Abstract:
:Multiple paleoclimate proxies are required for robust assessment of past hydroclimatic conditions. Currently, estimates of drought variability over the past several thousand years are based largely on tree-ring records. We produced a 1,500-y record of winter precipitation in the Pacific Northwest using a physical model-based analysis of lake sediment oxygen isotope data. Our results indicate that during the Medieval Climate Anomaly (MCA) (900-1300 AD) the Pacific Northwest experienced exceptional wetness in winter and that during the Little Ice Age (LIA) (1450-1850 AD) conditions were drier, contrasting with hydroclimatic anomalies in the desert Southwest and consistent with climate dynamics related to the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). These findings are somewhat discordant with drought records from tree rings, suggesting that differences in seasonal sensitivity between the two proxies allow a more compete understanding of the climate system and likely explain disparities in inferred climate trends over centennial timescales.
journal_name
Proc Natl Acad Sci U S Aauthors
Steinman BA,Abbott MB,Mann ME,Stansell ND,Finney BPdoi
10.1073/pnas.1201083109subject
Has Abstractpub_date
2012-07-17 00:00:00pages
11619-23issue
29eissn
0027-8424issn
1091-6490pii
1201083109journal_volume
109pub_type
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