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.

Twenty-first century discharge and sediment yield predictions in a small high Arctic watershed

“…For example, aggregate discharge from 64 Canadian rivers showed a 10% decrease between 1964 and 2000, likely due to a reduction in precipitation (Déry and Wood, 2005). Decreased spring discharge since 1820 has also been inferred from varved lake sediments from the Boothia Peninsula (Lamoureux et al, 2006b). These results contrast with studies of global river discharge into the Arctic Ocean that show historical discharge increases, largely attributed to Eurasian rivers (McClelland et al, 2006).…”

Dendrohydroclimate reconstructions of July–August runoff for two nival‐regime rivers in west central British Columbia

“…This low‐frequency signal is most prominent during the late 1600s, early 1700s and the 1900s while notably depressed during the mid to late 1800s. Findings from prior wavelet analyses on independent tree‐ring and sediment proxy reconstructions of hydroclimate throughout western and northern Canada corroborate with results from this study (Gedalof and Smith, ; Lamoureux et al ., ; Hart et al ., ). Coupled with the results from the correlation analyses, these findings confirm that the ocean‐atmospheric forcings described by the PDO and PNA indices have strongly influenced west central British Columbia discharge dynamics over the past 350 years.…”

“…Further similarities are detected with synthesized records of cumulative snowfall (Perkins and Sims, ), PDO and annual riverflow (Lamoureux et al ., ) derived using varved lake sediment thickness measurements from northern Canada and Alaska. In accordance with instrumental records (Moore and McKendry, ; Mantua et al ., ; Bitz and Battisti, ), periods of reduced cumulative snowfall, low riverflow and negative PDO in northern Canada and Alaska are predicted during periods of above average riverflow and end‐of‐winter SWE in west central British Columbia.…”

Multi‐century reconstructions of Pacific salmon abundance from climate‐sensitive tree rings in west central British Columbia, Canada

“…The signal waned in strength during the late 1400s (only observed in the BR chinook reconstruction), the mid‐1600s, the late 1700s, the mid‐1800s, the late 1800s and the early 1900s. Similar wavelet results, indicating a waning of low‐frequency oscillations during the late 1800s, have previously been reported in reconstructions of PDO and hydroclimate conditions in western North America (Gedalof and Smith, ; Lamoureux et al ., ; Hart et al ., ).…”