This is the final version of the article. Available from American Meteorological Society via the DOI in this record.The loss of Arctic sea-ice is already having profound environmental, societal and ecological
impacts locally. A highly uncertain area of scientific research, however, is whether such Arctic
change has a tangible effect on weather and climate at lower latitudes. There is emerging
evidence that the geographical location of sea-ice loss is critically important in determining
the large-scale atmospheric circulation response and associated mid-latitude impacts.
However, such regional dependencies have not been explored in a thorough and systematic
manner. To make progress on this issue, this study analyses ensemble simulations with an
atmospheric general circulation model prescribed with sea-ice loss separately in nine regions
of the Arctic, to elucidate the distinct responses to regional sea-ice loss. The results suggest
that in some regions sea-ice loss triggers large-scale dynamical responses whereas in other
regions sea-ice loss induces only local thermodynamical changes. Sea-ice loss in the Barents-
Kara Sea is unique in driving a weakening of the stratospheric polar vortex, followed in time
by a tropospheric circulation response that resembles the North Atlantic Oscillation. For
October-to-March, the largest spatial-scale responses are driven by sea-ice loss in the
Barents-Kara Sea and Sea of Okhotsk; however, different regions assume greater importance
in other seasons. The atmosphere responds very differently to regional sea-ice losses than to
pan-Arctic sea-ice loss, and the latter cannot be obtained by linear addition of the responses
to regional sea-ice losses. The results imply that diversity in past studies of the simulated
response to Arctic sea-ice loss can be partly explained by the different spatial patterns of sea-
ice loss imposed.This work was supported
by Natural Environment Research Council grants NE/J019585/1 and NE/M006123/1
