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All Disciplines (2)

Discipline
Other disciplines of Environmental Sciences
Other disciplines of Earth Sciences

Keywords (8)

climatology; Climate change; sedimentology; Geochemistry; Quaternary; Limnology; South America; Holocene

Lay Summary (English)

Lead
Lay summary
Seasonal to annual quantitative reconstructions of spatially-explicit climate state variables for the last 1000 years are recognized as one of the primary targets for current climate research (IGBP-PAGES / WCRP-CLIWAR). The lack of adequate paleoclimate data series is strikingly evident for the southern hemisphere.This proposal will (i) explore systematically the potential of in-situ reflectance spectroscopy as a novel tool for quantitative high-resolution climate reconstructions in a variety of lakes in south-central Chile, and (ii) produce a number of temporally highly resolved temperature and/or precipitation reconstructions for the regional expression of climate variability during the past 1000 years.The project contributes to the international regional multi-proxy climate reconstruction in South America (IGBP-PAGES LOTRED-SA).
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Multiproxy summer and winter surface air temperature field reconstructions for southern South America covering the past centuries
Neukom R, Luterbacher J, Villalba R, Küttel M, Frank D, Jones PD, Grosjean M, Wanner H, Aravena J-C, Black DE, Christie DA, D'Arrigo R, Lara A, Morales M, Soliz-Gamboa C, Srur A, Urrutia R, von Gunten L (2011), Multiproxy summer and winter surface air temperature field reconstructions for southern South America covering the past centuries, in Climate Dynamics, 37(1), 35-51.
Multi-centennial summer and winter precipitation variability in southern South America
Neukom R, Luterbacher J, Villalba R, Kttel M, Frank D, Jones PD, Grosjean M, Esper J, Lopez L, Wanner H (2010), Multi-centennial summer and winter precipitation variability in southern South America, in Geophysical Research Letters, 37(14), 1-6.
Age modeling of young non-varved lake sediments: Methods and limits. Examples from two lakes in Central Chile
von Gunten L, Grosjean M, Beer J, Grob P, Morales A, Urrutia R (2009), Age modeling of young non-varved lake sediments: Methods and limits. Examples from two lakes in Central Chile, in Journal of Paleolimnology, 42(3), 401-412.
Long-term multi-proxy climate reconstructions and dynamics in South America (LOTRED-SA): State of the art and perspectives
Villalba R, Grosjean M, Kiefer T (2009), Long-term multi-proxy climate reconstructions and dynamics in South America (LOTRED-SA): State of the art and perspectives, in Palaeogeography, Palaeoclimatology, Palaeoecology, 281(3-4), 175-179.
Pollution and eutrophication history AD 1800-2005 as recorded in sediments from five lakes in Central Chile
von Gunten L, Grosjean M, Eggenberger U, Grob P, Urrutia R, Morales A (2009), Pollution and eutrophication history AD 1800-2005 as recorded in sediments from five lakes in Central Chile, in Global and Planetary Change, 68(3), 198-208.
Quantitative high-resolution winter (JJA) precipitation reconstruction from varved sediments of Lago Plomo 47°S, Patagonian Andes, AD 1530-2002
Elbert Julie, Grosjean Martin, von Gunten Lucien, Urrutia Roberto, Fischer Daniela, Wartenburger Richard, Ariztegui Daniel, Fujak Marian, Hamann Yvonne, Quantitative high-resolution winter (JJA) precipitation reconstruction from varved sediments of Lago Plomo 47°S, Patagonian Andes, AD 1530-2002, in The Holocene.

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
XVIII INQUA - Congress Quaternary sciences – the view from the mountains 21.07.2011 Bern
Swiss Global Change Day 19.04.2011 Bern


Associated projects

Number Title Start Funding scheme
107598 Medieval Climate Anomaly and Little Ice Age Type Events in the South-Central Andes 01.07.2005 Project funding (Div. I-III)
116065 W.M.L. de Wette Briefedition 01.07.2007 Project funding (special)
133817 Environmental Analysis and Dating with Radiocarbon using MICADAS 01.12.2010 R'EQUIP
134945 Calibrating and validating scanning VIS Reflectance Spectroscopy data (380 - 730 nm) from minerogenic and biochemical varves: improving climate reconstructions from lake sediments 01.12.2011 Project funding (Div. I-III)

Abstract

Seasonal to annual quantitative reconstructions of spatially-explicit climate state variables for the last 1000 years are recognized as one of the primary targets for current climate research (IGBP-PAGES / WCRP-CLIWAR). This builds on the rationale that knowledge about the natural, forced and stochastic variability at different scales is critical (i) to discriminate the human fingerprint on the global climate system during the 20th century (detection and attribution) and (ii) to reduce uncertainty for ecological, societal and economic risks when natural variability and anthropogenic forcings are superposed in the future climate.While substantial advancements were made (i) in past global climate modelling, (ii) in northern hemispheric temperature reconstructions for the last 1000 years, and (iii) in the evaluation of statistical multi-proxy reconstruction techniques, it is increasingly recognized that the limiting factor to further scientific advancement is actually the lack of robust paleoclimate data series at an adequate quality and representative spatial distribution. This is strikingly evident for the southern hemisphere which is, paradoxically, the area with theoretically best chances for greenhouse gas signal detection. Three quality criteria are required for paleoclimate data series: (i) calibration and quantification, (ii) high resolution (seasonal to annual, sub-decadal), and (iii) scaling of amplitudes and to correctly assess the high- and low-frequency components of variability.This was precisely the target of the ongoing research project on lake sediments in Central Chile (NF 200021-107598; 2005-2008). During the past two years, we have made four major methodological innovations which are fundamental to produce such data sets from lake sediments: (i) high-precision chronologies of young lake sediments, which includes the SIT Sediment Isotope Tomography model, (ii) statistical tools from tree-ring research for calibrating lake sediments, (iii) exploration of new proxies and rapid high-resolution techniques (e.g., in-situ reflectance spectroscopy), and (iv) modification of the standard sampling protocol and flowchart of work. One of the latest results from that work is, for example a pigment-based (total chlorin) well calibrated (r=0.81; p<0.01; calibration period 1901-2000), quantitative (error of reconstruction = 0.24°C) high-resolution (2-3 years) austral summer DJF temperature reconstruction from Laguna Aculeo, Central Chile, back to the year AD 850. This data set is unique for the southern hemisphere and shows the great potential of in-situ reflectance spectroscopy as a novel tool for the rapid acquisition of high-resolution, quantitative climate proxies from lake sediments. The proposed research is the logic continuation and builds on the solid foundation of previous and current achievements by the research group in paleoclimate research in Chile. The proposed research follows two major thrusts (methodology and data):1. Methodology: Explore systematically the potential/limitations of in-situ reflectance spectroscopy as a novel tool for quantitative high-resolution climate reconstructions in a variety of lake types and sedimentary environments in south-central Chile, and2. Data: to produce a number of temperature and/or precipitation reconstructions from lake sediments (i) to shed light on the regional expression of climate variability during the past 1000 years, (ii) to contribute to the international regional multi-proxy climate reconstruction in South America (IGBP-PAGES LOTRED-SA, of which the applicant is the coordinator), and (iii) to assess the sensitivity of the global climate system to forced and unforced perturbations at a variety of temporal scales. Target sediment parameters with demonstrated skill are (i) relative absorption band depth RADB between 660-670 nm (indicative of total chlorin, highly correlated with Corg), (ii) reflectance R660nm/670 nm (indicative for chlorin diagenesis), (iii) RADB 610-620 nm and R570nm/R630nm (both indicative of lithic material), among others that need to be explored.The project will (i) systematically test the fundamentals of in-situ reflectance spectroscopy method for within-core, intra-site and intra-lake variability (3 x 3 cores in Lago Puyehue, Chile 40°S), (ii) cross-validate the reflectance spectroscopy data with ‘conventional proxies’ and calibrate the proxies with meteorological time series, and (iii) produce a quantitative regional composite climate reconstruction for the Lake District in Chile (38-42°S). The project contributes directly to international climate research programs (IGBP-PAGES / WCRP-CLIVAR).
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