Global-Scale Decadal Hyper Modes

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This article discusses the idea of stochastic global-scale multi-decadal Hyper Modes. The chapter will first illustrate the spatial pattern and time-scales of the leading mode of global-scale multi-decadal climate variability in observations and model simulations. It is further shown that the main characteristic of the leading mode of global-scale multi-decadal variability can be simulated in the absence of any ocean dynamics and by atmospheric teleconnections only. In a simple stochastic model for the Hyper Modes, local (basin-wide) modes of variability act mostly on interannual time-scales forced by atmospheric white noise. Most of these modes have a weak link to the tropical regions via atmospheric teleconnections, which on longer (decadal) time-scales become more dominant. The tropical link provides a synchronization of the local modes to near global multi-decadal Hyper Modes. The persistence of higher latitudes SST variability with an exponentially decreasing mixing into the deeper oceans leads to a power spectrum with a low-frequency tail and different slope compared to a red noise power spectrum. The main elements of this stochastic model do not involve any ocean dynamics beyond local vertical mixing.

Original languageEnglish
Title of host publicationClimate Change
Subtitle of host publicationMultidecadal and Beyond
EditorsChih-Pei Chang, Michael Ghil, Mojib Latif, John M Wallace
Place of PublicationSingapore
PublisherWorld Scientific Publishing
Number of pages11
ISBN (Print)9789814579926
Publication statusPublished - 2016

Publication series

NameWorld Scientific Series on Asia-Pacific Weather and Climate
ISSN (Print)2010-2763

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