How tropical Pacific surface cooling contributed to accelerated sea ice melt from 2007 to 2012 as ice is thinned by anthropogenic forcing

Over the past 40 years the Arctic sea ice minimum in September has declined. The period between 2007 and 2012 showed accelerated melt contributed to the record minima of 2007 and 2012. Here, observational and model evidence shows that the changes in summer sea ice since the 2000s reflects a continuo...

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Main Author: Baxter, Ian
Other Authors: Ding, Qinghua
Format: Other/Unknown Material
Language:English
Published: eScholarship, University of California 2019
Subjects:
Online Access:https://escholarship.org/uc/item/9pj660wm
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spelling ftcdlib:oai:escholarship.org/ark:/13030/qt9pj660wm 2023-05-15T14:35:34+02:00 How tropical Pacific surface cooling contributed to accelerated sea ice melt from 2007 to 2012 as ice is thinned by anthropogenic forcing Baxter, Ian Ding, Qinghua 2019-01-01 application/pdf https://escholarship.org/uc/item/9pj660wm en eng eScholarship, University of California qt9pj660wm https://escholarship.org/uc/item/9pj660wm public Atmospheric sciences Climate change Physical geography Arctic atmosphere teleconnection variability etd 2019 ftcdlib 2020-04-10T22:54:27Z Over the past 40 years the Arctic sea ice minimum in September has declined. The period between 2007 and 2012 showed accelerated melt contributed to the record minima of 2007 and 2012. Here, observational and model evidence shows that the changes in summer sea ice since the 2000s reflects a continuous anthropogenically forced melting masked by interdecadal variability of Arctic atmospheric circulation. This variation is partially driven by teleconnections originating from sea surface temperature (SST) changes in the east-central tropical Pacific via a Rossby wave train propagating into the Arctic (hereafter referred to as the “Pacific-Arctic teleconnection (PARC)”), which represents the leading internal mode connecting the pole to lower latitudes. This mode has contributed to accelerated warming and Arctic sea ice loss from 2007 to 2012, followed by slower declines in recent years, resulting in the appearance of a slowdown over the past 11 years. A pacemaker model simulation, in which we specify observed SST in the tropical eastern Pacific, demonstrates a physically plausible mechanism for the PARC mode. However, the model-based PARC mechanism is considerably weaker and only partially accounts for the observed acceleration of sea ice loss from 2007 to 2012. We also explore features of large-scale circulation patterns associated with extreme melting periods in a long (1800-yr) CESM preindustrial simulation. These results further support the role of remote SST forcing originating from the tropical Pacific in exciting significant warm episodes in the Arctic. However, further research is needed to identify the reasons for model limitations in reproducing the observed PARC mode featuring a Cold Pacific - Warm Arctic connection. Other/Unknown Material Arctic Climate change Pacific Arctic Sea ice University of California: eScholarship Arctic Pacific
institution Open Polar
collection University of California: eScholarship
op_collection_id ftcdlib
language English
topic Atmospheric sciences
Climate change
Physical geography
Arctic
atmosphere
teleconnection
variability
spellingShingle Atmospheric sciences
Climate change
Physical geography
Arctic
atmosphere
teleconnection
variability
Baxter, Ian
How tropical Pacific surface cooling contributed to accelerated sea ice melt from 2007 to 2012 as ice is thinned by anthropogenic forcing
topic_facet Atmospheric sciences
Climate change
Physical geography
Arctic
atmosphere
teleconnection
variability
description Over the past 40 years the Arctic sea ice minimum in September has declined. The period between 2007 and 2012 showed accelerated melt contributed to the record minima of 2007 and 2012. Here, observational and model evidence shows that the changes in summer sea ice since the 2000s reflects a continuous anthropogenically forced melting masked by interdecadal variability of Arctic atmospheric circulation. This variation is partially driven by teleconnections originating from sea surface temperature (SST) changes in the east-central tropical Pacific via a Rossby wave train propagating into the Arctic (hereafter referred to as the “Pacific-Arctic teleconnection (PARC)”), which represents the leading internal mode connecting the pole to lower latitudes. This mode has contributed to accelerated warming and Arctic sea ice loss from 2007 to 2012, followed by slower declines in recent years, resulting in the appearance of a slowdown over the past 11 years. A pacemaker model simulation, in which we specify observed SST in the tropical eastern Pacific, demonstrates a physically plausible mechanism for the PARC mode. However, the model-based PARC mechanism is considerably weaker and only partially accounts for the observed acceleration of sea ice loss from 2007 to 2012. We also explore features of large-scale circulation patterns associated with extreme melting periods in a long (1800-yr) CESM preindustrial simulation. These results further support the role of remote SST forcing originating from the tropical Pacific in exciting significant warm episodes in the Arctic. However, further research is needed to identify the reasons for model limitations in reproducing the observed PARC mode featuring a Cold Pacific - Warm Arctic connection.
author2 Ding, Qinghua
format Other/Unknown Material
author Baxter, Ian
author_facet Baxter, Ian
author_sort Baxter, Ian
title How tropical Pacific surface cooling contributed to accelerated sea ice melt from 2007 to 2012 as ice is thinned by anthropogenic forcing
title_short How tropical Pacific surface cooling contributed to accelerated sea ice melt from 2007 to 2012 as ice is thinned by anthropogenic forcing
title_full How tropical Pacific surface cooling contributed to accelerated sea ice melt from 2007 to 2012 as ice is thinned by anthropogenic forcing
title_fullStr How tropical Pacific surface cooling contributed to accelerated sea ice melt from 2007 to 2012 as ice is thinned by anthropogenic forcing
title_full_unstemmed How tropical Pacific surface cooling contributed to accelerated sea ice melt from 2007 to 2012 as ice is thinned by anthropogenic forcing
title_sort how tropical pacific surface cooling contributed to accelerated sea ice melt from 2007 to 2012 as ice is thinned by anthropogenic forcing
publisher eScholarship, University of California
publishDate 2019
url https://escholarship.org/uc/item/9pj660wm
geographic Arctic
Pacific
geographic_facet Arctic
Pacific
genre Arctic
Climate change
Pacific Arctic
Sea ice
genre_facet Arctic
Climate change
Pacific Arctic
Sea ice
op_relation qt9pj660wm
https://escholarship.org/uc/item/9pj660wm
op_rights public
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