In:
Journal of Climate, American Meteorological Society, ( 2021-10-14), p. 1-55
Abstract:
Reconstructions of past West Antarctic Ice Sheet (WAIS) climate rely on the isotopologues of water recorded in ice cores which extend the local surface temperature record back tens of thousands of years. Here, we utilize continuous flow sampling and novel back-diffusion techniques with the WAIS Divide ice core (WDC obs ) to construct a seasonal record of the δ 18 O value of the precipitation (δ 18 O p ) at the time of deposition from 1980-2000. We then use a water isotope enabled global climate model, iCESM1, to establish seasonal drivers of WAIS climate and of δ 18 O p variability at the WAIS Divide location to compare with the WDC obs and MERRA2 reanalysis data. Our results show that the WAIS seasonal climate variability is driven by the position and strength of the Amundsen Sea Low (ASL) caused by variations in the Southern Annual Mode and the two Pacific-South American patterns (PSA1 and PSA2). The largest year-to-year seasonal δ 18 O p anomalies at the WAIS Divide location occur with respect to PSA2 during austral winter (JJA) as a result of an eastward displacement of the ASL that shifts the associated onshore winds towards the Weddell Sea, reducing temperatures and precipitation near the WAIS Divide location. Additionally, the iCESM1 experiment suggests that changes to the moisture path from the source to the WAIS Divide location is an important driver of seasonal WDC obs δ 18 O p variability. This work highlights the potential of using a single ice core to reconstruct past WAIS climate at seasonal timescales.
Type of Medium:
Online Resource
ISSN:
0894-8755
,
1520-0442
DOI:
10.1175/JCLI-D-20-0822.1
DOI:
10.1175/JCLI-D-20-0822.s1
Language:
Unknown
Publisher:
American Meteorological Society
Publication Date:
2021
detail.hit.zdb_id:
246750-1
detail.hit.zdb_id:
2021723-7
Permalink