Synoptic scale controls on the δ18O in precipitation across Beringia. Issue 11 (3rd June 2015)

• Record Type: Journal Article
• Authors: Bailey, Hannah L.; Kaufman, Darrell S.; Henderson, Andrew C. G.; Leng, Melanie J.
• Is Part Of: Geophysical research letters. Volume 42:Issue 11(2015:Jun.)
• Page Start: 4608
• Page End: 4616
• Publication Date: 2015-06-03
• Subjects: oxygen isotopes -- precipitation -- Alaska -- Aleutian Low -- North Pacific Index; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2015GL063983
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Oxygen isotope records of precipitation (δ 18 Oprecip ) from Beringia are thought to reflect synoptic‐scale circulation changes associated with the Aleutian Low. To delineate the spatial pattern of δ 18 Oprecip associated with the two dominant modes of Aleutian Low circulation, we combine modern δ 18 Oprecip and deuterium excess data with climate reanalysis and back trajectory modeling. Aleutian Low strength and position are revealed to systematically affect regional moisture source and δ 18 Oprecip ; whereby a strengthened Aleutian Low causes lower (higher) δ 18 Oprecip in western (eastern) Beringia. We compare a new 100 year long δ 18 O record from the Aleutian Islands with the North Pacific Index, the primary indicator of Aleutian Low strength, and find a significant positive relationship ( r = 0.43, P < 0.02, n = 28) that tracks late twentieth century change. This study demonstrates synoptic‐scale circulation controls on our isotope record and provides a coherent framework for interpreting existing and emerging paleoisotope data from the region. Key Points: Isotopes in precipitation track North Pacific pressure‐driven circulation Oxygen isotope record from Adak correlates with the North Pacific Index East‐west pressure dipole is exhibited by regional isotope records