Multidecadal variations and decline in spring discharge in the Canadian middle Arctic since 1550 AD

Abstract

Annually laminated (varved) sediments from Sanagak Lake in the Canadian middle Arctic were used to reconstruct past spring discharge. Two years of sediment transport observations demonstrate that sediment delivery in this nival regime is limited primarily to the short period of maximum discharge. Interannual variability in catchment snow water equivalence (SWE) was the primary control over the length of the peak discharge period, resulting in substantially increased sediment transport and deposition in the lake in years with higher SWE. Analysis of annual sediment accumulation reveals high interannual variability with a persistent 64-80 year frequency as well as a prominent decline, particularly since 1820 AD. These spectral results suggest a linkage between the Atlantic Multidecadal Oscillation (AMO) and snowfall conditions through persistence of the characteristic frequency since 1550 AD. Copyright 2006 by the American Geophysical Union.