Identification

Title

Paleoclimate changes in the Pacific Northwest over the past 36,000 years from clumped isotope measurements and model analysis

Abstract

Since the last glacial period, North America has experienced dramatic changes in regional climate, including the collapse of ice sheets and changes in precipitation. We use clumped isotope (Lambda(47)) thermometry and carbonate delta O-18 measurements of glacial and deglacial pedogenic carbonates from the Palouse Loess to provide constraints on hydroclimate changes in the Pacific Northwest. We also employ analysis of climate model simulations to help us further provide constraints on the hydroclimate changes in the Pacific Northwest. The coldest clumped isotope soil temperatures T( Delta(47)) (13.5 +/- 1.9(degrees)C to 17.1 1.7(degrees)C) occurred similar to 34,000-23,000 years ago. Using a soil-to-air temperature transfer function, we estimate Last Glacial Maximum (LGM) mean annual air temperatures of similar to-5.5(degrees)C and warmest average monthly temperatures (i.e., mean summer air temperatures) of similar to 4.4 degrees C. These data indicate a regional warming of 16.4 +/- 2.6(degrees)C from the LGM to the modern temperatures of 10.9(degrees)C, which was about 2.5-3 times the global average. Proxy data provide locality constraints on the boundary of the cooler anticyclone induced by LGM ice sheets, and the warmer cyclone in the Eastern Pacific Ocean. Climate model analysis suggests regional amplification of temperature anomalies is due to the proximal location of the study area to the Laurentide Ice Sheet margin and the impact of the glacial anticyclone on the region, as well as local albedo. Isotope-enabled model experiments indicate variations in water delta O-18 largely reflect atmospheric circulation changes and enhanced rainout upstream that brings more depleted vapor to the region during the LGM.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d79w0kfr

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

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South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2023-02-01T00:00:00Z

Frequency of update

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Conformity

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name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact