Assessment of Arctic amplification based on new climate regionalization and analysis of surface air temperature variability and trends

Lead Author Ola, Johannessen
Institution Contact Nansen Environmental and Remote Sensing Centre (Nansen Centre, Bergen)/Nansen Scientific Society (NSS). Thormøhlens gate 47, N-5006, Bergen, Norway
Co-Authors Svetlana Kuzmina, Nansen Centre (St. Petersburg), Russia. Leonid Bobylev, Nansen Centre (St. Petersburg), Russia; Nansen Centre (Bergen), Norway. Martin Miles, Uni Research – Bjerknes Centre for Climate Research, Norway; Institute of Arctic and Alpine Research, University of Colorado, USA.
Theme Theme 1: Vulnerability of Arctic Environments
Session Name 1.1 Climate Change and Environmental Management in the Arctic
Datetime Wed, Sep 14, 2016 01:20 PM - 01:40 PM
Presentation Type Oral
Abstract text Arctic amplification of temperature change is theorized to be an important feature of the Earth’s climate system. For observational assessment and understanding of mechanisms of this amplification, which remain mostly uncertain, thorough and detailed analyses of surface air temperature (SAT) variability and trends in the Arctic are needed. Here, for evaluation of Arctic amplification, authors define an Arctic Amplification Index (AAI) as the ratio between absolute values of the Arctic and Northern Hemisphere 30-year running linear SAT trends, and present an analysis of Arctic SAT variability in comparison with mid-latitudes and the Northern Hemisphere. This analysis is based on an advanced SAT dataset – NansenSAT – and a new Arctic regionalisation created from hierarchical cluster analysis. It is demonstrated that the temperature amplification in the Arctic is characteristic not only for the recent warming but also the early 20th century warming (ETCW) and subsequent cooling. The amplification appears to be weaker during the recent warming than in the ETCW, simply because the AAI index values reflect the more pervasive nature of the recent warming that reflects the background of anthropogenic global warming. Cluster analysis identified six major natural regions in the Arctic that reflect SAT variability specific features. Statistical comparison with several climate indices showed that the Atlantic Multidecadal Oscillation is the mode of variability that is most significantly associated with the amplified warming–cooling in the Arctic, with a stronger correlation during the ETCW and recent warming than during the intermediate period. Regionally, SAT and AAI differences are identified in terms of annual and seasonal rates of change and in their correlations with modes of variability.
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