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United States Department of Agriculture

Agricultural Research Service

Research Project: MANAGING LIMITED IRRIGATION AND RAINFALL FOR CROP PRODUCTION IN SEMI-ARID ENVIRONMENTS

Location: Wind Erosion and Water Conservation Research

Title: Andean snowpack since AD 1150 inferred from rainfall, tree-ring and documentary records

Authors
item Masiokas, Marianos -
item Villalba, R -
item Prieto, M -
item Christie, D -
item Le Quesne, C -
item Betman, E -
item Luckman, B -
item Mauget, Steven

Submitted to: Journal of Geophysical Research Atmospheres
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 28, 2011
Publication Date: March 7, 2012
Citation: Masiokas, M., Villalba, R., Prieto, M.R., Christie, D., Le Quesne, C., Betman, E., Luckman, B.H., Mauget, S.A. 2012. Andean snowpack since AD 1150 inferred from rainfall, tree-ring and documentary records. Journal of Geophysical Research Atmospheres. 117 D05112.

Interpretive Summary: The Andean snowpack is the main source of freshwater and arguably the single most important natural resource for the populated, semi-arid regions of central Chile and central-western Argentina. However, apart from recent analyses of instrumental snowpack data, very little is known about the long term variability of this key natural resource. Here we present two complementary, annually-resolved reconstructions of winter snow accumulation in the southern Andes between 30°-37°S. The reconstructions cover the past 850 yrs and were developed using simple regression models based on snowpack proxies with different inherent limitations. Rainfall data from central Chile (very strongly correlated with snow accumulation values in the adjacent mountains) were used to extend a regional 1951-2010 snowpack record back to AD 1866. Subsequently, snow accumulation variations since AD 1150 were inferred from precipitation-sensitive tree-ring width series. The reconstructed snowpack values were validated with independent historical and instrumental information. An innovative time series analysis approach allowed the identification of the onset, duration and statistical significance of the main intra- to multi-decadal patterns in the reconstructions and indicates that variations observed in the last 60 years are not particularly anomalous when assessed in a multi-century context. In addition to providing new information on past variations for a highly relevant hydroclimatic variable in the southern Andes, the snowpack reconstructions can also be used to improve the understanding and modeling of related, larger-scale atmospheric features such as ENSO and the PDO.

Technical Abstract: The Andean snowpack is the main source of freshwater and arguably the single most important natural resource for the populated, semi-arid regions of central Chile and central-western Argentina. However, apart from recent analyses of instrumental snowpack data, very little is known about the long term variability of this key natural resource. Here we present two complementary, annually-resolved reconstructions of winter snow accumulation in the southern Andes between 30°-37°S. The reconstructions cover the past 850 yrs and were developed using simple regression models based on snowpack proxies with different inherent limitations. Rainfall data from central Chile (very strongly correlated with snow accumulation values in the adjacent mountains) were used to extend a regional 1951-2010 snowpack record back to AD 1866. Subsequently, snow accumulation variations since AD 1150 were inferred from precipitation-sensitive tree-ring width series. The reconstructed snowpack values were validated with independent historical and instrumental information. An innovative time series analysis approach allowed the identification of the onset, duration and statistical significance of the main intra- to multi-decadal patterns in the reconstructions and indicates that variations observed in the last 60 years are not particularly anomalous when assessed in a multi-century context. In addition to providing new information on past variations for a highly relevant hydroclimatic variable in the southern Andes, the snowpack reconstructions can also be used to improve the understanding and modeling of related, larger-scale atmospheric features such as ENSO and the PDO.

Last Modified: 9/21/2014
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