Oxygen isotope records of precipitation (δ<sup>18</sup>O<inf>precip</inf>) from Beringia are thought to reflect synoptic-scale circulation changes associated with the Aleutian Low. To delineate the spatial pattern of δ<sup>18</sup>O<inf>precip</inf> associated with the two dominant modes of Aleutian Low circulation, we combine modern δ<sup>18</sup>O<inf>precip</inf> 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<sup>18</sup>O<inf>precip</inf>; whereby a strengthened Aleutian Low causes lower (higher) δ<sup>18</sup>O<inf>precip</inf> in western (eastern) Beringia. We compare a new 100 year long δ<sup>18</sup>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.
- Aleutian Low
- North Pacific Index
- oxygen isotopes
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)