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Anthropogenic influence on recent circulation‐driven Antarctic sea ice changes
Author(s) -
Haumann F. Alexander,
Notz Dirk,
Schmidt Hauke
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl061659
Subject(s) - sea ice , climatology , arctic ice pack , lead (geology) , environmental science , climate model , atmospheric circulation , geology , antarctic sea ice , atmospheric sciences , ozone depletion , climate change , oceanography , stratosphere , geomorphology
Observations reveal an increase of Antarctic sea ice over the past three decades, yet global climate models tend to simulate a sea ice decrease for that period. Here we combine observations with model experiments (MPI‐ESM) to investigate causes for this discrepancy and for the observed sea ice increase. Based on observations and atmospheric reanalysis, we show that on multidecadal time scales Antarctic sea ice changes are linked to intensified meridional winds that are caused by a zonally asymmetric lowering of the high‐latitude surface pressure. In our simulations, this surface pressure lowering is a response to a combination of anthropogenic stratospheric ozone depletion and greenhouse gas increase. Combining these two lines of argument, we infer a possible anthropogenic influence on the observed sea ice changes. However, similar to other models, MPI‐ESM simulates a surface‐pressure response that is rather zonally symmetric, which explains why the simulated sea ice response differs from observations.