Long-term river discharge and multidecadal climate variability inferred from varved sediments, southwest Alaska

Claire A. Kaufman, Scott F. Lamoureux, Darrell S. Kaufman

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Sedimentological analyses of 289years (AD 1718-2006) of varved sediment from Shadow Bay, southwest Alaska, were used to investigate hydroclimate variability during and prior to the instrumental period. Varve thicknesses relate most strongly to total annual discharge (r2=0.75, n=43, p<0.0001). Maximum annual grain size depends most strongly on maximum spring daily discharge (r2=0.63, n=43, p<0.0001) and maximum annual daily discharge (r2=0.61, n=43, p<0.0001), while varve thickness is poorly correlated with maximum annual grain size (r2=0.004, n=287, p=0.33). Relations between varve thickness and annual climate variables (temperature, precipitation, North Pacific (NP) and Pacific Decadal Oscillation (PDO) indices) are insignificant. On multidecadal timescales, however, regime shifts in varve thickness and total annual discharge coincide with shifts in NP and PDO indices. Periods with increased varve thickness and total annual discharge were associated with warm PDO phases and a strengthened Aleutian Low. The varve-inferred record of PDO suggests that any periodicity in the PDO varied over time, and that the early 19th century marked a transition to a more frequent or detectable shifts.

Original languageEnglish (US)
Pages (from-to)1-9
Number of pages9
JournalQuaternary Research
Volume76
Issue number1
DOIs
StatePublished - Jul 1 2011

Keywords

  • Aleutian Low
  • Climate variability
  • Discharge
  • North Pacific Index
  • Pacific Decadal Oscillation
  • Southwest Alaska
  • Varves

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Earth-Surface Processes
  • Earth and Planetary Sciences(all)

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