How Tropical Pacific Surface Cooling Contributed to Accelerated Sea Ice Melt from 2007 to 2012 as Ice Is Thinned by Anthropogenic Forcing

• DOI: 10.1175/jcli-d-18-0783.1
• Publication Date: 2019-09-18T15:12:57Z
• Authors: Ian Baxter; Qinghua Ding; Axel Schweiger; Michelle L’Heureux; Stephen Baxter; Tao Wang; Qin Zhang; Kirstin Harnos; Bradley Markle; Daniel Topal; Jian Lu
• Keywords: Teleconnection; Forcing (mathematics); Arctic geoengineering; Arctic oscillation; Walker circulation; Lead (geology)

Abstract Over the past 40 years, Arctic sea ice minimum in September has declined. The period between 2007 and 2012 showed accelerated melt contributed to record minima of 2012. Here, observational model evidence shows that changes summer since 2000s reflect a continuous anthropogenically forced melting masked by interdecadal variability atmospheric circulation. This variation is partially driven teleconnections originating from surface temperature (SST) east-central tropical Pacific via Rossby wave train propagating into [herein referred as Pacific–Arctic teleconnection (PARC)], which represents leading internal mode connecting pole lower latitudes. warming loss 2012, followed slower declines recent resulting appearance slowdown over 11 years. A pacemaker simulation, we specify observed SST eastern Pacific, demonstrates physically plausible mechanism for PARC mode. However, model-based considerably weaker only accounts acceleration We also explore features large-scale circulation patterns associated with extreme periods long (1800 yr) CESM preindustrial simulation. These results further support remote forcing can excite significant warm episodes Arctic. research needed identify reasons limitations reproducing featuring cold Pacific–warm connection.