气候变化领域集成服务门户(CCPortal): Holocene paleoclimate change in the western US: The importance of chronology in discerning patterns and drivers

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DOI	10.1016/j.quascirev.2020.106487
	Holocene paleoclimate change in the western US: The importance of chronology in discerning patterns and drivers
	Zimmerman S.R.H.; Wahl D.B.
发表日期	2020
ISSN	0277-3791
卷号	246
英文摘要	Sediment in lakes and meadows forms a powerful archive that can be used to reconstruct environmental change through time. Reconstructions of lake level, of chemical, biological, and hydrological conditions, and of surrounding vegetation provide detailed information about past climate conditions, both locally and regionally. Indeed, most of our current knowledge of centennial- to millennial-scale climate variability in the arid western United States, where information about past hydroclimate is particularly important, comes from such sediment-based reconstructions. The pressing need for robust, precise predictions of future conditions is a significant motivation for paleoclimate science, and current research questions frequently require Holocene reconstructions to be resolved at sub-centennial timescales. Increasingly, regional syntheses seek to identify synoptic-scale patterns similar to those defined from modern observations (seasonal, interannual, multi-decadal, etc.) or to compare with the output of climate model simulations. However, the age control on existing records, especially those more than about 20 years old, is often sufficient only for millennial-scale interpretation. Here we assess the age control for 84 published and unpublished records from lakes and meadows in the Great Basin, California, and desert southwest, and use Bayesian modeling to evaluate the 95% uncertainty ranges for the 42 best-dated records. In the Late Holocene, about half of the 42 records have <400-year mean uncertainty ranges; however, high-precision age control is especially critical for young records, used to develop an accurate understanding of a proxy's response to known climate variations. In the Middle Holocene, records vary from 400 to >800-year mean uncertainty and records of the Early Holocene have 600- to >1400-year mean uncertainty ranges. We find that the largest control on modeled uncertainties is dating density, with at least 2 dates/kyr being optimal and suggest obtaining “range-finder” dates at the onset of a study to better predict the total number of dates needed for an adequate age model. Such a density avoids a commonly observed phenomenon of significant peaks in uncertainty arising in gaps between age control points. Analysis of the uncertainties associated with proxy shifts reveal that more than half are >400 years. Although such large uncertainties currently prevent sub-centennial interpretations in most cases, increased dating density, strategic use of limited funds (including budgeting for a 2 date/kyr minimum at the proposal stage), construction of age-depth models with Bayesian methods, and critical evaluation of chronological uncertainty will shed light on past climate variability at finer timescales, enhancing our understanding of global and regional drivers of western U.S. climate. © 2020 Elsevier Ltd
英文关键词	Chronology; Holocene; Lakes and meadows; Paleoclimatology; Western United States
语种	英语
scopus关键词	Bayesian networks; Budget control; Climatology; Glacial geology; Lakes; Range finders; Uncertainty analysis; Climate model simulations; Climate variability; Critical evaluation; Environmental change; Hydrological condition; Paleoclimate change; Past climate conditions; Western United States; Climate models; climate modeling; climate variation; environmental change; Holocene; hydrometeorology; lake level; paleoclimate; reconstruction; uncertainty analysis; vegetation cover; California; Great Basin; United States
来源期刊	Quaternary Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/151322
作者单位	Center for Accelerator Mass Spectrometry, Lawrence Livermore National Lab, Livermore, CA 94550, United States; U.S. Geological Survey, 345 Middlefield Rd. MS-975, Menlo Park, CA 94025, United States; Department of Geography, University of California, Berkeley, CA 94720, United States
推荐引用方式 GB/T 7714	Zimmerman S.R.H.,Wahl D.B.. Holocene paleoclimate change in the western US: The importance of chronology in discerning patterns and drivers[J],2020,246.
APA	Zimmerman S.R.H.,&Wahl D.B..(2020).Holocene paleoclimate change in the western US: The importance of chronology in discerning patterns and drivers.Quaternary Science Reviews,246.
MLA	Zimmerman S.R.H.,et al."Holocene paleoclimate change in the western US: The importance of chronology in discerning patterns and drivers".Quaternary Science Reviews 246(2020).