Details

Autor(en) / Beteiligte

• Kirby, Matthew E.
• Feakins, Sarah J.
• Hiner, Christine A.
• Fantozzi, Joanna
• Zimmerman, Susan R.H.
• Dingemans, Theodore
• Mensing, Scott A.

Titel

Tropical Pacific forcing of Late-Holocene hydrologic variability in the coastal southwest United States

Ist Teil von

• Quaternary science reviews, 2014-10, Vol.102, p.27-38

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2014

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• Change in water availability is of great concern in the coastal southwest United States (CSWUS). Reconstructing the history of water pre–1800 AD requires the use of proxy data. Lakes provide long-lived, high-resolution terrestrial archives of past hydrologic change, and their sediments contain a variety of proxies. This study presents geochemical and sedimentological data from Zaca Lake, CA (Santa Barbara County) used to reconstruct a 3000 year history of winter season moisture source (δDwax) and catchment run-off (125–2000 μm sand) at decadal resolution. Here we show that winter season moisture source and run-off are highly variable over the past 3000 years; superimposed are regime shifts between wetter or drier conditions that persist on average over multiple centuries. Moisture source and run-off do not consistently covary indicating multiple atmospheric circulation modes where wetter/drier conditions prevail. Grain-size analysis reveals two intervals of multi-century drought with less run-off that pre-date the “epic droughts” as identified by Cook et al. (2004). A well-defined wet period with more run-off is identified during the Little Ice Age. Notably, the grain size data show strong coherence with western North American percent drought area indices for the past 1000 years. As a result, our data extend the history of drought and pluvials back to 3000 calendar years BP in the CSWUS. Comparison to tropical Pacific proxies confirms the long-term relationship between El Niño and enhanced run-off in the CSWUS. Our results demonstrate the long-term importance of the tropical Pacific to the CSWUS winter season hydroclimate. •3000 year decadal resolution record from Zaca Lake, CA.•Winter season moisture source and run-off reconstruction.•Pluvial or drought conditions associated with variable moisture sources.•Record extends knowledge of drought beyond tree ring reconstructions.•Evidence for persistent coupling between El Niño and run-off over 3000 years.