Comparison between Ongoke Lake and other temperature records

Comparison of the Ongoke Lake record with temperature reconstructions from other sites in Alaska. a) Diatom principal component analysis (PCA) axis 2 (dashed) and reconstructed water depth (solid) from Ongoke Lake. b) Diatom PCA axis 1 from Ongoke Lake. c) Warm-season temperature anomaly estimated from oxygen-isotope composition at Farewell Lake (Hu et al. 2001a). d) Summer (JJA) temperature anomaly inferred from biogenic silica at Hallet Lake (McKay et al. 2008). e) Varve thickness from Iceberg Lake (Loso et al. 2006; updated 2007), with thicker varves indicating warmer climate. f) Warm-season temperature inferred from tree-ring records from the Wrangell Mountains (Davi et al. 2006). g) Warm-season temperature inferred from tree-ring records from areas around the Gulf of Alaska (Wiles et al. 1999).