The role of Amundsen–Bellingshausen Sea anticyclonic circulation in forcing marine air intrusions into West Antarctica

B. Daniel Emanuelsson, Nancy A.N. Bertler, Peter D. Neff, James A. Renwick, Bradley R. Markle, W. Troy Baisden, Elizabeth D. Keller

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Persistent positive 500-hPa geopotential height anomalies from the ECMWF ERA-Interim reanalysis are used to quantify Amundsen–Bellingshausen Sea (ABS) anticyclonic event occurrences associated with precipitation in West Antarctica (WA). We demonstrate that multi-day (minimum 3-day duration) anticyclones play a key role in the ABS by dynamically inducing meridional transport, which is associated with heat and moisture advection into WA. This affects surface climate variability and trends, precipitation rates and thus WA ice sheet surface mass balance. We show that the snow accumulation record from the Roosevelt Island Climate Evolution (RICE) ice core reflects interannual variability of blocking and geopotential height conditions in the ABS/Ross Sea region. Furthermore, our analysis shows that larger precipitation events are related to enhanced anticyclonic circulation and meridional winds, which cause pronounced dipole patterns in air temperature anomalies and sea ice concentrations between the eastern Ross Sea and the Bellingshausen Sea/Weddell Sea, as well as between the eastern and western Ross Sea.

Original languageEnglish (US)
Pages (from-to)3579-3596
Number of pages18
JournalClimate Dynamics
Volume51
Issue number9-10
DOIs
StatePublished - Nov 1 2018
Externally publishedYes

Bibliographical note

Funding Information:
We thank two anonymous reviewers for their constructive comments that improved the manuscript. We are also grateful for the ERA-Interim reanalysis datasets provided by ECMWF (http://apps.ecmwf.int/datasets/data/interim-full-daily). This project was supported by the New Zealand Government through GNS Science (Global Change through Time Programme, GNS-540GCT12 and GNS-540GCT32) and Victoria University of Wellington (RDF-VUW-1103). This work is a contribution to the Roosevelt Island Climate Evolution (RICE) Program, funded by national contributions from New Zealand, Australia, Denmark, Germany, Italy, People?s Republic of China, Sweden, United Kingdom and the United States of America. The main logistic support was provided by Antarctica New Zealand (K049) and the US Antarctic Program.

Funding Information:
Fig. 10 RICE mean PPAp frequency fields (events year−1, shading, starting at 3 events year−1) for the (>50%, 100 m, 3 days) thresholds for a the 1979–1999 IPO positive period and b the 2000–2013 IPO Acknowledgements We thank two anonymous reviewers for their constructive comments that improved the manuscript. We are also grateful for the ERA-Interim reanalysis datasets provided by ECMWF (http:// apps.ecmwf.int/datasets/data/interim-full-daily). This project was supported by the New Zealand Government through GNS Science (Global Change through Time Programme, GNS-540GCT12 and GNS-540GCT32) and Victoria University of Wellington (RDF-VUW-1103). This work is a contribution to the Roosevelt Island Climate Evolution (RICE) Program, funded by national contributions from New Zealand, Australia, Denmark, Germany, Italy, People’s Republic of China, Sweden, United Kingdom and the United States of America. The main logistic support was provided by Antarctica New Zealand (K049) and the US Antarctic Program.

Keywords

  • Amundsen Sea Low
  • Anticyclones
  • Ice cores
  • Meridional transport
  • Precipitation rates
  • West Antarctica

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