Event Title

Tree-ring reconstruction of Great Salt Lake level for hydroclimate diagnostics

Presenter Information

Matthew Bekker
Justin DeRose
Simon Wang

Location

Eccles Conference Center

Event Website

http://water.usu.edu

Start Date

1-4-2014 2:40 PM

End Date

1-4-2014 3:00 PM

Description

The Great Salt Lake (GSL) is a closed-basin remnant of the larger Pleistocene-age Lake Bonneville. The instrumental record of the GSL level (i.e., elevation) change is strongly modulated by Pacific Ocean coupled ocean/atmospheric oscillations at low frequency, and therefore reflects the decadal-scale wet/dry cycles that characterize the region. To enhance our understanding of the longer-term influence of Pacific Ocean forcing on regional precipitation variability we reconstructed a 576-year record of GSL level. A within-basin network of seven tree-ring chronologies was developed to reconstruct the GSL water year (September - August) level, based upon the instrumental record of GSL level from 1876 to 2005. All calibration-verification tests commonly used in dendroclimatology were passed. The reconstruction indicated three pre-instrumental extreme wet events rivaling the flood years 1983 1986, and two drought events that were much greater in magnitude than anything during the post-1900 record. We found strong evidence that the last GSL high stand occurred during the first half of the 17th century, the largest reconstructed pluvial. Significant periodicity at sub-decadal scales over the past six centuries was apparent in the GSL reconstruction. However, predominance of multi-decadal periodicity in the early half of the record shifted to quasi-decadal dominance in the latter half, and this was consistent with that of proxy reconstructions of the Pacific Decadal Oscillation. The GSL level reconstruction is a crucial component to improving our insight into the possible controls of coupled ocean-atmosphere interactions on precipitation delivery.

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Apr 1st, 2:40 PM Apr 1st, 3:00 PM

Tree-ring reconstruction of Great Salt Lake level for hydroclimate diagnostics

Eccles Conference Center

The Great Salt Lake (GSL) is a closed-basin remnant of the larger Pleistocene-age Lake Bonneville. The instrumental record of the GSL level (i.e., elevation) change is strongly modulated by Pacific Ocean coupled ocean/atmospheric oscillations at low frequency, and therefore reflects the decadal-scale wet/dry cycles that characterize the region. To enhance our understanding of the longer-term influence of Pacific Ocean forcing on regional precipitation variability we reconstructed a 576-year record of GSL level. A within-basin network of seven tree-ring chronologies was developed to reconstruct the GSL water year (September - August) level, based upon the instrumental record of GSL level from 1876 to 2005. All calibration-verification tests commonly used in dendroclimatology were passed. The reconstruction indicated three pre-instrumental extreme wet events rivaling the flood years 1983 1986, and two drought events that were much greater in magnitude than anything during the post-1900 record. We found strong evidence that the last GSL high stand occurred during the first half of the 17th century, the largest reconstructed pluvial. Significant periodicity at sub-decadal scales over the past six centuries was apparent in the GSL reconstruction. However, predominance of multi-decadal periodicity in the early half of the record shifted to quasi-decadal dominance in the latter half, and this was consistent with that of proxy reconstructions of the Pacific Decadal Oscillation. The GSL level reconstruction is a crucial component to improving our insight into the possible controls of coupled ocean-atmosphere interactions on precipitation delivery.

http://digitalcommons.usu.edu/runoff/2014/2014Abstracts/12