Teleconnected ocean forcing of Western North American droughts and pluvials during the last millennium

Type Article
Date 2016-08
Language English
Author(s) Routson Cody C.1, Woodhouse Connie A.2, 3, 4, Overpeck Jonathan T.2, 5, 6, Betancourt Julio L.7, McKay Nicholas P.1
Affiliation(s) 1 : No Arizona Univ, Sch Earth Sci & Environm Sustainabil, Flagstaff, AZ 86011 USA.
2 : Univ Arizona, Dept Geosci, Tucson, AZ 85721 USA.
3 : Univ Arizona, Tree Ring Res Lab, Tucson, AZ 85721 USA.
4 : Univ Arizona, Sch Geog & Dev, Tucson, AZ 85721 USA.
5 : Univ Arizona, Inst Environm, Tucson, AZ 85721 USA.
6 : Univ Arizona, Dept Atmospher Sci, Tucson, AZ 85721 USA.
7 : US Geol Survey, Water Mission Area, Natl Res Program, Reston, VA 20192 USA.
Source Quaternary Science Reviews (0277-3791) (Pergamon-elsevier Science Ltd), 2016-08 , Vol. 146 , P. 238-250
DOI 10.1016/j.quascirev.2016.06.017
WOS© Times Cited 14
Keyword(s) Western North America, Drought, Pluvial, Synthesis, Climate change, Multi-proxy

Western North America (WNA) is rich in hydroclimate reconstructions, yet questions remain about the causes of decadal-to-multidecadal hydroclimate variability. Teleconnection patterns preserved in annually-resolved tree-ring reconstructed drought maps, and anomalies in a global network of proxy sea surface temperature (SST) reconstructions, were used to reassess the evidence linking ocean forcing to WNA hydroclimate variability over the past millennium. Potential forcing mechanisms of the Medieval Climate Anomaly (MCA) and individual drought and pluvial events including two multidecadal-length MCA pluvials were evaluated. We show strong teleconnection patterns occurred during the driest (wettest) years within persistent droughts (pluvials), implicating SSTs as a potent hydroclimate forcing mechanism. The role of the SSTs on longer timescales is more complex. Pacific teleconnection patterns show little long-term change, whereas low-resolution SST reconstructions vary over decades to centuries. While weaker than the tropical Pacific teleconnections, North Atlantic teleconnection patterns and SST reconstructions also show links to WNA droughts and pluvials, and may in part account for longer term WNA hydroclimate changes. Nonetheless, evidence linking WNA hydroclimate to SSTs still remains sparse and nuanced especially over long-timescales with a broader range of hydroclimatic variability than characterized during the 20th century.

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